Title: 24SI Alternator check
Post by: dlkj07 on March 17, 2025, 12:24:15 pm
Post by: dlkj07 on March 17, 2025, 12:24:15 pm
I've searched and read plenty on this subject but unfortunately i may have confused myself.
Someone else installed a Delco Remy 24si so not sure if they transferred the wires correctly...pretty sure it's had low voltage off and on since. Getting 13.6 volts at B+ and center lug of my isolator while running at idle and 1100 RPM. Sometimes going down the road the voltage drops to 11.9 or 12. I have 2 other wires installed on the I and the R. The "S" lug does not exist on my alternator. (See Pic) Tried to follow the 2 wires on the I and R but they disappear in the wiring harness so not sure where they go.
I have solar so it's masked the problem some what because I can use the boost button to charge my chassis batteries when I dry camp.
Not sure but I think something is wrong.
Should I buy the other isolator that has 4 lugs that I read about? Should I just replace isolator with a combiner?
Someone else installed a Delco Remy 24si so not sure if they transferred the wires correctly...pretty sure it's had low voltage off and on since. Getting 13.6 volts at B+ and center lug of my isolator while running at idle and 1100 RPM. Sometimes going down the road the voltage drops to 11.9 or 12. I have 2 other wires installed on the I and the R. The "S" lug does not exist on my alternator. (See Pic) Tried to follow the 2 wires on the I and R but they disappear in the wiring harness so not sure where they go.
I have solar so it's masked the problem some what because I can use the boost button to charge my chassis batteries when I dry camp.
Not sure but I think something is wrong.
Should I buy the other isolator that has 4 lugs that I read about? Should I just replace isolator with a combiner?
Title: Re: 24SI Alternator check
Post by: Chuck & Jeannie on March 17, 2025, 03:36:10 pm
Post by: Chuck & Jeannie on March 17, 2025, 03:36:10 pm
Not sure but I think something is wrong.
Let's try to figure out what you've got going there. Looking at photo of back of alternator, that does NOT look like a normal 24Si model. AFAIK, a standard 24Si should have the large B+ lug, then 3 smaller terminals labeled (from left to right) "S", "I" and "R". See the diagram below. As you have noted, your alternator is missing the small "S" terminal. I don't know what 24Si version that is, but I DO know it is probably not connected correctly.
On a normal 24Si alternator the "S" terminal is the SENSE terminal. The "I" and "R" posts should NOT have any wires connected. Connecting a "12V always hot" wire to either of these posts can damage the alternator.
A properly wired 24Si alternator requires only two cables: the large B+ charging cable, and a smaller gauge "SENSE" wire. The large B+ cable goes to the alternator post on the isolator, or to a Voltage Sensing Relay (VSR). The small "SENSE" wire goes from the alternator "S" terminal to the POSITIVE post on the chassis (START) battery, or to the START battery post on the isolator.
If a diode type isolator is used with the 24Si it must include a special "IGNITION" or "ENERGIZE" terminal. This terminal is connected to a "HOT with ignition key ON" 12V source. When this terminal is activated by turning the ignition key ON, voltage is supplied to the ALTERNATOR post on the isolator. This voltage is required on the B+ charging cable in order to "turn on" the 24Si. Two examples of isolators with this feature are linked below.
Amazon.com: Victron Energy Argofet Battery Isolators 200-2AC (2 Batteries... (https://www.amazon.com/Victron-Energy-Argofet-200-2-Batteries/dp/B00NT9MTMQ/ref=sr_1_1?crid=IEDSD48S3GBH&dib=eyJ2IjoiMSJ9.e1zj-ktCIpPrZKvLrm6CR_4t6W_Bep8uve97jJkKXRMDb42jSJZcnz6MQeOOS18IcUEKedizul_tdl0_ifXVSqLd_qQ9ni3Mw1EzLlupp9LNxEQfXm1JosuKPA0GOTFrgUXc3ra0fJ7aiTZJeSvjdom1_OXB3K-5xkSV6aVNJ7pA1PRGucRhmQHBhQYQ-ofAH3eb-aYK97rb_iMudNv1LzDp4X39cqgpNKSoV5LgFrQ.jnjVKuLTuC4sFqtCkXO3jIGzr0NOWeoISLiu-1-ZPgk&dib_tag=se&keywords=victron+argofet+battery+isolator&qid=1742237331&sprefix=Victron+ArgoFET%2Caps%2C166&sr=8-1)
Amazon.com: Cole Hersee 48162 Battery Isolator : Automotive (https://www.amazon.com/dp/B07BYH6Q9M/ref=sspa_dk_detail_5?psc=1&pd_rd_i=B07BYH6Q9M&pd_rd_w=ICGts&content-id=amzn1.sym.7446a9d1-25fe-4460-b135-a60336bad2c9&pf_rd_p=7446a9d1-25fe-4460-b135-a60336bad2c9&pf_rd_r=3G9NVFV201F26APW074R&pd_rd_wg=quKeu&pd_rd_r=42feba68-d167-4909-bf3d-409f1ae435d4&s=industrial&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWw)
Title: Re: 24SI Alternator check
Post by: Chuck & Jeannie on March 17, 2025, 03:40:55 pm
Post by: Chuck & Jeannie on March 17, 2025, 03:40:55 pm
You could try removing, and then testing, the two small wires that are now attached to the "I" and "R" terminals. With any luck at all, you will find one of them is HOT all the time. That could be the original SENSE wire. The other might be HOT only with ignition key in ON position. That could be the original EXCITE wire. Report back on what you find.
Title: Re: 24SI Alternator check
Post by: Chuck & Jeannie on March 17, 2025, 04:09:58 pm
Post by: Chuck & Jeannie on March 17, 2025, 04:09:58 pm
I think I found an example of the 24Si model that looks like the one on your coach.
It is, indeed, a genuine 24Si that does NOT come with a "S" terminal. It is "Self excited" and it DOES require voltage on the B+ terminal to turn on (start charging).
Genuine Delco Remy 24 SI, 12V, 160A Alternator with Pulley - Seaboard Marine (https://www.sbmar.com/product/24-si-12v-160a-alternator-with-pulley/)
Because this alternator does not have the SENSE terminal, and DOES require voltage on the B+ terminal, it is not suitable for use with a standard diode isolator such as the one found on your coach. Even if the alternator puts out proper charging voltage (14.0 to 14.6 volts) on a test machine, it will never work properly as it is presently wired on your coach.
I see two possible ways to correct your situation:
1. Remove your isolator. Remove the two small wires, and connect the 24Si B+ terminal directly to the chassis (start) battery bank. With this "One Wire" hookup it should work properly. You would then need a way to direct alternator charging current from the chassis batteries to the coach batteries. This could be accomplished with either a manual combiner switch (or the BOOST switch), or with an automatic combiner relay (VSR).
2. Replace the 24Si with a proper DUVAC alternator that includes both the SENSE terminal and the EXCITE terminal. When connected correctly (including the SENSE and EXCITE wires) this should work fine using the isolator already in place on your coach.
Other Forum members may suggest other ideas, but that's the best I could come up with. Good Luck!
It is, indeed, a genuine 24Si that does NOT come with a "S" terminal. It is "Self excited" and it DOES require voltage on the B+ terminal to turn on (start charging).
Genuine Delco Remy 24 SI, 12V, 160A Alternator with Pulley - Seaboard Marine (https://www.sbmar.com/product/24-si-12v-160a-alternator-with-pulley/)
Because this alternator does not have the SENSE terminal, and DOES require voltage on the B+ terminal, it is not suitable for use with a standard diode isolator such as the one found on your coach. Even if the alternator puts out proper charging voltage (14.0 to 14.6 volts) on a test machine, it will never work properly as it is presently wired on your coach.
I see two possible ways to correct your situation:
1. Remove your isolator. Remove the two small wires, and connect the 24Si B+ terminal directly to the chassis (start) battery bank. With this "One Wire" hookup it should work properly. You would then need a way to direct alternator charging current from the chassis batteries to the coach batteries. This could be accomplished with either a manual combiner switch (or the BOOST switch), or with an automatic combiner relay (VSR).
2. Replace the 24Si with a proper DUVAC alternator that includes both the SENSE terminal and the EXCITE terminal. When connected correctly (including the SENSE and EXCITE wires) this should work fine using the isolator already in place on your coach.
Other Forum members may suggest other ideas, but that's the best I could come up with. Good Luck!
Title: Re: 24SI Alternator check
Post by: wolfe10 on March 17, 2025, 05:10:04 pm
Post by: wolfe10 on March 17, 2025, 05:10:04 pm
1. Remove your isolator. Connect the 24Si alternator you have directly to the chassis (start) battery bank, and remove the two small wires. With this "One Wire" hookup it should work properly. You would then need a way to direct charging current from the chassis batteries to the coach batteries. This could be accomplished with either a manual combiner switch (or the BOOST switch), or with an automatic combiner relay (VSR).
Easy to test: At the diode-based battery isolator, remove the wire that comes from the B+ terminal of the alternator (should be the middle lug of the isolator).
ADD it to the lug going to the chassis battery (you are now direct wired as mentioned by Chuck).
Let us know what it reads with engine at around 1,100 RPM.
Title: Re: 24SI Alternator check
Post by: Chuck & Jeannie on March 17, 2025, 07:24:27 pm
Post by: Chuck & Jeannie on March 17, 2025, 07:24:27 pm
If you try Brett's test (above) I would advise also removing the small wires from the "I" and "R" terminals. No matter where those wires terminate, they shouldn't be connected to those terminals on the alternator.
Title: Re: 24SI Alternator check
Post by: wolfe10 on March 17, 2025, 07:47:23 pm
Post by: wolfe10 on March 17, 2025, 07:47:23 pm
If you try Brett's test (above) I would advise also removing the small wires from the "I" and "R" terminals. No matter where those wires terminate, they shouldn't be connected to those terminals on the alternator.
Agreed.
Title: Re: 24SI Alternator check
Post by: dlkj07 on March 17, 2025, 08:03:04 pm
Post by: dlkj07 on March 17, 2025, 08:03:04 pm
What about just removing the two wires that we're talking about on the back of the alternator but leaving the isolator alone, would that tell us anything?
Title: Re: 24SI Alternator check
Post by: dlkj07 on March 17, 2025, 08:05:13 pm
Post by: dlkj07 on March 17, 2025, 08:05:13 pm
I'm checking this right now and I also forgot to mention that the little wire that is connected to the "I" has 12 volts when the key is on. Neither of them have any voltage when the key is off
Title: Re: 24SI Alternator check
Post by: dlkj07 on March 17, 2025, 08:30:09 pm
Post by: dlkj07 on March 17, 2025, 08:30:09 pm
Both small wires disconnected, wire from B+ of alternator connected to chassis battery lug of isolater
13.6 volts at idle
13.5 volts at 1100 rpm with lights and dash fan on high
Should I be getting more voltage or does it depend on how low the voltage is on my chassis batteries. They are at 12.6 resting right now.
Alternator bad??
13.6 volts at idle
13.5 volts at 1100 rpm with lights and dash fan on high
Should I be getting more voltage or does it depend on how low the voltage is on my chassis batteries. They are at 12.6 resting right now.
Alternator bad??
Title: Re: 24SI Alternator check
Post by: Dennis H on March 17, 2025, 09:02:54 pm
Post by: Dennis H on March 17, 2025, 09:02:54 pm
Where are you measuring the voltage? At the alternator or battery? Typical the alternator should be trying to create 13.8 to 14.2 volts depending on regulator set point. One of those terminals should be for remote sense. For a diode setup this is connected to the chassis battery or a terminal on the isolator and is used to increase the alternator voltage to compensate for the voltage drop across the diodes. This is ~1.1volts so with his working the alternator should be trying to produce ~ 15 volts. As you are getting 13.6 volts that indicates the alternator is at least trying. You need to know the current it is delivering to know if it is just maxed out or if it is weak. A bad diode or winding in the alternator can reduce output. A clamp on ammeter will allow you to get that current measurement to have a better diagnosis.
Title: Re: 24SI Alternator check
Post by: Chuck & Jeannie on March 17, 2025, 09:20:29 pm
Post by: Chuck & Jeannie on March 17, 2025, 09:20:29 pm
...wire from B+ of alternator connected to chassis battery lug of isolator
13.6 volts at idle
13.5 volts at 1100 rpm with lights and dash fan on high
Where are you taking the voltage reading? Ideally you should check the reading at the alternator B+ post, then at the isolator chassis battery lug, and finally at the chassis battery itself. This is to eliminate any chance of a bad cable or connections.
Try leaving everything connected as you have it. Turn the engine off. Turn ON headlights and switch to high beams. You could also turn on fog lights and docking lights for more load. Wait 5-10 minutes, then turn all the lights OFF. Check (record) the voltage at the three points listed above.
Next (with all the lights still OFF), start the engine, and set to about 1100 rpm. Check (record) the voltage at the three points.
Finally, with the engine still running at 1100 rpm, turn all the lights (including high beams) back on. Check (record) voltage at the three points.
Let us know the results.
Title: Re: 24SI Alternator check
Post by: Chuck & Jeannie on March 17, 2025, 09:25:54 pm
Post by: Chuck & Jeannie on March 17, 2025, 09:25:54 pm
One of those terminals should be for remote sense.
We have already determined that the OP's alternator does not have a sense terminal. See earlier posts in this thread.
Title: Re: 24SI Alternator check
Post by: turbojack on March 17, 2025, 09:27:19 pm
Post by: turbojack on March 17, 2025, 09:27:19 pm
What are you using as a volt meter?
I was given a Milwaukee volt, continuity, and ohm meter that was totally automatic. It would automatically change to whatever I was looking for. I then learned it was about 1/2 or more volts off when checking DC and way more on AC. When I learned i couldn't trust it, ithrew it in the trash.
I was given a Milwaukee volt, continuity, and ohm meter that was totally automatic. It would automatically change to whatever I was looking for. I then learned it was about 1/2 or more volts off when checking DC and way more on AC. When I learned i couldn't trust it, ithrew it in the trash.
Title: Re: 24SI Alternator check
Post by: dlkj07 on March 18, 2025, 12:24:12 am
Post by: dlkj07 on March 18, 2025, 12:24:12 am
13.6 is somewhat low, but not conclusive, so don't condemn the alternator yet.
Where are you taking the voltage reading? Ideally you should check the reading at the alternator B+ post, then at the isolator chassis battery lug, and finally at the chassis battery itself. This is to eliminate any chance of a bad cable or connections.
Try leaving everything connected as you have it. Turn the engine off. Turn ON headlights and switch to high beams. You could also turn on fog lights and docking lights for more load. Wait 5-10 minutes, then turn all the lights OFF. Check (record) the voltage at the three points listed above.
ONext (with all the lights still OFF), start the engine, and set to about 1100 rpm. Check (record) the voltage at the three points.
Finally, with the engine still running at 1100 rpm, turn all the lights (including high beams) back on. Check (record) voltage at the three points.
Let us know the results.
Ok, here it is...
I also disconnected my amp-l-start just in case it was messing with my readings...
Lights off after draw down, Engine off
Alt 12.5
Isolator chassis lug 12.5
Batteries 12.5
Engine on 1100 rpm, lights off
Alt 13.8
Iso chas lug13.8
Batt 13.7
Engine on 1100 rpm lights on
Alt 13.5
Iso 13.4
Batt 13.4
Title: Re: 24SI Alternator check
Post by: dlkj07 on March 18, 2025, 12:27:43 am
Post by: dlkj07 on March 18, 2025, 12:27:43 am
What are you using as a volt meter?
I was given a Milwaukee volt, continuity, and ohm meter that was totally automatic. It would automatically change to whatever I was looking for. I then learned it was about 1/2 or more volts off when checking DC and way more on AC. When I learned i couldn't trust it, ithrew it in the trash.
I have a pricy fluke meter, I doubt that's the problem...I'm a lineman so we have the good toys. ;D
Title: Re: 24SI Alternator check
Post by: Dennis H on March 18, 2025, 12:36:04 am
Post by: Dennis H on March 18, 2025, 12:36:04 am
Dennis,
We have already determined that the OP's alternator does not have a sense terminal. See earlier posts in this thread.
Title: Re: 24SI Alternator check
Post by: Dennis H on March 18, 2025, 12:43:57 am
Post by: Dennis H on March 18, 2025, 12:43:57 am
Ok, here it is...
I also disconnected my amp-l-start just in case it was messing with my readings...
Lights off after draw down, Engine off
Alt 12.5
Isolator chassis lug 12.5
Batteries 12.5
Engine on 1100 rpm, lights off
Alt 13.8
Iso chas lug13.8
Batt 13.7
Engine on 1100 rpm lights on
Alt 13.5
Iso 13.4
Batt 13.4
Title: Re: 24SI Alternator check
Post by: dlkj07 on March 18, 2025, 12:59:58 am
Post by: dlkj07 on March 18, 2025, 12:59:58 am
If the rig has a diode block for house battery isolation it needs an alternator with remote sense. Sorry for being late to the thread. Just trying to help. Is this a new alternator install with the plan of eliminating the diode block?
Title: Re: 24SI Alternator check
Post by: dlkj07 on March 18, 2025, 01:01:01 am
Post by: dlkj07 on March 18, 2025, 01:01:01 am
13.8 volts is a common set point for trucks running long hours using standard lead acid batteries. 13.8, 2.3 volts per cell is just below the Gassing voltage for a standard battery and is also desirable for the low maintenance versions. AGM and Lithium need higher. This indicates alternator is functioning. The voltage drop is due to the alternator getting loaded down. Does it increase if you increase engine RPM further? Often takes 1,200 rpm or more to reach full output. Pulley can be changed to increase low speed RPM of alternator. Would be good to know actual current draw on alternator. Regulator can be changed to increase voltage.
Title: Re: 24SI Alternator check
Post by: Michelle on March 18, 2025, 09:16:56 am
Post by: Michelle on March 18, 2025, 09:16:56 am
The thing is, I often get voltage in the low 12's intermittently when I'm driving at highway speed so not sure that's it...
Does this only happen when the headlights are on? If so, do you also show lower oil pressure? Do you also show higher coolant temperatures? Do you have the electroluminescent dash?
There are a couple of issues. First, especially with coaches with an EL dash that have a headlight conversion, is high coolant/low oil readings when the headlights are on. It's been mentioned sporadically over the last 12-15 years. James Stallings at Xtreme is working on a fix (wiring harness.)
Second is what Foretravel sometimes used for connections on the chassis battery wiring (low voltage readings). See this post
Chassis Battery Compartment Refresh (https://www.foreforums.com/index.php?topic=48940.msg493255#msg493255)
Either issue could cause intermittent voltage fluctuations.
Title: Re: 24SI Alternator check
Post by: Chuck & Jeannie on March 18, 2025, 09:19:20 am
Post by: Chuck & Jeannie on March 18, 2025, 09:19:20 am
Ok, here it is...
Lights off after draw down, Engine off
Alt 12.5
Isolator chassis lug 12.5
Batteries 12.5
Engine on 1100 rpm, lights off
Alt 13.8
Iso chas lug13.8
Batt 13.7
So, looking at your test results, first thing we can say is you don't seem to have any cable or connection problems, because volt readings at all three points remain consistent in all 3 tests.
Next, with your chassis battery bank pulled down to 12.5 volts, you started your engine. With engine running at 1100 rpm, and no big loads on the battery, you read 13.8 at the alternator and 13.7 at the battery.
In my opinion, your alternator is not producing sufficient voltage. Yes, it does seem to be "functioning", but it is NOT acting in the manner required to fully charge AGM batteries. The internal voltage regulator may have been damaged by running the alternator for several years with those two small mystery wires improperly connected to the "I" and "R" terminals. You can search online for "AGM Battery Charging Voltage Chart" and find this info for yourself. The excerpt below is from Google AI search:
Charging Stages:
AGM batteries go through three charging stages: bulk, absorption, and float.
Bulk Stage: The charger provides maximum current to bring the battery to about 80% capacity, with the voltage rising to around 14.7V.
Absorption Stage: The charger maintains a constant voltage (around 14.4V to 14.7V) to reach full charge, reducing the current.
Float Stage: Once fully charged, the charger drops the voltage to a lower level (13.6-13.8V) to prevent overcharging and maintain the battery's charge.
I went back and found the Forum thread where you first had this alternator installed. That is when your battery charging troubles started:
Alternator output (https://www.foreforums.com/index.php?topic=44822.msg454687#msg454687)
8600310 24SI New Alternator | Product Details | Delco Remy (https://www.delcoremy.com/find-a-part/product-details/8600310/24si-new-alternator)
You received the information at that time suggesting that you had a problem. But, as you say, because you also have solar panels and a generator to help keep your chassis batteries charged, it never became a BIG problem.
Again, IN MY OPINION, your best move would be to replace your 24Si with a proper DUVAC alternator. This will allow you to retain your battery isolator (which appears fairly new) and it should solve your charging problems. You can search online for J180 Hinge mount DUVAC alternators. Try searching for genuine Leece Neville 2824LC (beware of cheap clones). If you go this route, there is plenty of installation info available on this Forum.
If you want to stick with a Delco alternator, I would recommend your upgrade to a 200A 28Si (model 8600307). This will also require replacing your battery isolator. See the isolator links in my Reply #1 in this thread.
https://www.delcoremy.com/getmedia/90520e29-6966-4656-a04e-9053e59b5929/28SI-Single-Page-Brochure-4-16.pdf.aspx?ext=.pdf
Title: Re: 24SI Alternator check
Post by: mark f on March 18, 2025, 10:19:01 am
Post by: mark f on March 18, 2025, 10:19:01 am
My dash voltage gauge would read low sometimes too. I checked out alt, wiring, etc. The problem was the ignition relay at the dash.
Title: Re: 24SI Alternator check
Post by: dlkj07 on March 18, 2025, 10:45:15 am
Post by: dlkj07 on March 18, 2025, 10:45:15 am
Does this only happen when the headlights are on? If so, do you also show lower oil pressure? Do you also show higher coolant temperatures? Do you have the electroluminescent dash?
There are a couple of issues. First, especially with coaches with an EL dash that have a headlight conversion, is high coolant/low oil readings when the headlights are on. It's been mentioned sporadically over the last 12-15 years. James Stallings at Xtreme is working on a fix (wiring harness.)
Second is what Foretravel sometimes used for connections on the chassis battery wiring (low voltage readings). See this post
Chassis Battery Compartment Refresh (https://www.foreforums.com/index.php?topic=48940.msg493255#msg493255)
Either issue could cause intermittent voltage fluctuations.
I'll check into the connection post, thanks
Title: Re: 24SI Alternator check
Post by: dlkj07 on March 18, 2025, 10:51:28 am
Post by: dlkj07 on March 18, 2025, 10:51:28 am
We have not ascertained what type chassis battery you have. I am going to assume that it is AGM.
So, looking at your test results, first thing we can say is you don't seem to have any cable or connection problems, because volt readings at all three points remain consistent in all 3 tests.
Next, with your chassis battery bank pulled down to 12.5 volts, you started your engine. With engine running at 1100 rpm, and no big loads on the battery, you read 13.8 at the alternator and 13.7 at the battery.
In my opinion, your alternator is not producing sufficient voltage. Yes, it does seem to be "functioning", but it is NOT acting in the manner required to fully charge AGM batteries. The internal voltage regulator may have been damaged by running the alternator for several years with those two small mystery wires improperly connected to the "I" and "R" terminals. You can search online for "AGM Battery Charging Voltage Chart" and find this info for yourself. The excerpt below is from Google AI search:
Charging Stages:
AGM batteries go through three charging stages: bulk, absorption, and float.
Bulk Stage: The charger provides maximum current to bring the battery to about 80% capacity, with the voltage rising to around 14.7V.
Absorption Stage: The charger maintains a constant voltage (around 14.4V to 14.7V) to reach full charge, reducing the current.
Float Stage: Once fully charged, the charger drops the voltage to a lower level (13.6-13.8V) to prevent overcharging and maintain the battery's charge.
I went back and found the Forum thread where you first had this alternator installed. That is when your battery charging troubles started:
Alternator output (https://www.foreforums.com/index.php?topic=44822.msg454687#msg454687)
8600310 24SI New Alternator | Product Details | Delco Remy (https://www.delcoremy.com/find-a-part/product-details/8600310/24si-new-alternator)
You received the information at that time suggesting that you had a problem. But, as you say, because you also have solar panels and a generator to help keep your chassis batteries charged, it never became a BIG problem.
Again, IN MY OPINION, your best move would be to replace your 24Si with a proper DUVAC alternator. This will allow you to retain your battery isolator (which appears fairly new) and it should solve your charging problems. You can search online for J180 Hinge mount DUVAC alternators. Try searching for genuine Leece Neville 2824LC (beware of cheap clones). If you go this route, there is plenty of installation info available on this Forum.
If you want to stick with a Delco alternator, i would recommend your upgrade to a 200A 28Si (with "S" terminal). This will also require replacing your battery isolator. See the isolator links in my Reply #1 in this thread.
My chassis and house batteries are AGM, though I'm going to throw a wrench into all this when I upgrade to house lithium's in the future.
I'll look into a DUVAC alternator since it sounds like my alternator is not working at optimum output...maybe because it was wired incorrectly in the first place. 🤷♂️
Title: Re: 24SI Alternator check
Post by: Chuck & Jeannie on March 18, 2025, 11:09:28 am
Post by: Chuck & Jeannie on March 18, 2025, 11:09:28 am
Chuck,
My chassis and house batteries are AGM, though I'm going to throw a wrench into all this when I upgrade to house lithium's in the future.
At the same time, you could totally remove your diode based isolator and install some type of "smart" DC-to-DC charging device.
But before you buy anything, you will want to read through the Forum posts by members who have switched to lithium house batteries to get their thoughts on how to charge the lithium bank while protecting your alternator. Charging mixed battery types can get tricky, but others here have made this move, so no need to reinvent the wheel.
See sample DC-to-DC charging info post below from a popular ForeForum Influencer:
Update Isolator/Auxiliary Start Panel (https://www.foreforums.com/index.php?topic=49057.msg494278#msg494278)
Title: Re: 24SI Alternator check
Post by: Michelle on March 18, 2025, 11:16:29 am
Post by: Michelle on March 18, 2025, 11:16:29 am
I'm using a reading from my Bluefire app, which I believe comes from the ECM correct? All those other readings are working properly on my dash.
Correct, so real numbers.
It's only the dash gauges that read incorrectly/wonky with the EL/headlight issue, and the usual workaround has been to use VMSpc, ScanGauge-D, or Bluefire. We use Bluefire.
Title: Re: 24SI Alternator check
Post by: dlkj07 on March 18, 2025, 02:05:25 pm
Post by: dlkj07 on March 18, 2025, 02:05:25 pm
In that case, then I would change my recommendation and suggest you seriously consider upgrading to the 200A Delco 28Si (model 8600307)
At the same time, you could totally remove your diode based isolator and install some type of "smart" DC-to-DC charging device.
But before you buy anything, you will want to read through the Forum posts by members who have switched to lithium house batteries to get their thoughts on how to charge the lithium bank while protecting your alternator. Charging mixed battery types can get tricky, but others here have made this move, so no need to reinvent the wheel.
See sample DC-to-DC charging info post below from a popular ForeForum Influencer:
Update Isolator/Auxiliary Start Panel (https://www.foreforums.com/index.php?topic=49057.msg494278#msg494278)
Title: Re: 24SI Alternator check
Post by: Chuck & Jeannie on March 18, 2025, 03:19:33 pm
Post by: Chuck & Jeannie on March 18, 2025, 03:19:33 pm
...at this point I'll go with your recommendation and get the 28SI.
EDIT: Ignore my statement (above) about the SENSE wire. Even if alternator is connected directly to chassis battery, you should also run a SENSE wire from the chassis battery POS(+) post to the alternator "S" terminal.
With the chassis battery being directly charged by the alternator, you can still use the BOOST switch to combine the coach batteries with the chassis battery. OR, just keep your coach batteries charged using your solar panels when dry camping, or the inverter/charger when plugged in or running generator.
Title: Re: 24SI Alternator check
Post by: prfleming on March 18, 2025, 06:35:17 pm
Post by: prfleming on March 18, 2025, 06:35:17 pm
This will eliminate the need for a SENSE wire, because the alternator will directly sense the voltage on the chassis battery through the charging cable.
Title: Re: 24SI Alternator check
Post by: Chuck & Jeannie on March 18, 2025, 10:20:51 pm
Post by: Chuck & Jeannie on March 18, 2025, 10:20:51 pm
Peter,
I understand the purpose of the sense wire with the 28Si. In fact, as you may remember, when I installed a new 28Si on our coach, connected directly to our start battery, I DID elect to run a sense wire. So I'm not disagreeing with your comment in any way.
Delco Remy 28SI Alternator Installation (https://www.foreforums.com/index.php?topic=40778.0)
However, looking at the Delco factory brochure that you posted (above), it does raise a question in my mind. In the drawing labeled "With Remote Sense" the red sense wire appears to be longer than the B+ charging cable. Assume (for arguments sake) that this was the case in "real life". That is, the sense wire is actually longer than the B+ charging cable. The purpose of the sense wire is to compensate for voltage drop in the charging cable. Why would we not see the same, or greater, voltage drop in the sense wire?
Going back to my coach as an example, when I installed the 28Si I decided to upgrade the charging cable and the sense wire. The OEM charging cable was 2 AWG and the sense wire was 18 AWG. I elected to upgrade to 2/0 welding cable for the charge cable, and to 10 AWG for the sense wire. My new charging cable (unlike the diagram in your post) runs in one unbroken section from the alternator straight to my AGM8D starting battery. My new sense wire follows the exact same (unbroken) path. In fact, they are tied together along the whole length with zip ties.
So, on my coach at least, the charging cable and the sense wire are exactly the same length. In addition, the charging cable is much larger diameter than the sense wire. Thick wire has less electrical resistance than thin wire. Why is the battery voltage seen by the "S" terminal on my 28Si "better" (more accurate) than the voltage seen on the B+ terminal?
Like I said, I'm not disagreeing with your comment...just curious about the reasoning behind the whole "sense wire" concept.
I understand the purpose of the sense wire with the 28Si. In fact, as you may remember, when I installed a new 28Si on our coach, connected directly to our start battery, I DID elect to run a sense wire. So I'm not disagreeing with your comment in any way.
Delco Remy 28SI Alternator Installation (https://www.foreforums.com/index.php?topic=40778.0)
However, looking at the Delco factory brochure that you posted (above), it does raise a question in my mind. In the drawing labeled "With Remote Sense" the red sense wire appears to be longer than the B+ charging cable. Assume (for arguments sake) that this was the case in "real life". That is, the sense wire is actually longer than the B+ charging cable. The purpose of the sense wire is to compensate for voltage drop in the charging cable. Why would we not see the same, or greater, voltage drop in the sense wire?
Going back to my coach as an example, when I installed the 28Si I decided to upgrade the charging cable and the sense wire. The OEM charging cable was 2 AWG and the sense wire was 18 AWG. I elected to upgrade to 2/0 welding cable for the charge cable, and to 10 AWG for the sense wire. My new charging cable (unlike the diagram in your post) runs in one unbroken section from the alternator straight to my AGM8D starting battery. My new sense wire follows the exact same (unbroken) path. In fact, they are tied together along the whole length with zip ties.
So, on my coach at least, the charging cable and the sense wire are exactly the same length. In addition, the charging cable is much larger diameter than the sense wire. Thick wire has less electrical resistance than thin wire. Why is the battery voltage seen by the "S" terminal on my 28Si "better" (more accurate) than the voltage seen on the B+ terminal?
Like I said, I'm not disagreeing with your comment...just curious about the reasoning behind the whole "sense wire" concept.
Title: Re: 24SI Alternator check
Post by: prfleming on March 18, 2025, 10:37:29 pm
Post by: prfleming on March 18, 2025, 10:37:29 pm
Chuck,
Good question. The reason why the SENSE wire can be much smaller (and possibly even longer) and work fine is that it is sensing voltage with very little current (probably just a few micro-amps). So there is virtually no voltage drop on the sense wire.
The main alternator cable is carrying a very large current - possibly up to 200 amps - so the cable needs to be sized to handle this current. Your use of 2/0 cable was a good choice. The 10 gauge SENSE wire is fine, but it could have been 18 gauge with no issue.
Edit:
The reason the alternator B+ voltage is not accurate as the SENSE voltage is the alternator will be maintaining the voltage only at that point - to say 14 volts. But let's say the current demand is 200 amps with a resulting voltage drop of say .5 volts at the battery, now the battery is only getting 13.5 volts. A sense wire to the battery will tell the alternator now to maintain THAT point at 14 volts, raising the B+ voltage to 14.5 volts to cover the cable voltage drop under high load. Once the current goes back down the alternator will adjust to keep the battery at 14 volts at all times.
Good question. The reason why the SENSE wire can be much smaller (and possibly even longer) and work fine is that it is sensing voltage with very little current (probably just a few micro-amps). So there is virtually no voltage drop on the sense wire.
The main alternator cable is carrying a very large current - possibly up to 200 amps - so the cable needs to be sized to handle this current. Your use of 2/0 cable was a good choice. The 10 gauge SENSE wire is fine, but it could have been 18 gauge with no issue.
Edit:
The reason the alternator B+ voltage is not accurate as the SENSE voltage is the alternator will be maintaining the voltage only at that point - to say 14 volts. But let's say the current demand is 200 amps with a resulting voltage drop of say .5 volts at the battery, now the battery is only getting 13.5 volts. A sense wire to the battery will tell the alternator now to maintain THAT point at 14 volts, raising the B+ voltage to 14.5 volts to cover the cable voltage drop under high load. Once the current goes back down the alternator will adjust to keep the battery at 14 volts at all times.
Title: Re: 24SI Alternator check
Post by: Chuck & Jeannie on March 18, 2025, 10:40:39 pm
Post by: Chuck & Jeannie on March 18, 2025, 10:40:39 pm
Peter,
I figured you would supply a logical technical answer to my question. That is why I value your comments so highly. ^.^d
Cheers!
I figured you would supply a logical technical answer to my question. That is why I value your comments so highly. ^.^d
Cheers!
Title: Re: 24SI Alternator check
Post by: dlkj07 on March 18, 2025, 10:53:11 pm
Post by: dlkj07 on March 18, 2025, 10:53:11 pm
Yes, the Delco 28SI will function without a SENSE wire, but as recommended by the Delco brochure, a SENSE wire connected to the chassis battery terminal will allow the alternator to compensate for any voltage drop in the cabling for optimum performance.
Title: Re: 24SI Alternator check
Post by: dlkj07 on March 18, 2025, 10:59:05 pm
Post by: dlkj07 on March 18, 2025, 10:59:05 pm
Also, I drove the coach today and dropped it off to get some work done and the voltage on my Bluefire was reading 13.4 consistently. That is with the B+ from the alternator connected directly to the chassis battery lug on the isolator. Normally it would fluctuate to a lower voltage then back up as I drove so something is better.
Title: Re: 24SI Alternator check
Post by: Chuck & Jeannie on March 18, 2025, 11:13:20 pm
Post by: Chuck & Jeannie on March 18, 2025, 11:13:20 pm
So the wire that was hot with the key on and connected to the "I" lug on my current configuration wouldn't work as the SENSE wire once I install the 28SI correct?
Title: Re: 24SI Alternator check
Post by: prfleming on March 18, 2025, 11:19:31 pm
Post by: prfleming on March 18, 2025, 11:19:31 pm
To add to Chuck's comment,
No, the "hot" with ignition won't work as the SENSE wire. The SENSE wire needs to be directly connected to the chassis battery. I would recommend to run a new SENSE wire if you upgrade to an alternator with SENSE capability.
The "hot" with ignition could still be useful if you decide to put in a 28SI and also change your isolator to one with an excite terminal. If you remove the isolator and connect the 28SI alternator directly to the chassis battery you won't need the excite wire. As mentioned previously, connecting an excite wire to a Delco alternator can cause permanent damage. The "I" terminal is for an Indicator lamp connection.
It's hard to know where the other wire is connected with a reading of only 6V, I would leave that one disconnected and just tape it.
No, the "hot" with ignition won't work as the SENSE wire. The SENSE wire needs to be directly connected to the chassis battery. I would recommend to run a new SENSE wire if you upgrade to an alternator with SENSE capability.
The "hot" with ignition could still be useful if you decide to put in a 28SI and also change your isolator to one with an excite terminal. If you remove the isolator and connect the 28SI alternator directly to the chassis battery you won't need the excite wire. As mentioned previously, connecting an excite wire to a Delco alternator can cause permanent damage. The "I" terminal is for an Indicator lamp connection.
It's hard to know where the other wire is connected with a reading of only 6V, I would leave that one disconnected and just tape it.
Title: Re: 24SI Alternator check
Post by: prfleming on March 18, 2025, 11:40:39 pm
Post by: prfleming on March 18, 2025, 11:40:39 pm
Alternator brands is a vigorously debated topic on this forum, I wanted to throw a suggestion into the mix.
Here is a source (DelStar - made in Canada) that would be worth considering for anyone looking at upgrading. (I have no financial connection with this company).
DelStar offers alternators very similar to Delco models including the 28SI, here is a 200 amp model that is brushless which will provide improved performance and reliability over a brush design.
https://www.delstar-hd.com/pdf/160/D100-16100.pdf
Here is a source (DelStar - made in Canada) that would be worth considering for anyone looking at upgrading. (I have no financial connection with this company).
DelStar offers alternators very similar to Delco models including the 28SI, here is a 200 amp model that is brushless which will provide improved performance and reliability over a brush design.
https://www.delstar-hd.com/pdf/160/D100-16100.pdf
Title: Re: 24SI Alternator check
Post by: wolfe10 on March 19, 2025, 08:21:17 am
Post by: wolfe10 on March 19, 2025, 08:21:17 am
No, the "hot" with ignition won't work as the SENSE wire. The SENSE wire needs to be directly connected to the chassis battery. I would recommend to run a new SENSE wire if you upgrade to an alternator with SENSE capability.
Agreed. And a little more "reason why":
You want correct voltage to the chassis battery. A sense wire connected to the chassis battery or the chassis battery side of the diode-based battery isolator gives the alternator accurate data.
But, an ignition-hot wire is does not accurately represent chassis battery voltage. Depending on where it is connected to an ignition- hot source has gone through fuses, relays, connections and lengths of wire.
And, depending on where the ignition-hot source comes from, changing in loads on that circuit (head lights, dash HVAC fan, etc) will send falsely low voltage signals to the alternator which would lead to over-charging voltage to the chassis battery.
Title: Re: 24SI Alternator check
Post by: dlkj07 on March 20, 2025, 02:38:52 am
Post by: dlkj07 on March 20, 2025, 02:38:52 am
So would this eliminate both the islolator and the boost switch?
ML Solenoid - 12V DC - Blue Sea Systems (https://www.bluesea.com/products/7701/ML_Solenoid_-_12V_DC)
ML Solenoid - 12V DC - Blue Sea Systems (https://www.bluesea.com/products/7701/ML_Solenoid_-_12V_DC)
Title: Re: 24SI Alternator check
Post by: Dennis H on March 20, 2025, 02:51:39 am
Post by: Dennis H on March 20, 2025, 02:51:39 am
This is my go-to for battery combination. Automated and manual override for combination or isolation.
Mechanical interlock for service or if you really need to force it one way or the other.
ML-ACR Automatic Charging Relay with Manual Control - 12V DC 500A - Blue Sea... (https://www.bluesea.com/products/7622/ML-ACR_Automatic_Charging_Relay_with_Manual_Control_-_12V_DC_500A)
In automatic both lithium and AGM will keep the batteries combined even after charging stops due to the high resting voltage. Lithium House and AGM will actually complement each other with this set up especially for float-storage. This relay is rock solid reliable.
Mechanical interlock for service or if you really need to force it one way or the other.
ML-ACR Automatic Charging Relay with Manual Control - 12V DC 500A - Blue Sea... (https://www.bluesea.com/products/7622/ML-ACR_Automatic_Charging_Relay_with_Manual_Control_-_12V_DC_500A)
In automatic both lithium and AGM will keep the batteries combined even after charging stops due to the high resting voltage. Lithium House and AGM will actually complement each other with this set up especially for float-storage. This relay is rock solid reliable.
Title: Re: 24SI Alternator check
Post by: Chuck & Jeannie on March 20, 2025, 08:36:48 am
Post by: Chuck & Jeannie on March 20, 2025, 08:36:48 am
So would this eliminate both the isolator and the boost switch?
To use the full functionality of the remote control switch that comes with either of these solenoids, you MAY have to run a new multi conductor cable from your dash area to the solenoid. Your original boost switch used a single conductor wire to connect to the solenoid. The Blue Sea solenoid switches require 3 (or possibly more) conductors. I detailed the installation of my ML 7701 switch in the post linked below:
'93 U280 Isolator Panel Upgrade (https://www.foreforums.com/index.php?topic=34743.0)
Title: Re: 24SI Alternator check
Post by: dlkj07 on March 20, 2025, 10:30:27 am
Post by: dlkj07 on March 20, 2025, 10:30:27 am
Also, I didn't realize that when you search up 28SI alternator there would be so many...I know usually you get what you pay for but is it a horrible mistake to get one of the knock off's or am I asking for trouble? It's a 3-400 dollar difference depending on where you look between the Delco Remy and other brands.
Title: Re: 24SI Alternator check
Post by: prfleming on March 20, 2025, 11:08:54 am
Post by: prfleming on March 20, 2025, 11:08:54 am
Be careful with the imitators. I had a 28SI knockoff and then replaced it with a real one. In comparing the wire windings looking through the air slots the wire size was a noticably smaller gauge on the knockoff. Less copper, more resistance and I think would run hotter.
Also check eBay. I bought my Delco 300 amp alternator on eBay and it was in perfect shape and ran like a champ.
Also check eBay. I bought my Delco 300 amp alternator on eBay and it was in perfect shape and ran like a champ.
Title: Re: 24SI Alternator check
Post by: Dennis H on March 20, 2025, 01:49:36 pm
Post by: Dennis H on March 20, 2025, 01:49:36 pm
Also, I didn't realize that when you search up 28SI alternator there would be so many...I know usually you get what you pay for but is it a horrible mistake to get one of the knock off's or am I asking for trouble? It's a 3-400 dollar difference depending on where you look between the Delco Remy and other brands.
I have installed some knock offs. If you get past a few thousand miles you will be good for some time. Early failures tend to be the regulators going full on. For the long term bearings. For older vehicles, mostly VW Vanagons I have had much better luck with the knock off staters and alternators than the name brand rebuilds.
For the windings wire size and number of turns is affected by capacity. Higher amps bring larger wires, but less turns so output at low speed is often reduced. Everything is a compromise.
Title: Re: 24SI Alternator check
Post by: dlkj07 on May 26, 2025, 12:51:44 pm
Post by: dlkj07 on May 26, 2025, 12:51:44 pm
So I did end up purchasing a 28SI Part# 8600212
It's been awhile since this post so want summarize...
Since the 28SI I bought has the "S" terminal, I'm going to run a wire from chassis batteries to "S" on back of alternator.
What I'm a little confused about is can I use my 3 lug isolator currently installed or do I need to install one of the isolators with the ignition lug like Chuck mentioned above in reply #1 above for it to work correctly?
I am not ready to install a DC-DC at this time so just trying to get this back together without throwing more parts at it for now.
It's been awhile since this post so want summarize...
Since the 28SI I bought has the "S" terminal, I'm going to run a wire from chassis batteries to "S" on back of alternator.
What I'm a little confused about is can I use my 3 lug isolator currently installed or do I need to install one of the isolators with the ignition lug like Chuck mentioned above in reply #1 above for it to work correctly?
I am not ready to install a DC-DC at this time so just trying to get this back together without throwing more parts at it for now.
Title: Re: 24SI Alternator check
Post by: Chuck & Jeannie on May 26, 2025, 03:49:29 pm
Post by: Chuck & Jeannie on May 26, 2025, 03:49:29 pm
Dylan,
The 28Si must "see" 12 volt on the alternator B+ (output) terminal for it to turn on. This can be accomplished in one of two ways.
1. You can connect the alternator output cable directly to one of the battery banks - normally it would be the chassis batteries. Or, as Brett mentioned in one of the earlier posts, you could just move the alternator cable on the isolator from the center post over to the chassis battery post. This will provide the required 12 volt on the output cable to turn the alternator on. This setup basically bypasses the stock isolator. yYou could use the BOOST switch to combine/charge both battery banks, OR you could replace the isolator with either a dumb or smart combiner solenoid as mentioned in earlier posts.
2. You can replace your diode isolator with a model like the ones I mentioned in Reply #1.
Either way works. Do whatever works best considering your future plans for electric system upgrade/modification.
The 28Si must "see" 12 volt on the alternator B+ (output) terminal for it to turn on. This can be accomplished in one of two ways.
1. You can connect the alternator output cable directly to one of the battery banks - normally it would be the chassis batteries. Or, as Brett mentioned in one of the earlier posts, you could just move the alternator cable on the isolator from the center post over to the chassis battery post. This will provide the required 12 volt on the output cable to turn the alternator on. This setup basically bypasses the stock isolator. yYou could use the BOOST switch to combine/charge both battery banks, OR you could replace the isolator with either a dumb or smart combiner solenoid as mentioned in earlier posts.
2. You can replace your diode isolator with a model like the ones I mentioned in Reply #1.
Either way works. Do whatever works best considering your future plans for electric system upgrade/modification.
Title: Re: 24SI Alternator check
Post by: dlkj07 on May 26, 2025, 04:07:42 pm
Post by: dlkj07 on May 26, 2025, 04:07:42 pm
Ok, so what you're saying is I can't connect the 28SI B+ to the middle lug of my current 3 lug isolator as it was previously connected and be on my way.
It's either hooked directly to the chassis batteries (or lug on current isolator that go to chassis batteries) or I need to purchase the 4 lug isolator in reply #1 with the ignition hot lug. Then hook up the wire that has 12V when ignition is on to the 4th lug on new isolator.
Just curious, why does the 28SI have to use the ignition hot wire to work correctly?
It's either hooked directly to the chassis batteries (or lug on current isolator that go to chassis batteries) or I need to purchase the 4 lug isolator in reply #1 with the ignition hot lug. Then hook up the wire that has 12V when ignition is on to the 4th lug on new isolator.
Just curious, why does the 28SI have to use the ignition hot wire to work correctly?
Title: Re: 24SI Alternator check
Post by: Chuck & Jeannie on May 26, 2025, 04:14:03 pm
Post by: Chuck & Jeannie on May 26, 2025, 04:14:03 pm
1. Ok, so what you're saying is I can't connect the 28SI B+ to the middle lug of my current 3 lug isolator as it was previously connected and be on my way.
2. It's either hooked directly to the chassis batteries (or lug on current isolator that go to chassis batteries) or I need to purchase the 4 lug isolator in reply #1 with the ignition hot lug. Then hook up the wire that has 12V when ignition is on to the 4th lug on new isolator.
3. Just curious, why does the 28SI have to use the ignition hot wire to work correctly?
2. Correct
3. I don't know. That's a question for a EE major. I was a English major...to my great sorrow...shoulda studied computer science (this was in the time before Bill Gates became an unemployed college dropout).
Title: Re: 24SI Alternator check
Post by: dlkj07 on May 26, 2025, 04:35:14 pm
Post by: dlkj07 on May 26, 2025, 04:35:14 pm
1. Correct
2. Correct
3. I don't know. That's a question for a EE major. I was a English major...to my great sorrow...shoulda studied computer science (this was in the time before Bill Gates became an unemployed college dropout).
Title: Re: 24SI Alternator check
Post by: prfleming on May 26, 2025, 04:35:44 pm
Post by: prfleming on May 26, 2025, 04:35:44 pm
Just curious, why does the 28SI have to use the ignition hot wire to work correctly?
As Chuck said, the Delco 28SI (40SI, 55SI) need to have 12V on the B+ terminal either continuously or at startup using an isolator with the ignition terminal. The internal smart (digital) regulator needs this to boot up and be ready to regulate using the S sense voltage. Once the engine is running the "kick start" from the ignition wire is no longer needed, until the next time you start the engine. So, using the stock isolator will not work, you will get erratic or no output.
Title: Re: 24SI Alternator check
Post by: dlkj07 on May 26, 2025, 04:50:54 pm
Post by: dlkj07 on May 26, 2025, 04:50:54 pm
So if I'm going to spend around $200 or so for the isolator with the ignition lug but in the future going to upgrade to the Victron Orion XS DC-DC charger,($315 on amazon) I may as well get the Victron now because it will work with my current setup.
Then when I do upgrade to Lithium Ion batteries I should be good to go.
Amazon.com: Victron Energy Orion XS Smart DC to DC Battery Charger 12/12 50A... (https://a.co/d/4ahWLec)
Then when I do upgrade to Lithium Ion batteries I should be good to go.
Amazon.com: Victron Energy Orion XS Smart DC to DC Battery Charger 12/12 50A... (https://a.co/d/4ahWLec)
Title: Re: 24SI Alternator check
Post by: prfleming on May 26, 2025, 04:58:22 pm
Post by: prfleming on May 26, 2025, 04:58:22 pm
Here is the Delco Tech Bulletin on using an isolator.
Note - the initial image is the thumbnail, click again to see the high res document.
Note - the initial image is the thumbnail, click again to see the high res document.
Title: Re: 24SI Alternator check
Post by: dlkj07 on May 26, 2025, 05:20:44 pm
Post by: dlkj07 on May 26, 2025, 05:20:44 pm
Here is the Delco Tech Bulletin on using an isolator.
Note - the initial image is the thumbnail, click again to see the high res document.
Title: Re: 24SI Alternator check
Post by: prfleming on May 26, 2025, 05:21:20 pm
Post by: prfleming on May 26, 2025, 05:21:20 pm
Quick search for isolators with excite option
Amazon.com: Victron Energy Argofet Battery Isolators 200-2AC (2 Batteries... (https://a.co/d/ic4JkQ2)
Amazon.com: Quick Cable 303306-001 Battery Isolator : Automotive (https://a.co/d/hlArOYO)
Amazon.com: Cole Hersee 48162 Battery Isolator : Automotive (https://a.co/d/8uxBBOv)
https://www.waytekwire.com/product/eaton-s-sure-power-24023a-ib-multi-battery
Amazon.com: Victron Energy Argofet Battery Isolators 200-2AC (2 Batteries... (https://a.co/d/ic4JkQ2)
Amazon.com: Quick Cable 303306-001 Battery Isolator : Automotive (https://a.co/d/hlArOYO)
Amazon.com: Cole Hersee 48162 Battery Isolator : Automotive (https://a.co/d/8uxBBOv)
https://www.waytekwire.com/product/eaton-s-sure-power-24023a-ib-multi-battery
Title: Re: 24SI Alternator check
Post by: dlkj07 on May 26, 2025, 05:25:31 pm
Post by: dlkj07 on May 26, 2025, 05:25:31 pm
Quick search for isolators with excite option
Amazon.com: Victron Energy Argofet Battery Isolators 200-2AC (2 Batteries... (https://a.co/d/ic4JkQ2)
Amazon.com: Quick Cable 303306-001 Battery Isolator : Automotive (https://a.co/d/hlArOYO)
https://www.waytekwire.com/product/eaton-s-sure-power-24023a-ib-multi-battery
Title: Re: 24SI Alternator check
Post by: prfleming on May 26, 2025, 05:40:14 pm
Post by: prfleming on May 26, 2025, 05:40:14 pm
Thanks, but I do think I talked my self into the DC/DC charger instead.
Yes, awesome. My only comment is with 1 of those you are only using a fraction of the available alternator output to recharge batteries while driving. Some other members have added multiple B2Bs with good results.
Title: Re: 24SI Alternator check
Post by: dlkj07 on May 26, 2025, 05:51:02 pm
Post by: dlkj07 on May 26, 2025, 05:51:02 pm
Yes, awesome. My only comment is with 1 of those you are only using a fraction of the available alternator output to recharge batteries while driving. Some other members have added multiple B2Bs with good results.
Title: Re: 24SI Alternator check
Post by: Lon and Cheryl on May 26, 2025, 08:03:11 pm
Post by: Lon and Cheryl on May 26, 2025, 08:03:11 pm
Nighttime and cloudy days come to mind.
Title: Re: 24SI Alternator check
Post by: T and M Long on June 06, 2025, 12:38:38 am
Post by: T and M Long on June 06, 2025, 12:38:38 am
Peter. Could you turn the boost switch on while driving to get more power to the house batteries, while driving? I have lithium house batteries and a Orion dc/dc charger. I don't currently turn on my boost switch while driving. But have considered it.
Tom
Tom
Title: Re: 24SI Alternator check
Post by: krush on June 07, 2025, 04:24:12 pm
Post by: krush on June 07, 2025, 04:24:12 pm
I ditched the diode isolator for a Yandina combiner (relay based) years ago. I think Yandina has been bought out, but other companies make a similar unit.
Title: Re: 24SI Alternator check
Post by: prfleming on June 08, 2025, 09:03:09 am
Post by: prfleming on June 08, 2025, 09:03:09 am
Peter. Could you turn the boost switch on while driving to get more power to the house batteries, while driving? I have lithium house batteries and a Orion dc/dc charger. I don't currently turn on my boost switch while driving. But have considered it.
Tom
Title: Re: 24SI Alternator check
Post by: T and M Long on June 22, 2025, 11:57:30 pm
Post by: T and M Long on June 22, 2025, 11:57:30 pm
Thanks for the answer. That's what I thought, but wanted your thoughts.
Tom
Tom