As my coach seems to like stressing me out. It of course decided to continue with almost no voltage from my new (not Reman) Delco-Remy 28si 180amp alternator. As this alternator doesn't need an excite wire. I terminated that one and insulated it. I left the old diode isolator in for now and will install the sterling zero loss later. I hooked up the start batt. Sense wire to the S terminal which is next to the Pos output. That showed battery Voltage like it should.
Upon starting the coach, I went to high idle (1000 RPM) and saw low volts at the gauge. Then I measured voltage at the center terminal of the isolator. 1.7V. Measured the voltage at the pos output to ground. It was 1.7V.
To summarize:
Batt voltage, 12V
Sense wire at Alt, 12V
Alt input wire at isolator, 1.7V
Alt. positive output terminal, 1.7V
Bad alternator?
Bad alternator.
I hope so as that's an easy swap.
Need to find a shop that can test one. NAPA here is useless as it's not one of theirs so the computer has no data for it. Geez. You think they could just spin it up and measure voltage.
Had the same hassle at Auto Zone,Installed a 160 amp 28si 2 years ago along with a new isolator and everything new on the
mounting plate,haven't had a problem,charges much better at low rpm.
Well against my better judgement. I decided to save a few bucks and went big box truck parts place. Should have spent the coin and stayed local. A local truck shop that does my oily work has the 28si 160amp. I think I will go with that.
Nothing wrong with the alternator. Delco alternators won't work with a standard diode isolator, they need +12 volts on the B+ post to initialize the regulator chip. Either install a diode isolator with an ignition excite post, or wait until you get your Sterling. Connect the excite wire to either one, your Delco should then work fine.
Note: Do not connect ignition excite wire directly to a Delco alternator.
It will work fine with your Sterling as Peter says.
What? Wait now I'm totally confused.
There is a spot on the alt. for an ignition wire.
Jerry, you're not the first one...contrary to what you may have heard, Delcos are not a drop-in replacement alternator in a 2 battery isolator system. A diode isolator with excite post or the Sterling isolator with excite post will work with a Delco alternator to provide the B+ voltage needed at startup.
The "I" post is for indicator lamp. Connecting excite to this will permanently damage the alternator.
Hook up only the sense wire to the S post, nothing to the I or R posts, in addition to the big ground and the B+ output cable.
That's the way I have it hooked up now.
OK, So as i'm looking at the old diode isolator. The main thing that confuses me is that at both outputs. There are smaller wires on those terminal along with the big battery cables. What are those?
This will get you going until you get the Sterling.
Delco compatible isolator (https://www.amazon.com/dp/B001FQN5AK/ref=cm_sw_r_sms_apa_i_5fKtDbY8XDMH3)
I already have the sterling. I was just going to use the old iso until it isn't 100 degrees out. As in this fall when we get ready to go south. However, As this issue has come up. I'm going to install the Sterling in the morning. It just won't be a pretty mounting.
The part I was confused about were the two small wires coming off of each battery bank output on the old isolator. I would think the one on the start batteries is the sense wire. But the small wire on the house bank is?
OK. After reading and re-reading Rogers old post on his switch to the Delco/Sterling combo.
I terminate the old sense wire, Then run a new sense wire from the Delco S post to the Sterling Sense post.
Then I need to run a wire from the old FT excite wire to the Ign wire on the Sterling.
All the Battery cables from the old Diode iso are just pushed over to the new Sterling. I take it the two small wires that are confusing me on the old diode iso at the Battery cables are the two Solenoid trigger wires?
And yes it is a stupid question. Do those small wires also just get swapped over just as they are on the old Iso? I would think so.
Hi Jerry,
It is pretty straight forward. The Sterling sense to the Delco S post is right. The Sterling ign post needs an ignition powered wire to turn on so the excite wire will work. Often times these old wires have corroded connectors. I just ran new wires.
As built (on my coach) there were no other wires connected to the three isolator posts other than the alternator to the center post and a start post cable to the start battery side if the boost solenoid and the house (B2 I think they called it on the Sterling) post cable to the opposite side of the boost solenoid. Other wires may have been added over time. My Progressive EMS is powered off the house post.
There are many now with an added solar charger, battery charger and more stuff. When you make changes to your coach keep good notes, draw a new wiring diagram and save it and probably most important label the wires. Lots of variations on these but however label them.
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There was a mislabeled drawing in my old post but it is too old to edit.
Thanks Roger. I will look at the wiring chart before I get started. Not supposed to be as hot today & Sunday. So that will help. 100 degrees like it has been and parked on a sticker infested patch of dead grass with no shade is not a good motivator. :))
Thought a new efficient iso would be a nice option, Almost didn't buy it. I had ZERO idea that a new iso was mandatory with a Delco. :facepalm: Guess I missed that memo.
Peter was also a big help when I installed mine,good to see your still out there.
I only work on old stuff and only for my pleasure, but Delco used to use the "generator" light to provide the exciter voltage to the alternator. Bad light bulb means no alternator output.
You're right I think the old Delcos (before digital regulators) worked this way, the new Delcos have output with nothing connected to the "I" post.
On the flat bottoms we put a resister between the two male spade connectors to be able to just use one wire. No idiot lights on the boats.
Maybe the 2 small wires at the isolator go to a battery maintainer for the chassis battery, like a battery tender or heart echo charger.
I did see one wire on the wiring diagram that goes to a solenoid on the start battery side. I have the standard Heart interface 2500 and the Xantrex panel on the china cupboard. The interface doesn't have a trickle charger.
When I go back to the coach tomorrow. I will pull that second wire and see what changes. I suspect that perhaps it is the second Battery voltage readout on the panel in the coach? I didn't look at that section of the diagram. However if it was factory. It certainly should have been noted on the main wiring page that shows the Isolator.
Didn't get much done today though. Had a sleepless night. Then got out later than I wanted. Got out of the house without having drank any water. 2 hours later I was feeling the sun and unwell and so called it a day.
Here is the Delco bulletin on using the 24SI with isolator, this also applies to the 28SI, 40SI.
"I think" that you can use your still good diode isolator by adding a wire to terminal #1 from the ignition switch through one of the listed options, a 5W Diode, a resistor or a 3 candle power bulb.
Tell me why I'm wrong.
The Delco bulletin is confusing. The diagrams on the 2nd page are showing how plug style connections were done with older alternators with analog regulator. I believe you could use an older alternator as you suggest, but Jerry has the 28SI with digital regulator that requires 12v on the B+ to start up per the 1st page and 3rd page.
So why wouldn't the old excite wire work on the B+ post on the 28si? Then also use the old sense wire on the S post.
That way I could take my time and mount the Sterling in a much nicer way and muck around under the bus in a bit cooler weather. Right now I'm just trying to get this thing running/charging
Don't do that, once the alternator starts charging, charge current will flow back on the excite wire and you will fry the excite wire (or blow a fuse).
I won't. So it has to be temp 12V signal and the Sterling Ign post does that?
Kind wish I would have just bought a replacement Lecee-Neville.
Correct, either the Sterling, or diode isolator with ignition post.
As myself and others will attest, the new Delcos - 28SI, 40SI (brushless) are a superior alternator, but you need to also change the isolator to use one.
Sorry about the silly question. I have been taken aback that I actually needed a new iso. How would the average person even know that a question needs to be asked.
Starting to understand that the ign post on the sterling just de-islolates the alt in and pushes 12V into the B+.
Both the Sterling and diode isolators use a diode in the excite circuit to allow current to flow to the B+ post at startup, but then block it from flowing the other way when the alternator starts charging.
If you're comfortable doing this, a diode can be manually wired in to use a Delco 28SI/40SI with a standard diode isolator. Wire the diode in series with the excite wire to the Delco B+ post. To make sure you have it wired the right way, turn ignition on but don't start, there should be 12v on the alt B+ post, with ign off the voltage should return to zero. If no voltage with key on, turn the diode around and try the test again. Once you're sure it's wired correctly, start the engine, the Delco should now start charging. Remove the diode and connect the excite wire to the Sterling when you switch isolators.
O'Reilly universal diode (https://www.oreillyauto.com/detail/b/painless-wiring-4545/engine-sensors---emissions-25132/switches-25075/switches---rocker--universal--18222/7e8c1754a370/painless-wiring-multi-purpose-inline-diode/80111/4608860)
I know little and want to know less about alternators myself.
I replaced my rebuilt LN Duvac with another new duplicate unit.
We were going out of town so I took the coach into the Cummins shop and had them swap the good rebuilt for a new duplicate unit.
Supposedly has a new solid state VR.
Here's the LN
Applications
Popular RV Motorhome Alternator
CUSTOM CHASSIS INC EL-039
DAIMLER TRUCKS NORTH AMERICA LN 2824LC
GILLIG CORP 51-00179-008
INTERNATIONAL TRUCK & ENGINE ZLN2824LC
LEECE NEVILLE 2824LC, 90772, A001090772, A0012824LC, A0012825LC, 2825LC
MACK TRUCKS INC 2742 5034-2824LC,
Monaco A001090772, A0012824LC, A0012825LC
Newmar 2824LC 2825LC 2828LC
OSHKOSH CORPORATION 6HA518
PRINOTH 110954522
SPARTAN MOTORS INC 0499-GG1
VOLVO NORTH AMERICAN CORP. LN 2824LC
Series number: 2500JB, 2600JB, 2700JB, and 2800JB.
MODELS: 2524JB, 2624JB, 2724JB 2824JB AND 2829JB
NOTE: INCLUDES STANDARD 8 GROOVE PULLEY
OEM(s): Leece Neville
System voltage: 12
Output: 160 AMPS
Rectifier location: Internal
Excitation type: Ignition Excite
Regulator Location: Internal
Mounting style: J-180
Fan Location: External
Rotation: BI-DIRECTIONAL
Mounting bolt size: 1/2-13 UNC
Positive stud: 5/16-18 UNC
Negative stud: 5/16-18 UNC
For Duvac or Dual Battery Systems
Industrial, Recreational & Medium & Heavy Duty Truck Applications
Weight: 24 lbs. / 10.91 kg
Includes Simple Hook-up Instructions
*PLEASE VERIFY YOU HAVE DUVAC TYPE SYSTEM BEFORE PURCHASE*
Just about finished. Will go back in the AM and button it up. Ran the new sense wire from the delco to the Sterling. Then taped into the existing exciter at the Alt position and ran it back to the sterling. Removed old ISO and mounted the sterling. Only thing left to do is put larger ring terminals on two existing wires for the larger sterling posts and install ring terminal for the sense/ign and ground wires at the sterling.
Also made notes on the factory wiring diagram.
But lunch was calling. A pulled Pork lunch no less. So off I went.
Went out and finished my project. Coach didn't blow up or turn to a pile of ashes. So I must have not mucked anything up. Charging just fine. High idle has 14.33V at the alt. and 40 Amps on the house panel.
Awesome, another Delco conversion ^.^d
Can you reduce the voltage to a set of fully charged batteries to 13.6 volts?
Um, That's what a voltage regulator with a battery voltage sensing wire does.
The guys that design these alternators with internal digital regulators are pretty smart folk. So I'll leave electrical engineering stuff to the electrical engineers. So I'm not going to worry about it.
But as in all things. We humans often become overly pedantic about things and fret over minutia.
Congratulations on your success!
My Fiat has a generator.
And when the outside air temperature is 99° and the heat index is 110° there isn't much else to do.
FWIW my 1950 Chrysler was my summer transportation from 1976 until 2013. The way I figure it, this U225 and the '68 SIATA should take me to the end. Once I finish the SIATA.
I finally had to make my own heater valve as Fiat's failed time and time again. While very short, Fiat designed it with huge understeer so almost impossible to spin it even in the wet.
Pierce
Don't get me started on Fiat's. I had a 1973 124 sport coupe. Good looking, fun to drive. Not many coupes around as everyone had the spyder. Driving sedately on my way to trade it for a pickup truck. The con-rod decided it wanted a bit of fresh air and made a big hole in the engine block. That was the end of my Fiat experience.
We found that with the dog we needed a car and we wanted something easy to trailer. Our search took us past an XJ-12 that probably had heat issues and a any way you looked at it was run out, then back to the other extreme the Fiat 850 based Siata Spring. In the middle were any number of full size Chrysler products that blew the easy to trailer argument right out the window.
Is Yurre's rig supposed to have a pipe plug in the oil pan or was that something creative? I now own a 17mm hex key for an 850cc engine's cast aluminum oil pan's drain plug.
This guy has the best Fiat parts. Midwest Bayless.
Heres his car getting passed by my Red VW. @ Daytona ;
https://www.youtube.com/watch?v=c2HZk7QReTQ&t=95s
We (me included) are wondering off topic. Esp as it's in the tech forum.
We keep thinking your having more woes only to find where to buy Fiat parts.
My shop said if I installed a sense alternator I would get a constant 14.1 volts at the batteries.
I loved my 1970 Fiat 124 Coupe until I leaned on the driver's side front fender and my elbow fell through. It turned out much of the body sheetmetal was being held together by the paint!
My comment was to help nothing more.
14 volts at the batteries is quite a bit of overcharging both banks unless in zero degree weather.
Factory and Brett here both set the alternator at 13.6 volts at the battery.
The delco sense drawing shows 13.5 volts without the sense wire. 14 with.
I would remove the sense wire myself if possible.
If you have a Battery Temp compensating inverter with a remote panel you will see the battery charging voltages change with the batteries temp.
Most rv batteries "float" at 13.6 volts.
Yours will be permanently being overcharged, if full, at 14 volts.
50% decrease in battery life?
As you still seem to be having issues I am not sure if just removing the sense wire is as easy as it seems but killing $2000 worth of batteries quicker than necessary seems not a good thing.
What do your batteries "float" at at 77 degrees? Next to the motor the engine compartment batteries get much hotter.
Probably why Foretravel used optima red(or yellow in a few) top spiral wound AGM start batteries as they round cells dissipate heat better.
Lots of 10 to 12 year life redtop/mk gels reports here so the 13.6 at the battery volts is shown to work very well.
These are obviously not school busses and the rapid recharge rate at a higher voltage than "float" could shorten your batteries life considerably.
Just trying to help you and maybe others here with their coaches.
Old coaches had 14 volt battery boilers(chargers) only and I replaced every battery in every used coach I resold as they wore quickly. Especially in the desert southwest temps.
Hence the LN adjustable voltage regulator.
The smart inverters will start out at over 14 volts in moderate weather then reduce the volts as the batteries get charged then float.
Alternator does not know about float unless you have a temp compensating unit.
Those do not work well in a coach where the batteries are hot from the engine.
The charge volts can be close to 13 volts in those systems after a full charge in hot conditions at the battery.
The marine industry sometimes uses temp controlled alternator but the batteries are not normally that hot...
Aren't all the automobiles charging at 14.2 volts under a hot hood. I get 6 to 7 years out of my Costco car batteries.
Not a car. Not a car useage. Long drives versus stop and restart.
Look at a float chart.
Over 10 here on 13,6 redtops is not unusual.
Almost the entire rv and Gillig bus co used the 13.6 adjustable voltage LN for a reason
Yeah, but to play Devil's Advocate, most cars don't travel far enough at any one time to overcharge the battery.
But, 13.6 is also known as the absorption charge, 13.2 is the float voltage to prevent self discharge. 14.4 is the"Bulk" rate and is used only on flooded cell batteries and only up to 80% state of charge.
AGM batteries can be dried out since they start at 90% of the electrolyte needed and rely on recombiners to keep the out gassing "inside."
Gel cells are susceptible to pockets being formed in the gel from the out gassing and I haven't bothered to learn their best charge voltage.
FWIW I have an elderly motorcycle friend whose battery died while watching some racing in Baja, so he cut the top open, pissed in the AGM battery, waited, and got his bike started for the ride out.
Was he too old to push it????
I know the numbers as they are set on my inverter charger. And the 12.2 50% discharge. All I was commenting to is the batteries I use in the car last longer than what would seem normal with being overcharged. As far as not driving distances, the family car sits and only runs long distances. Here to Vegas and back for NASCAR I have to keep a trickle charger on to compensate for the parasitic drain between uses. The Jeep toad never goes less than 20 mile trips to the lakes we use it to get to, and usually 50 plus miles. The short trips at home for the jeep would need the 14.2
In an effort to clear up all this "it's wrong" "it's right" LN Vs Delco-Remy stuff.
I have placed a call to the Delco-Remy tech line and asked the question: if one is driving for a long distance and your AGM batteries have reached full charge. Wont this alternator be over charging them @ 14.3V when AGM's like a fully charged float voltage of 13.6V?
The tech guy said that this will be pushed up to the engineering section about this AGM charging and call me back.
Thanks. The answer would be of interest.
Yes it will.
And the answer could be in the middle.
Perhaps I'm off base and correct me if I'm wrong.
BUT! The manufacturers of dual battery bank RV's could have put on some sort of charge controller to cut alt charging to the batteries and still power coach electric demands. But it also seems that in an effort to sell the RV for a few hundred dollar less. They decided not to.
I have my LN alternator set for 13.6v as I use solar for battery charger and it is custom set for AGMs. The long drives we do a couple of times a year hopefully do not do much charging . The batteries were new in 03--2011 and still seem to be doing fine. I also have a n equalizer on each one 100% of time.
JohnH
But why would you need to do all this on a coach with a price point of nearly $400K. I would think that things like battery management systems would be the reason the coach is so expensive.
Here is a battery charge curve showing the bulk, absorption and float durations. What most don't realize is the absorption phase takes a LONG time, 6 to 8 hours. The alternator's purpose is to charge after battery use over night, not provide float/maintenance, the coach charger should do that. I think all this fear of excessive charging while driving is over-blown.
Thanks for that chart Peter. That helps a lot.
As an inexperienced RV owner. It can be a daunting task at times wading through all the info. Is an answer based on fact, urban myth, out dated truisms, Guessing? And figuring out which is correct without knowing what to even ask (the inexperienced part) is hard and makes one wonder if anything they are doing is correct.
I have noticed that when I'm using the on board Xantrex charger. It stays in accept (absorbtion?) for a very long while.
13.6 volts is too low to complete the absorption phase and you will not reach 100% charge.
Here is what Borg Warner sent me.
Hello Jerry, One thing I want to advise you to verify is to test voltage at S terminal of alternator with ignition off to verify you are getting battery voltage, to insure the circuit connection for remote sense. Typically AGM carries .2V higher reading than standard. Other than this it is not believed to be an issue for the AGM Batteries
Peter really good point. I had researched that, the Magnum inverter or the solar I have finishes the absorption great. Mk says up to weekly to get to 100% on their gels is ok.
Must work in general as there are hundreds of posts here with 10-12 year mk gels battery life set at 13.6 alternator and the inverter to finish the charge.
My alternator starts out at the dash lighter outputs at 13.86 after starting the M11. Within a few minutes starts dropping.
My 13.63 or so is fully charged long drive. Alternator basically shuts off as the solars 13.6 is running the coach with no other major loads. Engine loop heats the water.
Coach is outdoors and the auto combiner is always on.
I have a 250 watt adjustable load tester coming by boat, five hours to test an 8G8D to 50% to verify actual condition.
Big heat sink. Fan forced cooling. Separate the batteries or test hooked up. Lab grade. Separate 12volt power supply needed to run it. If the group does not show correct amp hours then I will separate them. And test again.
MK and Lifeline require 1/5th or 1/20th C charging.
We will see how they are holding up. Who knows. The amp hours used seems to match the battery voltage at certain SOC percentages.
The load bank/ resting voltage check should match what I see. Hopefully.
Bought the trick inexpensive load tester for another purpose.
Will report how everything is working. No ego. Just what is really going on.
This would seem to work.
250W DC 12V Discharge Battery Capacity Tester Module With DC Electronic Load... (https://www.ebay.com/itm/250W-DC-12V-Discharge-Battery-Capacity-Tester-Module-With-DC-Electronic-Load-Dig-/123860980466)
This load tester looks great. For our van with 400 AHs I do a make-shift load test using a 300 watt light bulb and monitor inverter amp draw with a clip on amp meter. 300 watts is approx 28 amp draw with inverter efficiency added in. I run the batteries down to 50% capacity on my Balmar SmartGauge and calculate the AH used. 200 AH should be approx 7 hours for the test. I try to do this twice a year.