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Topic: 24SI Alternator check (Read 9634 times) previous topic - next topic

Re: 24SI Alternator check

Reply #40 –
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...
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.

Re: 24SI Alternator check

Reply #41 –
Quote from: dlkj07 –
So would this eliminate both the isolator and the boost switch?
Yes.  The ML 7701 can eliminate both isolator and boost SOLENOID.  This is also true of the ML-ACR mentioned (above) by Dennis.  They are both the same basic solenoid.  The 7701 is pure manual control.  The ML-ACR adds some very nice "automatic" features.

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

Re: 24SI Alternator check

Reply #42 –
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.

Re: 24SI Alternator check

Reply #43 –
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.

Re: 24SI Alternator check

Reply #44 –
Quote from: dlkj07 –
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.

Re: 24SI Alternator check

Reply #45 –
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.

Re: 24SI Alternator check

Reply #46 –
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.

Re: 24SI Alternator check

Reply #47 –
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?

Re: 24SI Alternator check

Reply #48 –
Quote from: dlkj07 –
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?
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).

Re: 24SI Alternator check

Reply #49 –
Quote from: Chuck & Jeannie –
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).
Ha, well I don't have any major...except the major of hard knocks but that doesn't count I'm sure. 😋

Re: 24SI Alternator check

Reply #50 –
Quote from: dlkj07 –
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.

Re: 24SI Alternator check

Reply #51 –

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...

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Re: 24SI Alternator check

Reply #52 –
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.

The selected media item is not currently available.

Re: 24SI Alternator check

Reply #53 –
Quote from: prfleming –
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.

The selected media item is not currently available.
Well that explains it well, thanks.

Re: 24SI Alternator check

Reply #54 –

Quick search for isolators with excite option

Amazon.com: Victron Energy Argofet Battery Isolators 200-2AC (2 Batteries...

Amazon.com: Quick Cable 303306-001 Battery Isolator : Automotive

Amazon.com: Cole Hersee 48162 Battery Isolator : Automotive

https://www.waytekwire.com/product/eaton-s-sure-power-24023a-ib-multi-battery

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: 24SI Alternator check

Reply #55 –
Quote from: prfleming –
Quick search for isolators with excite option

Amazon.com: Victron Energy Argofet Battery Isolators 200-2AC (2 Batteries...

Amazon.com: Quick Cable 303306-001 Battery Isolator : Automotive

https://www.waytekwire.com/product/eaton-s-sure-power-24023a-ib-multi-battery
Thanks, but I do think I talked my self into the DC/DC charger instead.
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Re: 24SI Alternator check

Reply #56 –
Quote from: dlkj07 –
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.

Re: 24SI Alternator check

Reply #57 –
Quote from: prfleming –
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.
In my situation I think I'm good with one...I have solar too which pumps in more juice if needed. Not often will I need to rely just on an alternator to get my batteries charged...unless I'm missing something.

Re: 24SI Alternator check

Reply #58 –
Nighttime and cloudy days come to mind.

Re: 24SI Alternator check

Reply #59 –
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