Detroit 8.2 alternator

Covers engines and transmissions
TDJohn
Posts: 313
Joined: Sun Oct 27, 2019 11:34 pm

Re: Detroit 8.2 alternator

Post by TDJohn »

Thank you for the kind words but I sure am not a legend, I believe in the pay it forward/helping others concept and try to help when I can, just like many other members here. Over the years people have been very kind and helpful to me, and pretty much all RVers know how much it sucks to be broke down, so we all just try to help each other the best we can (it is the way the world use to function in the old days).

Sorry, but I don't know much about the quality of various brands of isolators out there. Some have used Noco brand, Cole Hersey seems to be rated well, so you will likely be ok. I personally don't care for diode based isolators because of their inefficiency (0.7 volt drop), but more importantly, even though they do seem overall trouble free, when they do fail, and they will eventually, they often can wipe out the alternator. So for this reason I prefer to use a heavy duty solenoid for an isolator. One thing is for sure, the isolator you have now is way too small and wont live long with that strong of an alternator.

To answer you other question, the solenoid shown in the photo below your blue isolator is your boost solenoid. It looks very similar to mine, so it might be a White Rogers continuous duty solenoid, mine is rated for continuous duty. If you decide to make your boost solenoid do dual purpose, I would suggest to buy a spare solenoid, as the one you have is pretty old, but likely didn't see that much use. I could also help guide you through the changeover if you like, but that would have to be next week.

Regarding the isolator, I found this info on one of the boating supply sights that you should be aware of.

Note: Battery isolators also have a "per leg" rating which indicates the maximum current it can deliver to either battery. All Cole Hersee battery isolators have a per leg rating equal to half the alternator rating. Thus the 48162 with a rating of 200A has a per leg rating of 100A per leg.

If your house battery bank is four 6volt batteries, it could easily exceed the 100amp limit if the batteries are pretty discharged or you have a substantion load on the battery bank, while you are driving. So, going to a larger isolator, as a precaution, would not be a bad idea, or just switch to a solenoid based isolator.

The alternator you ordered seems to be correct on all the needed items, lets hope you receive the actual alternator with the described specs. ;)
John
'95 Serengeti, Cummins C8.3-300
Allison 6spd.
Joeoren
Posts: 17
Joined: Wed Nov 11, 2020 6:08 am

Re: Detroit 8.2 alternator

Post by Joeoren »

So, john after reading what you have said and doing a little research, I think I will be not replacing the isolator and just delete it entirely. I think I would much rather use one of the new style battery separators (smart solenoids.)

upon further investigation I’ve realized not only did my alternator fail but so did the isolator as well as the boost solenoid :shock: but I’m pretty sure
the boost solenoids has been nonfunctional since I bought the motorhome.

I’ve been looking into the
Sure Power 1314/1315- 200 series.
I’m not sure if I should use a unidirectional or bidirectional though. I do plan to install solar soon so maybe the bidirectional makes more sense?

It seems like this unit would solve all my problems separating the batteries as well as having an auto boost feature in those dire situations when this Detroit motor HATES starting in the cold.

Unfortunately, it seems like it will be another week or so before I can get the parts in the alternator was supposed to be coming in tomorrow but I just checked the tracking and its looking like Friday. But yes, john if you’re willing to help guide me through once the parts are in, I’d really appreciate it just still trying to figure out what’s the best possible upgrade for my system.
You are also correct I do have a 4 6volt battery bank I am using as a house bank and the standard 12v 8d for the chassis. so, I’m not sure if the 200amp separator is going to be enough?
1990 safari serengeti High Tech editon 8.2T Detroit AT545
2009 Subaru outback xt - Toad 1
1999 mazda miata - Toad 2
TDJohn
Posts: 313
Joined: Sun Oct 27, 2019 11:34 pm

Re: Detroit 8.2 alternator

Post by TDJohn »

This might be better for you. It is pricey, but very good quality with redundancy to boot. If you search on the internet, you can probably pick one up for a bit less then the factory list price.

https://www.bluesea.com/products/7622/M ... 2V_DC_500A

Being that you are considering installing solar, there are other options that we can discuss. I will send you a PM shortly, so be sure to check your PM inbox.
John
'95 Serengeti, Cummins C8.3-300
Allison 6spd.
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