Two batteries with 35 amp alternator

Here's the situation: I have a 1980 International Harvester Scout II.  She has a very low rated alternator (35 amp).  I want to run one or two amplifiers for a decent sound system.  The standard 35 amp alternator is $700.  Rebuilding or higher amp one (if even availabe which I doubt) will likely be economically astronomical. 

I've been reading the posts about a two battery configuration with an isolator.  Can that be done with a low amp alternator?  Do you believe there to be any other options?  Anything will help!

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Thank you,
Aaron
jackjeckyl@hotmail.com

RIght now I have a second battery in my trunk with a 200 amp isolator and it works perfectly no more dimming and the power is twice as good.  Alot of these guys would suggest an altenator but who wants to pay that much money for one part.  My isolator cost me 65 bucks and I bought a regular battery from autozone and it hits like crazy.  But for better performance I would suggest a optima battery I am getting one when I get my L7's .  If you need any help let me know.

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Does it matter I have a low amp alternator?  Does it make any difference at all on the car or system to run the isolator?  No additional stress to the alternator?

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Thank you,
Aaron
jackjeckyl@hotmail.com

Just to make sure I understand, You want to feed two batteries with a 35 amp alternator. So the Alt will charge both batteries when the vehicle is running and them seperate them when off. So while the relay is active, your alternator will have the stock battery as a load and a second battery as a load? So is the second battery energy storage or a load at this point? The isolation relay would only help you when your are listening while the vehicle is off. Then when the relay connects both batteries wouldn't the Alt be under more stress trying to replenish both batteries? just a few thoughts.

get a one wire ac delco alt. get at least a 100amp. trust me you be sorry to run 2 batts and 3 amps off of 35 amps. I would get as big a alt as you can afford. it will be worth it.

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Big Dave

The isolator acts as a brain and determines which battery is lower in charge (don't ask me how, I just know that's what they do!). It then routes power from the alternator to that battery.

I agree with speedway, you're gonna fry that little 35 amp alternator. Second battery systems work well, but you need to have an alternator that can handle the load. I've run dual battery setups before without upgrading the alternator (before I learned a little more) and it worked fine. But I found out that I was lucky and didn't fry the alternator while I had the car. I also realized why I was still having problems keeping both batteries charged, the 90 amp alternator just wasn't big enough to handle the load. Spend the money for a better alternator, or you'll end up paying more in the long run.

Read some of the posts about alternators that have been made over the last week or so, and take the advice that has been given buy some of the other members. When it comes to Alternators, I've found that bberman1 and Big Purds are pretty much the sh*t around here. Take their advice, you wont be sorry if you listen to them

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Squirrel
"No more Cpt. Kirk chit chat"
If its too loud, then you're too old
Donate to the12volt.com

lol ty squirrel...

correct me if I am wrong, but the Scouts have a fair amount of room in the engine bay do they not? you will probably want to look at getting a higher output alternator (it may not need to be huge if you are only looking at running a couple of smaller amps) and getting some brackets custom fabricated to fit on your block...there are alot of factory alternators for reasonable prices under 140A, and if you arent going to be running a hwavy bass system you may not need more than that...I think if I am thinking of the right truck, you probably wont be drawing more than 20 or 25A with the vehicle, so with a 140A alternator, you will still have over 100A of current for your amplifiers, which is actually a fair amount until you get into really big amps for subs and such...

what are you looking at installing as far as equipment? (brands, model numbers, etc...) do you think that getting some brackets fabbed would be an option for you? I honestly see it as the cheapest solution for this situation...a second battery will surely fry your $700 alternator in a short period of time...and a very expensive machine shop will still probably charge you under 100 dollars for the brackets to be made for a different alternator...and any 140A factory alternator will probably be under 300 dollars at most auto parts outlets...so you are just over half of the budget for a replacement stock International alternator with 4 times the output...

one other thing you may want to do is contact Dominick at Irraggi alternators ( dominick@tds.net ) and give him the model number of your alternator...he may be able to build a high output alternator for you in the exact case for your truck...I am not sure if he can, but it never hurts to ask...

let me know if I can help you further...

Thanks guys, I will scrap the two battery config and concentrate on finding a larger amp alternator.

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Thank you,
Aaron
jackjeckyl@hotmail.com