the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
icon

Two batteries with 35 amp alternator


Post ReplyPost New Topic
< Prev Topic Next Topic >
scroley 
Member - Posts: 7
Member spacespace
Joined: July 21, 2003
Location: United States
Posted: July 21, 2003 at 12:54 PM / IP Logged  

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!

Thank you,
Aaron
jackjeckyl@hotmail.com
thomasbutler 
Copper - Posts: 91
Copper spacespace
Joined: May 17, 2003
Posted: July 21, 2003 at 2:48 PM / IP Logged  
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.
scroley 
Member - Posts: 7
Member spacespace
Joined: July 21, 2003
Location: United States
Posted: July 21, 2003 at 6:30 PM / IP Logged  
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?
Thank you,
Aaron
jackjeckyl@hotmail.com
audiocableguy 
Copper - Posts: 630
Copper spacespace
Joined: January 27, 2003
Location: Idaho, United States
Posted: July 21, 2003 at 7:00 PM / IP Logged  
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.
speedwayaudio1 
Silver - Posts: 879
Silver spacespace
Joined: March 18, 2003
Location: United States
Posted: July 21, 2003 at 10:22 PM / IP Logged  
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.
Big Dave
wvsquirrel 
Gold - Posts: 1,237
Gold spaceThis member has made a donation to the12volt.com. Click here for more info.spacespace
Joined: July 27, 2002
Location: Florida, United States
Posted: July 21, 2003 at 11:48 PM / IP Logged  
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
Squirrel
"No more Cpt. Kirk chit chat"
If its too loud, then you're too old
Donate to the12volt.com
Big Purds 
Silver - Posts: 574
Silver spacespace
Joined: November 25, 2002
Location: Canada
Posted: July 22, 2003 at 12:58 AM / IP Logged  
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...
scroley 
Member - Posts: 7
Member spacespace
Joined: July 21, 2003
Location: United States
Posted: July 22, 2003 at 11:14 AM / IP Logged  
Thanks guys, I will scrap the two battery config and concentrate on finding a larger amp alternator.
Thank you,
Aaron
jackjeckyl@hotmail.com

Sorry, you can NOT post a reply.
This topic is closed.

  Printable version Printable version Post ReplyPost New Topic
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot delete your posts in this forum
You cannot edit your posts in this forum
You cannot create polls in this forum
You cannot vote in polls in this forum

  •  
Search the12volt.com
Follow the12volt.com Follow the12volt.com on Facebook
Sunday, April 28, 2024 • Copyright © 1999-2024 the12volt.com, All Rights Reserved Privacy Policy & Use of Cookies
Disclaimer: *All information on this site ( the12volt.com ) is provided "as is" without any warranty of any kind, either expressed or implied, including but not limited to fitness for a particular use. Any user assumes the entire risk as to the accuracy and use of this information. Please verify all wire colors and diagrams before applying any information.

Secured by Sectigo
the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
Support the12volt.com
Top
the12volt.com spacer
the12volt.com spacer