# Pickup with 2 batteries--one battery continually loses charge **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [January 26, 2008, 6:25pm UTC](https://community.cartalk.com/t/pickup-with-2-batteries-one-battery-continually-loses-charge/9867 "2008-01-26T18:25:33Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Adriver](https://avatars.discourse-cdn.com/v4/letter/a/cc9497/32.png) [@Adriver](https://community.cartalk.com/u/Adriver)\ **Post date:** [January 26, 2008, 6:25pm UTC](https://community.cartalk.com/t/pickup-with-2-batteries-one-battery-continually-loses-charge/9867/1 "2008-01-26T18:25:33Z")
The battery that loses charge has been checked and said to be in good shape. I’m planning to get it rechecked. The other battery holds charge very well. The batteries are hooked up in parallel. If one battery holds charge and the other doesn’t, shouldn’t that limit the places to look for a short in an electrical line or device? ---
**Author:** ![mr\_josh](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mr_josh/32/3008_2.png) [@mr\_josh](https://community.cartalk.com/u/mr_josh)\ **Post date:** [January 26, 2008, 6:36pm UTC](https://community.cartalk.com/t/pickup-with-2-batteries-one-battery-continually-loses-charge/9867/2 "2008-01-26T18:36:22Z")
One battery is losing its charge to the other. You need a battery isolator like this one: [http://www.jcwhitney.com/autoparts/Product/tf-Browse/s-10101/Pr-p\_Product.CATENTRY\_ID:2006119/p-2006119/N-111+10201+600000926/c-10101](http://www.jcwhitney.com/autoparts/Product/tf-Browse/s-10101/Pr-p_Product.CATENTRY_ID:2006119/p-2006119/N-111+10201+600000926/c-10101) (Hope that link works, if not, just go to [JCWhitney.com](http://JCWhitney.com) and search for “isolator”. ---
**Author:** ![BustedKnuckles](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bustedknuckles/32/25_2.png) [@BustedKnuckles](https://community.cartalk.com/u/BustedKnuckles)\ **Post date:** [January 26, 2008, 6:40pm UTC](https://community.cartalk.com/t/pickup-with-2-batteries-one-battery-continually-loses-charge/9867/3 "2008-01-26T18:40:58Z")
What kind of truck? If they are hooked up parallel to each other, then there could be a problem with the cable connections on both batteries. I’d clean the terminals, and consider replacing them if caked with corrosion. Corrosion on either battery will prevent the batteries from charging and discharging evenly, as this set-up is most likely designed to do. ---
**Author:** ![GreasyJack](https://avatars.discourse-cdn.com/v4/letter/g/df705f/32.png) [@GreasyJack](https://community.cartalk.com/u/GreasyJack)\ **Post date:** [January 26, 2008, 7:24pm UTC](https://community.cartalk.com/t/pickup-with-2-batteries-one-battery-continually-loses-charge/9867/4 "2008-01-26T19:24:32Z")
Did you check the other battery? If the other one’s bad it can drain the good battery. The easy way to check if it’s a problem with the batteries themselves or something on your rig would be to switch the batteries and see if the problem moves with the battery or not. ---
**Author:** ![Adriver](https://avatars.discourse-cdn.com/v4/letter/a/cc9497/32.png) [@Adriver](https://community.cartalk.com/u/Adriver)\ **Post date:** [January 26, 2008, 7:35pm UTC](https://community.cartalk.com/t/pickup-with-2-batteries-one-battery-continually-loses-charge/9867/5 "2008-01-26T19:35:23Z")
It’s a 95 Chevy Silverado 3/4 ton 4 x 4. There is no corrosion–recently cleaned… Thanks. ---
**Author:** ![Adriver](https://avatars.discourse-cdn.com/v4/letter/a/cc9497/32.png) [@Adriver](https://community.cartalk.com/u/Adriver)\ **Post date:** [January 26, 2008, 7:37pm UTC](https://community.cartalk.com/t/pickup-with-2-batteries-one-battery-continually-loses-charge/9867/6 "2008-01-26T19:37:31Z")
Good idea on switching places with the batteries. I’ll try it. thanks. ---
**Author:** ![Adriver](https://avatars.discourse-cdn.com/v4/letter/a/cc9497/32.png) [@Adriver](https://community.cartalk.com/u/Adriver)\ **Post date:** [January 26, 2008, 7:43pm UTC](https://community.cartalk.com/t/pickup-with-2-batteries-one-battery-continually-loses-charge/9867/7 "2008-01-26T19:43:33Z")
This is the 3rd time I’ve tried a response–the first two didn’t show up. Anyway, I’ll have the system checked. If there is an isolator I suppose it could be defective also? thanks ---
**Author:** ![mr\_josh](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mr_josh/32/3008_2.png) [@mr\_josh](https://community.cartalk.com/u/mr_josh)\ **Post date:** [January 26, 2008, 7:48pm UTC](https://community.cartalk.com/t/pickup-with-2-batteries-one-battery-continually-loses-charge/9867/8 "2008-01-26T19:48:26Z")
Okay, if it’s a newer factory setup, isolation is probably either controlled through a solenoid or a diode pack (which is essentially what an isolator is). Either way, the JCWhitney link that I posted isn’t going to help much. BUT, hopefully it won’t be an expensive fix with parts designed for the factory system. GreasyJack’s idea of switching the batteries is a good one.