Parallel Batteries

[jamesh76]

OK- I am a little confused on using an onboard charger for 2x type 29 parallel batteries up front for my trolling motor and front fish finder.

I understand + to + and - to - on the wiring of parallel.

I understand with a 1 bank charger you hook the one + and one - to the same battery.

However, how do you hook it up if you are using a 15 amp 2 bank charger? I know you can disconnect the batteries and charge them seperately. But can you charge them left in parallel with a 2 bank charger? What would this charge time be like?

Do you just hook both banks to one battery? ++ to + and - - to -?

Thanks

 

[BrianNJ]

Re: Parallel Batteries

Do you just hook both banks to one battery? ++ to + and - - to -?

Thanks

You can do it this way.
Since you have a two bank charger, better would be to disconnect the parallel connection and use the two banks. This way, if one battery fails, it won't draw down the other battery too.

Charge time will have more to do with how much power you have used than the fact that you have two batteries.

 

[jamesh76]

Re: Parallel Batteries

Thanks. To me the time to disconnecting defeats the purpose of onboard chargers and increases error of accidentally hooking them back up incorrectly.

 

[Capt Ken]

Re: Parallel Batteries

Hook the charger to both batteries and add a battery on/off switch between the two. Then just break the parallel connection by switching it off. Easier than having to disconnect batteries.

 

[Splat]

Re: Parallel Batteries

Batteries ran independently will actually provide better capacity than 2 tied in parallel. It's not a huge difference, but it is more efficient.

 

[agallant80]

Re: Parallel Batteries

My charger has three banks. Two of the + go to the house and one + goes to the starting battery. I think the idea is each bank will only put out so many amps. When you start adding the batteries on it will charge slower but if you double the charger bank then you overcome that.

 

[alldodge]

Re: Parallel Batteries

OK- I am a little confused on using an onboard charger for 2x type 29 parallel batteries up front for my trolling motor and front fish finder.

I understand + to + and - to - on the wiring of parallel.

I understand with a 1 bank charger you hook the one + and one - to the same battery.

However, how do you hook it up if you are using a 15 amp 2 bank charger? I know you can disconnect the batteries and charge them seperately. But can you charge them left in parallel with a 2 bank charger? What would this charge time be like?

Do you just hook both banks to one battery? ++ to + and - - to -?

Thanks

Thanks. To me the time to disconnecting defeats the purpose of onboard chargers and increases error of accidentally hooking them back up incorrectly.

Question please ..... Are you installing a 2-bank charger to charge 2 batteries which both will be used by the trolling motor and other accessories, or will one battery be used to start the motor and the other to run the trolling motor and accessories?

 

[jamesh76]

Re: Parallel Batteries

Question please ..... Are you installing a 2-bank charger to charge 2 batteries which both will be used by the trolling motor and other accessories, or will one battery be used to start the motor and the other to run the trolling motor and accessories?

I am using a 2 bank charger to charge 2 batteries which are parallel. They both run the trolling motor and a fish finder.

I did not mention. But my 3rd battery is a multi purpose Deep/Cranking and runs my starter, GPS DI DD on console, bilge and lights if I fish at night. I normally do not have to charge this one often as the motor pretty much keeps it up unless I fish all night with lights on.

 

[alldodge]

Re: Parallel Batteries

I am using a 2 bank charger to charge 2 batteries which are parallel. They both run the trolling motor and a fish finder.

I did not mention. But my 3rd battery is a multi purpose Deep/Cranking and runs my starter, GPS DI DD on console, bilge and lights if I fish at night. I normally do not have to charge this one often as the motor pretty much keeps it up unless I fish all night with lights on.

OK thanks, I would suggest connecting your new batteries in parallel and leave them that way. While you said you don't really don't need to charge your start battery, IMHO it is always a good idea to keep a quality 3-stage charger on all batteries. Now keeping the 2 new batteries together and install 1 bank of the charger to the start and one to the trolling motor side. If you choose not to charge your starter battery then you could just get a single bank higher amp rated charger (best), or use the 2-bank and put one on each of the parallel batteries.

Installing a battery switch between trolling and starting is also a good thing incase need arrises