Battery charging question (yet another!)

[TonyNoriega]

I have a 36v trolling motor system. Two of those batteries are on an onboard 2 bank charger......I added the third recently and can't afford to change out chargers presently.

Can I charge the 3rd battery while it's still wired up in the 36v configuration, or do I need to disconnect it? I'll be using my old stand-alone charger to do the job.

Thanks!

Tony

 

[TonyNoriega]

Re: Battery charging question (yet another!)

Anyone out there know the answer?

 

[Silvertip]

Re: Battery charging question (yet another!)

It shouldn't be a problem. One question though -- How did you operate a 36V troller with just two batteries?

 

[PondTunes]

Re: Battery charging question (yet another!)

I'd think you would need to disconnect it and break the series connection between the batteries if your current charger can't handle 3 batteries in series 36v. If you had 2 in series then it was 24v I assume you're upgrading. A simple perko switch could be put between the 2nd and 3rd battery allowing you to connect your 12v charger.

The results of hooking up both chargers without breaking the series connection might hurt your chargers. I just assumed you were upgrading to a 36v trolling system and got another battery. Were you running a 36v system off of only 24v?


When you wire the batteries in series Ie the positive from one, to the negative of the other the voltage doubles ie 12 + 12 = 24 or three 12 + 12 + 12 = 36, if they are wired in parallel positive to positive, negative to negative then your system is still a 12v system, parallel wiring more than one battery makes the motor think that it has one really big battery rather than increasing the voltage.

 

[TonyNoriega]

Re: Battery charging question (yet another!)

I wasn't running a 36v motor on a 24v system (sorry I didn't clarify earlier); I replaced a defective 24v motor with a more powerful 36v motor and added the 3rd battery to get me the 36 volts. All of that went satisfactorily but of course I was left with an on-board charger with only 2 banks.

Thanks for your advice (although both responders have a different opinion) - I do appreciate you taking the time to help me out.

Tony

 

[PondTunes]

Re: Battery charging question (yet another!)

If the charger is rated for 24v *I* would say it wouldn't be a good idea to try to charge a 36v system with it. It may very well work. It might just charge slower, or it might not work..
The switch to interrupt the series connection WILL work, with your 2 bank 24v charger and a 12v charger.

The nice thing about this place is you often get more than one solution to a problem and one option may be better than another!

 

[Silvertip]

Re: Battery charging question (yet another!)

First, the 24V charger shown in PondTunes diagram is not really a 24V charger but two 12V chargers, with isolated outputs that can be bridged. However, it doesn't matter because bridged 12V outputs = 24V on a two bank charger. Breaking a series connection is only necessary if you have a two or three bank charger and the charger does not have isolated outputs. Since most newer multibank chargers do have isolated outputs, two outputs can be bridged to provide 24V as shown, or each output can be connected individually to each battery. The net result is the same. Adding a third charger means it's output is isolated from the others so there simply isn't a problem.

 

[PondTunes]

Re: Battery charging question (yet another!)

Thanks ST wasn't aware of the isolation on the multi bank chargers.. Learn something new every day!