charging 12V batteries in parallel

[radarbugs]

i had a 24v motorguide w75 electric troller on my boat and during the winter i think that it got water inside the housing somehow and then froze and wrecked the motherboard. i yarded that boat anchor off my boat and put a brand new Minnkota Maxxum 55 12V foot controlled bowmount on in its place. the way it was wired before was 2 12V batteries wired in series giving me 24V at the bow with 2 wires. i wired the batteries in parallel to get a strong 12V to the motor and it works puss. can i charge 2 12V batteries that are wired parallel at the same time or do i need to unhook one cable so i am charging 1 at a time, or will they charge together?:confused i have a 12V Schumaker solid state charger for deep cycle and maintenance. any info will be appreciated.
Radar

 

[ac0j]

Re: charging 12V batteries in parallel

You can charge them both at one time. As far as the charger knows its just one big battery!

 

[Lakemeadan]

Re: charging 12V batteries in parallel

You can charge them both at one time. As far as the charger knows its just one big battery!

Agree but I sometimes like to disconnect one neg or pos (separate) and charge each battery separately to see condition of each battery. Maybe just me.

 

[radarbugs]

Re: charging 12V batteries in parallel

thanks to you both. i didnt want to just try it and burn up or ruin $220 worth of batteries. i had an onboard charger when i bought the boat but it crapped out in no time. i always thought that water and electronics dont mix. is no hassle at all hooking a portable charger up for the night.
thanks and happy boating and fishing,
Radar

 

[fishrdan]

Re: charging 12V batteries in parallel

You can charge both batteries connected together as said earlier, but... If you leave the 2 batteries connected in parallel the stronger battery will stabilize to the weaker battery's voltage. Battery A at 12.8V + battery B at 12.5V will equalize both batteries to 12.5V after a day or so. Some of the charge is being bled off the good battery.

I used to run my 2 trolling batteries in parallel for simplicity, but after running them 1 at a time, I found that I had longer total run time. I now have an A, B, A+B, OFF switch on my jon boat to make switching between the batteries easier. I usually charge them separate since I have 2 chargers, but could just throw the switch to both and charge them at the same time. Like LMD, I like to keep track of the batter condition.