charging two batteries simultaneously

larryd49

Cadet
Joined
Sep 3, 2016
Messages
6
can I charge my starting battery and house battery at the same time? I have a battery switch. Can I select "Both" on the battery switch and connect the battery charger to one battery and charge both batteries at same time? If so, would a trickle charger keep both batteries charged?
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
15,416
Yes, you can use " both" and charge both batteries at the same time but beware....the two batteries will equalize, causing the higher charged battery to transfer power to the lesser charged battery until both batteries have equal charge.

Not necessarily a bad thing unless the house battery is dead and you combine the two and end up with two half charged batteries.

A better solution is to install an ACR. The ACR regulate the flow of current from the starting battery to house based upon the voltage of the starting battery. The relay will only pass current to the house battery when the starting battery is fully charged.
 

ondarvr

Supreme Mariner
Joined
Apr 6, 2005
Messages
11,527
And a trickle charger connected to two batteries will have tough time doing what its supposed to do, they have very few amps and they're being split between two batteries, so whatever it does with one, it will only do it half as well with two.
 

harleyman1975

Ensign
Joined
May 12, 2003
Messages
959
Yes but...If you are a weekend warrior this will work just fine if you are just trying to maintain the batteries when you are away from the boat during the week. I however would suggest you invest in a 2 bank charger like they have on fishing boats. Min kota (and I am sure others as well) makes one that will charge 2 batteries and float them when fully charged for right around $100.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
You have a battery switch!!!! Why not send charging current to the battery that needs it most and therefore gets charged quicker. Select the HOUSE battery and let it charge. The starting battery is vary rarely deeply discharged. Use the switch as intended.
 
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