How Do I Get the Alternator to Charge Both Batteries ?

[Aotearoa]

Ahoy...

My alternator on my Yanmar 2gm favours charging only one of my two deep cell batteries onboard my Alberg 30.

I thought to take the leads of Batt 2 and putting them on battery one so all the leads will be going to one battery, however this doesnt solve my problem. The only sensible solution seems to be simply to switch the batteries from time to time batt 1 to batt 2 position vice versa.

Any suggestions?

Ross

Alberg 30
Antares

[boasun]

There is, strangly, in this world an item called a Battery switch. And with two batteries on board. You can have the switch on battery #1 or #2 or Both. That way you don't have to mess with switching the battery cables from one to the other. Safer that way also.

[courageous cat]

also a battery isolator is for dual-battery powered vehicles! The battery isolator allows proper current flow to each battery and maintenance-free deep cycle batteries to be charged properly. Just a thought

[Aotearoa]

Yes I had seen the "battery switch" in fact its an obvious switch as its so big and red with a big dial 1 2 ALL OFF....... . However i cant start the engine on the flatter battery and it doesnt seem to want to charge on "all" both batteries evenly. I am reluctant to switch the battery to 1 or 2 while the engine is running (is it ok to switch while engine is running?) that would be to easy! Other wise i switch the batteries.....

cheers

I better do some homework eh!

[Andina Marie]

It is not advisable to turn the switch OFF while the engine is running but it is OK to go from "1" to "BOTH" to "2".
If you are charging both and only one is getting charged it is probably an indication that the battery is bad.
Normally you would dedicate one battery to starting and the other to house loads but original boat wiring frequently puts everything on the one switch so you have to do everything manually. That means select the starting battery to start, then when running put the switch on BOTH for about 10 minutes to replace the charge in the starting battery, then go to 2 so the starting battery is isolated and saved.

Then when you anchor out you are running down 2 for house loads and saving 1 for startng in the morning.

If you don't trust your memory to do all the switching many people install a Combiner (google battery combiner, Defender has them for about $65) It will do all the switching automatically and doesn't have a voltage drop like an isolator.

[cal40john]

Originally Posted by Aotearoa

Yes I had seen the "battery switch" in fact its an obvious switch as its so big and red with a big dial 1 2 ALL OFF....... . However i cant start the engine on the flatter battery and it doesnt seem to want to charge on "all" both batteries evenly. I am reluctant to switch the battery to 1 or 2 while the engine is running (is it ok to switch while engine is running?) that would be to easy! Other wise i switch the batteries.....

cheers

I better do some homework eh!

If you have a poor connection or a corrosion problem or bad switch the voltage drop would keep a battery from charging fully. Do you have a voltmeter? With the engine running and the switch on both, look for voltage drops where there shouldn't be any.

John

[Aotearoa]

Thanks Andina Marie and Cal40john.....I will get my voltmeter out (while running) and look into the Combiner.

all the best