How to charge multiple batteries at the same time

[scusset1]

Hi folks,
I am new to this repair stuff.. I have a class A with a residential fridge and Forest River has 4 batteries, I assume connected together that will keep it running while on the road.
My question's are as follows: if I put a battery charger on one of the batteries, will all of them get charged? Also, can I charge them while the coach is plugged in? And, how can I test to see if the converter is charging them while plugged in or on the road.
They appear to be taking a full charge and the charger (independent) shuts off or the green light comes on. If I shut it off and turn it back on it takes a full charge again.

Any suggestions are very much appreciated!

[ScottBrownstein]

The converter is charging them if the top LED on the battery panel is lit. That isn't 100% it is "charging." The engine is charging them if the same is true when running disconnected from shore power.

If you have a voltmeter, the converter will charge at 14, 13.6 and 13.3 or so, depending on how charged they are. The engine will charge them at around 14.2 or so.

You shouldn't need a separate charger.

[Ilovemywife]

The converter doesn't charge while on the road. It is powered by 120 volts AC. Your vehicle's engine alternator may charge the batteries while driving.

As to whether they are connected together, why not just look at the batteries and see if they are wired in parallel.

Previous poster is correct, you don't need a separate charger.

[Duckogram]

Be careful, you may have 4 x 6 volt batteries. Putting a 12v charger on one battery would be bad.

[scusset1]

Thanks so much. I have 12 volt in succession.

[Tom48]

Originally Posted by Duckogram

Be careful, you may have 4 x 6 volt batteries. Putting a 12v charger on one battery would be bad.

VERY TRUE. You have to see what you have. It may be 4 12v batteries in parallel or 2 pairs of 6v batteries. They will be two in series tied to two more in series by linking them in parallel. Usually charging one 12v or pair of 6s will charge the others but BE SURE TO LOOK AND KNOW WHAT YOU HAVE BEFORE YOU DO ANYTHING.

I disagree with some above. If you are staying off connections at camp and have to charge once or twice a day with the generator, a separate battery charger at the same time that the converter is charging and you can shorten the necessary generator time.

If I had a residential frig, I'd be looking for a convenient way to install two more batteries.

Oh, and goes without saying, a solar sytem, of at least 100 watts per battery.

Lots of good links on the forum and YouTube about battery condition meters, charging, solar and general battery use n maintenance.

Good luck. Enjoy.

[Bluepill]

Good basic info on multiple battery systems here:

The 12volt Side of Life (Part 1)

[camaraderie]

If you wish to charge 4 - 12V batteries separate from the converter which WILL charge them...then you need to invest in a charger that can provide at LEAST 10% of the combined amp hours of your bank. Example...if you have FOUR 100 amp hour batteries...you need a charge of 1/10 of 400 amps...or 40 amps. 80 amps would be better and anything over that would be overkill.
Unless you have a special reason...I would avoid going the separate charger route as your converter is quite adequate. To know if it is working...while plugged in OR running your generator...a voltmeter at your battery terminals (any battery +&-)
should read a minimum of 13.2Volts.
If you are storing your rig for some time...FULLY charge the batteries and then remove the negative ground wire from the batts. They will be just fine even after 90 days without attention if you do this. If you ever get a volt reading below 12.4 in storage...time to recharge fully.

[boondocking]

Originally Posted by Bluepill

Good basic info on multiple battery systems here:

The 12volt Side of Life (Part 1)

Interesting read, but a little too much misinformation.