"Ganging" 6-Volt Batteries

deuce

@Sharon_is_SAM, @4ncar, @lightningdon

In our recent discussion, you all provided a pic or diagram of your connection of 2 6-Volts.  Sharon's showed plus-to-plus and called it a Series, 4ncar and Don showed plus to minus, which I take it is parallel.

Which is is the way to do it to replace a std 12-volt?

4ncar

@deuce: I believe @Sharon_is_SAM’s diagram reflects - to +  as my photo depicts and calls it series...🤷🏻‍♂️

ScottG

Here are some good resources with clear graphics showing the differences between series and parallel connections:

https://www.batterystuff.com/kb/articles/battery-articles/battery-bank-tutorial.html

https://batteryguy.com/kb/knowledge-base/connecting-batteries-in-parallel/

If you are pondering a battery mod, this is definitely something you want to get straight before you start hooking things up. Study the advice on the forum, but confirm your understanding with your own research!

Sharon_is_SAM

@deuce Two 6 v batteries wired in series is wired + to - as noted in this picture.  With two 6 v batteries, you need a series configuration to provide the necessary 12 v.

deuce

So now will I also need to buy a new trickle charger specific to 6-volt?  I have a Duracell 12-volt Ultra (pictured).

Or, when you have two 6’s “ganged,” can you stil charge and/or maintain with the existing 12?

You guys - @Sharon_is_SAM, @4ncar and @ScottG, @Denny16, @VictoriaP, @TerryHutchinson, @lightningdon arre all so great for us folk still on the steep learning curve.  Thanks so much.

Sharon_is_SAM

I will let someone else chime in, but, once you have your 6 volts wired in series, you effectively have 12 volts and you can use a 12 v charger.  The type of battery and charging requirements are important factors in choosing a charger.  In general, you want a smart charger.  If you are purchasing AGM batteries, be aware that if fully charged, then isolated via the battery switch, they maintain a full charge for many months.  We always use our smart charger to confirm a full charge on our battery before storage.

4ncar

@deuce: as long as you have the batteries ganged in series, a “ normal” 12v auto charger with a deep cycle option will suffice.

pthomas745

I baffled myself with the "charging" and "monitoring" of a battery in series the other day. If I was going to charge with battery clamps or measure the state of charge with a multimeter, where should the clamps or the probes go?

On the picture above, my guess is: the battery terminal on the far left (for positive) and the terminal on the far right (for negative)? 

What would I get if I tried the two middle terminals? 

4ncar

@pthomas745: assuming 2 @ 6  volts. Easiest way to remember is to use the same posts that the trailer terminals are attached to. If you metered the “center two posts,” you will read 6 volts.

TerryHutchinson

If you measured the center two posts, you should see zero volts.  Those posts are tied together directly as part of the series connection and there is no potential across them.

pthomas745

@4ncar @TerryHutchinson thanks for the battery lesson.  There are billions of explanations on the web about wiring up batteries this way, but none about how to monitor/charge with a charger. 

4ncar

TerryHutchinson said:

If you measured the center two posts, you should see zero volts.  Those posts are tied together directly as part of the series connection and there is no potential across them.

Duh! Looking with eyes that see, I stand corrected.

deuce

Last query of day to the “ganging” panel:

about to charge the two BIG GC2s (Interstates from Costco)

They are dated 7/19, so they’ve been on the shelf 15 months.  The fluid is down about an inch+ from the top edge.

Should I fill with distilled to very top before I hook up to the charger?

(You guys - @Sharon_is_SAM, @4ncar and @ScottG, @Denny16, @VictoriaP, @TerryHutchinson, @lightningdon arre all so great for us folk still on the steep learning curve.  Thanks so much)

ScottG

You generally want to cover the plates, but not fill completely to the top. Overfilling can even dilute the electrolyte and reduce battery function.

I'm not sure if there is a rule of thumb with regard to filling. Maybe someone else can chime in.

4ncar

I had always filled to the top of the cavity, not up the round hole. Best I can describe. I’ll try to get a pic but not sure how well it will show...

ScottG

@4ncar, are you referring to the bottom edge of the little "well" that forms each hole? That's generally where I fill to, maybe a little less. 

4ncar

@ScottG: Yes!

ColoradoJon

For adding water to your flooded batteries get yourself one of these if you like to make things easy:

LubriMatic battery filler

ChanW

+1 @ColoradoJon. that's what we used in the maintenance shop I worked in 40 years ago. I'm amazed they still make them! Great tool.