12v to 6v house battery conversion

[Scuster1]

I want to change out my 12v house batteries to 6v golf cart batteries. Other than wiring these correctly in series, are there any modifications needed to the charging system for these batteries?

[wb7auk]

The short answer is no

[rdrv831]

Only change would if you will be using AGM or Gel type 6v batteries. The charger would need to have the setting for AGM/Gel enabled. If the type is wet cell then no changes needed. you might consider making the cables thicker.

[wa8yxm]

The long answer: You now have a bank of 12 volt batteries

When you convert.. You will have a bank of 12 volt batt-eries

That is each pair of six volt, make a 12 volt when properly connected.

Treat each pair of sixes exactly as you would a single 12.

[bamaboy473]

for those of us that follow threads just to gain knowledge, what benefit is served by going from 12V to 6V?

6V golf cart batteries weigh a ton, so they must be even stouter than deep cycle marine batteries.

I'm thinking that our house batteries ought to be deep cycle instead of starting batteries, so is the conversion just ramping up that concept to the max...or something else?

[terry735001]

if you are taking out 2 12v to install 2 6v you are only adding around 20 amp hrs

keeping both 6v at 6vs with out one going high and one going low on charging

well just say you have to keep a very good eye on it

some of the hard core guys love them

i have lived off gird solar for many years and tested many setups

my self i would stay with the 12v battery's

[bamaboy473]

Let's say that we have 4 12V house batteries and want to maximize our inverter's potential. Are we better:

a. keeping normal 12V batteries, because they're more than adequate?
b. changing to 4 12V Deep Cycle batteries, or
c. changing to 4 6V golf cart batteries (Heavy Duty deep cycle)

[Journey39n]

Important things, what is your use, lots of boondocking, or occasional use?

If you already own good 12v batteries, and they work, I would say stay with them, for now.

But in an RV, for the coach, deep cycle is the type you want.

In normal lead/acid batteries, the important thing is how much lead and acid is present. For the dollars spent, golf cart batteries give the most bang for the buck.

You can buy, very expensive 12v deep cycle batteries that will work very well. Some have high amp/hour ratings.

Keep in mind, 6v Golf Cart batteries would, be say 220ah each, when hooked in series, you get 12v, but still 220ah. With 2 pair hooked in parallel, you get 440ah, which will run a coach for a long time. And they are really designed for heavy draining and recharging on a long term basis, great for fulltimers.

With 12v batteries, the amp/hours can be from 130 to perhaps 300ah each, depending upon the size and price. Say you hook 4 in parallel, then you get 4 x 150ah = 600ah. Really great, but probably twice the price of the 6v batteries.

So like most things, you get what you pay for.

In your case, I would say, stay with the 4 batteries you have, but when it comes time for replacement, consider deep cycle ones, either 6 or 12v depending upon the space and dollars you have.

(personally, I had two 130ah 12v, and replaced them with 4 6v 220ah Costco Golf Cart batteries, a huge difference.)

[UMEKiki]

Originally Posted by Journey39n

Important things, what is your use, lots of boondocking, or occasional use?

If you already own good 12v batteries, and they work, I would say stay with them, for now.

But in an RV, for the coach, deep cycle is the type you want.

In normal lead/acid batteries, the important thing is how much lead and acid is present. For the dollars spent, golf cart batteries give the most bang for the buck.

You can buy, very expensive 12v deep cycle batteries that will work very well. Some have high amp/hour ratings.

Keep in mind, 6v Golf Cart batteries would, be say 220ah each, when hooked in series, you get 12v, but still 220ah. With 2 pair hooked in parallel, you get 440ah, which will run a coach for a long time. And they are really designed for heavy draining and recharging on a long term basis, great for fulltimers.

With 12v batteries, the amp/hours can be from 130 to perhaps 300ah each, depending upon the size and price. Say you hook 4 in parallel, then you get 4 x 150ah = 600ah. Really great, but probably twice the price of the 6v batteries.

So like most things, you get what you pay for.

In your case, I would say, stay with the 4 batteries you have, but when it comes time for replacement, consider deep cycle ones, either 6 or 12v depending upon the space and dollars you have.

(personally, I had two 130ah 12v, and replaced them with 4 6v 220ah Costco Golf Cart batteries, a huge difference.)

Go with the 6v.
My 2 6v give more ah vs. 2 12v by ah. Cost less. $300 for 2x 12v - $268 for 6v. 180 vs. 225.

[chboone]

The main point is if you stay with 12 V make sure they are true deep cycle. Most times people buy Marine/RV deep cycle 12 V batteries thinking they are true deep cycle. Those are not true deep cycle batteries, they are basically a starting battery that wants to be a true deep cycle battery. The Marine/RV deep cycle battery will not last more then a couple of years when used in place of a true deep cycle battery. Most people go with the Marine/RV battery because of cost and not knowing the difference between the two.

Chuck

[1ciderdog]

Originally Posted by Scuster1

I want to change out my 12v house batteries to 6v golf cart batteries. Other than wiring these correctly in series, are there any modifications needed to the charging system for these batteries?

Be sure to measure the height of your battery compartment. Six volts batteries (at least the ones I bought) are a couple of inches taller than 12 volt batteries. Keep in mind you need space to be able to add water to them - my battery tray does extend out but not to the point for easy access to the batteries at the rear side of the tray.

[Gocoffeer]

It is a worthy project and I have performed this to my rig. The golf cart battery has some macho plating and can handle the charge loads that the RV can offer to it. I was not getting a decent life out of a similar type set of 12v batteries at the same cost. I will add that not all charge systems offer multi-staged charging. I added solar charging and looked at the 3 stage chargers....they can make a huge difference.

[pyoots]

The simple rule for me when making a decision is battery lifetime which equates to $$$$. I just replaced 2 12v Interstates for 2 deep cycle 6v. The warranty deadline on the Interstates were: Guess What, you guessed it: August, 2014 or 36 months.

RV Club members have stated that their 6v deepcycle batteries are going on 7-8 years without replacement. More than double what I'm getting out of 12v.

Let's do the math: $120 per 12v battery for 36 months OR $159 per deep cycle battery for 72 -84 months.

I 'll pay a little more up front to save$$$$$$$$$$$$$ over the long haul.

Just my opinion, I could be wrong.

Phil

[tbethurum]

Have 3-12 Volt Trojans just waiting to go to 4 -6 volt will almost triple my amp hrs. will need to alter my battery tray and yes the height is an issue, the 4-6 volt are cheaper than the 3-12 volts.

[DonKarstedt]

chboone is right, if the battery has "marine" in the name, avoid it. It's not a real deep cycle.

--DonK

[TonyDi]

THe short answer is: you don't need to make any modifications.

[Scuster1]

I made the change. No modifications were necessary. I have substantially more capacity with 2 6v Golf cart batteries than I did with the 2 12v stock deep cycles. Success. Wish I had room for 2 more.

[DonKarstedt]

I've come to the same conclusion. My original 2 twelve volters gave me a nominal 170 amp hours. The two 6 volters give me 230 amp hours. I'm going to redesign my battery compartment for 2 more, for a whopping 460 amp hours total. I still can't find any AGMs in the Northwest, so I'm going to put up with flooded cell this time around.

--DonK

[sknight]

I have a question. I keep reading that two 6V in series doesn't multiply the ah, just the volts.

How is this?

A battery is actually a series of batteries. 2.1V per cell that provides 77ah each in the case of my ACDelco 6V 230ah golf cart batteries. They're connected negative to positive within the case so all together they produce 6.3V and I hope at least, 230ah as measured at a five amp draw.

So to make 12V we connect positive of battery A to negative of battery B, just like is done within the case of the individual batteries.

At the end we now have 12.65V, but reportedly no more amp hours?

Trojan claims this to be true. Many people on the net claim this to be true.

Yet I can't find anything explaining how this can be. That middle cable tying + to - is functionally no different than the bar tying the cells together internally.

Plus an 8D from Lifeline is 12V, 255ah. It's the same length as two 6V batteries though. I'm wagering that the internal structure is very similar to our 6V batteries.

This winter when I bring my batteries in out of the cold I'm wanting to try loading them. I have a headlight bulb I use to load test circuits (Crude, but effective.) that consumes 5A at 12V. I'm going to place that bulb on there and see how long it takes to reach 12.00V which is 50% discharged. I've got a hunch that it will actually be greater than 230ah.

Can anyone explain to me how this halving of available ah happens? Between it not seeming logical to me plus the reports of people experiencing far greater practical capacity I'm thinking that there's something getting lost in translation.

[nothermark]

What you are dealing with is the wattage that can be stored in the chemical reaction of each cell. For a 230 AH battery each cell has to be able to produce 230 AH at the cell voltage of ~2V. The only difference between a 6 V and 12 V battery is the number of cells in the box. If one wants to increase the power storage one increases the amount of lead. That can be bigger cells or more cells in parallel. If one wants to increase voltage one adds more cells in series to get more volts. That has nothing to do with the fact that each cell stores a given amount of power in the chemical changes in the cell.

What will change is the way the chemical reaction that releases power proceeds. Low load currents will extract more power than high load currents. If you want to know why ask a chemist or try this:

http://www.av8n.com/physics/lead-acid.htm

The nature of the reaction is part of why low current long cycle deep cycle storage batteries are made differently than large current short duration starting batteries.

If you need a different analogy think of it as a chain. Each cell is a link.