Charging 2 6V's with 12V Charger

[MTnestRobin]

After months of reading through this forum and weeks of waffling on 12V vs 6V, I finally went out and bought two 6V Energizers Golf Cart batteries today. Their ability to be discharged deeper and for more cycles is what tipped the balance for me.

I also picked up a Vector 1095APOB battery charger Vector 2/10/25 Amp Smart Battery Charger . Could someone please spare me more searching through the threads and tell me if this can be used to charge two golf carts in series or do I have to go back and get one for just 6V's. The clerk said it would even though it says for all 12V lead acid battery types. I'm not too inclined to trust all these clerks anymore as I had one tell me to stay away from the golf carts because they weren't deep cycle... Yikes, it is my understanding that they are "true" deep cycle batteries!

Also as a point of interest, my GlobeTrotter has dual electrical systems, completely independent of each other, so I don't need a converter which is why I only picked up a charger.

[Mexray]

Hi, I've been in the battery biz for years....you've made a good choice. The 6 volt 'golf cart' batteries are great for RV's, boats, remote cabins, etc. They are typically rated at 225 amp hrs and can provide additional hours of 'battery power' when compared to group 24, 12 volts (rated at 90 amp hrs x 2 = 180 AH total).

Yes, you should charge your two 6 volts hooked in series with a 12 volt charger. This will allow for even charging of all the cells. Keep all your battery connections clean and tight. I usually coat the terminals with heavy grease or petroleum jelly to keep the corrosion from gaining a foothold.

One proviso...there's no free lunch when it comes to recharging your battery bank...all the 'amp hours' that you use, must be replaced again to get the batteries back to a full charge state. If your 6 volts are 1/2 discharged, you'll have to pump back about 110 amp hours back...with your 25 amp charger that's probably about 6 hours, allowing for reduction in charge rate as the batteries approach 90 % charge or so...maybe even more depending on the type of charger you have!

If you allow your batteries to run even lower...you'll need to allow additional time to return to full charge. If you are boondocking, and don't keep up your 'recharge' schedule, you'll eventually run your batteries so low that it will take lots and lots of time to get back to 'normal', as it were.

And yes, 6 volt golf cart batteries are truly 'deep cycle' type batteries...just think about it, golf carts run all day long, then recharge each night to be ready to run again the next day...now thats what I call 'deep cycle' battery service! They operate this way for several years, depending on the terrain of the course...rugged stuff, indeed. That's what makes this type of battery great for we RV types....

[Campaz]

Great advice from Mexray. The only thing to add would be to check your electrolite level often, it's easy and only takes a few minutes if that. Use only distilled water, it's available at most grocery stores.

[Jim Foster]

I used 6v golf cart batteries (Trojan) on my houseboat (four,two in series, the two pair in parallel) for 27 years, and now in my Airstream (one pair in series).

The above advice is all right on. I truly think you have the "most bang for your buck".

[ROBERTSUNRUS]

Hi, basically two six volt batteries, in series, is a twelve volt battery in two cases. Or take the caps off; the six volt battery has three cells and the twelve volt battery has six cells. [two six volt batteries have six cells, two volts each] 12 volt charger, Yes.

[Kajtek1]

I would only add, that high quality charger pays for itself on the long run.
I have 4 batteries bank in my 24 V coach and use 3-stage charger build into inverter for recharging. In 5 years I had to add water only once and once I added because I pulled the batteries out for other reason. Some members report that with build in converter they have to add water every month.

[Over59]

I also believe that higher amp three way automatic converters are worth the money to keep deep batteries happy. It's what I use with my 6 volt marine batteries.
Don't forget to insult a 100amp fuse. I have on one each leg.

[doorgunner]

I have 2 golf carts at the airport, one has a bunch of trojan batteries and a 36 volt charger. Affectionately called the condom express.

[MTnestRobin]

Thanks everyone for the help!!! My husband and I have no experience with trailers of any kind so we feel like we are wading through murky water trying to get this up and going. The forum has been much appreciated.

One more thing if I may...I assume there is no trick to hooking the charger up on this set up?? I have a good drawing for wiring the 6v's in series, but am not sure if there is a difference in hooking the charger to a 6v setup as opposed to the 12v?

Over59, not sure what you mean by this- Don't forget to insult a 100amp fuse. I have on one each leg.

[bryanl]

Their ability to be discharged deeper and for more cycles is what tipped the balance for me.

I'd like to find some hard data on this

So far I have found no battery for typical RV use that will handle deep cycling (down to 80% SoC) on a regular basis without severe life degradation.

So far I have found no definition of "golf cart battery" that I can apply to any spec sheet or battery specification (other than maybe case size) to determine if a battery is or isn't one.

So far I have not found any data that indicates a 6v battery lasts longer, has greater capacity, or has a greater expected life than a comparable 12v battery.

Does anyone measure these things or do they just accept what seems to be common myths despite spec sheets and actual experience properly measured?

[Kajtek1]

In the past I've been buying 12V deep cycle batteries at Costco. They had 2 years warranties and usually died in 2 years and 2 months.
I bought Sam's (cheap) golf-sized batteries 5 years ago and still live happily with them.

[Mexray]

'Golf Cart' batteries are usually shown as a #GC2 in most mfg's spec sheets.

Typical lead-acid deep cycle offered to the RV trade are not designed to sustain large discharges every cycle...it's a cost thing! Most Mfg's suggest a 50% discharge usage to get optimal life. If you want batteries that will perform to 80% cycles, you'll have to spend LOTS more money for low production type, specialized applications.

There is no equivalent common single 12 volt battery with the same rating as a pair of 6 volt golf cart batteries. Deep Cycle batteries are rated in Amp Hours at a 20 hour discharge rate...these ratings are used so we can compare batteries, or battery systems. Divide the AH rate by 20 to get the optimum Amperage discharge rate per hour till the battery drops to about 1.75 volts per cell (10.5 volts in a 12 volt battery).

It's really simple, the more AH's in your battery system, the longer you can run your stuff! If you can design your system so that you only have to use 50% of it's capacity, you should enjoy the longest ultimate life of the system.

Most GC2 batteries are rated at 225 AH's these days. When you hook a pair in SERIES, you double the voltage to 12 volts, and the AH rating remains the same 225 AH's.

Conversely, when you hook a pair of similar 12 volt batteries in PARALLEL, the voltage remains at 12 volts, and the AH capacity doubles.

Ultimate 'life' of any lead-acid battery depends on how well the user takes care of it...keeping it fully charged, cells watered, connections cleaned of corrosion, etc. 'Life' of 6 volts versus 12 volt types will be similar...

The internal construction is some what similar, however the GC2 6 volt Deep cycle's use a rubber separator between plates that do a better job of keeping the grids in place. The grids are of a greater thickness also. Batteries used in a golf cart, bouncing around the fairways need to be vibration resistant. GC2's rarely fail due to plates shorting against each other because of the special separator...so, in effect, the GC2's might have a longer service life, other things being equal.

There are exceptions in the market place, and there are mfg's that specialize if 'heavier' construction for special uses, with much higher costs...but we are talking about batteries generally available to we RV'ers.

I like the GC2's for RV, boat and small rural solar uses...you usually get the most AH's for the money, and they are readily available.

[markdoane]

My Sam's Club has the 6V-220ah golf cart batteries on sale for $66.
I wish I had a pair.

[TomW]

Originally Posted by markdoane

... I wish I had a pair.

Father's Day is coming up...

Tom

[lewster]

Originally Posted by markdoane

My Sam's Club has the 6V-220ah golf cart batteries on sale for $66.
I wish I had a pair.

$66 At that price, they are almost disposable!!! The 4/0 cabling in my van's solar charging and inverter system cost more than that.

[rogerdodger]

Where are you placing the golf cart batteries? My AS has two battery doors, but it appears golf cart batteries are too large for the space??
Roger

[bryanl]

It's really simple, the more AH's in your battery system, the longer you can run your stuff!

use watt hours!

Lead acid batteries for RV's have about 22 watt hours per pound. The differences involve the cost, durability, and capacity trade-offs - not voltage or case size or whatever.

They had 2 years warranties and usually died in 2 years and 2 months.

This is an example of the kind of misleading anecdotal 'data' that often rides on an emotional fixation. I just replaced a 6 year old Exide in my B-Van and I have Costco 12v gr 27's that are starting their 4th year. I have also seen Trojan T 105's that didn't survive one season. -- Doesn't fit the 'just over warranty' implication and probably worth just as much.

The fact is that any of these lead acid batteries should last 4 - 7 years. If you don't get that kind of life from them you need to look at how you use and maintain them.

Again, the data (e.g. the Az Wind Sun FAQ) does not discriminate life expectancy as per the conventional wisdom you often see here.

Ultimate 'life' of any lead-acid battery depends on how well the user takes care of it...keeping it fully charged, cells watered, connections cleaned of corrosion, etc.
...
The internal construction is some what similar, however ...

I'd be very careful about generalities - consider the T105 vs T145 as compared to the SCS series. The fact is that the differences are more of degree rather than kind and the size or voltage is not the issue. If you look you will find that you can cover the range for any particular size or voltage. Capacity, cost, durability - choose any 2.

it appears golf cart batteries are too large for the space??

get the biggest batteries that will fit that are intended for RV service from a reputable retailer - don't fuss over irrelevancies such as the golf cart myths. Your Airstream isn't a golf cart.

[MTnestRobin]

Originally Posted by rogerdodger

Where are you placing the golf cart batteries? My AS has two battery doors, but it appears golf cart batteries are too large for the space??
Roger

Hi Roger,

We got tired of looking for a battery and box that would fit on the hitch, so we decided to get what we want and put them in the truck. We then found a heavy duty tote (vented) with hinged lid that would hold both. If we want to use the truck we just take them out and put them under the front of the trailer. Not very fancy, but it works for us!

[rogerdodger]

Another good idea.
Thanks,

[zapper]

Originally Posted by Mexray

'Golf Cart' batteries are usually shown as a #GC2 in most mfg's spec sheets.

Typical lead-acid deep cycle offered to the RV trade are not designed to sustain large discharges every cycle...it's a cost thing! Most Mfg's suggest a 50% discharge usage to get optimal life. If you want batteries that will perform to 80% cycles, you'll have to spend LOTS more money for low production type, specialized applications.

There is no equivalent common single 12 volt battery with the same rating as a pair of 6 volt golf cart batteries. Deep Cycle batteries are rated in Amp Hours at a 20 hour discharge rate...these ratings are used so we can compare batteries, or battery systems. Divide the AH rate by 20 to get the optimum Amperage discharge rate per hour till the battery drops to about 1.75 volts per cell (10.5 volts in a 12 volt battery).

It's really simple, the more AH's in your battery system, the longer you can run your stuff! If you can design your system so that you only have to use 50% of it's capacity, you should enjoy the longest ultimate life of the system.

Most GC2 batteries are rated at 225 AH's these days. When you hook a pair in SERIES, you double the voltage to 12 volts, and the AH rating remains the same 225 AH's.

Conversely, when you hook a pair of similar 12 volt batteries in PARALLEL, the voltage remains at 12 volts, and the AH capacity doubles.

Ultimate 'life' of any lead-acid battery depends on how well the user takes care of it...keeping it fully charged, cells watered, connections cleaned of corrosion, etc. 'Life' of 6 volts versus 12 volt types will be similar...

The internal construction is some what similar, however the GC2 6 volt Deep cycle's use a rubber separator between plates that do a better job of keeping the grids in place. The grids are of a greater thickness also. Batteries used in a golf cart, bouncing around the fairways need to be vibration resistant. GC2's rarely fail due to plates shorting against each other because of the special separator...so, in effect, the GC2's might have a longer service life, other things being equal.

There are exceptions in the market place, and there are mfg's that specialize if 'heavier' construction for special uses, with much higher costs...but we are talking about batteries generally available to we RV'ers.

I like the GC2's for RV, boat and small rural solar uses...you usually get the most AH's for the money, and they are readily available.

I noted that my battery box on my 2017 AS is much deeper than my 2007. Can I assume that GC2's will fit the 2017 w/o modifying the battery box?