Recommended battery brand and group size

[jwalt313]

We have a 21FBRS TT and will be replacing our single 6V battery with 2-6V golf cart batteries as we are planning to do long periods of state and national park camping now that we are retired. We are experienced with conserving electricity, water, waste, etc for short periods of time, but we can now extend our trips to a month or more. We are also planning to get a 2200 Honda or Yamaha generator to recharge the batteries. No current plans to use the generator for AC so I believe that we will not need the companion generator as of now. We are trying to decide on which battery brand and group size to get. Any recommendations? COSTCO sells Interstate batteries at a good price but I do not know anything about them. Trojans are over our budget but we don't mind paying more for a brand that is much better than others. Any recommendations would be greatly appreciated.

[pgandw]

Costco sells the Interstate GC-2 6V battery - I think that's the only size of golf cart battery they sell. Here in Colorado Springs, Costco sells GC-2s by the dozens - for both RVs and golf carts - so they are always fresh. Very similar in size to a Group 24 12V, but about 3/4" taller. $95 + $15 core charge.

I used them in my previous A-frame, and liked them so well I told the dealer to keep his Group 27 battery on my new A-frame (he gave me a $110 credit for not taking his battery). Went to Costco and bought 2 more Interstate GC-2s.

Fred W
2019 Flagstaff T21TBHW A-frame
2008 Hyundai Entourage minivan

[spock123]

I like Trojans

[dward51]

Originally Posted by jwalt313

We are also planning to get a 2200 Honda or Yamaha generator to recharge the batteries.

Just remember that although the Honda and Yamaha have a "12v battery charging cable" available, it is going to charge at a much lower amp rate than your converter/charger will. Just run the converter on the 120v side of the generator for the fastest charge.

[ppine]

For boondocking it is very worthwhile to purchase an AGM battery because you can generate more amp/hours and drawdown the battery to 50% without hurting it. Lithium is even better but expensive.

[babock]

Originally Posted by ppine

For boondocking it is very worthwhile to purchase an AGM battery because you can generate more amp/hours and drawdown the battery to 50% without hurting it. Lithium is even better but expensive.

The advantages of AGM is that they can charge faster than FLA which means shorter generator run time. For the same reason they charge faster, they also have less voltage sag when running a large inverter which means they don't hit low voltage cuttoff as easy. No water to add especially useful if batteries are hard to get at. Less self discharge. They still have the same characteristics as FLA which means the further you draw them down, the more capacity they lose and they still can suffer from sulfation when left at lower than 100% charged.

Personally, I would always pick an AGM over a FLA. To me, well worth the extra cost.

[NJKris]

I got the Deka golf cart batts, FLA (flooded lead acid). These are also fine to draw down to 50% without damaging them. Going to cost you about 300 bucks for the pair of them. https://www.lowes.com/pd/Deka-6-Volt...ttery/50183775 Many batteries are made by the same company and labelled for different sellers. Deka is made by East Penn battery company.

[bob213]

Deka (East Penn Mfg.)Duracell at Sam's Club and Batteries Plus all the same. Hard to beat price at Sam's or Batteries Plus.
Dekas at Lowes are not 448AH. They are 230 just like Sam's Club.
Sam's Club $89. Batteries Plus $119.

[NJKris]

That is correct about the error in the Lowes ad, it is supposed to be 230 AH. I got ripped! Even with my military discount I paid 130 each before the core charge and tax.

They closed my friggin' Sam's Club, and now the Batteries Plus (the one near me)is out of business. Thanks for heads up on the better pricing though.

[ppine]

If you want wet lead acid batteries to last you can only use 5% of their capacity. AGM will last much longer if they are not drawn down past 50%.

wla golf cart batteries have much greater amp hours than a lot of comparable 12v batteries, but since they are only 6 volts that produce half the watts.

100 amp/hr 12v produces 1200 watts total.
200 amp/hr 6 v produces 1200 watts total. Only the first 5% is available for long term use.

[babock]

Originally Posted by ppine

If you want wet lead acid batteries to last you can only use 5% of their capacity. AGM will last much longer if they are not drawn down past 50%.

wla golf cart batteries have much greater amp hours than a lot of comparable 12v batteries, but since they are only 6 volts that produce half the watts.

100 amp/hr 12v produces 1200 watts total.
200 amp/hr 6 v produces 1200 watts total. Only the first 5% is available for long term use.

There are 12v golf cart batteries too. They are the same construction as the 6v versions and share the same specs for depth of discharge vs capacity.

[NJKris]

If you want wet lead acid batteries to last you can only use 5% of their capacity

That can't be practical. If not using at least 5% or more, why bother having a battery? I know the shallower the discharge, the more charge cycles you will have, but only using 5% is insane.

[formerFR]

OP: I suppose you mean you are changing out your single 12v battery with two 6v deep-charge golf cart type batteries....


unless you are off-grid often, or are planning on being unplugged at campgrounds, I wouldn't worry with changing anything - your current battery is probably already sufficient. FLA(flooded lead acid) type batteries are just fine for your needs.

if you are, then two 6v deep-charge golf cart batteries are just fine, run in 'series'(postive of one to the negative of the other), will do you just fine, with a little more time 'off-grid' versus a single 12 volt battery. Name brand? I wouldn't worry about the name brand or 'type' - your local auto parts store, golf cart or boat/rv store, or 'batteries and bulbs' store will easily have what you need, at probably $100 to $125 each for FLA(flooded lead acid).

[boondocking]

If you want wet lead acid batteries to last you can only use 5% of their capacity...

Originally Posted by NJKris

That can't be practical. If not using at least 5% or more, why bother having a battery? I know the shallower the discharge, the more charge cycles you will have, but only using 5% is insane.

If that were the case my almost 7 year old batteries should have been toast several years ago.
Someone has been terribly misinformed about the 5% discharge.

[5picker]

Originally Posted by boondocking

If that were the case my almost 7 year old batteries should have been toast several years ago.
Someone has been terribly misinformed about the 5% discharge.

My experience too.

I've been discharging lead acid batteries for years in various trailers (camping, dump, cattle, horse, utility) to well beyond 5% of discharge and often in my dump trailers to well below being able to run the pump motor before charging and I regularly get 5-6 years out of a battery no matter the application.

[pgandw]

Originally Posted by ppine

If you want wet lead acid batteries to last you can only use 5% of their capacity. AGM will last much longer if they are not drawn down past 50%.

wla golf cart batteries have much greater amp hours than a lot of comparable 12v batteries, but since they are only 6 volts that produce half the watts.

100 amp/hr 12v produces 1200 watts total.
200 amp/hr 6 v produces 1200 watts total. Only the first 5% is available for long term use.

The 5% is crap. 50% SOC is generally considered the optimum trade-off between battery life and capacity for deep cycle flooded lead acid batteries. See the manufacturers charts for number of cycles vs SOC. For GC-2 batteries, the 50% line is generally at 800-1000 cycles. Which equates to many years of service in an RV.

AGM can go down to about 40% before the number of cycles starts dropping rapidly. And can be recharged at a slightly faster rate.

Many of us don't like to get down to 50% SOC because the time to get a battery back to 100% is at least 6 hours - and that's with the most optimum charging schedule. A properly functioning WFCO converter will typically take double that time to recharge to 100%, PD converters are around 7-8 hours. However, recharging is non-linear. It takes at least as much time to get from 90% to 100% as it did to get from 50% to 90%.

Fred W
2019 Flagstaff T21TBHW A-frame with dual Costco/Interstate GC-2 batteries, PD 4135 converter.

[ppine]

Thanks for the information.
I mentioned what I have read in the popular book everyone thinks is so great by Prowse.
Good news that people are being successful with wla batteries.

[BigH]

I don't know if this pertains to gentle RV use but we've abused every deep cycle mentioned on this thread (and more) at my work over the last 20 years in all kinds of equipment. Nothing compares to Trojan. They will outlast everything else by a margin that makes them the most economical.

If I'm buying a Deep cycle for home use...its a Trojan priced be damned.

[ppine]

I have two batteries in my diesel truck, two in the boat and two in the Rv, plus one in a car and one in a tractor. That is a lot of batteries and I have had good success with them, sometimes lasting up to 8 years or more. But using them in an RV is different.

Thanks for helping to sort out the real world practical experience from the hype and folklore.