Duracell GC12 Deep Cycle 12V Battery at Sam's Club

Al F · October 31, 2017

I was in Sam's club today and noticed a 155AH Deep Cycle 12V battery, Duracell GC12 for $200 ($199.99) Weight is ~90 pounds each.

I don't recall seeing this battery mentioned before. The dimensions are a little larger than the CG2 6V battery at 12.9"L x 6.9"W x 10"H (10.8"H including terminals).

This could be a choice for someone who has room for 3 batteries a little larger than the CG2 batteries but not enough room for 4 golf cart batteries.

I also saw on Amazon a package of 4 Trojan GC12 AGM batteries for $1400 ($1399.99) with free shipping. Price for each would be $350.

4 of these batteries would give you 620AH of battery.

Yarome · October 31, 2017

I went to Amazon to take a look at the GC12's and didn't see them. Might have already been sold, but just a point of correction (regardless of how they might have been advertised) GC12's are 140's so 4 would getcha 560ah vs. 620.

Wait a sec... I think I found what you might have been looking at. 4x VMaxx GC12's for $1399 advertising in the listing title as a Trojan T1275 replacement. That makes more sense. The VMaxx rate theirs at 155ah, but you could pick up some full river 150's for less... and would be much preferrable to a VMax, IMHO.

Of course.. we're talking 12v boxes here for those that don't have the storage dimensions to take 6'ers.

oldjohnt · November 1, 2017

Yarome, on a recent RV I used the 6 volt Good Sam I believe they were the EGC2 ??? batteries (more AH then regular GC as I recall) but they didn't perform quite as well as my current Trojan T-105's, although sure the Sam's cost less. If and when my four Trojans crap out (hoping 7 to 9 yrs the way I maintain and keep smart charged 70% to 100% SOC and equalized etc) I may go with Fullriver AGM. You just don't see many true deep cycle 12 volt batteries around like the 6 volt golf cart true deep cycle units. As you well know, I'm NOT talking about the Walmart so called RV/Marine 12 volt batteries I consider to be semi or quasi deep cycle at the best, but sure they still "work" for a casual user who doesn't want to spend as much and doesn't dry camp as much as I..........

John T Live dry camped (as have been the last 3 weeks, no need for shore power) from Escapees Rainbow Park in Livingston, Texas.

17 hours ago, Al F said:

This could be a choice for someone who has room for 3 batteries a little larger than the CG2 batteries but not enough room for 4 golf cart batteries

Good point Al, if 3 is all you have room for that can sure suffice...

John T

Sehc · November 1, 2017

I am using EGC2 Duracell batteries. Six set as 12 volt, 690 ah. Not a bit of trouble for three years now.

Yarome · November 1, 2017

10 hours ago, oldjohnt said:

Yarome, on a recent RV I used the 6 volt Good Sam I believe they were the EGC2 ???

John, sure. EGC2's. You can pick up another 15ah per set over GC2's if you're squeezing AH's, but everything comes at some kind of potential cost. The EGC2's have a bit longer plates than a GC2's so there is always the question about slough off. The EGC2's have less room in the bottom for build-up so, theoretically, they may be more prone to internal shorts. I have no idea if that theory holds water or not during the course of their typical lifespan. Never paid enough attention and I don't have any practical experience comparing the two, but the argument seems logical... especially the way our houses DO bounce. I dunna know nuthin fer sher'unough to make an edgiacated say so or not, tho.

Personally, I would stay with their GC2's if I were buying in that class. That's just me. My energy needs are low so when weighing a 3.5% (available) bump of juice, that I don't especially need, against the theroretical increased margin of risk of an internal short... I would opt for battery bank stability/longevity.

Just "babbling" in my own mind... it goes to dark places sometimes. If I'm looking at an internal short... which, if it happens, WON'T happen until at least 2 years into a 5-7 year bb, WILL happen 2 days into a 14 day stay, I'll only have 2gal of fuel for the genny, I'll be 50 miles from nowhere and 200 miles from the nearest Sam's/Costco. The second one won't short until year 4. :lol:

As for you, specifically, knowing your gear/settings, energy requirements, lifecycle usage, rough maintanence schedule... providing you're not pushing heavy amps in/out at extreme temperatures on a regular basis... 7-9 on a 105 bank is rather conservative. It never hurts to budget for a future bank on a conservative lifespan figure, but for practical purposes, I would consider 7 years (again, in your specific case) to be a pre-mature death. You'll likely be more in the 10-11 year range before you might start thinking about a new bank. You could sustain your current level of usage WELL beyond that, though.

Your heaviest load is what? Your nuker for a minute or 2 at a time on rare occassions? All things given... if your bb was batting around 65-70% @ year 13 I wouldn't be the least bit suprised.

Aside from keeping track of your in/out AH's a good "practical" indicator is the 10/15 rule. Meaning... your weekly consumption averages remaining fairly constant... once your SOC averages are landing you 10-15% below where you where landing when your bb was "fresh"... it's about that time to start shopping around. You're in no immediate rush, but it's time to start seeing what's what on the market and planning ahead.

I don't know how often you swap rigs, but it might be likely that your current rig might go before your battery bank does. Who knows what battery options will be available even 5 years from now?

Al F · November 1, 2017

On 10/31/2017 at 1:42 PM, Yarome said:

Deleted reply

oldjohnt · November 2, 2017

Yarome, thanks for the chat and tips, I was being conservative when I hoped for only 7 yrs life out of my four Trojans. However, my dry camping overnight loads increased a month ago when I started running a CPAP all night in addition to my extra dorm sized 120 VAC fridge 24/7 and when colder the forced air furnace has to run some at night, so with 450 battery Amp Hours I may have to dip down below the 60% to 70% I prefer overnight which may shorten battery life expectancy grrrrrrrrrrrrrrrrrrrr. Still, if in good sunshine running 715 solar watts I sometimes achieve 100% SOC by early to mid morning, but if its seriously rainy all day it may or may not just make it by 2 PM. However, my ace in the hole is to run the 4 KW Genset and my 80 amp charger maybe 30 minutes in the AM for coffee and the wife's hairdryer and maybe 20 minutes before bedtime in which case I can still get near 100% anytime I deem it necessary.

John T Sold the farm so full time for a while, been dry camped near 3 weeks including now at Escapees in Livingston Texas

Yarome · November 2, 2017

1 hour ago, oldjohnt said:

...dry camped near 3 weeks including now at Escapees in Livingston Texas

FUN t'aint it!

John, well.. you bought batteries to be used so... USE EM! There's no rule book saying you have to top off your bb every day and it's good for them to get a little exercise every now and again. Running your 4k is burning a lot more fuel than you need to push your 80amp. Even a full bore bulk will run you what(?)... 850 watts off your genny... for how long? (rhetorical) As long as you're not waking up below 50 there's no harm nor foul hitting the rack @ 85-90 (or whatever golden number keeps you where you want to be in the morning).

Once you get your stove-top dripper that will be one additional load you won't have to worry about.

Maximizing efficiency and longevity are great, but just to keep things in the proper perspective... considering a 7 year lifespan your 450ah battery bank cells are costing you right about $6/mnth or $.20/day. It doesn't always make sense to blow a buck on you're genny to save pennies on your bb if you don't have to.

As long as hitting 50% SOC is an occassional thing and you're reaching a good solid 100% every 4-5 days you're still in good shape. Balance in all things and don't sweat the two-bits.

Hindsight being what it is (a CPAP and mini fridge), you might have gone with another 225ah to "cushion" some of the poor weather and/or furnace days.. you've got the solar and charger capacity for it... but it is what it is. It's not as if it's going to create any hardships.

If anything... and if your CPAP is of the 12v or convertable variety... a single dedicated battery might be something that's workable to lighten the draw off your main bb. It would likely be sustainable off your excess solar production or... if your gensets going to be running anyway... a small secondary charger running at the same time would be simple enough. A battery sized to run your CPAP 2 to 3 days between charge cycles...

Might be something to consider if maintaining the SOC levels you want on your main bb starts getting more work than it's worth.