Battery Issues

[Michealbraunste]

Hi All,

I have noticed that the battery on our 19 doesn't have the capacity it used to have. When the sun is hidden the voltage drops more quickly than it used to. Under load, the voltage drops further than it used to. So we'll probably replace the battery next spring. I've read through a bunch of forum posts. I think I will go with an AGM battery so I am planning to order one from trailer parts online given that we are frequently offshore power and sometimes push our battery maybe further than we should. But which one? Have you bought an AGM battery in Canada? Are the Canadian Tire MotoMaster batteries ok? Is there a better alternative that I've missed?

[MrWizard]

every-time somebody says "less capacity"

i can only think, they are thinking of Optima 6 pack spiral wound orbital batteries

those are less weight and less capacity compared to the same group size
of other construction methods

[pnichols]

RJsfishin wrote:
AGM,....more expensive w/ less capacity,....don't know why I would want one.

Rich ... I'm not sure what "less capacity" you are referrring to?

My twin Group 31 12 volt AGMs have 115 AH each, for a total of 230 AH - about the same total capacity as a couple of the common size GC 6 volt liquid acid batteries used in so many RVs. Lifeline even has a Group 31 12V AGM battery model - of about the same cubic inch and form factor size as mine - that are 125 AH each, for a total of 250 AH when used two at a time.

As far as I can see, the only thing "wrong" with quality deep cycle AGM batteries as compared to common GC batteries is the cost of the AGM batteries. Of course those extra dollars are providing set-it-and-forget-it RV battery service.

[beemerphile1]

.

[babock]

RJsfishin wrote:
AGM,....more expensive w/ less capacity,....don't know why I would want one.

Less Maintenance
Lower internal resistance so charges faster and less low voltage problems with high current inverter draw.
Less critical venting issues.

[wa8yxm]

theoldwizard1 wrote:
A pair of 6V golf cart batteries are still the "best bang for the buck". Trojan does make an AGM golf cart battery (T105-AGM) but they are expensive.

The advantages of the GC (Golf Car) batteries are that they are DESIGNED to be run down (as far as 50%) and recharged over and a over and a over again without serious harm.

MARINE/deep cycle and starting batteries need to be kept fuller (75 to 85 percent full) and do not survive as many cycles.

FULL charging is important but as batteries age one symptom is loss of capacity

[mike-s]

Update. It appears that the OP is a sock puppet for a CA retailer of RV parts, abusing a competitor's site.

[MEXICOWANDERER]

Maroon embossed cases for T-105 batteries cost $11.00 in 1988. I can just imagine what they cost today. Rolls jars are embossed as well. For prestige.

Trojan used to market their 2nds in white jars with red lids. 30-years later why not black? They offered distributors a 12-month warranty.

Pull out your crying towel. Distributors were paying $36.00 each for embossed T-105 batteries then.

[mike-s]

Sure, the deeper you discharge a battery, the fewer cycles you get. But if you work the math, drawing deeper for those fewer cycles can cost less compared to adding more batteries.

In CA, you may be able to find Magnacharge batteries. They're a Trojan master distributor, and they sell Trojan "black box" GC2's labeled as their own GC-225s (They're 220 Ah). I picked up a couple in Michigan last spring for USD $100 each. More truthfully, $130 each without cores, but it would have been ~$100 if I had trade-ins.

[BFL13]

Mex you picked the wrong border to live across! (Assuming the Area 51 guys kicked you out of home) 🙂

[MEXICOWANDERER]

And if over discharging the battery saves a hundred or two hundred dollars in lost food screw the battery. Same principle as generator/fuel recharging vs cycle life. A few discharges to 20% or even 10% are not as hard on an AGM as it is on a flooded battery.

I have twice discharged my 2-volt cells to between 5 and 8% remaining capacity. Stalled tropical storms with horizontal rain. The freezers needed to be freezing and 90 degrees with 90% humidity was too much to endure. Six days without public power. Day 7 I would have started the Lombardini 385 amperes. But CFE power came on and remained on so the Trace charged for days on end. It showed up with an added 184 dollars on the power bill -- but still cheaper than diesel. It's a 100 meter walk to the genshed and arriving sopping wet and tangling with high voltage is not exactly wise. 50 mph horizontal rain and raincoats are not good battle contestants. The weather always winds. Ratz I need a pair of new Group 31 batteries for the generators.

[BFL13]

Thanks, Mex. Good info. I was not sure what exactly I have here, but that clears things up.

Just finished a four day off grid and ran it down to 25% SOC. So that's once! (Very unusual to go that low, but needs must.) Now recharging at 14.4 with 75 amper so above the 20% and will leave that till amps fall below 1.5a (0.5 per 100) before going to Float.

More evidence for the OP that all AGMs are not equal.

[MEXICOWANDERER]

This is a 150 lb absorbed glass mat surplus acid battery. 250 amp hours at the 20 amp rate and near normal charging amperage limit.

SERIES 4000
12 HHG 325P
8D BOX
325 amp hours
1069 CCA
1337 MCA
55.2 cm x 33.7 cm x 28.7 cm
90.5 kg 200 lbs.

The above are specs for the lesser of 2 Rolls 8-D flooded batteries.

Standby batteries have lots of acid to ensure that long periods of standby do not leave the plates exposed to stale (laminar) depleted acid. The 1.300 gravity helps.

It is important to remember that Telecom batteries are in the same boat as Golf Car and Scrubber batteries -- intense competition. Only cycle performance standards keep OEM halfway honest.

Think about Concorde's ambiguous specifications

Heavy but not absurdly so
Reasonably high CCA and ampere hours for the weight.
Absurdly high charging current values
Plates that are 160% as thick as the competition

Drift over to the R&S specs.
What do you think?

I definitely would not over-discharge the Chinese AGM on a regular basis. In fact I would tend to recommend not discharging it below 60%SOC and in addition get it back to 100% SOC as quick as possible. Observing the 20% amp hour recharging rule. Once every 30 cycles, discharge to 40% SOC then recharging the Telecom ASAP.

Imagine the duty of a Telecomm

Wait wait wait
Depend on the facility to size the bank according to estimated maximum on - duty cycle events. 1-hour? 3-hours? Coordinated with the entire chain of repeaters. No use in having a three hour duty when down the line a one hour repeater exists.

Once public power has been restored babysit a gentle recharge. An extremely gentle rate would boost cycle life a little but competitors would NYAH NYAH and point out the "excessive' hours "needed" to recharge. This is a cut throat business. After the contract time has expired, finding a 20 cycled battery is preferable to a 200 cycled battery.

[BFL13]

Oh no, three kinds! OK, so whatinheck is this 8D then?

I have this one too, and am using it as though a deep cycle as in "cycle use" in the spec vs its "standby use" ---I just use that "use" for picking the Float voltage. I recharge at 14.4v as in cycle use. No idea of plate thickness etc.

https://cdn.enfsolar.com/Product/pdf/storage_system/5a695a7096504.pdf?_ga=2.226216152.316921982.1542...

[SoundGuy]

Michealbraunstein wrote:
Have you bought an AGM battery in Canada? Are the Canadian Tire MotoMaster batteries ok? Is there a better alternative that I've missed?

I have. Here in Canada there's an RV dealer network called RV Care, last count there were 62 dealers across the country. They sell Traveler's Choice branded batteries which in reality are DEKA "deep cycle" batteries manufactured by East Penn. I bought a Group 31 AGM this past spring, will probably buy a Group 24 next spring for another purpose. That said, it's hard to beat Crappy Tire prices - I just bought a Group 48 AGM starting battery for my Silverado from Crappy Tire for just $219 + tax Cdn when I discovered the original flooded AC Delco from my local GM dealer was going to be closer to $400 Cdn. Hard to beat Crappy Tire for some things.