Bang, Buck, Batteries

Or my situation. Damned near everything has a lifetime warranty whether I like it or not. Actually zero warranty once this stuff goes south of the Rio Grande.

For 385 dollars, San Diego Battery has the 2-story group 31 Lifeline, and comparing that to 269 dollars for a FullRiver group 27 is self-explanatory.

But care must be taken in establishing a -value- for batteries. A thick plate is only valuable when thick plates would make a difference. A weekend warrior or power pedestal princess would need thick plates about as much as a grocery hauler would need 500 horsepower. Even .040" plates would last a casual weekender several years. But for serious boondocking (serious means heavy heavy use) the .040" plates would die at a young age.

The following needs to be said again regarding my personal choices: There are no warranties, there are no replacements, there is no competition, when something breaks I R screwed. Yesterday 11 refraccionarias (auto parts stores) did not have a fuel filter for my 20 year old K car. Hah, their fuel filters for say a 2012 Ford V-10 do not exist and the ones for the V8's won't fit US cars. So I choose stuff that does not break and is harder to wear out (or order 10 fuel filters from Rock Auto :)

A bad refrigerator down here is a crisis, not an inconvenience. Lamps that burn out mean replacing them (somehow) with a hothouse grade 60 watt incandescent. I do not have time for such nonsense. This is why I am pre-emptivly replacing the trouble-prone group 34 battery with a group 31 AGM. "Oh sorry sir, you'll have to go to Managua 315 miles over bad road to try and find a group 34 for two hundred dollars. Oooooo it's expensive because it is aged 2-years on the shelf"

The life of a weekend warrior, with seven delivery services to his front door is a lot different than the life of a off-grid, damned near off the face of the earth boondocker.

But I do remember the wails of RV campers in the Sierra. "I waited all year and spent four thousand dollars to take this here vacation, and now I have to bail out after day three because (name one: battery, refrigerator, hot water heater, space heater, charging system, generator) won't work? A year's wait and thousands of dollars for -this-?" Now if a person consciously decides to compromise, and shortchange themselves with such a plan of recreation, then so be it. It's their life. But I don't want to hear complaints. I especially do not want to hear their loud voice twisting elbows telling others "How To Do It".

I have had four Fullriver DC220-6 Group 27 AGM batteries for almost three years. Yes they want 14.7 V bulk/absorption and 13.6 V float. Magnum custom settings provide that. They weigh 72 lbs. each. Do I care how thick the plates are? Sure, but at this point I don't really think it matters. As far as I am concerned these batteries work very well and are worth every penny of the $269 each I paid for them. Fullriver AGMs now have a seven year warranty, two years full replacement, five years prorated. Better than Lifeline. Mariners love Fullrivers, RVers will too.

No idea on longevity really, that's either a mechanical engineering question or a chemistry question, and I'm not really skilled in either field. Their reviews, as far as budget brand AGM goes appear overall positive.

My typical usage of the bank is closer to weekend warrior than full timer.

On long trips, the batteries let me overnight in truck stops and Wallydock, without having to run a generator yet have everything in the coach work, like I was on shore power.

On weekend outings close to home in the National Forest, I can run anything I want all night, and still have plenty of power in the morning for the waffle maker and coffee pot, usually starting the generator at noon for the recharge cycle.

GordonThree wrote:
Yup just fancy grocery getter batteries... not like Sams sells telcom grade 2-volt storage cells.

How many years do you think you'll get out of them? Or are you hoping to get out of them RV'ing? Type of usage? weekend warrior or full timing?

Yup just fancy grocery getter batteries... not like Sams sells telcom grade 2-volt storage cells.

GordonThree wrote:

NinerBikes wrote:

GordonThree wrote:
Do tell, whats wrong with Magnum's AGM charging profiles? AGM2 matches up perfectly with my East Penn DEKA agm batteries.

What model East Penn DEKA AGM batteries did you acquire? Specs? Surplus telecom, or something else?

I am currently running a 150 AH surplus Telecom AGM battery. I have a hard time getting this 1.300 SG surplus acid battery to take much more than 21 amps, at 14.4V. Interested in model, and if you've logged how yours performs.

I bought mine new at Sam's Club, with the Duracell stickers on them... four of these on a Magnum MS2812 inverter+charger (125amp charger). That batteries will accept the full 125 amp output in bulk mode at 14.4v until reaching somewhere around 90% charge, then it steps down to absorb and finally float. As others have observed, the final few % take a while, so that's 31 amps and change per battery in bulk mode.

East Penn 8A31DTM

https://www.unavco.org/projects/project-support/polar/support/deka_battery_handbook_2007.pdf

OK, so they are Group 31M batteries, rated at 105 AH over 20 hours. That's a pretty fast recharge amperage they take... Lot of plates, and probably thin, when they mention starting amperage or CCA capacity.

Hi Gordon,

I see they are "cheating" and testing for capacity at 80 F (27 c) instead of at 77 F (25 c). Nice batteries all the same.

I think I'd limit charging to c/5 myself.

NinerBikes wrote:

GordonThree wrote:
Do tell, whats wrong with Magnum's AGM charging profiles? AGM2 matches up perfectly with my East Penn DEKA agm batteries.

What model East Penn DEKA AGM batteries did you acquire? Specs? Surplus telecom, or something else?

I am currently running a 150 AH surplus Telecom AGM battery. I have a hard time getting this 1.300 SG surplus acid battery to take much more than 21 amps, at 14.4V. Interested in model, and if you've logged how yours performs.

I bought mine new at Sam's Club, with the Duracell stickers on them... four of these on a Magnum MS2812 inverter+charger (125amp charger). That batteries will accept the full 125 amp output in bulk mode at 14.4v until reaching somewhere around 90% charge, then it steps down to absorb and finally float. As others have observed, the final few % take a while, so that's 31 amps and change per battery in bulk mode.

East Penn 8A31DTM

https://www.unavco.org/projects/project-support/polar/support/deka_battery_handbook_2007.pdf

Chris Bryant wrote:
What gets me is they are the same size as the Interstates I took out (4 years old and toast), but they weigh *14 pounds more* (78.5), and have ~20 AH more.

This is fairly common, improvements in the materials of which the case is made mean they can make the case thinner, and making it thinner means there is more room, inside, for plates (lead) and that means more capacity since the watts per pound of lead are dang near a constant.

Is that 21A across the entire stack or per battery?

Chris: I suspect you have some pretty old firmware. Mine is currently in the custom mode and dialed into the Trojan T-145 factory spec. I'll bet it's a factory flash to upgrade it too. Maybe the Magnum factory guy will see this and chime in.