Bang, Buck, Batteries

Sad to say Mex, but when I was looking at Surrette AGM's in L-16 cases I gleaned that they were being made by Full River with the exact specifications you linked to.

Chris, I use the custom setting on my Magnum remote because I chose surplus acid AGM telecom jars.

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.

Niner, my similar telecom jar recommends c/5 @ 20 hour rate maximum charging current. AGM's do taper above 85% state of charge, but not quite as much as flooded. A flooded would be at c/8 at 85%. Mine are 1.30 SG.

Anyway 21 amps is a totally respectable recharging amperage.

Is the 150 amp rating for the 20 hours? Mine are 139.2 @ 20 hours.

I've had to throttle back the Magnum inverter/charger to keep charging rate to 27 amps.

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.

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.

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

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.

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.

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

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?