Charging AGM Batteries

landyacht318 wrote:
I've also been researching Northstar AGM batteries.

Their list of approved chargers is much bigger than Odyssey, and they do not seem to have a minimum initial current. I'd like more info.

What is nice is that northstar makes a group 27

http://www.northstarsitetel.com/northstar/engine/literature.php

They are very pricey. and boast similar numbers and claims as odyssey, but appear to be even heavier in the same group size.

The Fullriver DC105-12 is a Group 27 105AH 12 volt AGM battery with a two year replacement, subsequent three year prorated warranty, and can be found for $250 each.

Here is the complete Fullriver AGM battery installation and operation manual: http://www.fullriverdcbattery.com/technical/manual/

I have four Fullriver DC220-6 Group 27 6-volt AGM batteries and they are working great so far.

Full River also has excellent documentation

They want 14.7v acceptance
and a recommended current of 0.2C upto no more than 0.35c

and a 13.65v float

http://www.fullriverdcbattery.com/technical/charging/

Was just on lifeline's page and am impressed with its depth


They say 14.3v max +/- 0.1v acceptance
and 13.3v +/- 0.1 float
and a recommended 0.2c minimum current and
bulk current should be as high as practical and up to 5xC is tolerable

at the standard 77f

http://www.lifelinebatteries.com/manual.pdf

I've also been researching Northstar AGM batteries.

Their list of approved chargers is much bigger than Odyssey, and they do not seem to have a minimum initial current. I'd like more info.

What is nice is that northstar makes a group 27

http://www.northstarsitetel.com/northstar/engine/literature.php

They are very pricey. and boast similar numbers and claims as odyssey, but appear to be even heavier in the same group size.

Apparently Batteries Plus sells these relabelled as X2Power

I ordered 2 AGM Lifeline 300 ah batteries. The dealer emphasized that the batteries "liked" to be charged as fast as possible, that 100amps or greater is great, and 60amps is a minimum.

He also emphasized that float needed to be no more than 13.1 or 13.2, otherwise the batteries would get "cooked" over time and lose more than half their life.

I did not get a chance to call the Odyssey tech line today, but on this chart I posted before:



It says 0.4c Min with a little 10 next to it, on the right side, next to the dotted line indicating current.

Not sure what that 10 means.

I might take the day off tomorrow and go get some AGM batteries after making some calls. My engine starting battery is dropping to 6 volts during 1.5 seconds of engine cranking, and my house batteries are currently reading, as I type, 12.1 under a 10 amp load with 14A/h removed from them. I was plugged in the last 2 days, Schumacher running. So they were full or very close as it did decide to do the 10 amp thing at 15.4 volts for 2 hours after a normal recharge.

US battery has a group27 AGM. Not sure of the price, but I found their spec sheet which lists charging requirements.

Less than 27 amps initial current, but they say 14.4 to 15.0 for cyclic use and 13.5 to 13.8 for standby.

My alternator might be able to produce slightly more current at higher rpm than this rating( 3 batteries) but it is within the vehicle's normal voltage range.

A 68 amp hour AGM battery with 930 CCA claiming a 0.4c minimum charge rate
Vs a 99 amp hour AGMbattery with 750CCa and a ~0.3c Maximum.

That's where I'm standing.

I hope the price is right on the USbatteryAGM

http://www.usbattery.com/usb_images/usb_agm_27_12volt_spec_Low.pdf

tplife wrote:
AGM batteries are designed as drop-in replacements for flooded batteries and while they can be charged at a higher rate, they can be charged safely using standard flooded-battery charging systems.

Ahhh, that's what I was hoping. Okay, game on, proceeding with AGM shopping.

Thanks,
Bruce

full_mosey wrote:
You know what happens when you ass-u-me. :)

I know but in this case I know he's mentioned it a few times so it's safe. I think. :)

mena661 wrote:
Assume that when MEX states voltages, he's referencing the standard 77F. You definitely want temp comp on AGMs although quite a few here on the forums don't bother.

I am a strong proponent of automatic temp-comp charging. Sadly, there are few converter/chargers that do temp-comp.

You know what happens when you ass-u-me. :)

HTH;
John

full_mosey wrote:

MEXICOWANDERER wrote:

...

14.4 volts for an AGM battery is fine. It is just a lot slower for the last 15% of ampere hours of charge.

What about temp-comp chargers?

Would I want to use 14.7V on a 110F battery? I use 13.5V via a temp-comp charger at that temp. A cold battery gets up to 15V.

HTH;
John

Assume that when MEX states voltages, he's referencing the standard 77F. You definitely want temp comp on AGMs although quite a few here on the forums don't bother.