battery charging voltage

MEXICOWANDERER wrote:
That lack of adjustment TIME AT ABSORBSION LIMIT has been what I have been roaring about for years on this forum. Adjustable voltage and adustable time are the two primary objectives of the BORG.

I'm spoiled, have been taking my solar controller for granted.

It has all this - adjustable V ABS with current-based termination of absorption, and adjustable timer. V ABS will change to V Float only when charging current has dropped to preset value. As long as there is any incoming power, controller will bring the batts to the stage when they are ready to float. Big question is this value of preset current - loads sometimes skew the picture. Time of absorption is also adjustable, and I prefer to err on the long side, setting the timer to 70 minutes so that the current-based end would prevail on most days. If there is any sun, charging current would usually drop to preset value and V ABS would change to V Float after 20-30 minutes.

AGM batteries.

Just thinking aloud - sorry.

That lack of adjustment TIME AT ABSORBSION LIMIT has been what I have been roaring about for years on this forum. Adjustable voltage and adustable time are the two primary objectives of the BORG.

Yes
(2) amperes but just to make your life miserable I am going to ask you to verify once or twice that all four are playing nice and each is getting an equal share.

Hi Mex,

Since I have four does that mean 2 amps instead of 0.5 amps? So far as I am aware the Magnum does not have a "timer" so it should stay in absorb until the batteries are ready to float.

MEXICOWANDERER wrote:
Yep. This is why Concorde issued succinct instructions for charging then knowing for a fact the battery is 100% charged before reverting to float maintenance. I would suggest trying their formula with your battery manufacturer's recommended VMAX. In your case sir, point five amperes then see if float amperage climbs. An increasing float amperage is a classic tattletale the battery has been forced to float before it is fully charged.

One small update. I could not custom set equalization charging to less than 14.6 volts. However, it is unlikely I'll accidentally trigger an equalization charge with the Magnum inverter/charger.

Yep. This is why Concorde issued succinct instructions for charging then knowing for a fact the battery is 100% charged before reverting to float maintenance. I would suggest trying their formula with your battery manufacturer's recommended VMAX. In your case sir, point five amperes then see if float amperage climbs. An increasing float amperage is a classic tattletale the battery has been forced to float before it is fully charged.

pianotuna wrote:
Hi Vulcan,

I define it as what the Magnum inverter charger does in the custom battery setting. I expect it is the same as bulk, but I'm not entirely sure--and being poor I have to try to treat things the best way possible to make them last.

Vulcan Rider wrote:

pianotuna wrote:

I saw the equalize charging rate and the float--but not absorption.

Please define "absorption charging", as you understand it.

Hi PT;

I have the smaller MMS 1012 Magnum. With the RC-25 remote, it takes on an AGM charging regimen. The remote has 3 LEDs to indicate Bulk, Abs and Float. The battery is a 12V Johnson Controls 31C 100AH AGM bought at Sams Club.

I usually watch the AC input with a KAW. I attach a Turnigy to the Magnum DC terminals to observe Volts.

During Bulk, the Watts slowly increase until the Vabs is reached. I have seen the Watts rise and then hold at the maximum 1000W input rating for a period of time.

During Abs, the Watts slowly decrease and the Volts hold steady.

In Float, the Volts drop but surprisingly, the Watts don't drop as you would expect, but instead the Watts continue to decrease. This means that the Amps must rise! :@

HTH;
John

Ok,

I'm going to custom set absorption at 14.6 and custom set float at 13.8. I'll set equalization at 13.8 just in case it gets triggered in some way.

Comments please?

Hi BFL13,

I got the SG from a web site that sells these instruments of torture.

pianotuna wrote:
Hi,

My new to me batteries will be installed tomorrow.

I know that recommended float voltage is 13.5 to 13.8 volts.

What would be a good voltage for absorb charging?

They are used telecom batteries so are a variant of AGM but are not a starved acid configuration. The are Dynasty UPS12-490MR

The chemistry is Lead Calcium AGM with a SG of 1.300

PT, just for education, not questioning anything! Those specs for your UPS batteries seem at odds with the table at the end of this blurb.

http://www.engineersedge.com/battery/specific_gravity_battery.htm

Also how did you get the SG of an AGM???? (1.3 seems way high for a UPS wrt the blurb above too?

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