Charging the Lifelines questions

MEXICOWANDERER wrote:
jim i wouldn't charge an 8-D AGM within anything less than 50 amperes, let charging continue to 14.4 @ 25c until amperes slump to 3.0 then maintain the battery at 13.6 volts to a temp max of 28c.

This would be when the battery is seeing daily cycling duty and the values above are for a single battery.

I pondered the point of minimum acceptable charge rate and came up with a chemical deduction. Yesterday I called a friend Fred Polanski who handles the tech issues at an AGM OEM. He chuckled over the phone when he heard my assumption and replied ("your rationale is right o the mark")

"The mat absorbed 1.300 SG electrolyte demands substantial amperage which encourages it to circulate"

The result of chronic under-amperage encourages -excessive- acid starvation. Free electrolyte and soaked-mat electrolyte are two different animals.

I noted this in my era way back when, with gelled electrolyte but that critter was a literal nightmare to manage correctly. if I was home I would have benefit of a lot more instrumentation. The only reason I have that divorced platform scale is to send it to Denver for recalibration. The gel battery could not be desensitized from reluctance of acid circulation thus it makes a horrible choice for regular cycling.

One Megawatt 36-ampere power supply adjusted to 14.4 volts would make a suitable charging source for each 8-D but one of the two polarity bridges would have to be opened to isolate the circuit for the sake of the Megawatts.

When I get home I will verify my idea that minimum charging amperage is only necessary until the battery reaches 14.4 volts and amperage slumps to 10% of total amp hour capacity of the DUT. For your 8-D's this would mean something in the neighborhood of 25 amperes.

The data above is pure conjecture on my part. Ideas put to print. Proofing will involve instrumentation and forty to fifty cycles. This I have a gut feeling OEM is aware of and practices it but getting data out of them is like extracting blood from a turnip. The title of this is called THE IDEAL CHARGE PROFILE.

Making this agree with a solar system will take some work. Compromises have to be researched and selected. But the batteries have a single demand that must not be ignored = chronic undercharging, regardless of which profile you settle on.

I am pleased that I can offer this information on a level that most of you can understand (a sharp group) yet present it at a professional level.I was fooling myself that retirement meant abandoning research for a hammock. Can't train a Labrador to not whine when he smells water.

If you know any connections at DEKA / East Penn, and feel like making a phone call or email about that Telco battery I just picked up, the 145 AH one, I'd be very interested in hearing what kind of recharging regime is optimum for it's longevity, and also deepness of SOC on a daily basis when used in dry camping situation. Also any kind of details you can get about it's construction, plate alloys of lead and tin, as well as aced SG used in the glass mats would be interesting... anything to explain the 12.92V phenomena at rest.