Amps jumping around on AGM finishing charge

I am about 70 percent sure this correctly indicates recombining of hydrogen and oxygen internally in the catalyst at an accelerated rate, before release of gas by the valve. I just reproduced it.

Temp works to control outgassimg but is the crudest indicator and generates many bubbles after removing power. Water over valves - fewer bubbles but still more than I want. Multidigit jump in hundredths of amps up and down, no bubbles but same situations that generate bubbles, such as running voltage up to charging voltage on nearly full battery.

I am happy. It was a good day for useable experimental results.

Jim

My brand new ones not in service yet. Yes they do, and they outgass during settle in.

I finally have some short #4 wires so I can do a realish (700w) load test and get some decent discharge plots. I'd like to start out charged. I have noticed there is no point in even attempting the last few percent charge when it is over 90 out. Sneeze and they want to outgas.

Jim

Are these your "operational" AGM's or your experimental one's? Do AGM's have a break in period?

pnichols wrote:
My AGM battereis come up against a "hard Stop" when they're fully charged. In other words, the ammeter in series with the AGM batteries reads a solid zero after so many hours of charging. Nothing I can do makes the ammeter show any more current flow into the batteries at that point. Even increasing the charge voltage back up to boost value will not make the ammeter show any charge flow once the AGM batteries are fully charged.

I've never seen any jumping around in current flow rates with my AGMs. That does sound strange ... I wonder if your ammeter or charger could have some instability somewhere in their cicuits ... IAW nothing to do with the AGM battery(ies)?

Hmm interesting. Mine will start to gas if I hit them that hard at the end. Amps do taper way down. On the 8 amp setting I am done when the volts jump up to the max charging voltage. On the 2 amp setting the amps will drop low but not stop and the volts don't spike. With the buck converter I can pick amp flows and voltages in between the two which I am doing now. I am trying to zero in on a real float voltage which can be on 24x7 if desired.

Jim

True! Once I learn.

Jim

My AGM battereis come up against a "hard Stop" when they're fully charged. In other words, the ammeter in series with the AGM batteries reads a solid zero after so many hours of charging. Nothing I can do makes the ammeter show any more current flow into the batteries at that point. Even increasing the charge voltage back up to boost value will not make the ammeter show any charge flow once the AGM batteries are fully charged.

I've never seen any jumping around in current flow rates with my AGMs. That does sound strange ... I wonder if your ammeter or charger could have some instability somewhere in their cicuits ... IAW nothing to do with the AGM battery(ies)?

Worth checking it all out when you know how for sure. At the end of the day, you have to kick them out of the nest and see if they can fly--fingers crossed.

I have not been quite ready to leave these AGMs under unattended solar care yet. For one thing the spec rating float voltage bubbles occasionally which may be ok but I need to understand that before I just leave the bank there drying out. For another I am just curious about real float so I'm dabbling with it.

I am thinking if mild gassing happens under float but below the release pressure of the valve, that could be the ideal state of the universe for minimizing plate corrosion and also reversing/avoiding sulphation. If that's true my LandStar won't quite achieve it since the temperature compensation factor is not quite right and is not programmable. But I could probably pick a voltage that is correct on the high temp side, and rely on the daily overcharge to get close.

Jim

Not a clue :) But I do note my LandStar plays with the amps to maintain the rating voltages when it gets past Bulk stage.