AGM Charging Profile Graph

[crashmaster]

I have a pair of 6V AGM batteries from Leoch and was a bit perplexed of the charging profile.

I am assuming, and probably incorrectly, that bulk and absorption charge max is 2.47V per cell, and float charge of 2.30V per cell. I am not sure what the 2.58V number in the graph represents. It seems like a pretty high charge voltage for an AGM as does the 2.30V float.

Can anyone tell me what that charging profile graph actually reveals for bulk, absorption, and float?

Thanks!

 

[Vic Harder]

2.3v for float is exactly what my Rolls AGM batteries call for as well.

2.47v looks like the absorb phase, which translates to 14.82v. That does seem a bit high (mine are 14.7) but that's what YOUR batteries apparently need.

2.4v is bulk, and it seems odd that they call for any specific voltage at all here. The .5 of CA is the key number.. don't try and stuff more than 1/2 of your battery AH capacity into them. Do if 200AH battery bank, no more than 100A charge current. That's not likely to happen unless you upgraded your truck/camper wiring significantly.

2.58 - I don't know what that is... on a FLA cell I would say it is the equalize phase, but AGM's don't call for that, usually.

Does LEOCH sell a controller that can be programmed like this? Very odd looking graph. I would think a phone call to their support line might be in order.

 

[crashmaster]

Odd looking graph is exactly what I thought.

I did call LEOCH this evening and they transferred me to an engineer in Shenzhen. The guy was very nice and his English was pretty good, way better than my Mandarin!

In any case, he did confirm the 2.47v bulk/absorption rate and the 2.30v float, all based on 20C. He then explained the 2.58v but I didn't understand what he was trying to explain but I gather it was for a different charge not done by most chargers. However, he mentioned if temperatures at any time are over 20C it is best to do the bulk and absorption charge from 2.40v to 2.43v.