Battery Upgrade
First let me set the stage. We boondock 1-2 weeks a year. The rest of the time the trailer is plugged into shore power either in storage or at campground with hookups. We have one house GP27 wet ce...
Forum Discussion
BFL13, communications companies use chargers designed to match their bank. A gigantic bank may have 8 chargers. Or 12. And shutdown of the emergency system happens before their bank gets an over draw down. Discharges are not common. So the 20% rule may not apply. If a bank were drawn down only 30% the 20% recharge rule is far less important than it the bank was drawn to 40% or 50% remaining capacity.
Battery chemistry just has to make itself complicated. The recharge rate is affected by the percentage of recharge achieved. Recharging slowly and constantly underachieving 100% makes life miserable for the battery.
This is why I hammer the hell out of my AGMs when power is restored. The BORG cannot do C1 but it can do 80 amps and that's what the Lifeline is hit with. The power may go off again before even 80% is restored. But I can tell you for a fact that a whamjam recharge makes it easier to achieve .5% later on. Once capacity is lost it's either play a guessing game or do a full on capacity test.
As a GUESS I would offer that if you discharge your AGM to no less than 70% remaining you can forget about the 20% rule altogether, but you cannot forget the .5% rule (ever). Once a week on the .5% followed the 2nd and third week by a recharge as much as is easily doable. Eqvt to your 50-90 rule, only 70-90%
Is the 70-90 doable or is it a real pain?
Battery chemistry just has to make itself complicated. The recharge rate is affected by the percentage of recharge achieved. Recharging slowly and constantly underachieving 100% makes life miserable for the battery.
This is why I hammer the hell out of my AGMs when power is restored. The BORG cannot do C1 but it can do 80 amps and that's what the Lifeline is hit with. The power may go off again before even 80% is restored. But I can tell you for a fact that a whamjam recharge makes it easier to achieve .5% later on. Once capacity is lost it's either play a guessing game or do a full on capacity test.
As a GUESS I would offer that if you discharge your AGM to no less than 70% remaining you can forget about the 20% rule altogether, but you cannot forget the .5% rule (ever). Once a week on the .5% followed the 2nd and third week by a recharge as much as is easily doable. Eqvt to your 50-90 rule, only 70-90%
Is the 70-90 doable or is it a real pain?
