It’s a ‘dumb’ charger. We bought it quite a few years ago from an industrial equipment shop that was going out of business. Heavy duty kit.
What about using the Victron from the Pv, one battery at a time? I’ve set that to Lithium so could separate the batteries and charge each to full using that. If that can be done in a day, each, would they then be able to be reconnected without diverging too much (though they were both the exact same voltage when I put them in).
I wonder, more fuss and bother than it’s worth? See if I can get my money back and get 4* AGM for the same, then connect them as 24v instead? I hate it when things don’t quite work as they should/promised. Amazon have a no-quibble refund policy here so it ought to be possible.
I have ordered the Victron. If the batteries aren’t getting over 26.7 I don’t know if it will work, but it’s worth a go I suppose. I shall let you know.
I’ve received the Victron Controller today. When I’ve connected it, the values are as follows (my inverter and multimeter show the battery at 26.7v):
Battery; 27.6v, 0.0A, Float
Pv; 1.17kwh, 65v, 0w (this flicks back and forth between 0 and 1 - because ‘float’?)
The support desk at Eco have said I need 7168wh to charge the batteries because they are 280Ah. Our SLA were 250Ah and they charged fine, with plenty of spare. I can’t imagine another 30Ah means the panels aren’t enough, not with the sun we get here.
The figure quoted is the energy required to refill the batteries from empty. It sounds like you are not emptying them everyday, so if you keep the same usage pattern as with your lead acid then you are set up OK. In fact you will be slightly better off as lithium is more efficient at recharging.
I believe the discrepancy between the charger and the batteries themselves is due to one Mr Ohm, so I’ve asked Eco-Worthy if I can set the charger to +1v on the settings without damage to the batteries; the cables are 6mm and will handle the slightly extra current. So that would mean a true value at the batteries of 27.4 if I set float on the charger at 28.4. This is slightly under their recommendations.
Also, I downloaded the latest manual for my charger from Victron. I was annoyed to find that on the lifepo4 setting ‘absorption’ is set to 2 hours maximum no matter what the Bv is. I will watch this over the next few days but I’d rather it was a ‘V’ limit than time, especially as we get towards shorter days.
Just be very very careful as voltage drop disappears when the current is very low so you may over voltage them. I have 16mm2 cable on my 50A MPPT to reduce voltage drop to a minimum.
