I have a solar electric system from many years ago. The setup runs on 400 to 480VDC from a string of solar panels.
I have a unit that converts 250 to 600VDC to 48VDC for charging lead acid batteries.
I was thinking of stringing a bunch of the inexpensive 12.8VDC $30 LiFePo4 batteries into a 4 kWh energy store.
Everyone including the manufacturer Miady tells me not to parallel the batteries. So series it is.
Could some one point me in the right direction for building a charger for this setup? To maximize battery life Miady says to stay under 0.2C charge rate. This would be around 960watts in the setup I am envisioning. So 400 or so VDC at 2 Amps.
I have around 400VDC at 7 Amps to work with. What would be appropriate to regulate the current so the battery bank charge is limited to a particular current? I am thinking along the lines of a switch mode regulator.
In addition to regulating the current, I would probably need a voltage cut off as LiFePo4 do not need a float voltage.
More or less the process would be: cut out, wait till VDC around 400 and then charge batteries at up to 0.2C (around 2amps) and then cut out later when the voltage reaches a certain level on the battery side.
Some people may feel I need to shunt the excess power somewhere. With solar electric panels you can just not draw off the power and nothing bad happens.