I recently converted to Lifepo4 Batteries and I must say I am impressed so far. I have on concern however. These batteries have required me to program my controller to disconnect at a fixed upper voltage, (in my case it is set for 27.7 volts) and then resume charging at a fixed lower voltage, which for me is 24.0 volts. A very simple charging scheme indeed! The downside to this though is that some days I do not reach the lower voltage until just before the sun sets. If this happens more than two days in a row I wind up driving my battery voltage lower than I am comfortable with. We have a BMS system in place that came with the batteries but I am much more conservative in their care at $1000.00 a piece than they seem to be :-)
What I have searched for on the internet in vain for hours an hours is a device that would allow us to monitor the batteries until they drop to exactly 24 volts and then trip a relay to allow line power to our charger until the battery voltage increases to at least 26 volts. I feel sure we would need to tweak these setpoints to offset voltage sag after charge disconnect, and other variables, so some adjustability is necessary. But his would easily put our charge sequence back on track, and not allow our batteries to go down to the manufactures lower voltage, and shorten battery life.
So I guess in simple terms I am just trying to find or build a charging control system that allows us to custom set the upper and lower charge points. I am hoping that MidNight might consider creating such a device. It feels awful lonely out here in the prototype world of Lithium Systems.
Great idea. Would be nice, maybe with help from the Whizbang Junior, if when there was a load during the day and there was sun available,
that the Classic could supply that power so nothing went into the battery at that time ?
Just thinking out loud but might be a bad idea too ?
Have you perused the LiFePO4 section over at the NAWS forum?
https://forum.solar-electric.com/categories/new-battery-technologies
if you search LiFePO4 there are other threads about Li batteries than just that part of the forum
hth