I recently switched to a single 200a/h LiFePO4 drop-in (cylindrical cell type) with internal BMS...
Other (typically less costly) drop-in type cell choices are Pouch and Prismatic (an encased variation of pouch), or build your own via a bundle of single cell prismatic and a stand alone BMS...For charger I’m still using the PD 9245 (with Charge Wizard in 14.4v boost mode) and actually prefer it over the current one size fits all Li spec’d chargers being marketed at present - each having it’s own unique shortcomings...
Voltage based ‘Dead On’ SOC readout has been a new ball of wax due to the uber wide breadth of the voltage plateau, though with a short bit of hands-on experience this should not present a problem, due to the aforementioned wide voltage plateau and an occasional top end-of-charge meter re-synchronization - in this way, you’ll always have a fairly close approximation of SOC (off by only a couple percent), and due to near stable voltage characteristics of Li, a ‘dead on’ SOC determination is of far less importance...Coulomb counting may yet be another option, though I’ve not pursued this possibility...
Understand too that to adequately provide for BMS cell balancing the battery will have to periodically be brought up to a full charge and held for a brief period (say a half hour or so - Note, once balanced, an ‘extended charge period is not recommended)...
I have found that at the completion of ‘regular charging’ (thus, the beginning of cell balancing...) the end of cell balancing’ phase can be ascertained by monitoring the periodic inrush amps ‘vs’ voltage (via shunt based SOC meter display) - kind of an ‘on and off again’ affair going on here, the brief cycling of amps up/down while voltage drops/rises...Once balancing completed, the ideal time for a meter re-sync...
Hope this helps!
3 tons
Upon edit, I seen no appreciable batt temp rises beyond ambient...As to FLA usable amps vs LiFePO4 goes, with my former two 210a/hr GC’s, I would normally only have available roughly 50% DOD or say 105a/hrs, but with 200a/h of lithium, I’d say that due to the near flat voltage curve, there’s roughly 90% capacity safely available, or 180a/hrs without issues...When off-grid I handle single-stage MPPT solar charging (@14.4v) the same as I do when using the charge wizard, monitoring the battery when nearing full to prevent unnecessary overcharge - sometimes shutting things down earlier since except for cell balancing, theres no real need for a full recharge ...Solar harvest is much improved (even with a marginal harvest) due to uber low internal charge resistance - SOC recovery time is much faster...
