With a failing ReLiON Group 31 LiFePO4 12V 100Ah battery at 3.5 years despite regular and reasonable use, I'm disabused of costly batteries with built-in BMS and exaggerated claims about expected longevity and number of cycles. I'm now planning v2 of my DIY portable power box with a 4S prismatic setup with EVE LF230 cells, whose standard charging current spec is 0.5C, or 115A. I'm brand-new to prismatic cells and configurable BMS, but quite comfortable with DC circuits. The 49-page thread on compression is a fun one, especially when @ghostwriter66 gets notes direct from EVE engineering. Feeling a little trepidation at the rabbit hole of separate BMS and balancing, but surely game!
While it would be fun to recharge in less than 2 hours, I'm not anxious to add a high-amperage charger at this time, after updating the primary wiring in this box for full power to a 1500W inverter, building a compression setup, etc. Since I've been quite happy with my Victron gear, my next step would likely be a Multiplus II, but that would be super overkill for a portable power box...
My current mains charger is just 25A, solar charger is 30A. Normally only one or the other is available. (I only get 30A out of the solar charger when its power source is my van alternator via DC-DC boost converter. Otherwise, max 200W with my DIY portable panel kit.) This was fine for 100Ah, but will be a bit slow for 230Ah.
I mostly recharge starting at 30% SOC, which in this case will initially leave ~161Ah to restore to 100% SOC. At 25A, that will take about 6.5 hours. This is within the EVE datasheet "BMS Protection" spec to terminate charging after 8 hours.
Are there any problems with always charging these slowly at 0.11C? Battery degradation? Balancing issues?
If I were to discharge all the way, it would take over 9 hours to recharge. Would I be better off keeping a BMS "too long charge time" setting at 8 hours in case of weirdness, and reset charging after auto cut-off? Or set it to 9 hours? I mean, there will be over-voltage protection too. What does a Daly Smart BMS 250A BT do when disabling charging for a "too long" condition, assuming it has such a setting? Does it just break the battery connection, or only disable inbound current flow?
Thanks for any input!
While it would be fun to recharge in less than 2 hours, I'm not anxious to add a high-amperage charger at this time, after updating the primary wiring in this box for full power to a 1500W inverter, building a compression setup, etc. Since I've been quite happy with my Victron gear, my next step would likely be a Multiplus II, but that would be super overkill for a portable power box...
My current mains charger is just 25A, solar charger is 30A. Normally only one or the other is available. (I only get 30A out of the solar charger when its power source is my van alternator via DC-DC boost converter. Otherwise, max 200W with my DIY portable panel kit.) This was fine for 100Ah, but will be a bit slow for 230Ah.
I mostly recharge starting at 30% SOC, which in this case will initially leave ~161Ah to restore to 100% SOC. At 25A, that will take about 6.5 hours. This is within the EVE datasheet "BMS Protection" spec to terminate charging after 8 hours.
Are there any problems with always charging these slowly at 0.11C? Battery degradation? Balancing issues?
If I were to discharge all the way, it would take over 9 hours to recharge. Would I be better off keeping a BMS "too long charge time" setting at 8 hours in case of weirdness, and reset charging after auto cut-off? Or set it to 9 hours? I mean, there will be over-voltage protection too. What does a Daly Smart BMS 250A BT do when disabling charging for a "too long" condition, assuming it has such a setting? Does it just break the battery connection, or only disable inbound current flow?
Thanks for any input!