Daly BMS gone crazy..Update Opinions
I was charging my 120ah lifepo4 battery yesterday and came in for lunch and saw it shut down..I figured it hit the 3.65 volt cell limit and shut down,I went out to check it and saw this on the Blueto...
Forum Discussion
I wonder how it calculates the capacity
It does read voltage and it does read amps, but does it do AH? Does it do auto-reset of AH count whenever it thinks the batts are full (however it defines that)? Can its AH count get out of whack by doing that auto-reset? (if it does AH count at all)
IMO you want to cross-check your "meters" to see they "agree", and that is why you want to measure SOC by some other means than just what the monitor says. Looks like the "smart BMS" is nifty in providing lots of info like a monitor does, but what is the means to cross-check it?
We have had folks on here who believed their monitor's or their charger's read out of SOC saying the batts are at a high SOC while in fact the batts were nearly dead. The big lesson is not to believe just the one meter.
IMO with the money at stake with LFP, you would want to be even more paranoid about what any one "meter" says, even if it is the "smart BMS" in the LFP. Actually- especially the battery's own BMS! Some independent "meter" would be my choice.
It seems the lower knee is the most critical. With the rapid drop off past the knee, you don't have much time to reverse course and not have the BMS shut you down with no 12v for anything.
And since one of the LFP advantages you paid for is to operate to lower SOCs, that means you will be pushing your luck going to that lower knee, so you want to have accurate SOC info.
It does read voltage and it does read amps, but does it do AH? Does it do auto-reset of AH count whenever it thinks the batts are full (however it defines that)? Can its AH count get out of whack by doing that auto-reset? (if it does AH count at all)
IMO you want to cross-check your "meters" to see they "agree", and that is why you want to measure SOC by some other means than just what the monitor says. Looks like the "smart BMS" is nifty in providing lots of info like a monitor does, but what is the means to cross-check it?
We have had folks on here who believed their monitor's or their charger's read out of SOC saying the batts are at a high SOC while in fact the batts were nearly dead. The big lesson is not to believe just the one meter.
IMO with the money at stake with LFP, you would want to be even more paranoid about what any one "meter" says, even if it is the "smart BMS" in the LFP. Actually- especially the battery's own BMS! Some independent "meter" would be my choice.
It seems the lower knee is the most critical. With the rapid drop off past the knee, you don't have much time to reverse course and not have the BMS shut you down with no 12v for anything.
And since one of the LFP advantages you paid for is to operate to lower SOCs, that means you will be pushing your luck going to that lower knee, so you want to have accurate SOC info.
