We have a couple of cheap LiFePO4 100Ah drop-in batteries (brand not important) here in the shop that feautre a Daly BMS. When ever we fire up a charge source the immediately trip the BMS on High Voltage. OK, no problem we've seen this before with elcheapo LFP drop-in batteries. We usually open the app and try to figure out where the lowest voltage is where the cells begin to balance, set it just a tad higher, like 0.1V higher, walk away for a while and let the cells balance. We did this...
We connected this battery to our labs equipment and set the power supply for 14.1V, after seeing in the APP that the manufacturer has it set to initiate balancing at 3.500 VPC.. I assume all is well and good. I let it balance for four hours and then turned the voltage up to 14.4V (manufacturers recommended charge voltage) and after a very brief in-rush the Daly disconnected the Charge FET's. One cell had hit 3.75V and initiated another disconnect. What the heck is going on here?
I attempt another re-balnce by applying a DC load to pull the voltage back down a bit to re-engage the charge FET's. I dial voltage back down to 14.1V, from 14.4V, and the BMS starts to balance. As I am standing there, and just before the BMS disconnects at 3.75V, the "Balancing" indicator light turns off! At this point in time the cells were:
3.731V
3.495V
3.427V
3.482V
I shut down charge, apply a DC load and repeat the process. Again, balancing initiates but as soon as accepted current drops to 0A (based on the Daly shunt info) the balancing instantly turns off.
We have tried every possible setting in this BMS (Yes, we have the password) and yet nothing allows it to balance when or if the cells are accepting 0.00A. What kind of BMS will not and does not use the chargers power or the high cell voltage to shunt current to the lower cells? If this is actually the way this BMS is designed to operate, it's a complete joke. I have spent hours this morning searching and have not found anyone reporting this behavior with a Daly BMS? While we've seen these issues before we can always set a low voltage and sit back and allow the cells to eventually come into balance. The Daly BMS will not allow that???
I am sure I am missing something but literature is impossible to find on this Daly BMS, the company does not answer emails. The documentation on the battery is worse than a joke. On top of all this the battery case is glued together with what appears to be a SuperGlue material and if any attempt is made to open this battery it will be 100% destroyed.
It appears the cells inside are grossly mismatched, the Daly can't balance the cells, and the ramp down from the cells reaching 3.40V is so fast that there is insufficient time to re-balance before the cells are accepting 0.00A.... The BMS it seems can only balance when the cells are actively accepting current despite a 0.304V imbalance!! At this level of imbalance, and the minuscule balance current, the cells will never, ever balance out..
Is this typical of the Daly BMS's?
Why does the cycle counter not work?
What is wrong with the SoC feature on this BMS? It is worse than a joke.
We connected this battery to our labs equipment and set the power supply for 14.1V, after seeing in the APP that the manufacturer has it set to initiate balancing at 3.500 VPC.. I assume all is well and good. I let it balance for four hours and then turned the voltage up to 14.4V (manufacturers recommended charge voltage) and after a very brief in-rush the Daly disconnected the Charge FET's. One cell had hit 3.75V and initiated another disconnect. What the heck is going on here?
I attempt another re-balnce by applying a DC load to pull the voltage back down a bit to re-engage the charge FET's. I dial voltage back down to 14.1V, from 14.4V, and the BMS starts to balance. As I am standing there, and just before the BMS disconnects at 3.75V, the "Balancing" indicator light turns off! At this point in time the cells were:
3.731V
3.495V
3.427V
3.482V
I shut down charge, apply a DC load and repeat the process. Again, balancing initiates but as soon as accepted current drops to 0A (based on the Daly shunt info) the balancing instantly turns off.
We have tried every possible setting in this BMS (Yes, we have the password) and yet nothing allows it to balance when or if the cells are accepting 0.00A. What kind of BMS will not and does not use the chargers power or the high cell voltage to shunt current to the lower cells? If this is actually the way this BMS is designed to operate, it's a complete joke. I have spent hours this morning searching and have not found anyone reporting this behavior with a Daly BMS? While we've seen these issues before we can always set a low voltage and sit back and allow the cells to eventually come into balance. The Daly BMS will not allow that???
I am sure I am missing something but literature is impossible to find on this Daly BMS, the company does not answer emails. The documentation on the battery is worse than a joke. On top of all this the battery case is glued together with what appears to be a SuperGlue material and if any attempt is made to open this battery it will be 100% destroyed.
It appears the cells inside are grossly mismatched, the Daly can't balance the cells, and the ramp down from the cells reaching 3.40V is so fast that there is insufficient time to re-balance before the cells are accepting 0.00A.... The BMS it seems can only balance when the cells are actively accepting current despite a 0.304V imbalance!! At this level of imbalance, and the minuscule balance current, the cells will never, ever balance out..
Is this typical of the Daly BMS's?
Why does the cycle counter not work?
What is wrong with the SoC feature on this BMS? It is worse than a joke.
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