I am assisting a relative who has a Watt Cycle 100Ah battery, and it has blue-tooth and BMS. The battery charge state on the app was 92% and we used it to power an inverter, and over time it went down to 48%.
We wanted to recharge the battery using a LIFeO4 charger, and set it at 20A and it read 14.6 V on the charger display. After many hours the battery charge had not risen beyond 55% and looking on the app the charge rate was only 25 W !!. So is the BMS limiting it ?? If so why ?? Is there a away to use the battery charger to its proper 20 A rate ??
The battery charger screen shows 20A, 14.6 V., and the App battery readout sits around 25 W.
We tried the battery charger setting at 10A, 14.6V and also 5A, 14.6V - and the App says in put is around 25W.
What on earth is going on, and why is the BMS behaving this way. Do we need to buy ANOTHER different LiFeO4 compatible charger ?? If so, Why ??
Completely stuck, disappointed, and desperate (and very grateful) for any assistance.
Many thanks
@Tim-peter I doubt the BMS is limiting the charge. Usually a bms will allow charging and then turn it off when at least one cell of the battery is at the maximum safe level. But it is an on/off switch, not a dial that can slow down charging. Are there any adjustments you can make on the charger? Can you test the charger on another battery? Otherwise the only option would be to try another charger.
Thanks for the response. The Wattcycle App is clearly showing that the battery is being charged at around 25W. It goes to zero when charger turned off. Returns to around 25W when charger turned on. Its set at 14.6V and can change current to 5A 10A and 20A and its consistent at 25W, which means charging will take forever. Charger works fine on other batteries but not the Wattccyle one with the BMS. Charging on solar the battery charges at 150 W and above from the solar set up. So its definitely the interaction with the Battery (and I guess BMS) and the charger - which is marketed as a LiFeo4 charger. I am beginning to think the BMS is way more trouble than its worth if it cannot take the range of chargers on the market. I guess we just try random chargers from Amazon and hope one is accepted by the BMS. Appreciate the feedback.
