Wanda Posted April 9, 2022 Posted April 9, 2022 Hello everyone. I have a Pylontech UP5000 coonected to a Kodak VM III (OG5.48) which when connected with a comms cable goes to low battery alarm mode even if the eveter is displaying voltage above 52V and the BMS soc lights are showing that the battery is full or almost full. The inverter fimware version is V41.17.7z. what could possibly be the problem. Quote
Beat Posted April 10, 2022 Posted April 10, 2022 19 hours ago, Wanda said: I have a Pylontech UP5000 coonected to a Kodak VM III (OG5.48) which when connected with a comms cable goes to low battery alarm mode even if the eveter is displaying voltage above 52V and the BMS soc lights are showing that the battery is full or almost full. The inverter fimware version is V41.17.7z. what could possibly be the problem. Tell us what your settings are. Quote
Coulomb Posted April 11, 2022 Posted April 11, 2022 On 2022/04/10 at 1:55 AM, Wanda said: when connected with a comms cable goes to low battery alarm mode even if the eveter is displaying voltage above 52V and the BMS soc lights are showing that the battery is full or almost full. I don't know what happens when you are connected directly to the BMS via a cable, but Axpert factory firmware has the "feature" that the low voltage alarm comes on 2.0 V above the low DC cutoff voltage setting, and doesn't go off until 4.0 V above that setting. This can be nearly full for a lithium chemistry battery. Try setting the low DC cutoff voltage lower. Your battery's BMS should shut the battery off well before that voltage is reached anyway. But if the BMS automatically changes that setting, this won't solve the problem. Quote
Wanda Posted April 11, 2022 Author Posted April 11, 2022 On 2022/04/10 at 1:27 PM, Beat said: Tell us what your settings are. I have the battery setting parameters set at Pylon on program 5 so I guess those are automatically set by the BMS. Quote
Wanda Posted April 11, 2022 Author Posted April 11, 2022 10 hours ago, Coulomb said: I don't know what happens when you are connected directly to the BMS via a cable, but Axpert factory firmware has the "feature" that the low voltage alarm comes on 2.0 V above the low DC cutoff voltage setting, and doesn't go off until 4.0 V above that setting. This can be nearly full for a lithium chemistry battery. Try setting the low DC cutoff voltage lower. Your battery's BMS should shut the battery off well before that voltage is reached anyway. But if the BMS automatically changes that setting, this won't solve the problem. I'm trying to have the battery BMS communicate with the Axpert. I would be a lot more comfortable with that kind of set up. In the meantime I have the battery setting on USER DEFINED where the charge voltage limit is 53V, low voltage is at 46V, charge current at 30A. It's working fine at the moment but I feel I lose very significant battery capacity as the battery voltage limit is 53.5V & and maximum charge rate is 50A. I don't want to be using those values as I fear I might run into trouble sooner than later. Quote
Beat Posted April 12, 2022 Posted April 12, 2022 18 hours ago, Wanda said: I have the battery setting parameters set at Pylon on program 5 so I guess those are automatically set by the BMS. I don't understand. In my manual there are only 3 options for setting 5: AGM, FLD and USE. Fore LFP (Lithium) batteries one must choose USE. Since the data sheet of my batteries (Averge, made by LOECH) states that its BMS cuts out at 40.5V, I set 29 to 42V. No "low voltage" alarm ever. There is no communication between BMS and inverters. Concerning charge current, that depends on the capacity of your battery. Ideal is 1/10 of Ah of the battery. But it supports quit a bit more. I let all my PV charging current through in order not to waste sun energy. Quote
Coulomb Posted April 12, 2022 Posted April 12, 2022 The OP has a VM III model, which has a removable display. For most such models, setting 5 (battery type) has extra options, including PyL for Pylontech. The display has its own processor and an RS485/CAN port intended for connecting to the BMS of a battery. Wanda 1 Quote
Wanda Posted April 12, 2022 Author Posted April 12, 2022 3 hours ago, Beat said: I don't understand. In my manual there are only 3 options for setting 5: AGM, FLD and USE. Fore LFP (Lithium) batteries one must choose USE. Since the data sheet of my batteries (Averge, made by LOECH) states that its BMS cuts out at 40.5V, I set 29 to 42V. No "low voltage" alarm ever. There is no communication between BMS and inverters. Concerning charge current, that depends on the capacity of your battery. Ideal is 1/10 of Ah of the battery. But it supports quit a bit more. I let all my PV charging current through in order not to waste sun energy. I'm thinking that when the battery bank is fairly of larger capacity than the loads one can get away with not having comms courtesy of that capacity gap. When load and battery capacity is tightly matched comms is of utmost importance. Quote
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