nolan7
New Member
I have Seplos BMS with optional balancer board. Reading forums here helped me a lot, I learned that to make it work, I have to change settings in "seplos BMS studio", lines 100 and 101. After changing these two values to something reasonable it works good enough for me. When charging, and when cells are getting into the region of voltage curve, where their voltages starts to get apart, active balancer kicks in and works nice. Before that I had ~250mV difference when fully charged. After making active balance board to kick in automatically the difference is less than 50mV. Some people here think it is not good enough, or that it is bad to balance through all of voltage range. I think it is not a problem, because when the battery starts to discharge, voltages get even closer, maybe 3, 5, max 10mV apart. Unless you discharge very low, they will stay together all the time. In Seplos documentation they explain their idea like this: even if it starts to balance through the range of discharging/charging anywhere on the voltage curve, it is helpful to keep all cells together voltage-wise. Even down there, when some of the cells drop voltage quicker, it pushes energy from stronger cells to weaker. It should help for cell longevity, because weaker cells are not stressed so much, and you can use more energy from your battery pack. This "disbalancing" happens only if you discharge too low. Otherwise, it stays top balanced and it keeps like that all the time. Yes, this process disbalances them when considering top-balance, but that is not a problem, because they got balanced again, when top charged, when they get there. All this process keeps voltages similar all the time, which is good. Not much energy is lost, because it is active, not passive balance. Stress on the cells is negligible compared to normal discharging and charging cycles. There is no downside, I think.
Now to the point of my post: THE ACTIVE BALANCER IS MANAGEABLE. Contrary to seplos statement and general consensus, that active balancer is a stand alone unit and all values are fixed, this is not true. In the seplos BMS studio v2.0.0.1 there is an option on start that lets you choose BMS or ABU. If you choose ABU, you can connect to the balancer board and have a look on the pictures what you get there. I used USB to RS232/RS422/RS485/TTL converter. On the Active balancing unit board, there is one white unused connector, with four pins. On the backside of PCB it is marked GND, MCU_RX, MCU_TX, +3V3. I connected them to my USB to serial converter (also I the pictures) and then I am able to connect to ABU. I can change anything I want. This is for you, who are not happy with default values. Sorry for the poor quality of the pictures.
There is one small problem with this but there is a workaround solution. On the "parameter management" page, when you would normally use "real all" to fill up fields with values from your balancer unit, it does not work. There is a problem with reading the last value, line number 33. Workaround is to read each line manually by clicking the blue arrow. It works on all lines except the last one. Also the writing with green arrow seems to work correctly. Login is the same as for BMS use.
Now to the point of my post: THE ACTIVE BALANCER IS MANAGEABLE. Contrary to seplos statement and general consensus, that active balancer is a stand alone unit and all values are fixed, this is not true. In the seplos BMS studio v2.0.0.1 there is an option on start that lets you choose BMS or ABU. If you choose ABU, you can connect to the balancer board and have a look on the pictures what you get there. I used USB to RS232/RS422/RS485/TTL converter. On the Active balancing unit board, there is one white unused connector, with four pins. On the backside of PCB it is marked GND, MCU_RX, MCU_TX, +3V3. I connected them to my USB to serial converter (also I the pictures) and then I am able to connect to ABU. I can change anything I want. This is for you, who are not happy with default values. Sorry for the poor quality of the pictures.
There is one small problem with this but there is a workaround solution. On the "parameter management" page, when you would normally use "real all" to fill up fields with values from your balancer unit, it does not work. There is a problem with reading the last value, line number 33. Workaround is to read each line manually by clicking the blue arrow. It works on all lines except the last one. Also the writing with green arrow seems to work correctly. Login is the same as for BMS use.
