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DC2100B-C Overvoltage problem

Category: Hardware
Product Number: DC2100B-C
Software Version: 1.2.0

Hello,

 

I'm going to design a BMS for 12s25p LIFEPO cells (in this case in particularly, the configuration is 12s1p and NMC chemistry) and I bought a DC2100B-C in order to test it.

 

This is the behaviour of my board:

  • As soon as it is connected to the PC, there is an OV in cell 6 and it will automatically transfer energy to cell 7 (without doing any action). That voltage measured is not correct, I measured that voltage with the multimeter and these cells are at 4.08V

  • If the board keeps plugged to the PC, the voltage in cell 7 will rise meanwhile voltage in cell 6 will drop (please see following image). But actually, if I measure that voltage, in the multimeter will appear 4.08V as the remaining cells (it is the same for cell 6).

  • When I try to balance the cells, and if voltages are OK, it suddenly stops because of an OV. This OV is not true because if voltage in cells 6 and 7 are read, they are at 4.08V.

 

Here you can find the characteristics of my board:

  • The firmware in the DC2100B is 1.2.0.
  • BOT6_TS is connected to TOP6_TS and these two are connected to C12
  • I have placed R23 as a jumper (0Ω 1%) (as it is said in page 23 in DEMO MANUAL). I also tried without this resistor and problems are the same

 

Thank you in advance!!

  • For those who have the same problem as me I figured it out.

    I bought two DC2100B-C and both have problems of OV, the first one between cells 6-7 and the second one between cells 1-2.

    What I discover is that the fuses were blown up therefore the LTC6804 was reading one cell that were not conected to anywhere. It is strange because I never managed to start balacing because of the OV problems and those fuses are 12A - 24VDC so I'm thinking that they were broken before I bought the demo board.

    I replaced them by 5A - 24VDC fuses and it works like a charm.

  • Hello,

    The fuses could have been blown from the inrush current in the initial connection if the capacitance on the DC2100 was not precharged first. Please see the precharge sections in the demo manual starting at page 7. I hope this fixes the problem.