Daly BMS

Daly Smart BMS - Frequently Asked Questions

Daly makes many variations of BMS units with and without fans, however we have standardized our product line. Any BMS under 300a rating does not have a fan, while any BMS 300a and up has a fan. Additionally, 300a and larger BMS units have a second set of B- and P- cables to handle the additional current.

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The main power cables vary depending on amperage rating of the BMS.

  • 150a BMSs use 6AWG 200°C Silicone wire
  • 200a and 250a BMSs use 2 AWG 200°C Silicone wire
  • 300a Fan BMSs use two sets of 2 AWG 200°C Silicone wire

It may seem like the wire size is a bit small for the current, but also bulky for being attached permanently to the BMS, but neither of these are true.  The wire is ultra-fine stranded tin-plated copper conductor, which allows for immense flexibility while maintaining great current-carrying capacity.

We wondered the same thing, so we hooked a 200a 4s BMS up to our lab-grade equipment and ran a test.

Measured across the ends of the 2awg silicone wires

  • Under a 100a load, there is a 53.9mv drop
  • Under a 75a load, there is a 40.9mv drop
  • Under a 50a load, there is a 26.9 mv drop
  • Under a 25a load there is a 13.4 mv drop
  • Under a 12.5a load there is a 6.73 mv drop
Measured across the metal connection points to the PCB
  • Under a 100a load, there is a 29.38mv drop
  • Under a 75a load, there is a 22.03mv drop
  • Under a 50a load, there is a 14.67mv drop
  • Under a 25a load there is a 7.345 mv drop
  • Under a 12.5a load there is a 3.600 mv drop
Based on this test data, we have concluded that the voltage drop across the BMS is predominantly based on the voltage drop across the wire, traces and internal shunt.

We have used many various models of these BMS units, and we never have been able to blow the MOSFETs that handle the current inside.  They are built like a tank…Even when we messed up and had a direct short across the output of a BMS, a simple reset & reactivation process had us up and running in notime.