Hi,
I'm planning to replace the perfectly good, NHW11 traction battery with one from ReInvolt that uses NHW20 modules:
The perfectly performing NHW11 battery will be retired to "plug-in" duty to provide additional charge for the ReInvolt battery. But I am running into a safety issue, how to 'fuse' the power cables.
With AC power, there is a zero crossing point so any arc as the circuit breaker contacts open will be extinguished. But with DC, there is no zero crossing. So far, I'm looking at:
- Digikey $75, 30A, 300 VDC - a purpose built circuit breaker, I would need four.
- snubber - a resistor capacitor that sinks the current as the contacts open to extinguish the arc . . . a design and testing challenge (how to test arc suppression of the arc suppression device.)
- two-step, relay - the first relay opens to shunt the power through a second relay with a resistor to reduce current flow. Then the second relay opens and with a snubber, the arc is suppressed.
- solid-state - instead of using air-contacts, a power MOSFET is used to isolate the external wires. I suspect these are somewhat expensive too.
It is a safety issue because in an accident, the power cables might short. A battery power, fire is no laughing matter.
Target goal:
- 30 A, 300 VDC - the maximum power drain for the NHW11 battery.
Bob Wilson