OK so any good BMS has a specific amp rating and will cut power for a short circuit. Is there any realistic time to exceed the limit for a short period to provide inverter surge performance? I see videos where the BMS seems to operate at 110% maybe 120% continuous. Can the BMS go overdriven for a second or two at 150%? Or what would be realistic? This question is in relation to a motor start up driven by an inverter.
Inverter Surge Performance
- Thread starter time2roll
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Steve_S
Offgrid Cabineer, N.E. Ontario, Canada
It really depends on the BMS. Some have adjustable surge delays or cutoff delays (terms vary) which allow for XXX seconds delay before cutoff. This kind of functionality is more likely to be found on BMS' which use Relays/Contactors than FET based BMS'.
In my design I will err on the side of ensuring there is enough base BMS rating to satisfy the surge. I could have put in one 4s battery with a 120 amp BMS. I instead chose to put in two 4s batteries, each with a 120 amp BMS. Now I have 240 amps of rating.
The Overkill Solar BMS (which I'm using) has been shown to operate continuously at its 120 amp rating and then some. But I'm not relying on the "and then some" in my design.
I briefly get an overload light from my 1000 watt inverter but the 1/2 HP pump starts right up with no BMS issue of limiting power.
Using Overkill 12v 120 amp BMS. Surge wattage on the motor had me wondering what might be the choke point but all works fine.
Using Overkill 12v 120 amp BMS. Surge wattage on the motor had me wondering what might be the choke point but all works fine.
