Quote:
Originally Posted by bennelson
My ammeter shunt is in series in the string of batteries, so I am measuring battery amps. I always felt that's the number to watch, because the batteries care a lot more about how many amps you pull than the motor does!
Anyone have a spare analog 500 amp ammeter kicking around? Mine only goes to 300!
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You can get like +/- 5% accurate using the copper cable from the controller M- to the Motor as the shunt. Then, just use a cheapo $2.99 volt meter from Harbor Freight set on the 200mV setting, and convert the measured voltage across that cable into current by doing I = V/R, where R is the resistance of your cable. It will be a tiny resistance. How long is that cable? What gauge cable?
The reason the controller senses motor amps is to protect the mosfets and diodes. It's also a really good idea to measure battery amps, to keep them safe too. That should be a feature we add later.