Home-brew battery measuring station

[glassdoctor]

Originally Posted by BrianG

I agree. The only valid data would come from perfectly repeatable and consistent test setup.

I've thought about this for a while and don't think a dyno would be sufficient. We know that the temperature of the motor affects efficiency, and the motor temp would certainly change in a dyno, which would affect the results. I think the load would have to be something static and relatively temperature-independent. Which means we are back again to the resistor concept.

And since I was at work, I forgot to bid on those 3ohm 50w resistors (240 count) that I was watching. Ended for ~$50 + shipping. Poo. That's a whole heck of a lot cheaper than retail!!! Hopefully I'm on the ball a little better for the next one.

IIRC, CC uses motors (not sure what kind or how big, how many) in a bath of oil (big drum actually) to load test their ESCs. Might be worth picking their brains to see if they can help setup a similar test bed. I'm sure it wouldn't be difficult or expensive to find some suitable large motors (car starter motors, etc)

Just an idea

[Finnster]

Originally Posted by glassdoctor

IIRC, CC uses motors (not sure what kind or how big, how many) in a bath of oil (big drum actually) to load test their ESCs. Might be worth picking their brains to see if they can help setup a similar test bed. I'm sure it wouldn't be difficult or expensive to find some suitable large motors (car starter motors, etc)

Just an idea

hmm.. that's an interesting idea. i was thinking more, and really being able to setup any load on a motor should work. Are they using something like a propeller, or just a really large motor? I would think you would need a prop or something to create a load. Could get really messy tho :)

I was thinking about a prop for my above setup, but not sure how much it would mirror a car setup. Perhaps it doesn't even matter. The static tests are easier to do, I just don't know how predictive they are in dynamic apps, and its hard to create the really high loads (ie 60C) it would be nice to test. Maybe it doesn't matter... something to investigate.