On board volt & amp meter

[Christopher Morris 2]

Hi, Now the larger electric planes can run at quite high amperage, so i thought a volt/amp meter on the outside/top of the fuselage from ebay so i can see the battery voltage & what amps it pulling on the ground permanently. Now the motors can quite often pull 60+ amps, so I am assuming a to go for a 100amp shunt. But they come in different Ma versions & it was this part i wasn't sure on. "What size milliamp to use" The batteries used are 5amp hour 14.5 volt lipo's. Any ideas on shunt types?

Thanks

[Andy48]

Use a wattmeter. Much simpler. It will give you the current consumption.

[Dickw]

Posted by Christopher Morris 2 on 06/03/2020 15:02:18:

Hi, Now the larger electric planes can run at quite high amperage, so i thought a volt/amp meter on the outside/top of the fuselage from ebay so i can see the battery voltage & what amps it pulling on the ground permanently. Now the motors can quite often pull 60+ amps, so I am assuming a to go for a 100amp shunt. But they come in different Ma versions & it was this part i wasn't sure on. "What size milliamp to use" The batteries used are 5amp hour 14.5 volt lipo's. Any ideas on shunt types?

Thanks

Without any more information I would guess the mA rating of the 100A shunt is to match it to whatever mA input your meter is expecting for full scale reading.

But as Andy said a wattmeter would be a more common and flexible approach, or telemetry if you have that option in your radio system.

Dick

[Chris Bott - Moderator]

Which radio do you use Chris?

Depending on the radio, this can be just as easy to do via telemetry and see the numbers on the Tx display. Then, you don't need to carry a display on the model.

[Frank Skilbeck]

Another option might be to see if you can get hold off an older Eagletree logger, I've got a V2 from before I had telemetry, with the optional display this shows Volts, amps, watts and mah, it also logs the results so you can view your flight data later.

Maybe try a wanted ad (note I'm not selling mine as I still use it from time to time as a watt meter)

[Christopher Morris 2]

It was just a case of me having several spare 0-30v 100amp DC meters that were very cheap & small enough to fit a permanent meter to the plane. I have a spektrum DX8e & 6E & just purchased some spektrum AR620 & Ar410 arial-less receivers & i believe these have limited telemetry as standard. But i believe it will only give the receiver/Bec voltage, which is not much good for electric planes. The only reason for the meter was to save taking the plane apart for a quick check on the battery.. I can land, have a quick look at the meter & if all ok, take off again.

 

Edited By Christopher Morris 2 on 06/03/2020 20:27:07

[PatMc]

Forget about checking the current, just fit the voltmeter leads to the outer pins of a 4 pin jst-xh socket then connect that with the battery balance lead when fitting the battery.
Check the voltage at rest then at WOT to see what the volts drop is under load.

OTOH use a tachometer to check what rpm you get at WOT between flights.