I have just check the Sears catalog for clamp on DC amp meters and it show a True RMS AC/DC Clamp Ammeter sears item # 03473756000 price $99.99. There is a higher priced model for $179. Has anyone used this meter (the $99) for our purpose and does it do what we need or do we need the $179 model.

Best,          Dennis

Hi Dennis - Long time no see.  Mine is a model 82062, bought for $50 about 3 years ago.  Accurate to within 2%, plenty close enough.  I'm not sure if that model no. is the same item no. you mention, but no need from this end to spend more money than the basic model.  Also doubles as a dandy troubleshooter for your auto battery and starter.  Tom H.

HI Tom

I have sold several people these for 49 bucks, they seem to like them

 Astro Flight's Super Whatt Meter - Digital Volt/Amp Meter No Plugs
Astro's new Super Whatt Meter takes the guesswork out of electric flight. Just look at what this new precision instrument can do for you. With this instrument, you will know
Measurements:

Current draw up to 70 Amps,
Nicad battery voltage up to 60 Volts,
Motor input power up to 4,000 Watts,
Nicad capacity up to 9,600 milliamp hours.
Motor timing for maximum power and efficiency.
Props and know which ones are the best.

Regards
Randy

www.aeroproduct.net


 

Actually the Astro Wattmeter Randy mentions is a better system (I think) than the clamp on since it also simultaneously measures the battery voltage along with current, as well as keeping track of the mAHr delivered. It can also be used while charging the battery if you are interested.. The best that can be said of the clamp on is that you don't have to unplug anything--but you do need to get access to one of the leads.

A potentially positive thing about the clamp-on is that if you put it on one of the motor leads, you may be able to measure the motor current. However I am not positive how this actually works out since at least 30% of the time one of the 3 wires isn't being powered. But anyway one should realize that battery current isn't the same as motor current except at full throttle (ESC on all the time). Most of us are flying at partial throttle, and in this case, battery current is actually less than motor current.

Decided to go with the $59 Sears AC/DC Clamp on (Sears item# 03482369000) thanks for the tip Tom. It is a nice size and also has the temp probe should do all I need. The $99 unit is a bit bigger and the only interesting extra is the infrared temp sensor. If one need that Sears a nice small one for $49. Hope to do some tests on the A123 set-up soon.

Best,  Dennis