jari Posted March 1, 2015 Share Posted March 1, 2015 (edited) Got a new toy from Hobbyking - one of the 130A watt meters. For use in car to take measurements like peak Amps, Amp hours, Watt hours etc....I have always wondered exactly what the electrics are doing in my cars. now I can find out. I wonder just how much we overspec our electrics... The device connects in line between battery and ESC. first for measurement is the newly converted Hyper 7. motor: 1900kv hobbyking4 pole - the cheap one ESC - Hobbyking 150A Lipo: 5000mah 60C hardcase pack. Car: hyper 7 converted. not sure of weight tyres: hobao angle spikes. surface - tarmac then short grass. pinion : 18t gearing should be good for 40+ ish. (ignoring all losses) So...what prediction would you make for peak amps? What ESC is small enough to run this system on 4S? Figures: Peak Amps: 87 Peak Watts: 1448 Runtime: 13 minutes or 780 seconds. Minimum voltage - 5.98 - now this is a bit worrying! Watt hours - 50.5 Amp hours - 3.3 So in my opinion what does this all mean? Peak amps - 87... is perhaps about what I'd expect. Maybe seems low for the speed. HK peak amps is listed as 120. this is way off. Have to try the motor on 5S or under more load. Peak watts - 1448 or 1.5kW, approximately 2 horse power. From a Edited March 8, 2015 by jari Quote Link to comment Share on other sites More sharing options...
Tug Posted March 1, 2015 Share Posted March 1, 2015 Had one for a few years, very handy for setting up a new car. Shame they don't make a larger version, 200+ Amps. Highest I've recorded on mine is 137 Amps, not bad for a 130 Amp limit! Most recently used it on my Super 5sc flux. The 1/5 scale, 58110, 380kv motor topped out at 113 Amps. That was on 8S too, so impressively low. Quote Link to comment Share on other sites More sharing options...
jari Posted March 1, 2015 Author Share Posted March 1, 2015 Had one for a few years, very handy for setting up a new car. Shame they don't make a larger version, 200+ Amps. Highest I've recorded on mine is 137 Amps, not bad for a 130 Amp limit! Most recently used it on my Super 5sc flux. The 1/5 scale, 58110, 380kv motor topped out at 113 Amps. That was on 8S too, so impressively low. your posts here have tempted me to get one... just seems really, really useful when setting up. to know how close to various limits you are, and as a second data point alongside motor temps. have you measured the 58110 on 6S, 7S and 8S? 113 amps is 3.6kw. so in theory... you could get close to that power with two of the small 4 pole motors running in parallel? Quote Link to comment Share on other sites More sharing options...
Tug Posted March 2, 2015 Share Posted March 2, 2015 Only tested it on 8S so far, but will test it on lower voltages just to see. Quote Link to comment Share on other sites More sharing options...
jari Posted March 8, 2015 Author Share Posted March 8, 2015 Update: Tried the same car today with different batteries and different gearing. Batteries used: 3S - Turnigy 5000mah 40C over 12 months old 4S - Turnigy 5600mah 60C - new, 5S - Dynamic 4500mAh 30C - over 12 months old. Gearing used: in order 18T 15T 20T Testing done on tarmac. on rather inappropriate hobao spike tyres. I did one run on grass nearby and it did not seem to affect the measurements, i.e. it was no higher than the road so I stuck with the road. 18T test was first. figures are for Peak Amps and peak Watts. I did take some minimum voltage readings and voltage. 3S start: 12.4V, 86A / 981W 4S start 16.7V 86A / 1342W 5S stat 20.8V, 18.3V min. 103A / 1924W verdict. 5S is mental. was trying to lift the front tyres on the tarmac. Stopped and changed pinion to 15T 3S 75A / 900 W 4S 77A / 1192W 15.2Vmin 5S 88A / 1685W 18.4Vm verdict: not sure. 5S manageable here. 4S still quite fun. Stopped and changed pinion to 20T 3S 82A / 909W 4S - ran out of time. did not do. 5S start: 19.9V - voltage drop reflected in power reading below. 103A / 1880W will work out theoretical speeds later. Quote Link to comment Share on other sites More sharing options...
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