Is the VESC 4.12 energy measurements reliable?

Hi guys! I have some issues regarding energy measurements.

I have a 15Ah battery connected to two VESCs 4.12 (different brands). According to them they each consume ~1,2Ah on a 7,8km ride (~5miles). That is a total of 2,4Ah. If I use 12Ah of my battery, that should then give me a range of 50km (~30 miles). This is far from the truth unfortunately. It’s like a factor 2 wrong.

When I charge the battery after a 7,8km (5miles) ride with initially fully charged battery, I get ~4,3Ah!! into the battery according to the IMAX b6 clone. Not the 2,4Ah stated by the VESCs. Using 4,3Ah in my calculations makes much more sense since I have around 25km range (15miles). ( 12Ah / 4,3) * 7,8km = 22km.

To add confusion… I don’t actually know the status of the cells. It is possible that they were aged before I got them and it would explain that I don’t get the 50km range. However, my two IMAX b6 clones I use for charging tells me another story. Not sure what to believe now. Either both IMAX chargers measures wrong, or both VESCs measures wrong… or my thinking is wrong :smiley:

So two questions: 1. Are the VESC energy measurment accurate and if so, what am I doing wrong? 2. I can only see two current shunts and they are for the phase current measurement. Does it mean the I_DC is calculated and not measured?

Here is a screen shot of energy calculations for a typical 7,8km ride. 3,5 *2,24 = 7,8km. Don’t mind the 0,4V battery voltage offset on VESC 2.

Interesting, sure sounds like your VESC measurement isn’t accurate. I might have to go back to my Lipo setup so I can charge them on my RC charger and test mine…

My VESC battery current measurement is not accurate!

Tested with an very old but good HP power supply.