Home-brew battery measuring station

[BrianG]

Update:

I was going to build the throttle control circuit myself, but found the Esky EK2-0939‏ servo tester that is probably more accurate and less prone to "drifting" with temperature, age, etc, so I ordered it. Coming from China, so it'll be a week or so before it gets here. In the meantime, I noticed it needed a power supply from 6v-9v, and since the ESC might not provide a stable 6v output on the BEC at the high battery loads I'll be testing, I made a regulated 8v power supply. Nothing special, just a small transformer, a couple caps, and a LM7808 regulator. I happened to have all the parts handy so it was effectively free.

I also picked up an Eagletree V3 datalogger from another member here. It came with one USB cable, but I needed another cable, so I made one from one of a billion USB cables I have and the speaker connector from a computer motherboard:



Then, since I needed a temperature probe, but didn't want to pay for one, so I scavanged a thermistor from my pile of computer parts and attached a servo connector on the other end. Works well, is accurate, and has a quick response time. I want to bond a small piece of aluminum to it so I can get a better reading and to reduce any stress on the delicate thermistor:



So, progress is slow, but coming along.