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Posted: Tue, 13 Jan 2015, 14:23
Back in 2013 designed an AH meter which was covered in the forum forums.aeva.asn.au/wanted-an-amp-hour-meter_topic3368.html.
Jonescg bought a couple to use on Voltron and found it not totally satisfactory as it didn't handle regeneration, so I thought I'd modify it to make it bi-directional. With a small change to some of the op-amp components and some new software, it now covers the range +- 511 Amps. Or, with a different current sensor it can do +-255 Amps with twice the resolution which may be better for high voltage, lower current systems.
This is aimed at the DIY enthusiast and everyone who converts any vehicle to electric power needs one!
If you want to build your own, send me a PM and I'll give you all the files.
Posted: Fri, 16 Jan 2015, 18:12
Thanks for putting these together Neville! And it was great to meet you when you were over here. The Ah meter is a pretty good system for simple machines like the race bike. We don't need to know how many Wh/km are being achieved, or even watt-hours, just a coulomb counter serves as a pretty useful range estimator. In the case of the race bike pack, when the number approaches 9 Ah, it's time to come in. There are other great products out there which connect to the fuel gauge of older vehicles, but this device is perfect for machines without such a meter.
Hope to put it to use this year!
Posted: Fri, 20 Mar 2015, 12:45
Hi, are you still selling the plans, circuit board or notes on the bidirectional Ah meter? It sounds like you have designed something that seems to not be available commercially.
Posted: Fri, 17 Apr 2015, 15:42
Sorry to not have replied sooner, I haven't looked on here for a while.
Yes, I have the plans for the AH meter. Drop me a PM with your email and I'll send them to you.
Posted: Fri, 17 Apr 2015, 16:33
Thanks for replying. My email address is firstname.lastname@example.org
Posted: Fri, 17 Apr 2015, 16:36
I'd edit that email address before a web crawler find it Andrew.
Common practice it to separate the username and domain name with plain english.
Posted: Fri, 17 Apr 2015, 16:38
doctordrewmoore (AT) gmail.com
is more like what you want to put in
Posted: Fri, 17 Apr 2015, 16:44
Oh, thanks for the reminder guys!
I actually connected my bi-directional Ah meter from Neville to a battery discharger and watched it count. Unfortunately the currents, and therefore the Ah values were about two times more than the value I read on the current clamp. I know my clamp isn't the most accurate measure either but a difference of 2x is pretty noticeable. Any idea what's going on?
Posted: Fri, 17 Apr 2015, 16:49
Sounds like the AH software doesn't match the current sensor.
Posted: Fri, 17 Apr 2015, 17:11
I forgot which meter was for which sensor (500 A vs 100 A), so I tried both, but the other one didn't work at all.
Posted: Fri, 17 Apr 2015, 21:09
I thought it was the 100A version.
I'll assume you zero'ed it before applying a load.