Timeline for Inverting amplifier to measure shunt voltage?
Current License: CC BY-SA 3.0
12 events
| when toggle format | what | by | license | comment | |
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| Jan 2, 2017 at 23:20 | vote | accept | user95482301 | ||
| Dec 16, 2016 at 6:24 | comment | added | jonk | I wasn't recommending that chip for your situation. You asked what I meant and I was merely pointing it out as the first google entry that came up in the search I suggested you try out. | |
| Dec 15, 2016 at 23:09 | comment | added | user95482301 | jonk: Thanks for the input. The bq26220 sounds interesting, but I think few of the commercial chips will be able to support 100A charge currents. I'll read more about it. JackB: I'm just using it for my own monitoring, and paired with SoC/voltage measurements (every night it will have 50mA load, so every morning it will be able to guesstimate the SoC from the resting voltage). But I agree that it probably won't be very reliable - even many commercial systems aren't... | |
| Dec 15, 2016 at 22:28 | comment | added | Jack B | I think he's talking about the way errors can add up when coulomb counting. If you're trying to keep track of the charge state over time, and you always have a small (random) error in your measurements, then as you add those measurements together, the error accumulates. Eventually, instead when the charge goes from 10% to 30% the electronics will tell you it's gone from 140% to 160%, or -5% to 15% or whatever. You'll need to occasionally reset it to zero or full. | |
| Dec 15, 2016 at 22:28 | comment | added | jonk | Google up "battery monitor IC" -- you will find a number of them and they often discuss the problem and some solutions, it seems. TI's bq26220 came up right away -- and it mentions it. But I'm not looking into the datasheet. You can do that, and/or check out others as well. So I'm not entirely wrong about the concern, it seems, now that I looked. (Which is nice to know, as I'm only going on math knowledge about integrating, generally.) | |
| Dec 15, 2016 at 22:22 | answer | added | Jack Creasey | timeline score: 1 | |
| Dec 15, 2016 at 22:15 | answer | added | The Photon | timeline score: 1 | |
| Dec 15, 2016 at 21:46 | comment | added | user95482301 | I'm not sure what you mean. I've searched google for "uncompensated accumulation electronics", but I didn't find any articles discussing the problem. Would you have a source where I could read more about it, e.g. what to expect and how to reduce problems? | |
| Dec 15, 2016 at 21:45 | history | edited | user95482301 | CC BY-SA 3.0 |
added 282 characters in body
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| Dec 15, 2016 at 21:43 | answer | added | Andy aka | timeline score: 1 | |
| Dec 15, 2016 at 21:37 | comment | added | jonk | I think the bigger problem is likely going to be dealing with the uncompensated accumulation (or de-accumulation.) You may need to figure out some method of automatically compensating the offsets to minimize that error (and/or using precision devices that have been calibrated against accuracy standards.) But how important this actually will be depends on details you haven't discussed about your usage, needs, and operational behavior overall. | |
| Dec 15, 2016 at 21:21 | history | asked | user95482301 | CC BY-SA 3.0 |