I have used the AMC1200 isolated instrumentation opamp, which was specifically made for isolated shunt measurement, it accept a differential input voltage within and close to its 5v power supply of +/-0.25V and has 8x gain, so its differential outputs will give you an isolated +/-2V that you feed into an opamp, for examply with a 2V offset to give you a 0-4V signal representing the full current measurement from negative max current to positive max, with 2V as zero current. At least, that is one of the applications I used, then fed that analog signal into an ADC to process it forther in SW. The AMC1200 expects 2 power supplies, one referenced to the shunt voltage and one for the output that typically is referenced to the digital low voltage system. This is also where you power an isolating dc/dc converter to power the shunt side. There are off the shelf transducers that have the amc1200 and get fed with 12v so you do not need to design your own circuit if you prefer. To do the same for voltage measurement, I have used the SVL1 but it is a chinese copy of a $100+ design and found almost 10% failures and unstable calibration. For quality current sensing, LEM makes fine sensors but there are several companies making nice Hall effect sensors. I like to plug in a few keywords into Digikey, select filter parameters such as current range, and see what rolls out. Hope this helps. Cor.
On Tue, Jun 17, 2025, 4:47 PM Lawrence Winiarski via EV <[email protected]> wrote: > I'm looking for a cheapo consumer battery monitor and I've been > discouraged in the past because I'm guessing the A/D is powered in the same > voltage range as the measurement. > i.e. A/D is powered at 0->12V and measurement is 0->0.075mvso the > measurement voltage lies too close to the power supply rails. > Any insight into a good cheapo monitor that has an isolated measurement > would be appreciated. > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20250617/7c81e8ae/attachment.htm > > > _______________________________________________ > Address messages to [email protected] > No other addresses in TO and CC fields > HELP: http://www.evdl.org/help/ > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20250617/a347eb88/attachment.htm> _______________________________________________ Address messages to [email protected] No other addresses in TO and CC fields HELP: http://www.evdl.org/help/
