Battery monitor reading incorrectly?

[LifeIsADeam]

Hi, im 1 week into testing my new lifepo4 setup in campervan. It looks as though the amps coming in/out reading on aliexpress battery monitor is off. My bms app (jdm) will for example read 3 apms coming out while the monitor states 11 amps. Any advice is appreciated . The monitor seems out as i rarely every pull 11 amps continuously.

 

[Just John]

Hi, im 1 week into testing my new lifepo4 setup in campervan. It looks as though the amps coming in/out reading on aliexpress battery monitor is off. My bms app (jdm) will for example read 3 apms coming out while the monitor states 11 amps. Any advice is appreciated . The monitor seems out as i rarely every pull 11 amps continuously.

Most meters will accurately measure up to 10 amps, sounds like one or the other (or both) needs calibration. Keep the load under 10 amps and use your meter to calibrate the BMS (most have calibration settings in the PC software). So far (knock on wood) all the cheap aliexpress shunts I've gotten were really remarkably accurate. None of them have any documented calibration procedure that I know of.

The least accurate piece of equipment I have is a Daly BMS.

 

[John Frum]

Hi, im 1 week into testing my new lifepo4 setup in campervan. It looks as though the amps coming in/out reading on aliexpress battery monitor is off. My bms app (jdm) will for example read 3 apms coming out while the monitor states 11 amps. Any advice is appreciated . The monitor seems out as i rarely every pull 11 amps continuously.

Please post a product link for your battery monitor.
One for the bms would also be helpful.

 

[LifeIsADeam]

Hi, its the ali monitor from Wills video. The bms is jdm same as overkills. Ive also seen the monitor saying its receiving much more amps than it is according to my victron app. Ex 2-3 amps in victron app and the bms app but 7 amps according to the monitor

 

[LifeIsADeam]

Most meters will accurately measure up to 10 amps, sounds like one or the other (or both) needs calibration. Keep the load under 10 amps and use your meter to calibrate the BMS (most have calibration settings in the PC software). So far (knock on wood) all the cheap aliexpress shunts I've gotten were really remarkably accurate. None of them have any documented calibration procedure that I know of.

The least accurate piece of equipment I have is a Daly BMS.

Thanks for the reply. Is it possible to calibrate an aliexpress monitor? The bms and victron app seem to share same reading with charging from solar unlike the monitor.

 

[Just John]

Thanks for the reply. Is it possible to calibrate an aliexpress monitor? The bms and victron app seem to share same reading with charging from solar unlike the monitor.

Not that I know of. I'm sure the manufacturer has a calibration method, but as far as I know, they haven't shared it.
I have two different ones, the Ali one comes with actually decent documentation. No real details, but how to install, wire it up, and operate, nothing else.

 

[chrisski]

Is the battery monitor shunt the first thing off the negative lead of the battery?

If it is why its reading differently is a mystery to me. Not uncommon in the day when I monitor power for something like a cup of coffee for my SCCs to show many more amps produced than my battery puts out. I have a 55 amp coffee maker and the panels can push 50 amps of it and the battery only 5. A shunt installed in the wrong area would produce something like that.