Recommendation for a bit accurate battery capacity/voltage/current monitor?

[ytwytw]

I currently have the following stuff

Clamp Meter, used by DavidPoz and I think I would take it as the point of truth???

UNI-T UT210E True RMS AC/DC Current/Voltage Mini Clamp Meters with Capacitance,Resistance Measurement : Amazon.ca: Tools & Home Improvement

UNI-T UT210E True RMS AC/DC Current/Voltage Mini Clamp Meters with Capacitance,Resistance Measurement : Amazon.ca: Tools & Home Improvement

www.amazon.ca

Voltage/Current/Capacity/Coulomb meter 1

Wireless Battery Monitor Voltage Meter Ammeter DC 100V 100A Watt Power Capacity LCD Digital Tester: Amazon.ca: Tools & Home Improvement

Wireless Battery Monitor Voltage Meter Ammeter DC 100V 100A Watt Power Capacity LCD Digital Tester: Amazon.ca: Tools & Home Improvement

www.amazon.ca

Voltage/Current/Capacity/Coulomb meter 2

WINGONEER Wireless Digital DC Voltmeter Ammeter Multimeter, 2.4" LCD Voltage Ampere Power Watt Coulomb Capacity Time Meter Temperature Tester Detector with Hall Sensor & Temp Sensor - 80V 100A : Amazon.ca: Electronics

WINGONEER Wireless Digital DC Voltmeter Ammeter Multimeter, 2.4" LCD Voltage Ampere Power Watt Coulomb Capacity Time Meter Temperature Tester Detector with Hall Sensor & Temp Sensor - 80V 100A : Amazon.ca: Electronics

www.amazon.ca

Ant BMS for my BYD Pack
Recommended by Will as it has bluetooth config + low temp cut-off (very important to me)

MPP Solar LV2424

Problem:

All of the above 4 devices are reporting the same voltage value, but the current value are very different.

When MPP Solar reporting 13Amp, BMS said 14.8Amp, monitor1 said 15.3Amp, monitor2 said 15.8Amp
Clamp meter said 14.6Amp

I did calibrate the hall effect sensor for monitor2, but it seems always 1Amp more than BMS
monitor1 is shunt based current sensor, about always 0.5Amp higher than BMS reported value
MPP Solar always report the lowest current value, maybe it's definitely not accurate?
The clamp meter, I did reset to zero prior to use, but could that be the problem?
Ant BMS does have current calibrate feature, and I did use it when everything is off including all other monitors

I am a bit frustrated now since I am not sure what is correct, and what is incorrect

Because when I am doing capacity test with them, the value for BYD pack could go from 3.5kWh to 3.95kWh

 

[BiduleOhm]

Your best bet is the shunt based monitor, it should be the most accurate of all.

Actually it's pretty crappy for a shunt based meter; from their description they say it's +/- 2% + 5 counts so if you read 15.3 the real current can be anywhere from 14.5 to 16.1. The hall effect based one gives the exact same precision in the description... The shunt one should be at least 2 times better, oh well...

So your best bet is the clamp meter on the 20 A setting, zeroed just before the measure

 

[tictag]

If you're looking for an accurate energy meter, just buy one of the Victron BMV units. Resolution down to ±10mA, accuracy at ±0.4%. You've got Bluetooth options, remote automation via a programmable relay, temperature and Puekert compensation ... blah, blah, blah.

 

[ytwytw]

If you're looking for an accurate energy meter, just buy one of the Victron BMV units. Resolution down to ±10mA, accuracy at ±0.4%. You've got Bluetooth options, remote automation via a programmable relay, temperature and Puekert compensation ... blah, blah, blah.

I have eye on the Victron 712 but wayyyyyyy to expensive

I was hoping someone on the forum can recommend cheap one, trying to get the meter tha Will has but they are all gone from Amazon (I assume they are so good that all gone)