I never did this before and had always the feeling that the Victron shunts were spot on regarding measurements, but today I’ve conducted several measurements on the Smartshunt 500A and it did not perform as expected. At very low currents (1A) the Smartshunt was 5% off (1.0001A; Shunt shows 0.95A). A…

Very interesting thread. I came to it because my SmartShunt shows small currents in the VRM portal with 0.1A resolution, even though the datasheet says the resolution is 0.01A. The official software on Venus OS rounds the value before it reaches D-Bus. This bothered me enough that I wrote a script t…

[image] dmitrych: I can share the details if anyone is interested Please do

Disclaimer first: everything I mention here is at your own risk. It works on my system, but I can’t tell if it will work on yours, use your judgement. You’ll need SSH access to your GX device (as a new user somehow I can’t post links here): victronenergy. com/live/ccgx:root_access Proof of concept …

[image] mystudio: JK BMS is a horror in getting the current consumption right. They are terrible. If you calibrate at 10A, then everything is wrong at lower and higher currents. You keep calibrating these things. But that’s a complete other problem I tried calibrating a JK BMS several times a…

[image] dmitrych: Proof of concept I’ve attached a proof of Thanks, very interesting. I ran into the same serialstarter issues when writing a custom USB-GPS filter in Node-RED.

Nice! Regarding accuracy; the thing is more accurate than man might think. Did some quick tests today, now it has been tuned and it is SPOT ON. First impression it’s accurate upto 10mA. Tested with very small currents and even 10 mA and 20mA are visible and spot on. And going up it gets easier, and …

[image] mystudio: Curious if you’re able to go to the 1mA domain/resolution I do see that the shunt returns numbers that differ by 1 mA from each other (either noise or real), so at least ADC resolution appears to be good enough, but unfortunately I don’t have lab grade equipment to ensure an…

[image] mystudio: do you see those weird SOC changes only on the BMS The soc jumps and sometimes it doesn’t register an soc drop even though there has been a draw. Yes. [image] mystudio: 5/1: SOC 63% Consumed Ah: 121.0 Ah 3/1: SOC 64% Consumed Ah: 120,5 Ah 2/1: SOC 64% Consumed Ah: 120…

JK BMS is measuring peak current and not average. A Multiplus II with AC IN active, induced peak DC current on the batteries, and this is why the BMS never sees 0A current and always jumps between plus an minus amps. This is why JK BMS is inaccurate in the low current range.

[image] mystudio: I think the resolution indeed is in the 0.01A or 10 mA Do any of you open it and see which microcontroller a shunt is using? To know which resolution its ADC has? Because if the resolution is the usual 12bits, the current quanta will be 500A/2^12 = 122mA, for 16bit the reso…

Mismatch Smartshunt 500A and specifications

Q&A and troubleshooting

UpCycleElectric (Jan) January 21, 2026, 12:55am 49

Good find

SmartShunt SOC measurement for infrequent recharges

Venus 3.70 - lowest and highest cell voltage - reduced precision after upgrade

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Mismatch Smartshunt 500A and specifications

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