SmartShunt shows impossible charging rate

wainscott
Sat, 04 Apr 2026 16:00:45 +0000
DIY

I have a SmartShunt 500A with 600ah of Renogy LiFPo batteries and 880w solar (with a Victron MPPT smart solar charger).

The shunt seems to properly record batter discharge, but DRASTICALLY overestimates recharging, which makes the SOC completely unreliable.

Here are my shunt settings in the app:

And here are two screenshots from the app which show the battery being charged at an impossible rate:

The first shows the battery at 85% SOC at 11:28:51, and 334 W coming in from the solar panels. The second shows that at 11:39:00 (10 minutes and 9 seconds later), the panels are providing 295W and the battery is now fully charged!

15% of my 600ah battery would be 90ah. 12 minutes at 330W at 12V is 5ah. (At 14.4V it is even less). That is off by a factor of 18X

This screenshot from the app also shows impossible arithmetic:

The previous day about 40Ah are reported as having been used. With 64 on this day, the 84% SOC looks correct. But then the SOC shoots back up to 100 during the first couple of bars of solar charging, and then significantly MORE energy is added after supposed 100% SOC. But the total Ah reported added to the battery are only 49 even then, which is 55Ah less than was taken from the battery since the last charge of any kind. This SHOULD leave the SOC at 91% at most, not 100%+++.

So what might be wrong here?

4 posts - 3 participants