OpenEnergyMonitor Community

Voltage reading is 1.333v


Stuart, I have a unique situation. I built my bms modules over the course of a year, I have 36 assembled so far. They’re gong to be used in a 4 bank array, 7s 74P in each bank. With the slow process I made, there ended up being two batch orders of parts.

I’m using the 4.21 modules and It looks like the last batch of 28 I assembled I did so with the tiny841-U chip by mistake and so my voltages are not correct. Is there a fix for this, or do I need to remove these chips and start over? The modules with the tiny841-U chips read around 1.333v max.

Appreciate all your effort and look forward to getting my diybms implemented soon. This will replace the dumb bms’ I have. This 25kwh pack powers my RV and is built from Tesla Model-S battery modules with an additional 1s custom module added (to make 7s total) which keeps my inverter happier. With 3kw of solar I’m generator free 90% of the time even running AC 24/7!

Screen Shot 2021-06-13 at 5.46.56 PM

Please disregard, I figured out I’m missing D1 on the 2nd batch of boards.