Hi All,
I have my diy powerwall (18650 cells 14s120p), for about 2 weeks. So as you can see I'm at the beginning of my journey. I'm learning more and more about the way how thesystem is working and I'm tuning the settings to make it work the way I want.
I'm using batrium BMS (WM4 + Longmons) and I've noticed that the voltage accuracy is not great. In my case all my longmons reading to low. I've measured my cells with my Fluke multimeter (which was calibrated a month ago), and the best longmon is -0.01V off (which I'm OK with) and the worst one is -0.03V off (which I'm not happy with).
From what I've noticed of the forum, everyone (including myself)is configuring system voltage with accuracy to second decimal place.
Being off 0.03V onthe entire pack is not an issue, but if you are out 0.03V on individual cells is not great. According to spec longmons can be as much as +-0.1V (typical +-0.05V off), which I didn't know before I've purchased my bms. It looks that I'm actually quite luck that my readings are just 0.03V off (the worst case).
From spec 0.05V accuracy for 3.7V cell is 1.3% measurement error, which is huge comparing to my Fluke179 which is 0.09% accurate.
Batrium is quite expensive (my set cost me over 700) and I would expect better accuracy from it, especially that the system is using values with 2 decimal places (or at least an option to adjust the reading in software to much true values).
Does anyone ever re-calibrated longmons? Does anyone know how to do it? I can't find anydocumentation on batrium website.
I've sent them a question about it and waiting for reply, but I thought I will ask community what is your experience with longmons accuracy.
Regards
I have my diy powerwall (18650 cells 14s120p), for about 2 weeks. So as you can see I'm at the beginning of my journey. I'm learning more and more about the way how thesystem is working and I'm tuning the settings to make it work the way I want.
I'm using batrium BMS (WM4 + Longmons) and I've noticed that the voltage accuracy is not great. In my case all my longmons reading to low. I've measured my cells with my Fluke multimeter (which was calibrated a month ago), and the best longmon is -0.01V off (which I'm OK with) and the worst one is -0.03V off (which I'm not happy with).
From what I've noticed of the forum, everyone (including myself)is configuring system voltage with accuracy to second decimal place.
Being off 0.03V onthe entire pack is not an issue, but if you are out 0.03V on individual cells is not great. According to spec longmons can be as much as +-0.1V (typical +-0.05V off), which I didn't know before I've purchased my bms. It looks that I'm actually quite luck that my readings are just 0.03V off (the worst case).
From spec 0.05V accuracy for 3.7V cell is 1.3% measurement error, which is huge comparing to my Fluke179 which is 0.09% accurate.
Batrium is quite expensive (my set cost me over 700) and I would expect better accuracy from it, especially that the system is using values with 2 decimal places (or at least an option to adjust the reading in software to much true values).
Does anyone ever re-calibrated longmons? Does anyone know how to do it? I can't find anydocumentation on batrium website.
I've sent them a question about it and waiting for reply, but I thought I will ask community what is your experience with longmons accuracy.
Regards