Horsefly
Solar Wizard
I'd forgotten that I had written stuff here about the Thornwave Labs Powermon-5s long ago. I've had it for quite a while now, so I have more experience with it. Unfortunately it is mostly not good.
At it's basics, I would expect the powermon-5s to do a good job coulomb counting, and giving an accurate representation of the SoC (State of Charge) of the battery pack. At this it seems to fail. It looks as though the algorithm it uses is for lead acid batteries, as it assumes there is some sort of self-discharge. I had a BMS, a Victron Smart Shunt, and the Powermon-5s connected to my test LFP pack for several weeks, with no loads. The initial state was about 82%, and that was reflected on all three units. After about three weeks the Victron and the BMS still showed about 82% (I think one of the two may have dropped to 81%), but the powermon-5s showed 71%.
The data logging does not work in any useful way. You can set the sample period to anything from one sample per second to one per minute. Unfortunately the labeling of the data only works for one sample per second, and even then the data appears to not be logged correctly. There is no way to export the log data anyway, as you can only look at it on the App.
The one very handy feature of the Powermon-5s is the relay control. It has a relay that can be programmed for a number of conditions, including a high voltage disconnect, low voltage disconnect, high current disconnect, or timers. I will be using the powermon-5s in my system, but only for this relay control.
At it's basics, I would expect the powermon-5s to do a good job coulomb counting, and giving an accurate representation of the SoC (State of Charge) of the battery pack. At this it seems to fail. It looks as though the algorithm it uses is for lead acid batteries, as it assumes there is some sort of self-discharge. I had a BMS, a Victron Smart Shunt, and the Powermon-5s connected to my test LFP pack for several weeks, with no loads. The initial state was about 82%, and that was reflected on all three units. After about three weeks the Victron and the BMS still showed about 82% (I think one of the two may have dropped to 81%), but the powermon-5s showed 71%.
The data logging does not work in any useful way. You can set the sample period to anything from one sample per second to one per minute. Unfortunately the labeling of the data only works for one sample per second, and even then the data appears to not be logged correctly. There is no way to export the log data anyway, as you can only look at it on the App.
The one very handy feature of the Powermon-5s is the relay control. It has a relay that can be programmed for a number of conditions, including a high voltage disconnect, low voltage disconnect, high current disconnect, or timers. I will be using the powermon-5s in my system, but only for this relay control.