FE-Shunt 4+

I like the way this shunt works but there is one issue which looks like a problem with the app.

First one of the more useful fields is on the history page and is called Max Battery Voltage. If you are using this with a lithium battery which has a BMS that field tells you how much overshoot there was when the battery reaches full charge and the BMS shuts off. There is energy stored in coils on the output of most charge controllers and it has to go somewhere. That shows up as a voltage spike on the output. My battery is 12 volts and right now it is showing a spike of 19.78 volts. This can blow up boards that are not protected such as a fridge board in an RV.

The problem is on the same page and is labeled Energy. There is both in and out and normally they should be almost the same. Instead the energy out is almost twice the energy in. That is not possible. This battery cannot generate more than you put in.

Bluetooth range is short, probably a shortcoming of the device and not the app specifically. I wish the data ranges were more configurable. I’d like to be able to see “last hour”, “last day”, etc. instead of just “now” and “last 7 days”. 7 days is too much data to represent accurately on a phone screen. It would also help if I could download the data to csv for analysis on a computer.

App works VERY good and haven’t had any issues with the hardware. Bluetooth works better than other Bluetooth shunts I have tried