Here is the response from Matt:

"Thanks for the message. The battery readout is a little fiddly and I'm trying to improve it through the software, because it doesn't represent the battery capacity through the discharge voltage curve. The meter's current draw is around 30mA and an alkaline AAA's capacity is around 1000mAh, so the expected useful life is around 30 hours.

Metering accuracy on a plain large subject is very good, the variations are introduced with the size of the target, surrounding conditions, and other real-world complications."

This was a very fast response and good, useful info on the battery readout and expected life. I will keep a check on battery life in the field and keep a set of spares on hand. Hopefully Matt will be able to get a software update out to improve the accuracy of the battery readout before too long. Also, btw, I put in fresh Duracell batteries and the readout was 90%, so...better than the 70% when I installed the Amazon batteries that came with the meter.

Regarding accuracy, I sent a follow-up inquiry. Will let you know what more I learn, if anything.