After struggling with power problems for years and buying several brands of 12v batteries and also using multiple batteries in parallel, I discovered I was looking in the wrong area. The solution for me was to find where power was being used and replacing inefficient modules with efficient ones. And the problems I found were surprising and probably NOT what you would expect. You really have to measure the current drain on all your devices to see where the problem lies – and it’s NOT going to be the Mayfly. In my case, the problems were:
- The 12v to 5v converter. Don’t believe the advertisements – measure it. I found cheap small buck converters are the best, but they vary widely.
- The solar panel charging circuit (if you have an external module) or the solar panel itself (if the charging circuit is built in). There should be very little current drain when the sun is not shining. BTW – bad charging circuits can kill a good battery too.
- A defective 10 year old SDI-12 sensor that was still working but using more and more power.
After fixing these problems, my stations need very little sun to keep the single 12v battery charged. I can even run my stations with no sun for months. Of course you should be putting the Mayfly, Modem and other devices to sleep between activities. Good luck.
Ps. you don’t need a LiPo battery on the Mayfly if you are powering it from the USB 5v. The LiPo’s cause problems too.