My battery pack is made up of Fullriver DC100-12 and HC100-12 batteries. The HC series is really not the best for this application, but I got a good deal. Having a mix of batteries means monitoring them is really important. When one battery goes out before the others, it consumes power instead of producing it. This puts a significant extra load on the rest of the batteries.
Here’s an example of how I look at my battery data. The voltage comes from a PakTrakr. The mileage is derived from GPS. The plots are made with gnuplot.
Here’s a good battery on a recent drive. This is a brand new Fullriver HC100-12.
Here’s a bad battery on the same drive. It’s a Fullriver DC100-12. I’ll be replacing it soon.
Here’s another battery that’s old but still in good shape (it’s also a DC100-12):