That's fine, but NiMH was exactly what I needed for my specific requirements. I too have LiFePO4 batteries including a 12.8v unit by Battery Tender and a handful of LiFePO4 18650 and 26650 cells. LiFePO4 would not have been a good fit for my needs. At 3.2v per cell LiFePO4 batteries or battery packs would have put me too far below or above my ideal voltage range and I didn't want to use a voltage regulator.
I used what I had on hand for my specific application, and it was good fit. I already had one 7.2v NiMH battery pack and the battery charger to go with it so I just bought another larger 7.2v NiMH pack, along with a couple cables. While one pack is on the charger, I can use the other pack to play music. With NiMH it is much easier to arrive at the ideal voltage range I wanted (7 VDC for mRendu) as each NiMH cell is 1.2v.
Many of the former battery lovers went ahead and switched to Super/UltraCaps some years back (I think it started around 2010/2011). That'll relieve you from the annoying battery charging process and can provide even lower ESR
Really? UltraCaps don't need to be charged? Sign me up!
I also own some UltraCaps but the complexity of safely charging them unattended is more than I want to deal with. Do you know of any readily available off the shelf wall wart or power brick style UltraCap chargers with auto shut-off? ;-)
