[NLRS] Previous presentation on batteries?

[Doug Reed]

I've bought a couple cheap LiFePO4 batteries for portable use, but
haven't used them yet. Earlier this year the Miady brand batteries
became the cheapest 12V batteries on Amazon. I bought two of the 16AH
batteries for $50 each, the price has gone up since then.

There is one major difference between the Miady batteries I bought and
the Bioenno LiFePO4 batteries. The battery cells in the Miady are
rated for low discharge currents, typically under 0.5C. With 16AH
batteries that means peak currents around 8 amps per battery. Most
other top-line LiFePO4 batteries are rated for higher discharge
currents, usually over 2C rating. So I bought two batteries to
parallel for 16 amp (or higher peak) discharge where the more
expensive batteries will do it in one higher priced battery.

Most of the LiFePO4 batteries also have the battery management system
(BMS) built in. The Miady BMS will disconnect the batteries from the
output terminal when it is fully discharged. It reconnects the
batteries when they get back to a safe voltage. It also monitors the
charge voltage and disconnects the batteries when they hit full charge
around 14.5 volts. The BMS is also responsible for balancing the
battery cells in series so they each have the same amount of charge.
If the battery cells started out with equal amp-hour capability, the
BMS will keep them equal for longest life.

<https://www.youtube.com/watch?v=iy3hga_P5YY>
<https://mortonsonthemove.com/best-rv-battery-test-results/>
The best YouTube video I've seen compared SLA vs LiFePO4 and had a
chart in the video that compared estimated battery life based on
depth-of-discharge for different chemistries. They tested at room temp
and cold temps, so it was very interesting. Just remember you must
warm the LiFePO4 above freezing before charging.

73, Doug Reed, N0NAS.