Originally Posted by _CY_
excellent feedback on starting your R1200 in -15(f or C?) degree weather with Shorai batteries. which model? LFX ?
HUGE advantage having an intelligent charger with balancing features with LiFePO4 batteries. 13.6v resting charge indicates a fully charged condition. LiFePO4 fully charged is 14.4v which quickly will scrub off surface volts to about 13.8v. depending on which charger was used. 14.4v to 13.6v represents about 10% of total capacity. voltage drops rapidly to 13.6 range. then voltage remains very flat until about 10% remains. only about 1/2volt drop for the working 70% of amp hour capacity. don't drop below 80% DOD or 12.86v if you want your battery to have a long life.
note just because a small LiFePO4 battery successfully starts a motorcycle at low temps with a fully charged/balanced battery. doesn't mean that same small LiFePO4 battery is recommended for adventuring. Amp hour is amp hour, there is no substitute. IMHO Shorai overates their batterie's actual amp hour capacity.
go with a larger battery than recommended.
The temp was -15F. The batteries are the LFX21A6-BS12. The battery used to start the bikes was first charged to the store level (which as I understand it is not 100% full charge), then left outside for two days to chill to outside air temperature and to allow the charged state to "settle". I suspect those two factors contributed to the initial low voltage reading. I have not take a voltage reading immediately after a full charge on a "warm" day so I don't know what a fully charged voltage level is for this battery but I suspect it is higher than 13.2V. As far as amp hours, I have no comment, not having the tools to do that kind of testing.
My choice of the Shorai was more out of frustration with the OEM AGM batteries, that never seemed to last more than a year and a half to two years for me. I took care of them, kept them on the BMW "special" and expensive charger and they still died prematurely IMHO. So the Shorai choice was really to try new technology and to vent my frustration with the OEM battery. So far the Shorai has lasted longer than the OEM. We'll see.