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I'm keen to buy a used FEH.

However I work overseas 8-10 months at a time. I'm concerned this will degrade the hybrid battery pack.

There is a "disable" switch for the hybrid battery for maintenance, would this be used to store the vehicle?

I would need to store the vehicle outside with a car cover and probably would not have access to electrical power for a charger.

I have noticed others using a solar charger to keep their starter battery charged in ICE vehicles where I currently store my vehicle. Could this be done for the Hybrid battery?

Or will I likely degrade the hybrid battery and should postpone an FEH purchase.

Thanks

I'd suggest buying a conventional vehicle. I've looked at hybrids but I don't think I drive nearly enough to get my money's worth out of a battery pack over its lifetime. If the vehicle is only in use for a few months at a time, I don't think you'd get your money's worth either. Let someone who racks up a lot of miles buy the FEH.

NiMH batteries lose most of their charge over just a few weeks. After 8-10 months your pack would be dead as a doornail, and I could be wrong, but I believe this would cause long term degradation of your capacity. Most of the quality NiMH batteries that I buy include a warning to recharge them periodically and not let them self-discharge too far. I don't think this would be good for your pack. Use it or lose it.

And keeping it on a charger continually would be even worse for the pack.

If you really want a maximum-FE vehicle even though you don't drive very much, I'd strongly advise to get either a diesel or the highest-mpg conventional vehicle you can find.

NiMH batteries lose most of their charge over just a few weeks.

That has not been my experience. During the summer I ride the bus to work and let the FEH sit, except when we go camping or go on vacation. The most recent rest period was between June 22nd, when we returned from camping until July 17th. I do worry about pack leakage during rest periods, so I took note on June 22nd when I stopped I was at 41.2% SoC. On July 17th, when I started up, I was at 40.9% SoC. So it does lose a little, but not a significant amount over nearly a month. Once we got going, the hybrid battery pack gradually charged up to 52% SoC, just like it normally does, so I saw no difference in that aspect after sitting for that long.

Since the normal operating range for the FEH is 52-40% SoC, I would think that if you got it to 50+% SoC prior to the rest period that it would still be fine over time. This is observational only though, I really don't understand battery chemistry.

I'm keen to buy a used FEH.

In regard to the original post, if you are truly "keen" to buy one, than I don't think that the hybrid battery pack would cause you problems. You could certainly use one of those solar chargers to keep the starter battery charged, because I think that once it started, that the FEH ICE would recharge the hybrid battery pack just fine.

That has not been my experience. ... June 22nd when I stopped I was at 41.2% SoC. On July 17th, when I started up, I was at 40.9% SoC. So it does lose a little, but not a significant amount over nearly a month.Whoa, that is really amazing. Only a fraction of a percent down after sitting for a MONTH?! Wow.

The NiMHs I use for bike lighting are usually depleted by half or more if I let them sit for a month. Even if I have fully charged my pack after the last ride in the lighting season (generally late Feb to early March), if I try to go for a night ride in the summer without recharging I find almost no juice left. I've found this behavior to be very consistent across the various brands of NiMH batteries I have -- from AAA and AA cells to C and D based packs (approaching the cell sizes used in most hybrids).

The one exception has been the handful of Sanyo Eneloops I have (which are designed to hold their charge, but cost WAY more and have somewhat lower power density) -- maybe Ford's hybrid batteries are using similar expensive technology?

The one exception has been the handful of Sanyo Eneloops I have ...

I use the Sanyo Eneloops on my bike lights for the same reason. I ride to the gym early each morning (when the weather allows), so they are never idle for very long, but they seem to last 6-7 months on each charge. I have replaced about half of my rechargables with Eneloops over the last few years. I always try to buy them at Costco, when they are on sale.

Perhaps the other factor is that my FEH stays in the garage? So it would not be exposed to the same temperature extremes as a vehicle outside with a car cover on it? Just speculating here.