Hybrid vehicles sitting for a long time?

[some_other_dave]

Hey, all. I'm doing some research for a potential new vehicle purchase. I've been looking into hybrids for the obvious benefits.

One issue I just realized is that the car will almost certainly wind up sitting for several months at a time, unused. I know that can be very hard for the 12V battery in a traditional gas-only vehicle, but I was wondering if it would cause any issues with a hybrid's traction battery? We probably won't be able to put a battery maintainer on it, either.

Thanks!

-soD

[ksa8907]

I would not recommend any hybrid, ev, or any combination where you expect to let the car sit for months at a time without powering the bms.

I know with my volt I had it plugged in 24/7 so I never had to worry about it sitting unused.

[Piotrsko]

The lipos in a volt have extremely small idle currents which is the bane of all batteries, aka self discharge. For a while my pack sat all winter at 95% max charge for a couple of winters and the decay is so small I can't accurately measure it. The BMS which increases the self discharge somewhat is disconnected but that's not a major impediment. There were packs that sat in a wrecking yard for years in a damaged condition which have a majority of still spec cells.

[Vwbeamer]

Most hybrids have a regular 12v lead acid battery that's going to discharge also, as it maintains all the 12 volt equipment.

On my C MAX hybrid, the 12 volt battery would discharge fairly quickly, as it ran the cellphone radio that allowed the user to remotly find the car, unlock it, etc

I doubt the traction battery would completly discharge, but if it did you would be unable to start the car and I don't think you would want to try jump starting a 400 volt battery.

[Piotrsko]

You actually cant jump start it, there's no external access to those high voltage connectors without a major disassembly, and there's also the possibility the the electronics won't allow it.

[Vwbeamer]

Originally Posted by Piotrsko

You actually cant jump start it, there's no external access to those high voltage connectors without a major disassembly, and there's also the possibility the the electronics won't allow it.

Yea, that was a tongue in cheek comment, unless it was a plug in hybrid, I wouldn't know what your options would be if the traction battery completly died. A plug-in hybrid could of course be simply plugged in.

[Isaac Zachary]

I bought a Prius that had been sitting and had a dead traction battery. I got a 6 cell NiMH hobby charger and took apart the battery and charged every module. (Mind you on a Prius the modules need to be squeezed together or they will inflate. Don't ask how I know.) I also got a discharge meter and measured each module. One was completely dead and two were a bit worse than the rest so I changed those for some used modules off of eBay. I also tested those of course. After charging them all back up I then connected all three modules in parallel and did one last charge up to make sure they were all top balanced.

I put the traction battery back in and tested it out and it worked fine now. No codes or anything (except for catalytic converter). Checking the voltages the modules all stay pretty close. I haven't driven it though since then some I'm doing more work to it. So I start the engine every couple weeks and put it in gear and step on both the brake and accelerator at the same time so it charges up the traction battery. About a year later it still seems to be working fine.

[Piotrsko]

Bottom balancing is better because you can use time to top back up as a rough remaining capacity indicator

[some_other_dave]

Sounds like the consensus is that the 12V battery is the major concern, as it would be in an ICE vehicle. I'm relieved to hear that, though it sounds as if I have some more research to do.

Thanks!

-soD