Yesterday I took my Prius out of storage. 11 months ago I force charged my HV battery and it stopped charging at one bar from the top of the battery meter on the display. I had a battery maintainer on my 12v battery so it was at 13.1v. I powered my car up and the HV battery was at one bar from the top Exactly where I left it 11 months ago and the car was not powered on at all during the past 11 months. So I drove it around a bit and it still is under 1500 miles I hope to drive it a bit this month before putting it back in storage until next season. Mike
I used a homebrew maintainer. It is a walwart that is labeled 12v 500ma but it puts out, when connected to the battery, 13.1v and maintains that voltage forever. Force charge I would have to look it up again but I think it was power on the car, foot on the brake and right foot to the floor on the Go pedal The computer maintains the gas motor at a somewhat elevated RPM and I could hear it loaded until the battery came up to one bar from the top and I could hear it unloading which meant it was not charging anymore. I then powered it off and closed the garage door. The previous season I drove the car running the gas motor as much as I could until the battery meter showed one bar from the top and put the car in the garage for 9 months I believe it was. The battery held it's charge that season too. The 12v battery had the same maintainer on it. Last season ended kind of abruptly as the road crews around here like to salt dry roads before it even freezes in the late fall so I was expecting to drive it more but couldn't after waking up one day and seeing the roads salted So I wanted to make sure the HV battery was charged fully before putting it away for the winter and had to do the force charge in my garage. It worked I bought a Kia Soul for a daily year round driver so my Prius is just for the fun of it during the warm season. I have not driven my Prius in any rain either It rained today and is forecast for rain tomorrow so my Prius will sit in the garage until a nice sunny day comes around again. Mike