For the last 18 months I took my 2013 prius off of insurance and jumped it every now and then to get the fluids running. I started a new job and need to now drive it once a week, but the battery has been dying over the course of the week. I got a battery maintainer, but how do I plug in the negative side? Is it ok to use a random bolt, or do I need to get into the trunk?
It would be best to make a permanent connection on the battery itself. Plug left out in the back to plug the charger into. You can close the back hatch on the power cord. Posted via the PriusChat mobile app.
First, where are you connecting the positive cable, at the back with the battery, or in the engine bay, say at the fuse box? I've done the latter, intalling the quick-connect cable (that came with my CTEK charger) and my connections are as follows: For the positive, I connected where the 12 volt is supplied to the (under the hood) fuse box. It's a little tricky to get to; @NutzAboutBolts has a video on accessing it: Then for the negative cable, I noticed nearby atop the front/left rear well there was a threaded hole with nothing, used that: You’ll need to scrounge up a bolt: it’s the common metric 10mm (socket size) bolt size. Thread diameter is maybe 6mm?
That bolt in my pic was more’n likely picked up by one of our kids, 35~40 years ago, when we were window shopping in a new car lot on a Sunday (shut down). I noticed a lot of such bolts scattered around the lot, set my kids to reaping them.
No good reason to go directly to the battery with a tender that at most puts out maybe 2 amps. The same good ground bolt that you would use for a "jump point" will be fine. BUT.....you probably should get the 12 V battery tested after it is fully charged because your extended down time might have "killed" it. The next time it fails might be very inconvenient.