12 volt Aux. battery Question

Nope won't hurt a thing tend away. That's what its made for long term battery maintenance. Your battery will thank you.

Best place is to bolt it to the jump start points up front as you surmised. Cut the clip leads off it and crimp lugs that you can slide under a bolt. Install it permanently to the car. Tie wrap it all down.

Set the tender ac plug in end up so if you forget the tender is hooked up and drive away it will just unplug the tender ac plug from the car so no matter what happens no drama.

I did that on another car I had an wife forgot about it and drove away no problem.

 

If you read this thread, you will find a fantastic place to attach a positive ring type lug to:
12v Power Terminal Cover (fuse box) | PriusChat

The negative I have connected to the bolt just to the right of where the OP's negative clamp is attached to - there's already a couple of ground wires attached to that bolt in the OP's photo, but my 2011 did not have any wires connected there.

 

The ground point you used will work, just I do not know, it being part of the inverter case makes me nervous. But it is grounded. Anyway: I used to connect ground cable here, a bolt with little spigot, on right side of engine:



I've since hooked up a quick-connect cable that came with my CTEK charger, per the method used in Navy's link. Just more convenient, saves prying off the fuse box lid.

If you're charger runs through a charging program, and then shuts down, to just a trickle as needed, it should be ok to be left on indefinitely. I sometimes leave my CTEK charger on thus, for days on end.

 

The positive, ring terminal, goes under the 10mm bolt head that was exposed under the cover discussed in the linked thread.

The bolt anchors a heavy gauge wire connecting the 12v auxiliary battery positive terminal to the fusebox. Therefore, it can essentially be treated as the positive terminal of the battery.

 

If you're going to wrench on that bolt, disconnect the ground wire of the 12v auxiliary battery in the hatch from the body ground point first. That bolt is always +12v live when the battery is connected.

 

In the photos in the OP, charging.jpg, there are already ground wires connected there which appears to be something part of the vehicle from Toyota.

 

More likely aftermarket. I think that same point is in my pic, originally a conduit hold-down point?

 

No bolt it in so you can permanently put the cover back on. Sometimes you may have to nibble a little hole in the cover edge to snake the wires.Tie wrap the charger in the engine compartment. Dangle the ac cord end about 8 inches form the ground and secure that tender side of the plug so it can not be pulled out. Then to charge just open the hood....throw the ac ext cord under the car...reach down and grab it through the engine compartment ...plug it in to the dangling end just far enough to turn on the charger on and close the hood. I don't own a G3 so not sure if you can see pavement anywhere in the engine compartment as the bottom cover may cover the whole engine area. if so my plan may not work then. Not sure how extensive that bottom cover is. My plan is good only because nothing is bolted to the car like a fixed charger ac plug.

When you want to drive away just give the power cord a little tug from outside the car. Don't even have to open the hood. Ext card pulls away form the tender ac end and you can drive away.

 

Yes, that was all the bolt was doing on my car too. That's why I picked that particular one, it definitely was not doing anything for the inverter case itself, just there for the conduit clamp only.

 

I don't know about that; might be a little bit too warm for the charger..../

 

In the link, @NutzAboutBolts provides a video on how to get the cover off the 12 volt positive terminal, here:

12v Power Terminal Cover (fuse box) | Page 2 | PriusChat

I got the cover off (after some struggle, and disconnected the 12 volt before taking the bolt off the terminal to put on a charger quick connect spade connector. When I hooked the battery back up, I basically needed to:

1. Reset the dash clock.
2. Didn't need to reset window auto-up, but you may need to. What you do: push and hold the window to run it right down. Push and hold window to run it right up. Continue to hold up switch for a couple more seconds.
3. Reset radio presets. (as much as you care)

The first time I restarted the car after the battery disconnect, it behaved a little "weird". Told me something about shifting to Neutral, maybe? Some nonsensical "Prius" message. I shut it down and restarted, and it was ok the second time. Then, within about a minute of start up, revs shot up quite high, for a few seconds, then went back to normal. I got the sense it was calibrating something, not sure.

BTW: I see those ground wires on nutzaboutbolts' vehicle, the ones I don't have on mine. Guess it depends on the year, US vs Can, headlight config or something:

 

Yes, gotta be.