How to disconnect battery 2017 prius

welcome!
just loosen the nut on the negative terminal and cover it with a rag or something. in your pic, it's the nut toward the bottom right, but do the negative, it's safer.
the other nut may be a quick disconnect, but i've never seen that either. give it a try, loosen it and see if it pulls off.

 

that's pretty funky, huh? still, loosen it and give it a wiggle. or try the one hiding beneath the plastic.

 

i think so, but now i'm starting to sound like a dope. not unusual though.

 

I thought you just needed to turn off SKS when storing for a few months.
@bisco has done this with his PiP. He should have some hints on what is usually required.

 

i don't even turn off sks, up to 6 weeks in unheated but attached garage. and the gen 4 battery is larger and more durable.
but ottawa might be a lot colder than here, and a detached garage would be very cold.

 

The 12V battery on Gen 4 is under the hood instead of in the cargo area. I doubt that would make much difference though.

 

They've really boxed in the negative cable clamp there. But it's gotta be doable. Also, there is no sks off switch, as far as I know.

My 2 cents: the simplest route would be to hook up a smart charger, one that can be left on indefinitely, done.

The only issue: it makes me a bit nervous leaving something plugged in thus for months, especially unattended. Accordingly, I would lean towards: hook up smart charger, let it run to completion of program, then disconnect, and disconnect negative cable and isolate. It's the phantom charges that'll kill it, pretty much for sure, if it sits connected for months.

That's a nice conventional looking battery btw. Has exposed/accessible caps, if you wanted to add water, down the road. Probably cheaper and more replacement options too.

 

I remember a menu option for that.

 

Ok. It was gone on 3rd gen, back then. Maybe that's the main phantom load on 3rd gen...

 

Apparently it is changed from the MFD.

 

Hmm, see third gen does have Smart Key disable, but only with dealership intervention, assume Techstream involved. That's not so smart...



We're kinda wandering off-topic. But what else is new, lol.

 

The 3 column above says that Techstream is an option for that on Gen 4 too.

 

From the angle of your picture, it looks to me that the right hand nut holds the clamp to the battery post.
Whichever nut you loosen, do not let the metal wrench touch any other metal part of the car while it is contacting the nut.

 

I'd always known to disconnect negative first, but not really thought about. Yeah googling:

why is it safer to disconnect negative terminal first

gives lots of info.

Basically, you want to avoid a short circuit, ie: providing a very easy/direct path between the two posts. And as long as the negative post is connected to the car body (and the engine), any wrenching at the positive post is mere inches away from touching car body, and completing that short circuit.

I recently did do a short circuit, on a jump pack battery. Scared the crap out of me. Good rule: connect positive terminal first, and completely, installed and tightened. Then move to negative terminal and repeat. What I did was install both terminals loosely, then returned to the positive terminal to tighten: wrench handle touched a wire (which was running back to negative terminal, fused instantly) with a nice bang and puff of smoke.

 

i crossed them once. it's basically an electric welder.