12volt battery/jump starting issues, help!

Hi. So I will state up front I am really not well versed in the auto world but am trying to learn as best I can.

Today, my 2008 prius's 12volt battery had quite a day. A customer at my work (also in a prius) asked for a jump, I obliged, we each attached the cables under the engines of our respective cars and the jump worked great.

Not long after, another costumer (in a Honda Pilot) needed a jump! I was feeling like the good samaritan and so I drove my prius over to her car (no problems) and turned it off. She pointed out the battery to me, which was positioned very oddly. I assumed she knew what she was talking about, and attached the cables where she directed as best I could, even though the whole setup seemed odd. There were two exposed connection points, and one of the was painted red and I assumed it was positive, and then I placed the ground on the other. There was a small spark, but not out of the ordinary (I think??). I went to try to turn on my prius to start the jump, and it wouldn't start at all. All dark.

I immediately took off all the cables and went to grab a friend (with his truck). After looking at her owner's manual, we all realized that her battery was actually much more complicated than we thought and required removing a bunch of engine stuff to fully access. Plus, she had pointed out the terminal to me incorrectly. In the end, it seems like I definitely put the grounding cable on the Pilot's positive terminal, but that I had put the positive cable on a second positive terminal next to the primary one? Very weird? Does this count as reverse polarity?

After that, my friend's truck successfully jumped both me and her (after much finagling in the Pilot's engine).

I was able to drive home (about 10 minutes) but forgot that I should probably keep my car running and turned it off. So, I tried to start again, and it did not work. I was worried that I just hadn't driven it long enough, so I successfully got a jump from my landlord and drove it for much longer (about an hour) with no problems. When i got home, though, it wouldn't start again.

I tried to look and see if any fuses were burnt and it didn't seem like it, but I wasn't sure of which fuses to check (the diagram in my manual was very confusing).

What is the most likely prognosis? Was two jumps in a few hours too much? Did I just drain my battery? Destroy the battery? Fry a fuse or something bigger? If something in the electronics got busted from the reverse polarity, would my car still start when jumped (as it has twice)?

I'm trying to see if I can borrow a voltage reader and trickle charger before I just go and replace the battery. Would love any and all suggestions!

 

Yeah, doing research now, I saw that. I could have sworn I'd jumped someone from my prius before, but perhaps I'm misremembering. And I did successfully jump the other prius earlier in the day. But maybe that only worked because it was another prius?

 

Yeah, I've learned that now! It was a crazy day and I was not thinking straight. Not something I will attempt again. Thanks for setting me straight.

I'm going to go get my buddy's volt meter now and will see how the battery and that main fuse are reading. Thanks so much for the detailed photos!

 

Okay, so I've checked the battery itself and its pretty consistently reading 12.5 volts or so. Using TMR-JWAP's instructions, I tested the voltage through the spot where the cable enters that main 120A fuse relay above the battery and still got 12.5 volts.

But, when testing the power in the engine compartment, on the jump starting spot, I was not reading anything on the meter. Can I assume the issue is somewhere on the connection between the battery in the back and the connection up at the front? It does make me think - at one point in all the shenanigans yesterday, a friend did try to jump me from the back (because of the way I had parked) and it didn't work, but I've been jumped twice now up front and that got the car started just fine.

As to Johog's question - I've got no light at all in the dome. No beeping noise if i leave the key in the ignition slot. No response at all from the car unless its jumped up front and then it functions normally until its turned off again. I've used the volt meter to test the smaller fuses in the engine and they all seem to be unbroken.

 

whoops again. I got a better look at it this morning and yes, that 120A fuse is definitely blown. I don't know how I was getting any voltage reading through it yesterday, cause today I'm definitely not. I think I've bought the right replacement fuse and will try to fix it after work today. Any words of advice?

 

Thank you all for all your guidance! Yesterday I was able to replace the fuse and get the prius back up and running. Those pictures were absolutely crucial, TMR-JWAP. You're a prince among men!