Prius 2015 No Power At All

welcome!
you probably need a new 12v. 5 years is a decent run for these little batteries.

the only way to know if the original is bad would be to take it to an auto parts store and get a load test.

you could put a volt meter on it to see if it charged up at all. if it was at least 12.5 volts at the front jump point, then the problem would lie elsewhere.

personally, i would just replace it, but if you're not driving much, even a new one might require a charge once in awhile, or a maintainer.

btw, when you reinserted the orange safety switch, did you complete the third step of sliding it?

 

Did you run out of gas and drive until the hybrid battery died?
The 12v battery might be dead, but if the hybrid battery is dead, the 12v battery won't help.
You can get a volt meter from an auto parts store or department store and check the 12v battery.

Hopefully, it's just the 12v battery....

 

+1

Replace that, post results.

Good Luck!

 

+2
HIGHLY likely that one of two things is the problem:
A completely failed and dead 12 V battery.
A loose connection on one of the main battery cables.......at either end.

 

Most 12v chargers will take a look at the battery voltage when first connected -- if its too low, then the charger says, "Yo, that doesn't look like a decent 12v battery to me, I'm not even going to try to charge that -- bad battery!"

There are three ways around that -- one is to connect a good 12v battery parallel for awhile to raise the "bad" 12v battery to a level where the charger will recognize it. Another is to just charge the batteries in parallel. A third is to get a higher end battery charge that can deal with 12v batteries that have very low charges (e.g. https://tinyurl.com/yabe7k5t)

I'm not saying that's your problem. But just a data point to consider. And while replacing the 12v battery can't hurt and is probably warranted based on the fact that its five years old, this would be a good/quick test.