12V battery problem

Check your fuses... If you jumped with reverse polarity you may have caused some damage, but not too serious... If you google search "reverse polarity jumpstart priuschat" you can compare your symptoms to others.

In your owner's manual you can read about the manual rear hatch release so you can access your 12v to inspect all the connections... It's common for people to have problems with the negative battery terminal that connects to the frame of the car. Also I've had experiences after changing a battery where some of the stuff that connects to positive terminal would need a good shake to work normally again. So inspect and tighten everything down if your battery is still healthy.

How old is your 12v battery?

 

you can put 12v (not a charger) to the jump post and open the hatch, or crawl in back and pull the manual lever. no need to tow.

 

It could be that your battery is just really really dead and you don't have a smart enough charger. My charger checks the polarity before it starts charging and it also allows me to choose the charging current.

Old fashioned chargers will try to apply charging current without checking the polarity. We've all had brain farts where we thought we did one thing but really did something else. No shame in that. I was going to bring some paper plates to work with me this morning. After I got here, I discovered that I had no put them in the bag. And that's why newer chargers give you a chance to double-check. If you don't have one, it would be a super good idea to get one.

 

Just a note that it is NOT good to try and measure the resistance to ground of a circuit that normally has power on it.
It is possible that your meter how has a blown fuse in the OHMS section.

 

That wont hurt your ohm meter. Just wont read right. Theirs no fuse in the ohm section.


This dead battery is the perfect scenario that has blown up many a G2 Prius over the years.

Typical scenario we have seen many times is the 12 battery has been so perfectly and deeply discharged by a light bulb left on to 0 volts which does really present a dead short to a charger load wise.
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Along comes a AAA tow truck with huge battery jumping current capability much more power than a normal car. They hook up the jumper cables to the Prius and wham there's a massive inrush of current across the 12 volt buss. A surge the Prius 12 volt buss was not designed to handle.
Expensive hilarity sometimes ensues.

Lucky for the op his pos charger just said nope.

This is why if I'm out and get a dead 12 and I don't have a voltmeter with me to see how dead it really is (but turn on the headlights if no headlights at all be aware your in dangerous territory) I would never ever get a jump start. Its getting towed home I got AAA so i can take the 12 out of the circuit and charge or replace it.
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This is why we used to see so many AAA jumps that would blow up the car. Hard to believe that many AAA guys hook up jumper cables backwards but I don't think they are. Its the car and a flat dead shorted little time bomb in the trunk.

100% dead battery and an AAA jump can be lethal to your wallet with a G2.

Btw, when that little 12 is perfectly discharged it sometimes damages the battery. If its a few years old just get a new 12 volts.

 

Overall a good post, Ed.

But you still are having a problem with stating facts that are just simply WRONG.
The OHMS section of most meters is the ONLY place where there IS a fuse.
If the meter also reads current, there is another fuse there too.

IF you stick an ohmmeter across a voltage source, something will blow.
If there is no fuse, something else will go.