Externally charging the 12V battery

Did you have the negative clamp on bare metal? If it was on painted metal it probably didn't have a very good connection. And under the hood at the fuse block is just fine for charging. No need to dig into the back of the car unless you want to do an inspection while you're at it.

How many amps is the charger putting out? If it's more than just a trickle charger and the battery isn't taking a charge, you may have killed it. In fact, if that's the original, you got your money's worth out of it and now it's almost for sure time for a new one.

As for the lights, I'm curious about that, too. Still experimenting with my PiP I bought just over two weeks ago.

 

mine doesn't turn any lights off automatically. are we talking headlamps or interior? some models may shut off the headlamps, not sure. but none will shut off the dome light if left on or a door not fully closed.
the prius battery works like any other, positive + red/red, negative - black/black. if you are at the battery, shouldn't be a problem.
if you're under the hood jump point, there is only metal on one side of the terminal.

you may want to check the negative cable for corrosion and tightness both at the battery and the body.
you don't want to charge a prius battery at more than 2 or 3 amps i think. should be in the owners manual.
jerry is right^^^ your battery might be fried.

 

Something's wrong with your charger or technique. It should work at the jumpstart point under the hood: I'm doing that regularly with a CTEK 4.3 now, never any problems.

Does your charger maybe have only one side of the jaw that will complete the circuit? That could be the problem, at the jumstart point. And yeah make sure the ground is substantial bare metal.

5 Volts is really dead btw. Maybe your charger's assessing that somehow, just refusing to charge??

 

great. keep an eye on it now, they don't like being discharged. all the best!

 

The car's just running?

 

I would persevere with the charger. I'm not sure an idling car would ever really charge it. Especially a Prius, alternately running and shut down. Maybe others can comment.

 

I am not sure a 5.5 volt battery can be resuscitated. You might need a new one.

 

i think i have read that 8 hours of idling will charge it, but i doubt that is from 5.5 volts. i hope the garage is detached, or the door is open.

 

This. You need a new battery, fully charged.
And then the charging voltage needs to be checked.

Lights being left ON may or may not have caused the problem.

 

NO it is not "fine".
At least you have no good way to know that.

It is silly to waste gas trying to charge the 12 V battery......especially when you have a charger RIGHT THERE. The fact that the engine never shuts off is an indication that everything is not "fine".

If you don't get that battery tested and thoroughly charged externally (and probably replaced), it will bite you in the butt again......VERY soon.
Guaranteed.

 

Be aware most "chargers" and jump cables only apply power to half the clamp. You need to match that half to the half of the jump point in the fusebox that you are connecting to (only half of it is metal). Usually the clamp half that the cable it attached to is the powered one. The jump terminal half is the copper coloured one.

 

I have charged my 12v recently and took some pics, which might be helpful.

What I use:


Battery Minder Model 1510

How I use it:



I use one of the bolts on top of the shock tower for the ground and ensure the side of the alligator clip with the wire is connected to the positive jump point in the under hood fuse box.

We have a 2010 Prius II bought in August 2009 and still on the original 12v battery.

As others have said, that might have been the cause of the charger not working.

10.5 v seems low to recover, but depending on your charger, you might be able to resurrect it.

I would contingency plan for replacement though.

 

EXCEPT......that the entire clamp is metal, including the hinge and spring and it would be REALLY hard to NOT have power on both halves.
REALLY HARD.

 

Most do not. Not hard at all.
Mainly because the only metal parts are the "jaws" and the spring and hinge pin. Oh, and the cable conductor.