12v battery jump start?

welcome!

you should start by replacing the 12v battery, then you won't have to go through any of that.

but if you do, connect it and try to start right away.

donor car should be off.

don't cross polarize the connections!!!

all the best.

 

For what? To restore the battery? That would likely take forever. If you start the car, leave it running, drive across two or three states, that might do it. Or:

1. Check the voltage with a multimeter, with the car off, and post the results. The likely outcome of that though, is more'n likely: yup, it's near death, not worth charging, replace it.

2. Not very likely, but maybe it'll be borderline, and with intervention: a full charging session with a smart charger, you may wring a few more months of service out of it. At least some breathing room, time to go battery shopping.

 

Yeah check it with a multimeter (can be purchased for $10~20) first and post. Strong likelyhood you need to spend more money though.

Optima Yellow Top are not the only option. There are several now. Check with dealership first, doesn't hurt to ask. There's a few others: Bosch, Exide too. The Yellow Top is a bit of an odd duckling too: it has high cranking amps, maybe at the expense of amp hours? FWIW, I've had a Yellow top for a bit over two years now, but will likely go with rebadged Exide next time.

 

Anything under 12.4 is pretty bad, I'm guessing yours is toast, in the yellow zone, but have a look. Again, shelling out additional $50~80, you can get a decent smart charger, see what it can do. It will monitor the battery as it charges, will let you know if it deems it useless.

The bees knees for DIY assessment, is something like the Solar BA5 ($75). It will test at-rest voltage, AND the cold cranking amps, basically the underlying "health" of the battery, and will give a verdict, either good, good-but-recharge, or fail.

 

how long has the battery been sitting?

 

if you don't want to buy a charger, you can try leaving it on for 8 hours and see if that will charge it up. if not, you need to replace. is it original?

 

Whenever jump starting a Prius, make sure the donor car stays turned off the entire time.

While not at all definitive, there have just been too many Prii wounded (usually a blown fusible link) or killed (blown inverter) from jump started problems. Thus, besides the risk of crossed connections, I strongly suspect there is a risk from some (not all) donor car charging systems putting an overvoltage condition on the Prius. When you already have car trouble, it is best to not add this possibility into the mix.

An isolated battery pack, like the AAA guy used, is much safer. And when it doesn't work, you can be much more confident of not having inflicted additional damage.

I would take this as a strong hint that the 12V battery is beyond salvage.

And even if you do manage to salvage this battery, your problems will repeat again, much sooner than later. And you'll have to go through this process all over again, exposing your Prius to additional risk of jumpstart-related electrical damage.

 

What is it being jumped from? Another car, or an isolated battery, or a battery charger?

Now that you actually having it running from a jumpstart, you may as well follow through and see if the battery does come up to a reasonable level -- and survive the night with a usable charge. It will require a considerable time in 'Ready' to receive that charge, so it must be in a safe place to leave turned on while unattended.

Your Gen2 should have a voltmeter gauge buried somewhere inside the display menus.