Toyota Prius front battery sorted/sparked during jump start

We hear this story every few days. Your 12v battery is history and is in the back. There is no front battery. Replace the 12v battery.

This did it. Never let it sit for more than a week. If you ABSOLUTELY have to let it sit for months, buy a Battery Tender Jr and keep it running 24x7.

By the way, placing the charger up front and waiting as is effective asvcrawling through the boot to charge and wait back there. What happens in either scenario is the car's 12v battery is so low in voltage that it drags the charger voltage down.

 

You might be sending OP on a wild goose chase, depending on where in the world they are. English doesn’t seem to be their first language.

Yeah a “smart” battery charger, one that can be left connected constantly, with around 3~4 amperage rating, would be ideal.

This assumes access to suitable power source. If that’s not possible, and the car will continue to sit for long times, then either disconnect the 12 volt battery negative cable, or remove the battery from the car and periodically charge.

 

To repeat a really important point here:
There is only ONE 12 volt battery.
Likely that it needs to be replaced.
After that, you can see if you blew any fuses by making a mistake during the first attempt at jumping.

 

from my foreign language class in high school, i am deciphering the 'front battery' as the jump point under the hood.
if that is the case, it is just a wire to the battery in the hatch. it is possible that there is a problem with the connection, but unlikely unless rodents chewed it.
why do you think the battery in back is good?

 

There is no way to repair an old 12-volt battery allowed to be fully discharged for that long. Corrosion builds up on the plates and its ability to retain a charge is lost. It must be replaced.

 

The "one and only" 12v battery is located in the trunk at the rear passenger side corner. The "+" terminal of that battery has a heavy cable connected to it (plugged in to the black box) and the other end of that cable is bolted to the underhood fuse box. Where that cable is bolted to the underhood fuse box IS the jump point. This is where 12v battery power is distributed to all the other 12v systems in the car.

 

how to test:
measure the voltage at the battery with the car off, and then at the jump point. if the jump point is similar to the battery, it's the battery.
how old is it? do you drive the car frequently? if it is 12.5 volts or better, it may be okay, but you need a load test.
turn on the headlights for 5 minutes, and record how much it drops.

 

This should help.

The 12 volt battery as has been stated," is in the rear of the car." The front jump point is for convenience, if you have to jump the car. It is electrically tied to the battery so you don't have to go into the back to jump start the car. For what you need to do, just forget it's there for now.