prius c start up problem

You can try to charge it. You need to use agm battery charger that has 4A or less. But since it has been problem many times it’s likely that you just need a new 12V battery.

 

With a near-new car, batteries don't just go bad. Well, typically they don't. Most likely something drained the battery: it's small, doesn't have a lot of reserve. Leaving your doors open for an extended period, just a few hours, will do it. Leaving a map light on. Leaving the hatch open. Sitting with the car off listening to it's radio. Vacuuming out the interior, doors open and and using the radio. Lots of ways.

A jump start does not fix it completely, restore your battery to what it was. Read up, check the voltage with a digital multimeter. Get a low amperage smart charger and give that a try. It may work, or you may end up needing a new battery. Either way:

Learning, a multimeter and a charger are worthwhile to acquire, regardless if they do the trick this time, or not.

 

You pressed the brake pedal to the floor and then did it again and it didn't go to the floor? That's just normal operation of the brake fluid building pressure. Why are you pressing the brake pedal to the floor? It's not a clutch pedal and doesn't need to go all the way down.

 

A jump start gets the car started, and from then on it will need to work overtime, trying to recharge the battery. But it's not really designed for this: it's ok for maintaining charge on a battery in good health, but not for a battery in poor condition, this overloads the car's charging system.

A few things you can do:

1. As you said, replace the battery.

2. Read up on battery voltage, get a multimeter and assess your current battery, check it's voltage. This is not a complete load test, but will give a decent idea of how it's doing. If it's reading 12.5~12.6 volts or higher, it's in great shape. 12.4 volts, or lower, it's not so good. Under 12.0 volts, you have serious issues, it's near dead, needs immediate charge or replacement.

3. Get a smart charger, hook it up following the instructions and see what it will do. Consult your Owners Manual to verify, but likely you want a charger that's 4 amp or lower. It should be able to run unattended, a so called "smart charger". After complete charging, drive the car for a day or two before trusting multimeter voltage readings: right after charging they'll be falsely high.

 

i thought you already replaced the battery.

 

If you leave your car off for long times, the battery will discharge. Jumping it will not charge it back up. You would need to drive for a long time to recharge it. Idling won't recharge it, since it doesn't really idle very long. You would have to drive it on the highway for 20 miles at least to make any kind of charge.

A better way would be to use a small charger. A trickle charger. Many will use a small charge of 1.25amps. They will shut off when full charge is reached. That is the kind you want. A battery minder or a battery tender. Hook it up, walk away, come back later to a full charge and no problems. Better than what's going on now.

Prius batteries are expensive, though, if you have to replace them. Wife's 2009 Prius battery was $200+. Special size, special construction, and special gas vent tube/location. I suspect the C would be about the same if I had to look.

Also, with your battery so dead for so long, it may not be good any more. A good charge for a 12v battery at rest is 12.3 to 12.8volts. Running, the battery should read 14.3volts or so with a multimeter.

Best luck to you.