Had to jump start my street-parked prius yesterday!! Tips?

More important than miles on the car is how old is it and why did the battery go flat? Also how ofen has the battery been flat?

I'd replace my battery if it went flat just once and it was over 4 years old, I like my car to start and lead acid batteries don't live long past their 4th birthday anyway. Running a lead acid battery flat will harm it a bit each time.

 

It seems that many owners underestimate the amount of time that it takes to charge the 12V battery. If the car needed a jumpstart, the battery had close to zero capacity. It will take many hours in READY mode for the battery to come back to a reasonable level.

To provide a datapoint: I recently bought a new battery for my HiHy. The battery is liquid lead acid and the physical size is small, similar to the Prius battery. The battery measured 12.6V off the shelf, which is around 75% charged.

I decided to see how long it would take to charge the battery to full capacity (12.9V) using a lab power supply set to 13.8V. That is similar to the conditions the battery would face when the vehicle is READY.

It took ~11 hours for the charging current to drop down to 70 mA, at which time I decided the battery was charged sufficiently.

Bottom line: don't think that you can run the car for 30 minutes and expect your battery to be restored to full capacity.

In the case of the OP who had to have the car repeatedly jumpstarted, I would recommend replacing the 12V battery, then drive the car frequently and long enough, so that the battery does not discharge to the point where a jump is needed.

 

It would help if it OP filled in the profile information. That way we would know the age and generation of his Prius.

I agree with Pat. Once a battery starts going flat, it's time for a replacement. If this is a one-time thing, then it's okay. Just be aware that each time it goes flat you kill a bit of its life.

Tom

 

What the above posters didn't tell you is you should check for a light being left on. Note that the interior lamps have three positions on the switches. There is "off", "door", and "on". Check each of them. Especially the hatch lamp. It's hard to tell if it's on all the time in the daylight, as it's so weak.

If -any- of these lights are in the "on" position they -will- drain the 12V battery.

Also, be sure to exit the car from the drivers door (to ensure the headlamps go out), or at least open and close the drivers door when you shut off the car.

Finally, ensure all doors are left fully closed when you shut off and leave the car. Especially be careful with the hatch. Many owners have left it not fully latched and drained the 12V battery because of that.

 

what does this mean?

respectfully, i think you're doing something wrong

explain how you use the car please

particularly leading up to the jump-start episode

and yes, i do think your Prius is going to die on you again

 

Agreed. The first step is to find out what is wrong, or what someone has been doing wrong:
- always lock the car when you park, no matter where. If a door is not fully shut the car will give a long warning beep.
- never leave the car in ACC for more than a few minutes. If you want to listen to the radio or whatever leave the car ON, in Park and the parking brake set.
- Did the first drain happen soon after an accident? or soon after installing some aftermarket electronics? *slap*