Prius not starting

[GillPrius]

Tried my ‘09 Prius which has been standing for 3 weeks and not able to start it. Would it be the Battery and is it easy to jump start it?

[TonyHSD]

Hi, 

yes very likely it’s the 12v Battery. You can jump start easily from under the bonnet jump start point located in black fuse box near left shock tower. Connect positive terminal to the red point and the negative to the ground point, shock bolt to any bare metal nearby. After jump start the Prius disconnect the negative then the positive leads and let the car stay in ready mode for 1 hr, you need to be around and preferably switch off heating. 
If your Battery is old you will most likely need a new one to buy and replace. In 90% of the cases once the 12v Battery been totally dead they can’t be saved afterwards. 
Good luck 

[BhxTrev]

1 hour ago, GillPrius said:

Tried my ‘09 Prius which has been standing for 3 weeks and not able to start it. Would it be the Battery and is it easy to jump start it?

I had a similar problem during the covid lockdowns. Tony HSD gave you you a perfect answer but I would stress that if your Battery, like mine at the time, has a few years behind it, do what I did & invest in a new one. I got a 5 year guarantee with the replacement & peace of mind that it should hold its charge for a few weeks especially when I park the car & go on holiday. 

[GreenJuice]

This first happened to me about 4.5 years ago. 
 

After topping up the 12V Battery with a trickle charger, all has remained well for me. 

I then bought a Suaoki U3 jump starter pack (as discussed in the thread above) which I keep in my glove box to give me the peace of mind in case this happened again. It really is small and it really does work!

So far, I have been lucky and have not needed to replace the 12V as yet. 

One of the speculated causes for the current drain, when the car is left unused for some weeks, was apparently the key fob if it is kept relatively close to the car. 

[CPN]

37 minutes ago, GreenJuice said:

This first happened to me about 4.5 years ago. 
 

After topping up the 12V battery with a trickle charger, all has remained well for me. 

I then bought a Suaoki U3 jump starter pack (as discussed in the thread above) which I keep in my glove box to give me the peace of mind in case this happened again. It really is small and it really does work!

So far, I have been lucky and have not needed to replace the 12V as yet. 

One of the speculated causes for the current drain, when the car is left unused for some weeks, was apparently the key fob if it is kept relatively close to the car. 

...and putting the key fob to "sleep" should fix that also.