How Long Can A Prius Be Left Unused And Still Function?

[Simon D L]

I am thinking of buying a Prius, but I may be abroad from 3-6 months in any year, as I intend to travel more extensively. Would I have problems with the batteries upon my return?

In other words could this be the wrong choice of car for this lifestyle?

What would be the maximum period it could be safely left unattended, yet still function ok?

I JUST POSTED THIS QUESTION AND NOTED A SIMILAR ONE

The car would not be garaged.

I was thinking of potential problems with the main batteries also.

Would it be sufficient as one person has said to simply have it turned over every week or so?

[Chris Dance]

It would not be sufficient "just to turn it over". It needs to be run, leaving it stood for 3-6 months is not good; all systems need to function at least every 2 weeks.

I was advised a long time ago that if I left my car which in this case was a year or more I should stand it on blocks, remove the Battery and spray into the engine cylinders an inhibiting oil. The Battery would have to be recharged prior to fitting on my return. As it turned out I part exchanged that car before I left for another new car on my return.

Suggest you get someone to drive your car every couple of weeks or so for a few miles. Make sure they are fully insured to drive it etc.

[Simon D L]

Thanks for your reply.

What would happen to the drive unit batteries, if unused for a considerable period of time?

[timberwolf]

For the HV Battery, 30 minutes or 10 miles every 2 months. I've seen comments that say the HV Battery will be okay if the Prius is stored for 2-3 months.

The 12v Battery has a much shorter storage capability, about 3-4 weeks (some claim 5 weeks) on a new battery that is fully charged, and the Prius on-board charging system isn't apparently very good. If the car is left outside, you can disconnect the 12v battery, or disconnect the DOME fuse - you lose a few settings in the car, the auto window function needs reinitialising and the car alarm will probably activate when the 12v supply is reconnected.

[timberwolf]

Thanks for your reply.

What would happen to the drive unit batteries, if unused for a considerable period of time?

The HV Battery would slowly self-discharge. The question I don't have an answer for, is how long it would take before the stored high voltage got too low.

According to the following site http://www.eaa-phev.org/wiki/Prius_PHEV_Te...uses_for_errors

the Prius would not be happy if the HV Battery dropped below 175v, although that are lots of different voltages posted on that wiki. I haven't found a specification for what a typical self-discharge rate might be but I did come across another site http://www.mpoweruk.com/traction.htm that suggested that less than 5% discharge per month was desirable. I haven't got very far in what that might mean in months. :(

Another little snippet, is that a post in 2006 on another forum apparently by a Toyota trained mechanic, he thought that were only five Battery chargers in North America at $35,000 a piece that were able to charge a depleted HV battery. How many HV battery chargers are there in the UK or Europe?

I'm sure that must be a technically authoritive answer somewhere out on the web...

[Simon D L]

Many thanks for your reply.

I will have to digest all this.

It seems, however, that the Prius may not suit my proposed lifestyle.

[Ogo]

Many thanks for your reply.

I will have to digest all this.

It seems, however, that the Prius may not suit my proposed lifestyle.

Hi Simon!

The problem in Prius is not so much a high voltage NiMH traction Battery and its self discharge. The biggest problem is small 12V Battery powering things like smart key system and enabling Prius's computer to boot up and start the hybrid high voltage system. When high voltage system is up and running it will keep both the 12V Battery running by charging it via inverter and its self running by starting up the internal combustion engine and charging the high voltage battery up.

As 12V battery is a standard lead-acid one with quite high self discharge ratio plus Prius tends to "eat" some of the energy from it even when powered down, even fully charged 12V battery will usually go belly up within 6 weeks of time. Then you will end up with car which will not unlock, will not boot its computer and so on.

You can fix this latter problem by either disconnecting the 12 V battery (you will loose all the radio settings, clock and some other minor things) or hook up the battery to a charger which will keep the 12V battery from discharge. Another workaround is that you let someone keep your Prius for at least an hour per two weeks in Ready mode. Prius can be parked but must be in Ready mode - hybrid system being online and will charge the 12V battery plus will start the ICE and charge the high voltage battery if voltage was depleted enough.

If you are alone and with no one to take care of your car while away, but you have your own locked garage with electricity, I would personally buy a 12V battery charger and hook it up to a 12V battery inside a Prius. Then when you arrive back home, just turn on your Prius in a Ready mode or take it for a spin and it will take care of its HV battery. HV battery will not self discharge enough for quite some months. Keep in mind that many Priuses were in shipping or/and on stock somewhere for months and were not delivered dead. They just kept the 12V battery disconnected for the time it was stored for longer time.

Ogo