I am leaving the country for a year and intend to store my 2006 Toyota Prius without driving it. I am trying to find information on whether or not this is feasible. The advice I have gathered so far falls into two camps:

• just disconnect the 12V battery and the hybrid battery will be fine
• get someone to start it up (for 15 to 30 minutes) every so often (advice on this time interval ranges from every 2 weeks to 2 months)

Does anyone have real life experience with long term storage of a Prius without driving it and the effect on the hybrid battery? Or enough technical knowledge to explain what I should do and why my battery will be OK if I do that?
Thanks

 

Hi,

A variation of the first approach is to get a "battery minder," a type of 12 volt battery trickle charger. Once plugged in, it will keep your 12V battery at an operational level until you return.

As for the traction battery, the NiMH chemistry has a self-discharge characteristics. I just don't know if it is enough to let the voltage drop so low that it won't start after a year. There are techniques for putting a charge on the traction battery but the ones I've read are a little exciting for lay people.

Since it takes a couple of months to ship the Prius from Japan to a USA dealership, my thinking is the "battery minder" and a start and run to auto-shutdown, say every six months sounds about right. Now rigging up a timer would be a neat trick.

GOOD LUCK!
Bob Wilson

 

Thanks for your reply, Bob.
Excuse my complete ignorance, but will having a 'battery minder' to keep the 12v aux battery charged keep the hybrid battery charged if the car is not run? I think I understand you to say that that will only keep the 12v battery charged and the 'traction' battery is a separate issue. (I'm definitely looking for a protocol that could be described as 'reliable' and 'easy' rather than 'exciting'...)
It sounds like, in your opinion, the battery minder along with a start up twice in the year would be sufficient. Can you explain what you mean by "a start and run to auto shutdown"?
Thanks

 

Thanks for your reply, Bob.
Excuse my complete ignorance, but will having a 'battery minder' to keep the 12v aux battery charged keep the hybrid battery charged if the car is not run? I think I understand you to say that that will only keep the 12v battery charged and the 'traction' battery is a separate issue. (I'm definitely looking for a protocol that could be described as 'reliable' and 'easy' rather than 'exciting'...)


Correct, the 'battery minder' is designed for just the 12V battery but that is important. By keeping the 12V battery "on," the small amount of current needed to keep the memory of the different car computers (called Electronic Control Units (ECU)) will be preserved. Not only will that keep the clock running but your radio stations and the operational characteristics of your car that these ECUs remember.

It sounds like, in your opinion, the battery minder along with a start up twice in the year would be sufficient. Can you explain what you mean by "a start and run to auto shutdown"?

Once someone starts the car, it is desirable that the engine reach 'operating temperature' and the traction battery get a clean charge. The engine will continue running until all of these things have been accomplished and then "auto shutdown" and turn off the engine.

A good protocol would be to have the car blocked in so no one can "hop in and drive it off." Then have the person start the car and go do something else. They can check the car every 10 minutes or so and when they find the engine is not running, it is done. They simply turn it off, take the key away and everything is done.

BTW, do have a fresh oil change done before you put the car in storage. The old oil will have various 'contaminates', primarily from combustion blow-by that you really don't want to have in the engine for a long time. Be sure a new oil filter is put on it at the same time. When you get back, treat the oil normally and you're good to go.

Look at your maintenance schedule and if you are coming up on an engine coolant change interval, do it sooner rather than later. Again, the reason is we like to have any fluids that might have weak, anti-corrosion characteristics replaced before storage.

You might "GOOGLE" up car storage and see what else pops up.

As for tires, I'd rather let it sit on tires 'to be replaced' than new ones. Gasoline, I think our exceptionally air-tight gas tanks handle that without a problem but I'd put in a container of injector cleaner when I return.

Can you keep it out of the rain? Water is the 'universal solvent' and you don't want the brake rotors to rust. Probably a good idea to have a general inspection when you get back.

GOOD LUCK!
Bob Wilson

 

Thank you so much for taking the time to write such a thorough and thoughtful response. This is the most complete information I have found and I really appreciate it! I feel so much better about leaving my Prius (still wish I could just take it with me...) I may be the first person to store a Prius for this long, so I will post the results on my return.
Thanks and More Thanks!

 

The engine run until self-stop will keep the high voltage battery from too much 'self-discharge'. Six months has been mentioned elsewhere as a good interval, but not much additional effort to make it 4 months.

I'd say that there is a pretty good chance of 'flat-spotting' the tires in a year. It would be unsightly to put the car up on blocks, but maybe a good idea anyway.

Depending on the storage consitions, there may be a risk of rodents etc. moving into the ventilation system, chewing wire insulation, and other damage. Not sure what the favored way of preventing that would be - usta be mothballs under the car.

DAS

 

Hi,

A couple of late thoughts:

1) introduce your car 'baby sitter' to GreenHybrid.com If they run into any problems, invite them to post here and no doubt some friendly person will walk them through what needs to be done.

2) running the car - some folks are of the opinion the main traction battery may need a more frequent recharging than once every 4-6 months but we're checking our sources. This is not the sort of experiment many of us get to pull. So far, the shortest time claimed is two months but I and my fellow technologists are looking at the problem.

BTW, Doug is right about the risk of critters in and about the car. But we've always had cats and dogs about so it hasn't really been a problem. As for tires, if they are worn enough, I'd replace them when I got back. If they are new, blocks sounds good but they are a 'pain' and you don't want someone stealing the tires off of them . . . .

Bob Wilson

 

Modern gas will start to go stale after 4 to 6 months. Storage at temperatures over 80F accelerate the break down. After a year of storage, gasoline will have formed varnish and gums that will not do your engine or injectors any good.

Before you park the car for storage, pick up a bottle of Stabil (fuel stabilizer) and add 5 ounces to your tank, and fill up. You want a full tank to limit the oxidation and water vapor the gas is exposed to. Be sure and drive at least a few miles before parking to make sure the Stabil has time to mix with the gas and fuel lines.

 

I wouldn't worry about tire flatspotting. I store my RX-7 for 6 months each winter and it doesn't flat spot the tires when I don't put it on jackstands. Modern tires are better than you may think!