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I was just wondering what happens when you leave a Prius sitting for weeks/months. Will the battery "die"? If you truly have a "dead" battery, will the ICE start up as soon as you put your foot on the pedal? Just wondering in case I took a trip to Europe for a few months or something... Any thoughts or answers?

thanks
 

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you'd need to disconnect or do some other maintaining of the 12v accessory battery if you're leaving the car undriven for that long...

Without the 12v battery, which powers up the car's computers and connects up the hybrid battery, you cannot start your Prius. The hybrid battery is the one that starts the gas engine, but the hybrid battery isn't connected until the computers are powered up by the 12v battery... The hybrid battery should be fine for the timeframe you're talking about, but the 12v battery won't last that long without some help.
 

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ephrumsirc said:
I was just wondering what happens when you leave a Prius sitting for weeks/months. Will the battery "die"? If you truly have a "dead" battery, will the ICE start up as soon as you put your foot on the pedal? Just wondering in case I took a trip to Europe for a few months or something... Any thoughts or answers?

thanks
You need to turn off the Smart Entry feature if you leave your car for more than a few weeks. The sensor sends out a small signal, every 30 seconds or so, looking for the "fob". Over a period of time, this will drain the battery. The security system will also drain the battery. Smart entry is disabled by means of a small button under the steering wheel just above the cutout where your feet go.
 

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I've been thinking about this problem as I usually leave my car for two weeks in an airport carpark and I may have to leave it for four weeks next winter. A possible solution might be to leave a solar panel on the dashboard and plugged into the cigarette lighter socket. This would supply a trickle charge to the battery whenever there is any bright sunlight so would be useless in an enclosed carpark.
Incidentally, the cigarette lighter socket is inside the central armrest storage box in the UK version. There is no cigarette lighter as such and if you want an ashtray it's an optional extra. Luckily I don't smoke.

I've had my Prius for nearly 11 weeks and I still haven't seen another one.

Cheers, Nick
 

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US 2004 Prius has two 12v accessory outlets, one on the dash, center, close to the passenger's knee, and the second is in the center console box. No cigarette lighter (just plastic plugs), and the ashtray is an optional accessory.

Problem is, the 12v accessory outlets are powered off when the car is off, so a solar charger plugged directly into the outlets will not work. You'd have to wire it directly to the 12v accessory battery.

(The classic Prius also shuts off its outlets when the car is off. Coastaletech does have a jumper mod to make the outlet always on, though.)
 

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I checked and the UK Prius 2004 has only one 12 V outlet and this is in the centre storage compartment and it is isolated when power is off. This means I have to switch on to ACC to be able to use my compressor to pump the tyres, something I never had to do with any other car I owned.

I suppose the solar panel could be connected to the 12V battery and could sit on the rear 'shelf'. Those I have seen advertised in UK come with croc clips as well as cigarette lighter plug.

It would be really useful if there was a list of which devices were driven by which battery.

Nick
 

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The dealer PDI information stated the 12V battery should be charged if the car is left unused every 2 weeks. Trickel charge is recommended. If left longer, the engine should be run in maintenance mode for 30 minutes every 2 months. If the HV battery goes flat, it has to be changed :(

Best would be to get someone to give it a short drive once a week. For parking at the airport for 2 weeks or more, maybe you should put a portable gas generator with 12VDc output (or mains and a charger) in the back incase the 12V has gone flat so you can get enough charge to start up.
 

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Thanks for the suggestions Victor.

I'm not very happy about having somebody from a hotel or carpark take it for a drive. They might even make the situation worse because they are not familiar with the car. I think I will explore the idea of a trickle charger powered by sunlight or perhaps an auxiliary dry cell battery.

I wonder how likely it is that the 12v battery would run down if left for two weeks. Usually when you arrive at the airport after a long drive the battery will be as fully charged as it is ever likely to be. I have never had a problem with other cars, including ones with an intruder system switched on while I was away. Is there really a larger load than normal when everything appears to be switched off (except the alarm)?

I could always leave the car in my garage at home and take a taxi to the airport but it's 150 miles so would be expensive and an admission of failure. After all the Prius is the most technologically advanced production car in the World so it should be able to do the job!

Nick
 

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Nick said:
It would be really useful if there was a list of which devices were driven by which battery.
Easy enough. Everything is powered by the HV battery when in Ready. Most via the DC-DC converter which powers the 12V system (and recharges the 12V battery at this time). Only the two motors, the DC-DC converter, and the A/C (2004 only) are connected to the HV side. Everything else runs off the 12V side.

When not in Ready, every thing that still has power is powered by the 12V battery.
 

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Nick said:
......

I wonder how likely it is that the 12v battery would run down if left for two weeks. Usually when you arrive at the airport after a long drive the battery will be as fully charged as it is ever likely to be. I have never had a problem with other cars, including ones with an intruder system switched on while I was away. Is there really a larger load than normal when everything appears to be switched off (except the alarm)?
The 12v battery in the prius is a lot smaller than on a normal car as it doesnt need to turn a starter motor. Therefore the peak load it a lot less so a smaller unit is ok, but this leads to a smaller overall capacity. Think of it as a motorbike battery! You can replace the standard one with a higher capacity unit, but I dont know what is involved off hand. Space maybe the main problem.
 

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I wonder how likely it is that the 12v battery would run down if left for two weeks.
I just returned from a 2-week vacation (12 days to be exact) and my 2004 Prius started right up with no problem. Before I left for vacation (the night before) I turned off the smart entry system, turned the climate control off, radio off, muli-functional display off, all interior and exterior lights off. In my mind I figured that if there was any 12V drainage, I did not want to overtax the battery with having to supply energy to turn on so many things when I started the car again upon my return. Whether or not this really helped, I'm not at all sure, but it made me feel a bit better about leaving it unattended for 2 weeks.
 

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It's good to hear that the car can be left for 12 days without any problems (any advance on 12 ?) and some useful tips re turning things off so there is less load when you turn on again.

Also the point about the battery being a lot smaller in capacity compared to most cars. It certainly looks smaller. There is an empty compartment on the other side of the luggage compartment so, in theory, it should be possible to carry a charged up spare of some kind which could be wired in as and when necessary. Maybe it won't be necessary and Toyota are just being over-cautious.
 

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Mine had some serious problem! I was on a vacation for a week then when I was back and started my 2004 Prius, it just went crazy! It won't start and I can hear some annoying noise. Any idea?
 
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