when it snows, the Prius needs to be jump-started

It sounds like your 12v battery may be week. Have it tested before starting in the morning. It should be 12.0 volts or better. H

 

I suggest that you replace the 12V battery now (and do not bother having it tested.)

 

So why get a whole new car when just a new 12V battery will definitely fix it. That seems like just tiny bit of an overkill to me.

 

Replace the 12v battery!!!

 

Hi TM...,

When you leave the car (2nd Gen Prius), make sure you lock the car with the remote. The yellow marker lights should flash. If they do not, then you have a door ajar. This runs the interior lights contiuously, and will run down the battery. Do this a few times, and like any vehicle 12 V battery, it wont hold a charge very well.

The most common door ajar for me was the Hatch. Make sure you really bring that hatch down firmly when you close it. The trunk light is below the tonneau cover, and is not visible from outside the car with the hatch down.

You may also want to upgrade to a deep cycle battery. Checkout elearnaid.com for their Prius replacemetns. the Optima yellow-top batteries they sell are combination starter and deep cycle batteries. They sell a kit of parts ot adapt the Prius to the larger SAE style terminal posts on the Optima battery. This battery is also stocked at Advance Auto. But, you will need the adapter kit to use it on the Prius.

 

wait a second guys, what is the correlation between snow and the battery?

 

There is a correlation between snow and cold weather.
Snow -> Cold Weather -> Impaired functioning of weak 12V battery

 

right, but doesn't it seem an odd way to put it? when it snows? when it's cold? in the winter? i would take it as only when it snows.

 

It's a case of coincidence or over-interpretation.

 

That's *exactly* what I thought Richard, up until now that is. Just now I checked the OP's other posts here (there's only two of them) and in this thread in the Gen3 forum http://priuschat.com/forums/gen-iii...rst-car-in-history-in-winter.html#post1246232 he says :

So that's a weird one.

Hopefully the OP can provide some more details as I've never heard of this one before. The one off post nature of the OP makes it seem like perhaps this is more for the purpose of a rant than a serious attempt to solve the issue though.

 

You have hit the proverbial "nail on the head"

 

There is one more reason too.

With snow covering the ground day time temperatures would not go as high as if the snow cover was not present. Much of the energy from sun would be used up in surface melting of snow.

While in the night , there would be more than usual radiational cooling. Nights with snow cover are supposed to be cooler, that when there is no snow cover, other variables remaining same.

If it was my car, I would have definitely changed 12 V battery.

 

The mere presence of snow all by itself is not causing the battery to die. There's some associated factor we don't know about. For example, when it snows a foot does that mean that the car is left sitting and not started for a longer time? say, for a few days instead of the usual one day? This gives the (already damaged) battery more time to self-discharge.

The OP needs a new battery regardless.

 

First off...... I know squat about the 2004 Prius. As others have said it's probably your battery. But, if your 2004 has a sensor on the dash to tell the car it's nighttime, as my 2010 does. Try this, during a day without snow....throw something over this sensor....see if your battery goes dead.....this could help find your problem.

Just fishing........but sometimes that what we have to do !!

 

I sort of see where you were going with this, but it doesn't quite add up. Snow on the ground reflects sunlight, which keeps the ground colder. The snow also insulates the ground, which may keep it colder or warmer, depending on initial conditions. Regardless, we aren't talking about the temperature of the ground, but only the temperature of the OP's Prius. Snow on the ground will help warm a Prius on a sunny day, as it increases the amount of gradient energy striking the car. Snow covering the Prius would have the opposite effect, although it would also serve as an insulator.

Snow at night works mostly as an insulator. Cloud cover is one of the bigger factors, keeping heat from radiating into the sky. If you want cold, go out on a dry, clear winter night.

Tom

 

I just don't see anything logical about snow or snowfall itself that would cause a battery to drain. Something else is going on here. If there have only been 2 snowfalls, this isn't enough to establish a pattern.

If we were talking about rain, then yes, there could be things caused by rain. Note that there is not a known issue with rain and starting problems on a Prius. I can think of other issues on other vehicles (particularly older vehicles), but it's not helpful to the topic at this point. But snow, especially on a parked car that has been sitting overnight, is not going to creep in somewhere and cause a battery to drain. BOTH batteries are well protected from rain/snow (assuming the car is stock, not hacked up). I would also be finding a new dealer or new mechanic at the dealer.

A paperclip? Seriously? Maybe if it had somehow been rigged to trigger a cargo or dome light to stay on AND just coincidentally only happen to do that twice during 2 snow falls (in other words, not likely).

 

doesn't make sense to me either unless the snow is being driven under the hood, melting and shorting something? either way, i agree with richard. if it's the original battery, might as well change it before it dies on you somewhere. if that isn't the problem, it was money well spent anyway. are there any gaskets along the edges of the hood where it meets the body that could be missing?