car battery drained after 2 week vacation

"The headlight switch was on but I don’t have auto headlights." That means the headlights were left on. Is that what you meant?

How do you know that XM Commander has no drain when the car is off?

If you have Smart Key System and did not turn it off using the button under the dash, two weeks could have been enough for that alone to have drained the battery.

 

If you have SKS, it can slowly drain the battery. Toyota recomends turning this off (the button beneath the steering wheel) if you are going to be gone for extended periods of time.

Also, if your battery happens to die again while in the garage, rather than stringing together jumper cables and creating a potentially hazardous situation, you can pop the trunk (if you can get it unlocked, not sure how that would work), pupp up the cover to the cargo area above the spare tire, then pull out the cover over the 12V battery on the passenger side (it's in taht little recessed area behind the wheel).

It's been posted on here before for people in similar situations that draining a battery completely can significantly reduce its life time or lead to the potential for easier draining in the future... i'll let others post more to that effect.

<div class='quotetop'>QUOTE(richard schumacher @ Jul 18 2006, 10:46 AM) [snapback]288166[/snapback]</div>

Given the location of texas, means it's a US car, which means the headlights will automatically turn off when the car is off and the drivers door is opened.

 

Yes, *if* one follows the right sequence in opening and closing the doors. As we have read here more than once, people do forget. And the poster wrote that despite having an '06 he does not have auto headlights. I don't what to make of that.

 

I don't believe that package #1 includes SKS, so we can probably rule that out.

 

<div class='quotetop'>QUOTE(brandon @ Jul 18 2006, 12:18 PM) [snapback]288188[/snapback]</div>

Toyota info I have indicate package 1 does not have smart key(SKS). Sure fix if the car is in your garage is to hook the car up to a battery tender. Get one with auto shut-off so the battery doesn't over charge.

 

I went on a 2 week vacation earlier this month and did the same thing - left the car in the garage without disconnecting or disabling anything.

I was a tad bit nervous when I jumped in my car to start it when I got home. But it started without a hitch! The battery levels were within one or two bars from green.

 

D'ohh!! I should've remembered that #1 does not have SKS. Anyway...

<div class='quotetop'>QUOTE(dreichla @ Jul 18 2006, 02:45 PM) [snapback]288284[/snapback]</div>

That meter shows the state of charge on the big "traction" battery, not the little 12V battery which is used to boot up the car. The 12V is the one that can run down when the car is left standing for a long time. Presumably for safety reasons the traction battery does not recharge the 12V battery when the car is off.

 

Fully discharging lead acid batteries will always reduce their capacity a bit, but the effect is much more serious in the winter if the electrolyte freezes.

If your Prius 12 volt battery becomes weak you will find that Toyota charges quite a bit for their replacement. An alternative battery from MK has been used by several classic Prius drivers (incl me) and can be ordered from www.elearnaid.com Uncertain if this battery is compatible with the new model Prius, because the terminals have been reversed. One could ask the elearnaid guy.

Conicelli online catalog also lists the battery for sub-$100, but AFAIK none of those have been put into either Prius model yet.

 

I read someplace on Priuschat that the current draw from the 12V auxillary battery (the tiny one in the trunk) is about 50mA. This current draw is a function of the options on the car but still illustates the point.

50mA X 24 hours X 2 weeks = 16.8 A hours.

That's quite a bit of charge to remove from the tiny 12V auxillary battery.

My recommendation is to keep a float charger on the 12 V auxillary battery if you are going to be gone on vacation for more than a week or so.

You may have also compromised the battery life time as lead-acid batteries don't like to be deep discharged as do marine batteries.

Dave

 

I read somewhere today that Reverse is a completely electric motor function (no ICE involved.) So if the traction battery goes dead you can't back up. Is that right?

 

I also read in the '04 manual that if you are going to leave the car alone for a long time you should not leave the headlight switch in the "on" position. It seems counterintuitive (when lights are off, they are off!) but there may be some additional drain. I have never had a car sit unused for more than two days. It sounds to me like disconnecting the battery or buying the float charger is the way to go. Also, if you have the security system that has the little flashing red car on the dash whenever the car is off, that adds to the drain of the battery. If you disconnect the battery remember that you will lose radio presets, and any changes you have made to "things that beep"!

<div class='quotetop'>QUOTE(Alnilam @ Jul 19 2006, 11:13 PM) [snapback]289161[/snapback]</div>

If the traction battery (the hybrid battery) goes dead you're not going anywhere! If the 12V battery goes dead the computer system won't boot, the car won't start, you can't open the back hatch, and you can't shift into Neutral to push the car. It happened to me and it was not fun (but my own fault).

 

<div class='quotetop'>QUOTE(tochatihu @ Jul 19 2006, 04:40 PM) [snapback]288913[/snapback]</div>

Can you check to see if the website you wrote is correct. When I copied and pasted the elearnaid website it brought me to an on line CD learning center.. Thanks

<div class='quotetop'>QUOTE(marjam @ Jul 19 2006, 11:21 PM) [snapback]289166[/snapback]</div>

I'm not so informed about battery chargers, so excuse my ignorance here. I have a car battery charger that I have had for years. Is there any difference between a standard battery charger and a "float" charger? Are they one in the same thing? Thanks. I get a lot of education on this forum and I really appreciate it.

 

<div class='quotetop'>QUOTE(eagle33199 @ Jul 18 2006, 08:51 AM) [snapback]288168[/snapback]</div>

There's a manual release handle for the back of the trunk, but it's not particularly easy to get at if you have no power. You need to crawl through to the back of the car, then remove the spare tire cover panel, then take-out the tray underneath, then pull a handle located underneath the hatch locking system.

Dave