2nd time - needed to jump start - starting battery drained -

Don't know about a car, but back when I rode a motorcycle this used to happen to me all the time. Two weeks was enough to drain the battery.

 

if you have SKS, then two weeks is plenty of time to drain the battery. you can disable SKS with button under dash by steering wheel.

 

A few have had premature battery drains. I think one poster indicated his dealer found many of the external amps were causing sporatic drains. If memory serves me, they couldn't solve his problem and ended up lemon lawing the car.

 

Strike that, it wasn't lemon lawed. Toyota preempted that and bought back the car.

Have a dealer check the standby idle current. It should be really low. Now there could be intermittent loads that won't show up during the dealer's standby load test, but that would be a start.

The car should be fine for two weeks, though that is close to the limit. If you have SKS, be sure it is either off, or the fob is at least 10 feet from the vehicle. Also turn off headlights all the way. Auto-Off does put some drain on the battery too.

Also, be sure you haven't foobared. I thought I drained my battery, only to realize I turned off SKS and was trying to turn the car on without it!
Dome light was lighting up OK, so that was my clue that the battery was OK.

 

Re: 2nd time - needed to jump start - starting battery drain

Not an expert on the newer Prius model but this is what I've heard about the little battery.

Current load when "off" should certainly be less than 50 milliamps. There were problems posted with one of the audio options that presented a higher load. So, this should be considered.

Your battery may have been discharged before you got the car, have heard of that also. In which case Toyota should replace it? One would hope that they would respond aggresively to any problem at such low odometer.

Possibly it was not fully recharged after the earlier run-down? This could take more than an hour in "ready" mode. I am not going to suggest a battery trickle charger, but others have done so, either here or in the Yahoo groups.

If you need a new 12v batt and have to pay for it, there are alternatives to the ones sold by Toyota, and at lower cost. I paid <$100 for a replacement in my 2001 Prius; the original having lasted 42 months.

 

Re: 2nd time - needed to jump start - starting battery drain

As tochatihu pointed out,the max draw for the electrical system, as Toyota has taught us, is 50ma. I checked a couple of 04 Prius' , SKS and non SKS , and found the draw to be about 12-18ma. In the dealer here, I have seen aftermarket installs causing drainage problems if you let it set 1-2 weeks. An example is a DVD player installed in a Land Cruiser and was draining the battery in about 1 week. The dealer should be able to check the draw and let you know what it is. They can also test the battery with a Midtronics tester we all have. It tests the storage capacity of the battery and is a real good indicator if it needs replace or is low on charge. 8)

 

Re: 2nd time - needed to jump start - starting battery drain

I have had the battery replaced and if I leave the car for 30+hr. it will not start. 15000mi 2004.
The dealer thought that when the battery was replaced in was not fully charged.
Other than that I was told to drive the car daily and not let is sit.

 

My 2004 Prius, package #3, does not have SKS and the only add-on I have is Lo-Jack. Is my Prius prone to battery draining in two weeks as well? I'm going to be going on vacation and would like to prepare an intervention to prevent coming back to a drained battery. Thanks.

 

Even with the fob in the slot, car would not beep continuously unless a door was left open. After all, haven't you sat in the car doing nothing on occasion?

Make sure you didn't forget a map light on, or have any dome lights in constant ON position. In such a state, the body ECU has no control of the dome lights, and it never has control of the map lights.

 

Others have reported here how long the current Prius can sit without dying, and others have done a calculation based on current draw and total battery current. The new Prius is less prone to battery drain and even with SKS everyone has reported two weeks is OK (less reliable after that). I would expect the dealership to check the idle draw and battery condition. If either is out of spec, after removing any aftermarket accessories, they should fix the problem. If not, it is very possible the vehicle isn't being turned off properly, especially since someone unfamiliar with it (except for your lesson) actually turns it off, and they won't be able to reproduce the problem.

Others have reported on larger capacity batteries, though the limited space can make significant upgrades difficult.

I purchased from Wal-Mart an $8 DC plug charging cable for my Prius. This would only start your Prius if you can use ACC mode or have the $10 Coastal Tech mod making front DC plug always active. Starting the car only requires a small amount of juice from the 12V battery, just enough to power the computer. The main battery does the actual (and much higher power drain) engine starting, it's condition is independent of the 12V battery (and MUCH more difficult to drain.. haven't read anyone's story but it's possible.) I believe efusco (apologize if wrong person) reported if your dome lights come on at acceptable brightness, the car should start OK. You could use this device to jump another vehicle (warning: it's not recommended to use the Prius to jump another vehicle, but if you disconnect the vehicles before starting the dead one it should be ok) though a conventional vehicle with a deeply discharged battery (no noise when turn key) could take up to 40mins. The device limits current to 10A so it's safe for Prius since current is limited, though you have to disconnect before starting to protect device's 10A fuse. I haven't had a dead battery yet, despite leaving dome light on a few nights, so haven't tested it.

I was planning on getting a cordless inflator (when did gas stations stop giving free air???) with DC plug and trying that with the device above for a start. I don't know how much juice the Prius actually needs or how big of a battery these devices have, but seems OK. A portable jump start device, even a very small one, should work fine too and could be used with the above device.

Of course, disconnecting the battery or having a quick disconnect switch works. This is very impractical for your situation, personally I think it's easier to jump the car if needed than bother with disconnect.

 

We have a 2008 Prius (bought new) with 20 K miles. In that time, the battery has discharged overnight and had to be jump started.twice (good old AAA). Fob not left in car.. Everything "off".
Any ideas?

 

Replace the battery.

 

Unless there are aftermarket electronics that were installed incorrectly the most common cause is operator error. Do you *always* lock the car when leaving it, no matter where? (Doing that has twice saved me from draining the battery in mine while in my garage.)

 

See below.

After the 12V battery has been replaced, you should figure out a way to keep it charged up. Log more miles on the car; or connect a 12V battery charger overnight, every couple of weeks; or use a battery tender.