dealer replaces small battery that went dead for no reason?

Should dealer replace auxiliary battery that failed out of the blue? No the dome lite was not left on. The dealer can't tell me why it failed. He says it's fine now. ??? Patrice

If you don't know why it was dead, you don't know that replacing the battery would fix the problem. There could be an unknown drain on the battery, the charging system could be defective, OR you could have a bad 12v battery. You'll probably have to wait and see whether it happens again. Good thing the car comes with roadside assistance!

How long was the RAV sitting between the time it was last used and when the aux battery died? While the Li-ion Tesla battery drains very slowly, the lead-acid aux battery is continually used by the keyless entry and telematics systems even when the car is off, and will drain after a few weeks.

If you need to let the car sit for more than a week or so, you should probably get a battery tender for it.

eschatfische said:

the lead-acid aux battery is continually used by the keyless entry and telematics systems even when the car is off, and will drain after a few weeks.
If you need to let the car sit for more than a week or so, you should probably get a battery tender for it.

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I like what Nissan did with the leaf with a small solar cell (5 watt ?) in the rear spoiler to charge the 12V battery.
That would be an easy modification but how to do that nicely ......
Of course when you park it inside a garage it doesn't help much

fromport said:

eschatfische said:

the lead-acid aux battery is continually used by the keyless entry and telematics systems even when the car is off, and will drain after a few weeks.
If you need to let the car sit for more than a week or so, you should probably get a battery tender for it.

Click to expand...

I like what Nissan did with the leaf with a small solar cell (5 watt ?) in the rear spoiler to charge the 12V battery.
That would be an easy modification but how to do that nicely ......
Of course when you park it inside a garage it doesn't help much

Click to expand...

The 12 volt "hot" lead is in the rear view mirror (for the Homelink garage door opener). Use this:

http://www.amazon.com/Sunforce-50022-Battery-Trickle-Charger/dp/B0006JO0TC/ref=cm_cr_pr_product_top?ie=UTF8

Thank you all for your replies. It is true that the problem could be something other than a bad battery...Waiting to see if it happens again is not appealing but I will start...I like the idea of that Sunforce Trickle charger...and now for the next car? Honda Fit EV? Chevy Bolt 2017? I want a reliable car. Do all electric cars now available have dead batteries some mornings when we are rushing to work and grad school? This car is only one and a half years old. I have been driving the car every day. I plugged in the car Monday nite as usual. On Tuesday morning the battery was dead although it was still plugged in. I had to rush to work using other means. The tow guys charged my small Battery with a Rockford Pocket Power jump starter. The car powered up for 5 minutes, sat and died again. It was towed to the dealer. Relatively speaking, my problem is small. I realize some of you have dealt with getting the "sudden death message", repeated replacement of the drive train and more. I apologize for complaining. We all need a safe and reliable vehicle. Best, P.

I haven't experienced the 12v battery going dead in the RAV4 (yet), but have in the Focus EV, the LEAF, my Prius before that, my dad's Honda Element and his Ford F-150. Dead auxiliary batteries are a car thing, not an EV thing.

Also, charging the battery for 5 minutes is rarely ever sufficient. In order to get the Prius to boot up properly it needed about 20 minutes on the wall charger. The FFE needs about 10 minutes. Both at the "high speed" mode on our Canadian Tire charger.

I suspect you left the car "on". That is the number one way to kill the 12 volt.

The other way to kill it is to leave the car unused for a week or more (and not have the 12 volt on a trickle charger).

Or the DC/DC is bad and the 12V gave all that it could the first time. Then when hit with 5 min recharge, died again because the DC/DC should have taken over.

longrangeview said:

This car is only one and a half years old. I have been driving the car every day. I plugged in the car Monday nite as usual. On Tuesday morning the battery was dead although it was still plugged in. I had to rush to work using other means.

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My 12V battery also died last night: sometime between 9pm (parking the car) and 1am (when it would normally start charging and sent me an email notification). I've also driven daily for almost two years, too. My commute is 100 miles round trip, so I really don't think the battery should have died. Unfortunately I'm past 36K miles, so the dealer says it's out of warranty. I guess I'll suck it up and get a new one, but I really hate that the battery can't last 2 years with regular use. What a piece of junk!

30 months and 50,000 miles on my 12 volt. It was replaced under "good will" from the dealer.

i had this happen to my car 6 months after i bought it.

once i replaced the battery (a dealer wasnt convenient) i've never had another 12V problem again.

Its possible that the batteries degrade during shipment of the vehicles (or sitting on the lot) so when you get a new one, you might get a weak battery.
The battery is pretty cheap to replace so i never bothered the dealer about it.