12V battery problem and dealer reaction

<div class='quotetop'>QUOTE(CVS @ Sep 5 2007, 01:28 PM) [snapback]507386[/snapback]</div>

Stop in at a different dealer.

 

On a regular vehicle, when I've had a bad battery, I've taken it to the local auto parts store, they hook it up to a machine and after a minute or two, it tells you if the battery is good or not. Since we're talking about a 12v battery (although smaller than normal) surely Toyota could do some sort of diagnostic on it.

I second the vote for trying another dealer.

 

for the dealer saying that 12v batteries goes dead in a few days is crap.

the 12 v battery on the prius isnt some small batt

 

<div class='quotetop'>QUOTE(CVS @ Sep 5 2007, 01:28 PM) [snapback]507386[/snapback]</div>

Replace the battery. It's too marginal to keep in service. Yes, I recommend a Toyota battery, even though it's more expensive.

As for diagnosis, it's surprising how few technicians - even good technicians - can accurately diagnose the condition of a 12V battery. The Prius complicates this, since the traditional load test specs are not given for this battery.

Toyota just obsoleted their existing battery testers in favor of a supposedly dummy-proof diagnostic charging station. However, it will probably be a while before many dealers pony up for this piece of equipment.

When you go to the airport, make sure all interior lights are OFF (including the one in the cargo area) and disable Smart Key if you have it. By the way, many of today's cars will drain their 12V battery after sittlng a week or two. Mercedes even sells a solar panel accessory for their cars, to minimize this problem.

 

The dealer is being a typical dealer and is full of it. You need to replace the 12V battery if it can't last more than a couple of days. It should be able to go for a couple of weeks (with the SKS) if nothing else is left on. Completely discharging the battery doesn't do it any good.

Tom

 

<div class='quotetop'>QUOTE(CVS @ Sep 5 2007, 03:59 PM) [snapback]507478[/snapback]</div>

Oddly enough, I had a dead 12V battery on my Prius Classic. We parked it on the street for a 2 or 3 hour meeting, and when we came back, no boot. Luckily, I noticed that the power brake pump was running (poorly). I waited for the pump to build up pressure and stop, and then I was able to boot. Drove around for a while to charge the 12V, and never had the problem again, even leaving it for several weeks. It was the darndest thing.

Of course, yours seems to be getting worse and worse. Sounds like a replacement would make you a bit safer. (You know where the jump point is in the front under the hood, right?)

Burns

 

<div class='quotetop'>QUOTE(CVS @ Sep 5 2007, 09:54 PM) [snapback]507788[/snapback]</div>

It could be a bad battery, but it could also be a pesky hard to find electrical problem that draws down a good battery. If you have 5,000 miles on the car, make them fix it.

 

My long lifetime experience is once you deep deplete the battery like that it becomes very sulphated and will never be the same. Leaving a small light on for a week is the best possible way to destroy a car battery. Not to mention it could damage the alternator. And like has happened to me leave you at the worst possible time. If it was me I would have just bit the bullet and bought a new battery...like an Optima. Good luck!

 

my salvaged 05 prius had a deeply discharged 12 volt battery, in my past experiences you must give it a trickle charge for a long time in order for the battery to perform normally, i also had a 01 prius salvaged, the battery was deeply discharged ( over a period of 2 years ) i charged it up using 10 amp charging and it subsequently damaged the 12 volt battery ( it swell up and wouldnt hold any charge) so i had to replace it.

 

<div class='quotetop'>QUOTE(Drifty'sDad @ Sep 6 2007, 09:25 AM) [snapback]507891[/snapback]</div>

You can take the battery through an equalization charge which will reduce the sulfate, but there is no way to replace the lead that is now on sitting on the bottom of the battery.

Tom

 

Is the dealer stupid, or did you fail to tell the him how you killed the battery?

Stop trying to screw Toyota out of a new battery. You broke it, you pay for it.

 

we traveled for two weeks when our Prius was near new, and came back and the car started right up.

I'd buy a new battery, stop your whining and just do it! They're only a couple hundred bucks.

 

<div class='quotetop'>QUOTE(CVS @ Sep 7 2007, 04:45 AM) [snapback]508466[/snapback]</div>

Hey CVS,

I strongly disagree with the previous two posters. The battery is under warranty. It is NOT normal for the battery to lose charge in two days unless you have something (abnormal) draining it while it's parked. IMHO, you should go to a different dealer to verify whether the battery is defective. if so, it should certainly be replaced under the warranty. Good luck.

 

<div class='quotetop'>QUOTE(CVS @ Sep 7 2007, 07:45 AM) [snapback]508466[/snapback]</div>

The person that said something about an alternator is not allowed to say anything anymore. There is an inverter that charges up the 12V battery....No alternator on a prius gen 2.
If you charged the battery after it was killed with a regular charger vs. a low current <2 amp charger then you have probably done long term damage to the battery. Purchase yourself an emergency jump start device. An inexpensive one sells at communist walmart for about $40-50. It is a quick backup and you don't need cables. Since the Prius only needs 30 amps to boot the computers to allow the traction battery to start the ICE this device will work great until the 12V batt either fails or gets better. Good luck on the latter.

 

<div class='quotetop'>QUOTE(D Rock @ Sep 7 2007, 04:51 PM) [snapback]508755[/snapback]</div>

The Toyota PDI specifically mentions the use of an automatic 10 amp battery charger. They do not recommend a 2 amp setting due to the length of time required to charge.

A good way to maintain the battery is to always keep it plugged into one of those automatic float/desulfator battery tenders. I have the VDC Electronics Battery Minder plugged into the FJ and the Prius, and at the hobby farm I keep the old truck and tractor plugged into Battery Minder's. They work as advertised.

I've attached the Toyota PDI regarding 12 vdc battery maintenance.

<div class='quotetop'>QUOTE(statultra @ Sep 6 2007, 08:43 AM) [snapback]507894[/snapback]</div>

A severely discharged 12 vdc battery - especially one left dead for 2 years - is probably beyond help. Once enough sulfate drops out, it will build up on the bottom of the battery case, then short out the cell. A desulfator will take care of minor sulfation on the plates, but cannot help the sulfate sediment at the bottom of the battery.

You're lucky the battery case only bulged. One thing that severely sulfated batteries and frozen batteries have in common: they can explode

 

to summarize what others are saying:

1. leaving the light on for a week will indeed kill your 12v.

2. after doing this, it will never be the same.

3. 10 days of sitting should be ok for a battery that hadn't been run down before. but 10 days of sitting for a battery that already had been drained once- well it's no surprise it died.

i wouldn't expect to find any parasitic drain, given that it only discharges when left to sit for the instances listed- 1 week with a light on or 10 days after having been drained previously.

now if it couldn't hold a charge overnight or maybe 2 days, THAT is parasitic drain.

from the sound of it, you can either cope with this battery not being able to sit for more than a few days alone by starting it and letting the car run for maybe 1/2 hour every few days, or buy a new battery.