Re: 12 Volt Battery
 

Odd....

I got really sick last winter (almost died in Feb) and my 2007 TCH sat outside for 4 months without being started. When I finally did get into it in April, it started right up as though I had shut it off just the night before.

The brakes - however - were not as cooperative. The right rear rotor was rusted tight - although it did break loose after rocking the car back and forth. The pads have since been replaced.

It's cold here in Minneapolis in the winter. Our coldest day was around -25f (without windchill). Maybe the cold helped in this case?

I was really expecting to find that the battery was dead and broken (they break when they freeze)...

Re: 12 Volt Battery
 

The AGM (Absorbent Glass Mat) batteries are much more able to handle temperature extremes than the traditional fluid electrolyte types. These are also a 'deep cycle' type battery that can withstand deep discharges without damage.

From what I gather, the 12v battery is used to power the electronics (computers, radio, climate control, etc...) and the engine uses the traction battery to start.

There is even a "legend" about "some guy" using a couple of 6v lantern batteries to start his Prius.

Re: 12 Volt Battery
 

Include the fans under the hood, headlights, taillights and anything else that uses 12 volts for power.

I believe that to be true if the fellow disconnected the deep cycle first. Evidently the ECU itself don't draw that much current. A smaller 12 volt source may be enough to boot up the ECU for it to start the engine.

The heavy current drain on the deep cycle battery is it's ability to run all the AC fans, while sitting at long red light in the hot summer heat.

Re: 12 Volt Battery
 

Big-Foot, sorry to hear about your February illness. I had the flu twice in the past and thought I would never pull though. About the time I was to give up I started getting better. I still don't see how a microscopic bug can knock over a big dude like me.

Re: 12 Volt Battery
 

This last week I documented the voltage drop of the battery. It dropped from 12 volts down to 10.5 volts in several days. After charging, it dropped to 11.3 volts the next morning, and of course was dead. The dealer checked the amp output after I had driven for 2 hours and found it at around 36 amps. They charged it for an hour and brought it up to a little over 70 amps. It should have been somewhere in the 300's. Battery was replaced under warranty. I believe the problem was that the battery sat for long periods and was found dead numerous times, since it only had 28 miles on the odo when I purchased it in June. I am hoping that this should solve the problem. Now I am wondering about the traction battery not showing a full charge after a day of driving. Could not being used for long periods of time, between manufacturing, shipping, and sale, effected the traction battery as well?:)

Re: 12 Volt Battery
 

I hear you... I had/have a nasty case of Atypical Trigeminal Neuralgia - I won't go into details here but Wikipedia has a pretty knowledgeable writeup on it... I'm back but not at 100% yet...


I think you had a battery with a bad cell. Batteries can also short out internally. If someone else runs into this - I would have the battery out of the car, charge it all the way up on a 5 amp charger overnight/ Then remove the charger and see how fast it bleeds off the surface charge. You can also have a Load Ballast put on it which will approximate the loading of your car's systems on it.. After 30 seconds with the load cell on it - the battery should still read over 12v. If it doesn't - your battery is ready for the recycle pile.

Re: 12 Volt Battery
 

Is the Onboard Diagnostic System (or what ever that think is called where they hook up a plug to the car and figure out what's wrong) smart enough to tell if some of the cells in the battery are bad, or going bad?

Re: 12 Volt Battery
 

Honestly - I don't know... But I doubt it...

It's not like the technology isn't there, but I think they've already got a full bevy of other technology embedded into the car and for them to have a load-cell embedded in the car's system would take additional weight/space and for what little use it would actually get - I just don't see it happening...

certainly they "could" use other things (MG?) to act as a Load Cell - but the additional complexity would also increase the risk of failure..

Re: 12 Volt Battery
 

I once read that the traction battery contains a small computer that scans the groups of cells in it. If any or weak or have a single dead cell, it then reports this information to the ECU to provide a trouble code.

Re: 12 Volt Battery
 

I wouldn't worry about the traction battery simply on the basis of it not showing a full charge. Not having the energy screens in my NAV display (Canadian version:() I can't say what the battery readings are typically supposed to be there. HOwever, using the MFD on the dashboard, the battery almost never will show full, unless you've just gone down a very long very steep hill (ie. in the mountains). My battery display typically fills up to the minus sign in the picture, with the top area left empty.