Complete 12 volt electrical failure

[kiwiguy]

As an engineer whenever to are trying to find a weird bug, you try to eliminate anything non-standard from the system, even trivial things. So I understand why Tesla asked to remove it, even if it should have no influence.

 

[TonyWilliams]

Ok, time for another (belated) update . . . I picked up my car on Friday, the 16th of January and returned the rental. There was no charge, and my Toyota Service Manager said during the entire time they had my car in the shop (nearly two weeks), there was no trouble found. Furthermore, Tesla advised removal of my cigarette lighter battery voltage monitoring device as it may be the cause of "interference" with their DC to DC battery charging control module in the car. Does that sound plausible to anybody here and least of all me???

Anyway, the problem has indeed gone away just as mysteriously as it first occurred. The weather is not quite as cold as it was then, but still fairly cold during early morning, so perhaps the problem will flare up again this coldest time of year. I'm watching it closely and have instructed my wife to stop driving the car immediately if the 12V battery low voltage warning instrument panel red light comes on steady again. So far so good . . .

That is f-ing HILLARIOUS... sure, interference. Great insight there (wink, wink, nudge, nudge). What a clown.

Wait until owners pull into their Toyota dealer with a JdeMO. I absolutely guarantee everything will be blamed on that.

 

[Kohler Controller]

Ok, time for another (belated) update . . . I picked up my car on Friday, the 16th of January and returned the rental. There was no charge, and my Toyota Service Manager said during the entire time they had my car in the shop (nearly two weeks), there was no trouble found. Furthermore, Tesla advised removal of my cigarette lighter battery voltage monitoring device as it may be the cause of "interference" with their DC to DC battery charging control module in the car. Does that sound plausible to anybody here and least of all me???

Anyway, the problem has indeed gone away just as mysteriously as it first occurred. The weather is not quite as cold as it was then, but still fairly cold during early morning, so perhaps the problem will flare up again this coldest time of year. I'm watching it closely and have instructed my wife to stop driving the car immediately if the 12V battery low voltage warning instrument panel red light comes on steady again. So far so good . . .

That is f-ing HILLARIOUS... sure, interference. Great insight there (wink, wink, nudge, nudge). What a clown.

Wait until owners pull into their Toyota dealer with a JdeMO. I absolutely guarantee everything will be blamed on that.

"Sorry sir, your flat tire cannot be repaired. You have this strange device that may be causing interference with the Tire Pressure Monitoring System."

 

[Sun2Drive]

Just picked it up from my local Toyota dealership. All they did is replace the 12V battery, which is what I thought the problem was after the failure occurred.

My 12V battery just died, too, and so did longrangview's battery - http://www.myrav4ev.com/forum/viewtopic.php?f=7&t=1575. Is this the start of a trend?

 

[Dsinned]

In my particular case, thank God I have had no reoccurrence of the same problem since the first time in January of this year. Fwiw, as ridiculous as it may be, I have not had anything plugged in to my cigarette lighter per Toyota's recommendation during this time. I still really don't know why this happened. Just a random failure of my 12V battery, where for some strange reason it was incapable of being recharged?!?!?

It is certainly more likely that "something interfered" with proper operation of the HV to LV, DC to DC converter module, and this is what caused my 12V battery to completely discharge while driving the car. I still have the original converter module, which apparently worked reliably before and after this one time complete electrical failure. I have not seen another Low Battery Warning red light come ON either. I am tempted to put my aftermarket 12V battery voltage monitoring digital readout device back in to the cigarette lighter, AND just as a precaution, get a high capacity Li-ion 12V battery booster EPS - see link below - to carry in the cargo hold.

http://www.amazon.com/dp/B00T49SF1O?psc=1

 

[davewill]

Apparently the Tesla owners have been seeing a lot of 12v battery replacements, too:

Near annual replacement of 12V battery is typical according to Tesla Service Tech

 

[Dsinned]

Hmmm . . . interesting! Apparently the lifecycle of a Tesla battery is only ~18 months. In a Model S, due to heavy "vampire" loads, the 12V battery may have to withstand "3" discharge cycles per day. That's a lot! And because of this, it may lead to a much lower life expectancy. This explanation certainly suggests my complete electrical failure was indeed caused by a totally dead 12V battery that had reached EOL after only 26 months of service life in something around 8000 miles. This was approximately the mileage on my car when the failure occurred, which at the time did not seem like it could have been a big big factor in causing the failure. However, even if a lot of its service lifetime was relatively "inactive" while not actually driving the car over that period of time, it could have been under strenuous use all the while. This seems to correlate fairly well with what Tesla owners are saying over on the Model S forum.

If all this is true, here again, why is Toyota seemingly so clueless about the RAV4 EV's 12V battery life? When my failure occurred in January, I would have thought by then a definite trend would have been seen in Toyota's dealer service network with a lot of prematurely failing 12V batteries, at least in model year 2012 RAV4 EVs. This ***should*** have resulted in a TSB being issued to all servicing dealers in CA, to warn customers to have their RAV EV battery checked periodically before a complete electrical failure occurs and an expensive tow to a servicing dealer becomes necessary.

Could it be that 12V lead acid automotive batteries are still fairly expensive to replace and Toyota just does not want to own up to this being a legitimate warranty issue? :roll:

 

[smkettner]

Three cycles per day is especially a lot for what is probably a start battery when a deep cycle is needed.

 

[TonyWilliams]

Three cycles per day is especially a lot for what is probably a start battery when a deep cycle is needed.

Exactly.

Not just EVs, but any modern car with telematics and other heavy loads on the 12 volt when the 12 volt isn't being charged will drag down the voltage.

Lead acid batteries don't age well below their optimum 12.7 volt state.

Lithium 12 volt solves all these issues. The lithium can be spec's for 16 volts (4 cells in series) that would leave the the cells in their near ideal of 3.5 volts per cell when fully charged to 14 volts. It could still be safely charge at 4 * 4.2 = 16.8 volts without issue.

The cells could drop to 3 volts (12 volts total) before cutoff and 16.8 cutoff on the top end.

Now, just keep the cells cool and balanced, and it will last 10 years or more, with big enough ah capacity so that it never gets depleted in even abnormal use.

 

[Kohler Controller]

Three cycles per day is especially a lot for what is probably a start battery when a deep cycle is needed.

Lithium 12 volt solves all these issues. The lithium can be spec's for 16 volts (4 cells in series) that would leave the the cells in their near ideal of 3.5 volts per cell when fully charged to 14 volts. It could still be safely charge at 4 * 4.2 = 16.8 volts without issue.

The cells could drop to 3 volts (12 volts total) before cutoff and 16.8 cutoff on the top end.

Now, just keep the cells cool and balanced, and it will last 10 years or more, with big enough ah capacity so that it never gets depleted in even abnormal use.

Lithium Iron Phosphate (LFP) would be a better solution than mixed oxides (that operate between 3-4V in the above application). LFP works best from 2.6 to 3.65V/cell (10.5 to 14.6V for a "12V" battery), which is exactly the same working range as sealed lead acid. Same advice holds with regard to keeping them cool and balanced, and it will last 10 years or more.

One thing I notice with my LPF 12V battery is that it gets warm from 1/2 of it sitting directly behind the radiator fan. I would recommend a heat shield to redirect the warm air around the battery, otherwise one corner of the battery (1/4 of the cells inside) will get hotter than the others.

 

[TonyWilliams]

I think I'm going to move my battery inside the car, perhaps in the rear storage area.