2010 II 12 Volt Battery Dead After 17 Days of Parking

Use a clamp-on meter; that way you don't have to unhook anything. I have a nice hall effect dc clamp-on ammeter that would do the trick, but I'm not interested enough to take it out to the car and clamp it on. I believe hobbit did some testing in this area awhile back.

Tom

 

I think that's exactly what needs to be done, I'm retired now and, unfortunately, no longer have access to much test equipment. I have a couple of engineer friends. I'll ask them what they have.

 

Well, I am late to this discussion - because I just returned from a trip, leaving my two month old Prius in the garage, untouched for 23 days. It started up just fine. So, it seems to me that, with the new battery, at least, the 10 day limit is a bit . . . conservative. Admittedly, it was in my garage and I did not have to unlock it - just start it up.

However, it also occurs to me that the question of dealing with 'long term' storage for a new car at the dealer is not exactly the same as my leaving my car in my garage. For an undelivered car, is not one, if not both, of the key fobs INSIDE of the car? It seems to me that this would be likely to prevent the timeouts for the system for operating, leading to a more significant drain on the battery.

I was careful to insure that neither key fob was 'within range'.

Based on my experience, I am probably not going to worry about the issue for trips of three weeks or less. However, if or when I go on longer ones, I guess I am going to have to find a 'car sitter.'

 

zippo,
So, it was unlocked, and the alarm system, if any, was not armed.

It might be that the locked condition (monitoring for the unlock fob), and alarm armed state cause a much greater drain on the 12v battery.

I / we should measure both states: "securely garaged", and "airport lot".

 

Perhaps you should just leave the car unlocked in a long-term airport lot?

 

I Just made a measurement with a Fluke 289 with a Prova CM-5. My prius (Canadian Tech Packing) use around 160 mA 2 minutes into sleep.

But there is one problem with my measurement. The keyless entry no longer work while I recording the data (Interferece from the 289!?). This may affact the result.

 

A 40 Ah battery would be "dead" in 160ma x 6h = 1000 mAh = 1 Ah ...
6 hours times the 40 Ah capacity --> 240 hours, or 10 days.

Could you determine the Ah spec for the battery?

With the doors locked, it might draw more current, but could also draw less.

 

The 2G battery has an amp hour rating in the mid-30s. Since the 3G battery is the same physical size I would assume the amp hour rating is similar. Usually you would not want to discharge the battery more than 50% of its amp hour rating.

A 0.16 amp drain is quite high, I hope that your measurement is wrong and the actual current drain is substantially less than that. If this were true, the 3G would use ~4 AH per day (24 hours/day x 0.16A = 3.84 AH/day) and the battery would be totally drained in nine days.

For comparison, 2G current drain is around 20 mA or 0.02A while Classic current drain is around 35 mA or 0.035A.

 

I think the interference from the meter may cause the keyless entry system to use more power then it should. Any one have any idea so that I can avoid that? (Wrap the meter with foil?) I don't have a very long test lead.

 

Finally have time to download all data points and work out the average in Excel. The actual average current should be 104mA (Don't trust our eye all the time). Also, resolution for the clamp probe is 10mA +-2%.

This is the sampled data:


This is the data use for averaging:


Please note that 100mV=1A.

 

I'm wondering this: Was the battery totally dead when you found the car? Done lights totally off, etc? I'm just wondering because a totally dead battery in 17 days...

Oh, for the guy that left his car unlocked: The SKS is still running as is the keyless entry .. I can't imagine the unlocked setting is any different than locked.

I left my map light on the other day and when I found it in the morning everything was fine. Voltage was still normal, etc.

 

Strange, the measurement is steadily climbing (approximately doubles, or a bit more) over the 3-minute interval shown.

Averaging by eye, the first minute appears to 92.61 (grin) ma, the second 120, and the third at 150, for an average of more like 121 rather than 160.
Is my "eye" wrong (again)?

So, this would appear to be NOT steady state current drain, or possibly some problem with the meter?

 

Regarding the measurement of ~100 mA, I'm wondering whether the Smart fob is far enough away from the car so that the Smart receiver can be quiescent. Also, is the car locked with all doors/hatch closed while the measurement is going on?

 

The LED lights might draw only 20 ma.
Has anybody measured?

 

I inspected the data set. It appear to be consistent over the 3 minute interval. Since its very close to the minimum range of the current clamp, noise of this magnitude appear normal. There are around 350 samples so the average should be good.

The fob was 5 meter away from the car while I logged the data. The doors was locked via the button on the hatch. None of the touch sensor on the doors work while the meter was sampling. I originally think that this may affect the reading. But upon closer inspection of the 1st graph, its look like current drop twice over the 1st minute, seem like the radio actual go to sleep after a while!

I am open to any suggestions to how to rerun the test to minimum the effect of radio interference.

 

Ok, it is interesting all this measuring and so forth, but no one has yet
given us the ANSWER. Why hasn't anyone contacted TOYOTA about the
problem with parking a Gen III Prius for 3-4 weeks in a parking lot
and having the battery go dead.

Has anyone contacted TOYOTA on this issue? What did they say?

Jeff (about to go on a trip by plane)

 

I emailed TOYOTA to ask about this problem. Here is their response
to that email:


Thank you for contacting Toyota Motor Sales, U.S.A., Inc.

We appreciate the opportunity to address your inquiry.

To prevent excessive auxiliary battery drainage, charge the battery at least once every two weeks by driving the vehicle for 15 - 20 minutes with all non-essential electrical accessories (such as air conditioning and audio equipment) turned off. As an alternative, you may disconnect the negative terminal of the auxiliary battery. If the battery was disconnected, it will have to be reconnected before the hybrid system is started.

For the hybrid vehicle battery, charge the battery at least once every two months by starting the hybrid system for about 30 minutes. Check that the "ready" light is on and all lights and electrical accessories are off. It is not necessary to drive the vehicle, but do not start the hybrid system in an enclosed area unless the tail pipe is connected to an exhaust hose to prevent harmful build up of fumes.

We certainly hope that this information is helpful. If we can be of further assistance, please feel free to contact us by responding to this email or by calling 1-800-331-4331. We are available from 5 AM to 6 PM, Pacific Time, Monday through Friday and from 7 AM to 4 PM, Pacific Time, on Saturdays.

Sincerely,

Eugene Des Jardins
Toyota Customer Experience

 

Not much comfort there.

I was hoping to hear the response that the auto shut-off (for the key fobs) would be protection enough.

Also, not enough warning that disconnecting your 12v battery will cause you to loose all save data, including preset radio stations and MID data.

 

If I'm not mistaken, that answer is straight out of the owners manual.
Remember, it has to be able to do that anywhere and under any conditions, like -50f in Alaska.

 

Curious why Toyota did not spec an aux battery with higher reserve capacity ? 10 days is kinda short to be considered long term storage.