12V battery issues (error messages/car charging problems)

[CapitalistOppressor]

My 12V is a goner but I spent the day learning about the system.

One thing I learned is the S is charging the/a low 12V battery at 14.8-15.0 volts whenever the car is "on". But as soon as the car turns off or goes to sleep again then the charging stops and you have another dead S until you get another jump. (or unless of course the charging worked and your 12V battery is now working at 12V)

One simple way to keep the car from becoming dead again after a jump is to leave the driver door open when not driving. I kept it going this way for about six hours.

My 12V won't recover. All day charging it and it still measures less than 4 Volts. I've got 4.0 firmware with 4.1 waiting but failing to update every time so far.

It's crazy that you have a 85kW battery right there that's capable of jump starting and charging the 12V battery, but no way to activate it. It just takes a moment of 12V on the terminals to get the S going under its own power.

They could add a hidden button somewhere to activate the 15V charging momentarily and then you would never be stranded.

If Tesla isn't able to make it self jumping because of hardware limitations then I plan to add something to allow me to jump it without removing then nose cone. (Hopefully Tesla will figure something out)

I need to determine if there is a way to open the frunk or trunk when there is no 12V power.

Auto Jumper Jumpstarts your car without needing jumper cables.

Edit: I'd consider trying something like this, but my car background is mechanical and emphatically not electrical so hopefully some of our experts can comment. But if using this doesn't damage anything, and can work as a successful workaround in case you are away from home, then it might be worth trying.

Edit2: Also, I'm not endorsing this particular model of jump starter. This was just one of the first ones that pop up on Google. I think the one I have in my BMW is a DieHard.

- - - Updated - - -

Yes the case was distorted. Wish they were going back in with a Lithium Ion battery. That thing is burried and a LI would last 3-4X longer than lead acid. It would also be much smaller and lighter.

In fact I was thinking since we don't have to crank a starter to turn an ICE you could mount a very small 12V lithium battery right behind the nose cone and just remove the burried lead acid.

Wow. That's a serious issue. Hopefully the new firmware fixes that.

- - - Updated - - -

The battery message reappeared for me on 1.19.31. Service told me they were aware of this issue and an update is coming soon to address it. Asked if I could safely drive it with this message and was told yes. Awaiting update (4.2?)...

Seems possible that the bad firmware might have permanently damaged some batteries, which would then cause a seemingly identical error despite the underlying cause having been fixed. Certainly reports of a distorted battery provides at least some evidence that the firmware issues could cause real damage (which might not be visible).

 

[lolachampcar]

FlasherZ started to take a more detailed look at how the 12V system works in this thread-
http://www.teslamotorsclub.com/show...ery-and-Vampire-Load-How-does-this-work/page2
The first data collected was -
"It's too early to draw any conclusions based on anything I've posted. I just checked again, after charging had been completed, and it still showed 14.5v. I didn't get the car to sleep because I (stupidly) left it plugged in. I'm waiting for the car to go to sleep now so I can measure it.

EDIT: After the car entered "deep sleep" mode, displays powered down, the terminal voltage went to 12.8v. Based on this, I'm guessing the battery voltage itself might be 12.8v... the DC-to-DC converter runs and supplies 13.8v when the car is doing more than sleeping as a float/maintenance charge, and when the car thinks the 12v battery needs an active charge, it uses 14.5v... That seems like the most plausible scenario but I could be wrong.

Keep in mind this is all with v1.19.31.

Given the physical description of the faulty batteries that have been removed (bulging, etc.), I can only guess they were somehow overcharged. 14.5v seems pretty high for an active charge, wonder if that's causing it?

I keep hearing that 1.19.31 has definitely fixed whatever problem was there with the low-voltage battery. Let's hope so."

It looks like there are different charge modes/sources in different operating areas. The next step for me is to put a current probe on the 12V system and look at voltage and current in on, off not plugged in and off plugged in modes.

 

[jerry33]

Given the physical description of the faulty batteries that have been removed (bulging, etc.), I can only guess they were somehow overcharged. 14.5v seems pretty high for an active charge, wonder if that's causing it?

14.5 seems pretty normal to me (that is the voltage the Prius charges its 12V AGM battery at too). I guess what's happening is that it's charging during the entire time the car is running, rather than charging only when the battery requires it, which will overcharge the battery and cause the bulging like you suggest.

 

[tezco]

I wonder how much air circulation the battery gets nestled down in the frunk. It may be getting too hot considering how much energy is getting pulled out, and then dumped back in. Most car batteries have some room to breathe, and have much less work to do in comparison to the current loads we have secondary to our large display, the contactor and all the other computers on board.

 

[Ingineer]

In order to properly care for the 12v battery, There must be a 3-stage charge algorithm, and it should also be temperature-compensated. This means the first stage is bulk charging, which should charge the battery at a constant current. This means the Model-S computer will watch the current drawn by the 12V battery and command the duty cycle of the DC-DC converter to regulate this amperage. During this stage the voltage will likely be 12-13v. After the temp-comp voltage climbs to a certain "knee" indicating around 80% SoC (State-of-charge), then it should switch to stage 2, called the "absorption" phase. During Absorption, the voltage will be held at a constant 14-15v (again depending on temperature). Once the current falls to a certain threshold, this will indicate charging is complete and this will kick in the final 3rd stage, called "float". The battery should then be held around 13 volts (temperature dependent) to maintain it's charge and the DC-DC will then be powering all the 12V loads directly.

If the S isn't doing this, then this is why 12v batteries are dying left and right.

-Phil

 

[jomo25]

In order to properly care for the 12v battery, There must be a 3-stage charge algorithm, and it should also be temperature-compensated. This means the first stage is bulk charging, which should charge the battery at a constant current. This means the Model-S computer will watch the current drawn by the 12V battery and command the duty cycle of the DC-DC converter to regulate this amperage. During this stage the voltage will likely be 12-13v. After the temp-comp voltage climbs to a certain "knee" indicating around 80% SoC (State-of-charge), then it should switch to stage 2, called the "absorption" phase. During Absorption, the voltage will be held at a constant 14-15v (again depending on temperature). Once the current falls to a certain threshold, this will indicate charging is complete and this will kick in the final 3rd stage, called "float". The battery should then be held around 13 volts (temperature dependent) to maintain it's charge and the DC-DC will then be powering all the 12V loads directly.

If the S isn't doing this, then this is why 12v batteries are dying left and right.

-Phil

Welcome to the forum, Phil! I assume you are the same person from MNL forums? If so, very happy to see you here!

 

[Ingineer]

Welcome to the forum, Phil! I assume you are the same person from MNL forums? If so, very happy to see you here!

Yes, Long time lurker. I've actually posted before, but for some reason the posts never make it. (It always shows "waiting for moderator approval")

-Phil

 

[Bearman]

There is a very good battery charger manufacturer that ive used for years personally and i recommend them if anyone needs a good 12V charger. They are called C-TEK and are suppliers for Aston martin, Lamborghini, Landrover, Bentley and BMW among others. They use eight different modes/cycles depending on battery type and condition, like after ten days they resort to a storage mode with slow pulsing because a float charge may damage the battery if unused for a long time. Their chargers also have a supply mode that can act as a battery if the 12V battery has to be taken out without resetting the memory settings in the car etc.

 

[tezco]

Welcome to the forum, Phil! I assume you are the same person from MNL forums? If so, very happy to see you here!

Likewise (although the Leafsters know me as zowland over there...)

 

[Ingineer]

There is a very good battery charger manufacturer that ive used for years personally and i recommend them if anyone needs a good 12V charger. They are called C-TEK

Yes, I can second that these are proper 3 stage (and then some) chargers.

Of course if it is found that the reason the 12V batteries are dying in the S because of excessive overcharging, a charger will not help! As soon as I get my hands on an S, I'll be happy to test for this and post the findings.

-Phil

 

[lolachampcar]

Phil,

I started a nerd thread on the systems end of all this. One of my goals was a current logger so we can see the whole charge/discharge profile of the 12V system. I'll do it when I get my car unless you get yours first.
Bill

 

[dtich]

xposting:

just a data point here: i went out of town for 10 days, left the car plugged in, 14-50 set to 24A (not sure if that setting stuck after first charge..? was back on 40 when i looked..**) with about 180 miles on it.

came back, all fine. car sitting with 231 miles, happy as clam. no 12v batt issues (was nervous, slightly), no other kinks. just fyi.

this is 4.1 (.31) on VIN ~1600. (and, this is a ca car, so temps never got much below 45...)


** correction: i guess i must have checked the charge current setting about a half mile from my house when it said 40, as i plugged in last night it was again set to 24 as i left it 10 days ago -- i forgot that there is geofencing for the charge current setting. it seems to work! lol. fwiw.

 

[Ingineer]

Hi Bill,

A quick search cannot locate your new thread, care to share a link?

-Phil

Phil,

I started a nerd thread on the systems end of all this. One of my goals was a current logger so we can see the whole charge/discharge profile of the 12V system. I'll do it when I get my car unless you get yours first.
Bill

- - - Updated - - -

Nevermind Bill, I found it.

-Phil

 

[dennis]

When I got the 12V Battery Needs Service message this morning (running 1.19.31) I was eventually connected to the Fremont Service team. After they remotely checked my battery voltage and found it to be within spec (14.something), I was told that this was an erroneous message coming from the software and was fixed in 4.2.

 

[Lloyd]

When I got the 12V Battery Needs Service message this morning (running 1.19.31) I was eventually connected to the Fremont Service team. After they remotely checked my battery voltage and found it to be within spec (14.something), I was told that this was an erroneous message coming from the software and was fixed in 4.2.

I upgraded to 4.2 last night with the help of a Ranger. The update would not load due to the battery warning. We first had to clear the battery warning by doing a 'hard reset' by pulling one of the 20 amp fuses up front, then waiting 10 minutes for all of the capacitors in the system to discharge. From there update went smoothly and there have been no issues. BTW: Great Ranger service.

 

[lolachampcar]

Phil,
My bad. Sorry.

 

[dennis]

I upgraded to 4.2 last night with the help of a Ranger. The update would not load due to the battery warning. We first had to clear the battery warning by doing a 'hard reset' by pulling one of the 20 amp fuses up front, then waiting 10 minutes for all of the capacitors in the system to discharge. From there update went smoothly and there have been no issues. BTW: Great Ranger service.

Service pushed me the 4.2 update and it failed to install because of the battery warning, just as you described. When I called back I informed them of your episode and Ranger solution and asked if they could walk me through the fuse pulling. After going offline to consult with someone else, I was told they were unaware of this software issue (my voltage is still remotely reading 14.7), so they were forwarding my case to the firmware group, and I should await a call.

In the meantime, I decided to run the logs for the past week from my eMonitor power monitoring system after noticing a weird pattern in power usage last night. All of my charges looked normal, ramping up to 9.3kW (NEMA 6-50 @ 40 amps) and staying there until charge complete, except for last night. Instead of a continuous 9.3kW, it looks like this:

1/17/2013 20:18 4317 4103
1/17/2013 20:19 4782 4546
1/17/2013 20:20 4764 4529
1/17/2013 20:21 4779 4544
1/17/2013 20:22 4780 4544
1/17/2013 20:23 4780 4544
1/17/2013 20:24 4777 4541
1/17/2013 20:25 945 900
1/17/2013 20:26 0 0
1/17/2013 20:27 0 0
1/17/2013 20:28 0 0
1/17/2013 20:29 0 0
1/17/2013 20:30 0 0
1/17/2013 20:31 0 0
1/17/2013 20:32 0 0
1/17/2013 20:33 0 0
1/17/2013 20:34 2263 2128
1/17/2013 20:35 4773 4491
1/17/2013 20:36 4776 4494
1/17/2013 20:37 4782 4499
1/17/2013 20:38 1932 1819
1/17/2013 20:39 0 0
1/17/2013 20:40 0 0
1/17/2013 20:41 0 0

Some of the power cycles are longer, but it always goes back to zero for some number of minutes before resuming. And then this morning I got the 12V Battery warning message.

Any ideas? Could the power cycling be the cause or the effect of the 12V battery erroneous message?

 

[dennis]

Service pushed me the 4.2 update and it failed to install because of the battery warning, just as you described. When I called back I informed them of your episode and Ranger solution and asked if they could walk me through the fuse pulling. After going offline to consult with someone else, I was told they were unaware of this software issue (my voltage is still remotely reading 14.7), so they were forwarding my case to the firmware group, and I should await a call.

Service called back and remotely "reset the gateway" which removed the erroneous 12V message. This allowed me to successfully install 4.2 (1.19.41). So it appears that a Ranger visit may not be necessary if you are unable to install 4.2 because of the 12V battery issue.

No explanation yet for the change in charging behavior last night, or whether that was related to the 12V issue.

 

[Lloyd]

I suspect that you had some line voltage fluctuations which cleared and then allowed charging to resume.

 

[dennis]

I suspect that you had some line voltage fluctuations which cleared and then allowed charging to resume.

My eMonitor system also has voltage monitoring for each sub-panel and it was always within the range of 118.6-121.3. There were a total of 16 instances during the 8 hours of charging where the charge current went to zero and then ramped back up to 9.3kw. Definitely odd behavior.