Longer term Ohmmu experiences?

[gearchruncher]

I'm assuming your not getting the 12 volt error code right now yes? If you do have that code popping up, as long as it will accept a reset you are never stranded. People get stranded only when the car has been showing the error for a while, meaning that the 12 volt subsystem is not getting charged and eventually the 12 volt drains down to zero.

There is more than one error and more than one response in the system. It appears that in newer firmware, for some errors, the car just stops using the 12V, and switches to the DC/DC ("PCS") fully. This means a dead 12V won't disable the car. However, what it does mean is the HV battery is engaged all the time, and you'll get very high vampire drain on the order of 5% per day (although this is just the same as having sentry on all the time).

It's a good idea to try and reset and get the message to go away.

 

[Dysan911]

Has anyone gotten V4 yet? Sean doesn't respond anymore.

 

[dfwatt]

Heard from him about 14 days back. No word, since but first reset on V2 with module holding fine so far. Knock on wood. Suspect they are underwater with testing for V4, and holding back on making a lot of them until they are confident.

 

[Flybyglass]

I heard from Sean about a week ago. A dozen V4 were out in vehicles being tested with another dozen set for last week. He is being cautious this time before going into wide release.

 

[James Cole]

I'm assuming your not getting the 12 volt error code right now yes? If you do have that code popping up, as long as it will accept a reset you are never stranded. People get stranded only when the car has been showing the error for a while, meaning that the 12 volt subsystem is not getting charged and eventually the 12 volt drains down to zero. This happens of course with either the OEM lead acid or aftermarket lithium ferric phosphate. We had a trickle charger during the period we were getting this error on my wife's car which had the stock battery and that kept us from draining the battery down to zero. As soon as you get the warning do the reset and you have a period (poorly defined of course in terms of length) of no issues. Whether that's a week a month or four months is unclear. I got four months with Version 2 without any issues until having to do the first reset. Having a 12v trickle charger or even a regular battery charger is a good idea given all these uncertainties.

Thanks for your detailed response Watt,

Yes I only have notifications in history but not active… I do have a lot of history notifications though…

 

[Dysan911]

I used to get just those from my V2 battery but upgraded it to V3 and what was supposed to be better made it worse. I then got the other type of alert that stated my 12v failed and had to be replaced.

Hang onto that one until they release a final V4.

 

[dfwatt]

I used to get just those from my V2 battery but upgraded it to V3 and what was supposed to be better made it worse. I then got the other type of alert that stated my 12v failed and had to be replaced.

Hang onto that one until they release a final V4.

So if I'm understanding you properly you are suggesting that version 3 had more frequent battery failure errors then version 2? The real question is does version 3 accept a reset and then does the error go away? At least for a while

 

[Dysan911]

So if I'm understanding you properly you are suggesting that version 3 had more frequent battery failure errors then version 2? The real question is does version 3 accept a reset and then does the error go away? At least for a while

That’s correct. I was only getting those soft alerts that never showed up on the left screen. The only way to see them was to go in and look at the alerts. Then on the advice from Sean, stating that the V3 was better than the V2. I thought that I would get even less problems by upgrading to V3 but it only made it worse and now those soft alerts became left screen amber alerts including the one that stated I needed to replace my 12 V battery immediately.

A hard reset was performed when v3 was installed. Do you think another reset after that last one might work? I’m thinking 2 weeks is all I would get.

 

[dfwatt]

That’s correct. I was only getting those soft alerts that never showed up on the left screen. The only way to see them was to go in and look at the alerts. Then on the advice from Sean, stating that the V3 was better than the V2. I thought that I would get even less problems by upgrading to V3 but it only made it worse and now those soft alerts became left screen amber alerts including the one that stated I needed to replace my 12 V battery immediately.

A hard reset was performed when v3 was installed. Do you think another reset after that last one might work? I’m thinking 2 weeks is all I would get.

A hard reset is only useful if you're getting alerts. Do you have any version of alert showing right now? And which alert if you have one?

 

[James Cole]

Guys… do we have another option of Lithium Battery replacement that works well ?

 

[gearchruncher]

Guys… do we have another option of Lithium Battery replacement that works well ?

No. Tesla's 12V battery charger algorithm will easily detect any chemistry that is not lead acid. It has nothing to do with a specific brand.

 

[scottf200]

No. Tesla's 12V battery charger algorithm will easily detect any chemistry that is not lead acid. It has nothing to do with a specific brand.

"detect any chemistry" -- perhaps I'm confused but I thought the BMS electronics on the "Lithium Battery replacement" were simulating, in a sense, what the car expected.

Example of the 12v levels from my Model X Ohmmu 12v yesterday:

 

[gearchruncher]

"detect any chemistry" -- perhaps I'm confused but I thought the BMS electronics on the "Lithium Battery replacement" were simulating, in a sense, what the car expected.

Nope, not possible with reasonable electronics.
BMS is a device that protects the Lithium cells. It disconnects the battery from the system if the voltage gets too high or too low such that the battery will be damaged. It also balances the cells so that the battery performs maximally.

It does not convert the voltage from the battery to a different voltage. It's just a switch. The reason we use 4 LFP cells is that the voltages are very close to 12V lead acid, close enough that a normal dumb alternator works fine. Not so close that a smart charger couldn't easily detect this. Even your graph above shows this- No flooded lead acid floats at 13.0V with any load on it at all. All you have to do is charge to ~14.4V, then shut off the charger, then wait 10 minutes. If the voltage is >12.6, you have something that isn't a flooded lead acid, just like you show above.

If the BMS wanted to emulate a lead acid it would need to convert the 13V raw cell voltages to <12.6V, which is not inexpensive nor efficient to do, particularly across a broad load envelope as low as a few mA all the way up to 100A, both directions as you have to support charge also.

 

[scottf200]

... No flooded lead acid floats at 13.0V with any load on it at all. All you have to do is charge to ~14.4V, then shut off the charger, then wait 10 minutes. If the voltage is >12.6, you have something that isn't a flooded lead acid, just like you show above. ...

Thanks for your detailed response. Funny about the numbers you put in because I was just testing a 2012 Volt and it's 12v AGM battery to see how it was being 'charged'. First/top block below is with the car off and no DC-DC "help".

 

[Dysan911]

A hard reset is only useful if you're getting alerts. Do you have any version of alert showing right now? And which alert if you have one?

No because I had switched back to Lead Acid when I got the "Must replace 12v" alert. FWIW. I just put my V3 back in. So we'll see how long I can go before I get a soft alert and then how long before the big ugly amber alert (the one that says replace now).

 

[dfwatt]

No because I had switched back to Lead Acid when I got the "Must replace 12v" alert. FWIW. I just put my V3 back in. So we'll see how long I can go before I get a soft alert and then how long before the big ugly amber alert (the one that says replace now).

The real question is how long can you go between resets once you put the lithium ferric phosphate battery back in. If it's 4 months (which was the interval from getting version 2 with the module and doing a reset), I'm okay with that. Once a week obviously not acceptable

 

[chiapet15]

The reason this started, Tesla hired a new engineer who specialized in the Lead acid batteries and started this. Ohmmu even knows the name of the engineer. So a meeting with the engineering team is sought by Ohmmu to prevent this from happened.

Hopefully this engineer wasn't impacted in recent layoffs, since it seems excessive to have a dedicated headcount to optimize a legacy configuration, especially as cars are starting to fall out of warranty coverage.

Guys… do we have another option of Lithium Battery replacement that works well ?

I have been using a Braille 24AH G30HD lithium battery (which doesn't have BMS) since December 2018 without issue until a few weeks ago, when I saw an amber VCFRONT_a180 error pop up on the left screen while the car was parked. It didn't recur, but this prompted me to check the notification history, where I saw that it had been popping up sporadically (maybe once every 1-3 days). I took the battery out to test the floating voltage (13.3V) as well as voltage under a 100A load (showed 12.xV toward the end of the 10 second long 100A load test), and saw that it was fine, so I wasn't as worried about the battery itself. Nowadays, I just monitor the notifications messages and battery voltage (with one of those bluetooth based voltage sensors that connect at the battery posts), and will reset as necessary.

 

[gearchruncher]

which doesn't have BMS

Braille sells a $650 battery that doesn't have a BMS? Leave the key on just once on your bike and it's dead? Alternator regulator fails and it catches on fire?

 

[chiapet15]

Braille sells a $650 battery that doesn't have a BMS? Leave the key on just once on your bike and it's dead? Alternator regulator fails and it catches on fire?

Yes, as their stance has been that the car itself won't over charge/discharge, and the reliability of the BMS electronics are usually the limiting factor to the battery service longevity.

 

[gearchruncher]

Yes, as their stance has been that the car itself won't over charge/discharge,

Wow! A single failed alternator does lead to over or under discharge, and so does leaving the key on. I had no idea there were companies selling multi-cell Lithium batteries without any kind of balancing or protection, much less at a premium price.