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Longer term Ohmmu experiences?
- Thread starter Durzel
- Start date
With a failure with amber notice, it's hard to say what is happening without charging data. Ohmmu is slowly rolling out V4 but I would add a monitor module (it takes a minute to install especially if replacing battery). For now a reset procedure is on the Ohmmu site. What version software do you have? This gadget will help. https://www.amazon.com/gp/product/B07NSVMY4S/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1 I will be adding the module when I install the V4 battery so I can build a charging profile and compare it to the lead acid charging profile.Alright so recap I reinstalled my v3 Ohmmu on 7/5. On the way home tonight 7/13. Got the 12volt battery failure alert.
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scottf200
Well-Known Member
I've used this before on my X but perhaps that is too diff: moderate reset (change tire config, let it reboot, change tire config back, let it reboot)
Hard reset via Ohmmu page: Tesla | All Models | Hard Reset Procedures - Ohmmu Support
Dysan911
Member
Are you saying to try the Tire config change reboots first or combine that with a hard reset?
scottf200
Well-Known Member
Well Ohmmu had me use the Tire Config change to get rid of a msg on my TMX. I don't know if it works for all your guys TM3 scenarios.
The Tire Config change is simply and only a couple minutes. On the TMX access to the battery is a pain in the butt (remove frunk tub).
Other TM3 owners in this thread (my kid has one) can tell you if the Tire Config works for some TM3 scenarios. Sorry for any confusion.
Dysan911
Member
No worries. I gave the wheel config reset a try and it didn’t resolve the amber alert that the 12v requires replacement.
I went ahead and put the LeadAcid back in. I'll just be patient and wait for V4 with fingers crossed that it's getting the job done and soon this will be over with.
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I believe this is critical, as it’ll help identify the problematic waveform/behavior that’s triggering the error. Based on what we’ve seen so far with waveforms, my hypothesis is it’s a transient downward voltage spike. I wonder if they intentionally present the battery with a large, short duration load to check for specific health characteristics, and when it doesn’t match expectations for a lead acid, errors are thrown.
On my end, nothing interesting happened on my car yesterday. No soft errors. The spikes (14.2V) are from wake up events for the morning/evening commute and errands. Doesn’t seem to have charged the battery because voltage floor remained the same throughout the day at 13.34V. The plateau from 19:00 to 20:00 is at 14.13V.
I'm wondering if it throws soft errors expecting a lead acid and after a few reads the voltage (slightly higher) and settles in as its OK. Meaning it may adapt to the battery type. No proof yet just changes in charging that seem to stabilize after a few days. My lead acid pattern hasn't changes and I will install V4 next week.
I didn’t get any errors yesterday either, but my graphs are incomplete because I pulled the 12V battery cables to reinstall my automatic frunk, and I did a capacity test to confirm if the battery could still perform.
I hooked up this electronic load tester I got on Amazon and monitored the voltage with the bluetooth voltage probe as it got near the knee in voltage dropoff. The battery started at 13.18V under the ~0.42-0.46C load, and I stopped the test when the voltage probe was reading 12.8V under load. This roughly 70% to 20% SoC discharge yielded 15.17 Ah or 192.82 Wh. Note that the new OE lithium battery is rated at 6.9 Ah or 107 Wh.
A couple of caveats: The voltage under load as determined by this cheap tester is 0.2V below what the bluetooth voltage probe and what my fluke multimeter were measuring, and the current was about 0.5A below what the fluke clamp meter was showing. So the actual measured capacity of the battery is slightly higher than what’s shown on the display.
I wish I could discharge the battery at 1C (this off-the-shelf tester only has a 150W power handling capacity, so ~11A discharge current leaves 10W of margin at ~140W) so I can verify the 24 Ah capacity that Braille originally spec’d, but for now my conclusion is that any potential degradation from 3.5yrs of use without a BMS hasn’t reduced capacity enough to impact its ability to meet EV use cases in a California coastal climate.
Tester display at the end of the test:
Previous ICE cranking current load test, and at the end of a 10sec window:
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I tried a version 4 on Sat. Worked well for about 4 hours as it was charging. Normally, on a first install any of these batteries (lead or Lithium) seem to go through a charger cycle even if fully charged. At the end of the charging voltages dropped off as expected then I got 3 VCFronts_a180's within an hour and on the last 2 got a hard warning and the last one it stopped charging. Charge level keeps dropping so removed the 12 volt and swapped back to a lead battery. Ohmmu notified with all data. I'm running FSDBeta 2022.12.2.20 so it's 6 weeks behind others in software changes but based on what you have the issue still exists. Peak voltages were similar to yours. Maybe it would have started charging again but since the 12 volt was down to 80% (nothing for the Lithiums) and the charger had not started back up after 40 minutes I swapped. Graphs attached. Originally you could just put this battery in and it worked flawlessly for months until Tesla started tinkering with the charging software.
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Absent the hard warnings, I would have left the battery on there longer to see what would happen, especially since I’ve seen it linger in the 13V range for a 4 hr drive before charging kicked in again.
Also, it’s not clear to me why the graph would generate the hard warnings that triggered the 12V charging to turn off. I think what we’d need is a similar data logger for the battery current to really know what’s going on…
I was expecting maybe a soft warning but not the 2 hard amber ones that prompted me to swap. I waited watching the voltage and charge levels steadily drop until 80% and 13.35 volts (load was reduced at that point). It should not generate any warnings soft or hard as the originally installed so there is more work here needed.
Dysan911
Member
Well, shoot, I was hoping V4 would have been the answer but it doesn't sound like it's as promising as we were led to believe. Not sure why Sean is expanding his testing with it into a dozen cars if V4 sounds like it's not really any different than my V3.
Unless there is some major software update. In my case running FSDBeta 2022.12.3.20 it was actually worse in V4 than V3. Now I notice the latest FSDBeta release notes a clause that says:
"You can now view additional information about your car by tapping Controls > Software > Additional vehicle information.
The list of information will now include the type of low-voltage battery installed and whether your vehicle has a heat-pump."
I will be curious about this. What is the software looking at to determine battery type and has there been a modification to allow for changes. After all, some of the 2018's just by age are now out of warranty and open to purchasing a 12 volt replacement. Today, I notice Advance Auto offering a Diehard EV AGM replacement battery B24 that supposed to match the AtlasBX 85B24LS that is factory lead acid (non AGM). The cranking amps are less but the amp hour rating is 41 (the Atlas is 45) and all that is needed according to the owners manual is something 33Ah or greater. This battery or a 51R would exceed that.
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Ok… running 2022.16.3 with V2 Battery.
Haven't encountered any errors since that update… anyone else?
Haven't encountered any errors since that update… anyone else?
android04
Active Member
If you are referring to this S46B24R battery (Advance Auto Parts - Down for Maintenance) you might as well get the 51R version instead (https://shop.advanceautoparts.com/p...latinum+AGM&brandUrlName=diehard-platinum-agm). The 51R had slightly better cranking amps (which aren't really needed) and SAE posts that are the exact size needed for our Tesla battery cables. The B24 battery looks like it has the thinner JIS posts that you will need to buy post adapter inserts for (just like the ones Ohmmu requires on their battery).
referring to this one although a 51R works too. This one is marketed as Diehard EV. Shows in narrative it is 85B24LS size (same as AtlasBX) but is a AGM. I currently have a 51R AGM and it works fine.
Advance Auto Parts - Down for Maintenance
Any update on error notifications? Took my 4 hours before I started gettig them.
android04
Active Member
Ok, that one has the same specs as the 85B24LS I linked above but looks to have the correct SAE posts. I'd buy it to replace my OEM battery if it died. The two reviews seem to be contradicting each other though, with one implying it has SAE posts and the other that it has the smaller JIS posts. Unless one of the reviewers mistakenly bought or reviewed the wrong battery.
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