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Longer term Ohmmu experiences?
- Thread starter Durzel
- Start date
mstatkus
Member
With the added heat element on the new models I suspect colder climates have the potential to reduce the life/capacity charged at those temps . That’s why I’m yanking mine soon. I can’t find any evidence why this would avoid that fate.
Without data its unknown if heating would increase cycle count. Regulated heating would increase capacity at lower temperatures compared to non-heated models. It's unknown how much energy is used for heating. I do know from observation that at a certain voltage level the car wakes to recharge the 12 volt. Temps are dropping here and I just swapped and reinstalled my DiehardEV battery (AGM). It tested good but my backup Atlas (I keep both batteries charged to full once a month) did not pass the CCA test showing around 525 CCA rather than close to 625. When removed I would note the monitor graphs I generated looked irregular while the AGM graphs were smooth adept for waking charges. There is no information on the heated model what temp it starts and shuts off. I have noticed other manufactures are adding heating to their lithiums. I continued to have no errors or messages for about a month now. Occasionally I would get a secondary autopilot computer transitory message only visible in service mode and I will check to see if those occur with the AGM installed.
LFP is fine at lower temps unless you recharge it at those temps. So it doesn't need to run the heater off the battery's own energy. If it was a really smart battery, it would take all the charge current to run a heater if it was too cold, and then once warm would then transition to using the charge current on the actual cells. You know, exactly like Tesla does for the HV pack when you charge it at cold. It doesn't just sit there self heating all the time.
There's zero way Ohmmu is doing this however, and it would further cause Tesla to see the battery as a broken lead acid.
The fact that Ohmmu's own parameter set for the battery shows that it allows charging to -20F when the battery spec is 32F is really crazy. But of course if they don't do this, they either need to heat the battery all the time or hard disconnect anytime they get a charge at below freezing which will totally piss off the car.
Oh, and we know they aren't heating the battery all the time since there is absolutely nothing in that parameter set about heaters, and if there was a functional heater, you wouldn't need to allow charging to -20F because you'd never be in that condition. In fact, there's nothing in this very detailed app that shows a heater at all, so I doubt this battery has a heater.
One post on another thread is trying to claim the heating can’t possibly work and it’s fake. I disagree as several makers are now adding heating to the batteries.
I don't think they are saying that the heater won't heat the battery to allow charging, I think their point is that the additional energy usage to heat the battery will cause the Tesla BMS to think the "lead acid" battery has a huge phantom drain and has failed.
The problem is that the battery is being managed by two different BMSs, at the same time, and one of them thinks the battery is a completely different chemistry than it actually is.
Then they add an extra heater battery that trickles slowly off the main battery.
Or just get a good old lead acid battery.
I assume you are referring to my post three above yours in this thread?
I said no such thing that it's fake. I said based on @Perscitus cryptic "I can't say more" post, that the screenshots they show don't indicate a heater in that configuration at all, and that it's concerning that it is configured to accept charging at -20F. I also suggested that any kind of heater in the battery is likely to make the Tesla see that as a non-lead-acid battery, because you know, what lead acid has a 10W+ quiescent internal drain?
![(@r8[]np4nd4](/tmc/data/avatars/l/153/153664.jpg?1711743159){kind=avatar}
(@r8[]np4nd4
Member
I received the new battery with heating element today but i can't connect it with the ohmmu android app.
Do you found a solution?
Ohmmu devs are working on a fix.
Android v13 is potentially to blame with the new bluetooth stack forced with v13 breaking things.
v14 appears to fix it again but few devices around the world have it deployed at this point in time.
Trickle charge the battery and install away, out of the box it will run the Ohmmu5 config which is fine for older 3/Ys.
Android v13 is potentially to blame with the new bluetooth stack forced with v13 breaking things.
v14 appears to fix it again but few devices around the world have it deployed at this point in time.
Trickle charge the battery and install away, out of the box it will run the Ohmmu5 config which is fine for older 3/Ys.
Android 13 that was released 13 months ago, is the most popular Android version in use, and is on 1/3 of all Android devices? Which uses a Bluetooth stack that has been available for testing in Developer Options since Android 11? And works fine with basically every Bluetooth device out there, including the Tesla keys?
Hope Ohmmu tests their batteries more than their apps.
I mean, zero have it deployed since it's not released. It's in beta.
Yes, but judging by the chatter across the interwebs, seems like many medical device, monitor, and other BLE gadget manufacturers did not get the memo.
Why the config is called Ohmmu5 beats me, but it is what it is. Ohmmu says is roughly equivalent to the latest 3/Y config so makes little difference if either one is on your v4+ or v4++ (w heating element).
So here is the question: Below freezing the Ohmmu needs to be warmed to accept a low amperage charge. The M3 trickles as low as .01 amps. The heating of the V4++ would solve this. How many amps does the V4++ use to warm itself or keep itself at a charging temperature (probably above 40 F)? I see the sequence as this: The battery cools, thermostat starts the warming cycle. Once the Ohmmu gets to about 12.8-12.9 volts the M3 wakes and recharges the V4++ back to 13.3 to 13.8V shuts off and sleeps again. This is a normal cycle that when the V4++ volts drops to a level the car wakes and recharges. That is OK if plugged into a wall charger. But if sitting outdoors (say an airport) for a week with no charger after repeated waking cycles 24/7 the main battery would run down. Each waking cycle draws about 25 amps before recharging the V4+. I parked a MY for 10 days and lost 1% mainly for checking once a day for 10 days to see charge level. (Sentry and overheat was off). I like the V4++ and if current draw was extremely small waking may not happen for several hours. The goal would be to minimize wake cycles. Anyone in cold temps yet testing this? Being connected to a wall charger when not in use is my situation but could be limited it traveling.
Yeah, except the Tesla will see this as an unhealthy lead acid battery, because it is. The Tesla puts 200Wh into the battery in charge. It then draws 100Wh out, but then the battery needs to be recharged again? Where did those 100Wh go? This looks like a really, really broken battery because no lead acid battery has that much quiescent drain, and this is exactly the kind of testing Tesla is running in order to determine the health of the lead acid battery.
A "Waking cycle" cannot "draw 25A before recharging." This is just bad physics and units.
How many Watt-Hours does the Ohmmu lose due to heating? And then how much longer does the car need to be on to recharge it, and what is the watt overhead when charging?
I mean, even if the heater in an Ohmmu was 50W and it was on 24/7, that would take 70 days to discharge a Model 3 main battery.
Are you counting the normal overhead for when the vehicle is awake/recharging the 12v battery? (Isn't that 150-200W?)
I seem t recall the battery would read about 100-150W during recharging the 12 volt after a wake up and would only take a few minutes.
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