Lithium 12v battery upgrade question

[WhiteM3P-]

Why would the battery type here matter?
If you have sentry on, the DC-DC converter is on and the battery isn't even in use.

That said, Ohmmu isn't shipping right now as a recent firmware update to the car started throwing codes and they are having to revise their design.

My concern is that the charge rate is lower than the discharge rate in my case. Essentially running the ~15kWh 12v battery down before it can be brought up to full charge. Maybe I'm not understanding the DC - DC correctly. I'll do some more research.

 

[gearchruncher]

My concern is that the charge rate is lower than the discharge rate in my case. Essentially running the ~15kWh 12v battery down before it can be brought up to full charge. Maybe I'm not understanding the DC - DC correctly. I'll do some more research.

The 12V battery is not 15KWh. The stock battery is 40A @ 12V- that's 480 WATTS. 0.480 KWh.
The charge rate is always lower than the discharge rate. This is why we have batteries- to store energy. A Model 3 basically never charges the battery quicker than 8 amps, but it can peak at 40+A discharge at times.

The DC-DC in the Model 3 is complex, and you'd need to do a lot of research to really understand it. But simply, it converts the HV to 12V, and when it's on, your 12V battery is either being charged or completely unused. When you have sentry on, your car is drawing 300+W from the HV pack in order to power the computers and keep the pack healthy. The addition of a radar detector at 5W will make absolutely no difference.

If your HV pack ever does turn off, so does your radar detector, so the 12V battery doesn't care you have one.

The only thing a different sized 12V battery will do is cause the car to wake up more or less often in order to recharge it, given the load is fixed on the battery when the car is asleep.

 

[nitrous]

Many many threads about this already. There is a quirk in the Tesla firmware that doesn’t always play nice with these batteries as well.

I wonder if it’s a bug or a ‘feature’

 

[TomT]

Tesla seems to be ignoring the problem.

It's a non-standard aftermarket part... Why should they care?