I had an attention-grabbing expertise the opposite week when the 12V battery wanted changing in my 2019 Tesla Mannequin 3.
For me, it highlighted how a lot of a lead Tesla holds by way of their automobile programs engineering and total buyer expertise. Different automakers may actually study one thing by understanding how Tesla does what they do greatest in these areas.
Some folks assume that EVs don’t want a separate 12V battery as they’ve bought an enormous battery pack already. Nonetheless, they will’t perform with no working 12V battery. This battery basically powers all the electrical elements besides the drive motors, together with lights, wipers, door mechanisms, infotainment system and so forth.
Once I wakened on a Sunday morning, there was a notification from the Tesla app saying my 12V battery should be changed quickly. Sadly I didn’t take a screenshot, however the message was the identical as consumer @BLKMDL3 posted on Twitter/X.
Lower than 5 minutes later I’d efficiently booked an appointment for the next afternoon with a cellular technician. Fortunately my automotive was nonetheless lined below guarantee for a number of extra weeks so the fee estimate was $0. Although I’m roughly 10km from the closest Tesla service centre, a cellular technician was provided by default which was handy as effectively.
From the consolation of my lounge I had organised the service via the Tesla app while not having to verify the automotive first or communicate to anybody.
Examine this with different automobiles, the place you wouldn’t even know you had a problem together with your 12V battery till you tried to drive it. You’d both have to take your automotive someplace to get fastened or utilise a roadside help service, which might be comparable by way of comfort not less than.
What impressed me subsequent was how the automotive continued to perform completely wonderful within the meantime. I’ve had flat batteries in outdated petrol automobiles and been stranded in one other model of EV that required a leap begin when the 12V battery was low.
The display on my Mannequin 3 cycled via three totally different warnings, though I used to be in a position to begin and drive it with none issues.
The “Be taught Extra” button takes you to the on display proprietor’s handbook the place you’ll be able to learn extra about what these messages imply. For instance, sure inside options could also be disabled on this state of affairs reminiscent of seat heaters and local weather management.
Studying via the automotive handbook signifies the automotive depends extra closely on the DC to DC converter on this state of affairs. The DC to DC converter in an EV performs the identical perform as an alternator in an inner combustion automotive. It retains the 12V battery charged through the use of the primary excessive voltage battery pack.
Compared to an alternator, DC to DC converters can function at any time as a result of it doesn’t depend on an engine working to generate electrical energy. As a substitute, it merely converts the 400V or 800V from the primary battery pack right down to the required voltage to maintain the 12V battery charged.
Maybe much more spectacular is that Tesla has nearly eradicated this entire failure mode by engineering a significantly better resolution. For the reason that begin of 2022, Tesla has delivered all new automobiles with a brand new lithium-ion low voltage battery that’s designed to final the lifetime of the automobile.
Given the ramp up of Tesla deliveries since then, nearly all of Tesla homeowners in Australia gained’t expertise this drawback. Sadly, the newer lithium-ion low voltage batteries can’t be retrofitted into older automobiles with lead-acid 12V batteries.
On Monday afternoon the Tesla technician arrived and accomplished the 12V battery swap in round quarter-hour. He mentioned the anticipated lifespan for one of these lead-acid 12V battery is round 3 years. He additionally mentioned you’ve bought roughly every week to exchange the battery after the service message first seems.
Total, I discovered this expertise very informative and thought it was price sharing. Granted, it’s possible you’ll not have this easy expertise if you’re situated outdoors a significant metropolis, however not less than you’ve bought a while to supply the substitute battery. The proprietor’s handbook features a detailed process to exchange the low voltage battery for those who’re OK doing it your self.
In case you’re concerned with studying extra about how varied electrical programs work in EVs, I might extremely suggest the Ingineerix channel on Youtube. The creator takes aside and reverse engineers many alternative elements. For instance, this deep dive into how the low voltage system works in a Tesla is especially related.
Tim has 20 years expertise within the IT trade together with 14 years as a community engineer and web site reliability engineer at Google Australia. He’s an EV and renewable power fanatic who’s most enthusiastic about serving to folks perceive and undertake these applied sciences.