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Comment by AdrianB1 | Hacker News Reader

If you need an entire application to reset a battery status (btw: why is that even needed?) the problem is with the process of resetting the battery status, not with having the source code of the application. Why is there not a simple procedure like pressing a button or a combination of buttons or a menu in the radio?

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I can partially explain this since I've had to do this in the past. You have to program the BMS for the specific chemistry and capacity of the battery you install. It's not a reset. 99% of the time you don't even need to reprogram the BMS. But a lead, SLA, AGM, and Rolls have different properties. Like you couldn't replace a lead acid with a lithium ion battery because the charge algorithm could destroy the new battery.

Finally, cars are doing a lot more with the onboard starter battery. Or in case of hybrids, a lot less. A modern car is never truly off once the key is out. The BMS will need to know the real capacity of the battery so it can reserve enough charge to start the car.

If the car is able to disconnect it's starter battery, and can start up and run just fine after a disconnect, why does it need to be powered up at all when the car is off? What's so important for the car to do, that it can sit there draining the battery, but still be happy to completely disconnect the electrical system to preserve a startup?

At a minimum and at its most benign, it has to power sensors to detect key commands when you get near it, or functions like keeping the headlights on for a while after you lock it (usually branded "follow me home" or similar). There are probably more debatable things like checking for OTA updates or sending sensor data to some online services.

Mostly driver convenience. I drive a mid-tier VW with infotainment, power seats, satellite navigation, etc. If I don't drive the car after a few days it takes a few minutes for the car to fully boot up. No radio, GPS, climate control goes full blast, and it won't know what my power seat settings are. Now imagine having to do that every time you pull the key out, run in the supermarket, and go back to the car.

We're demanding a lot from the car battery lately and the BMS needs to know where it stands.

I know how a BMS works and I kind of understand why a reset is needed, but to replace a battery with a new one of the same characteristics (capacity, chemistry etc) should need a very simple reset procedure with no external tools. With the modern displays in most of the cars, you can put that in a menu there.

I am still riding a motorcycle with no battery and kickstarter. That is the ultimate reliability and dependability, the last thing you want in the middle of the mountains is the vehicle to stop because it does not have the latest monthly Windows update for .Net framework that works only OTA and there is no signal in that area. I am exaggerating a bit, but only for artistic purposes :)

Driving battery replacement to the authorized dealer network, when combined with various up-sell charges that they concoct some reason to tack on and it represents a very significant profit opportunity. It has nothing to do with the actual BMS and they aren't particularly interested in optimizing anything but their sales/service funnel.

So at this point the battery needs to come with a QR code on a piece of paper that, once installing the battery and starting the car then entering some service mode, you can hold in front of the backup camera so the car can read in the characteristics of the battery, eh?

Fine, but why do you need a special tool to reprogram the BMS? The car should have a "reset" button or something built into it that you can trigger when needed to accomplish this.

Yes. Why not have a texeditor for a config save file in the radio?

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