Comment by GhettoComputers
4 years ago
Keeping them within a certain range is useful but not as much as preventing them from overheating, heat and fast charging is more dangerous, basically if you limit them to 80% it will prevent trickle charging, you can do this in hardware by monitoring the speed it charges at and shutting off when it lowers with wattage monitoring equipment. Apple has this as well, and every lithium charger has trickle charging at 80%, but not all of them are able to end charging at this percentage.
https://linrunner.de/tlp/settings/battery.html
https://support.apple.com/en-us/HT210512
The best implimentation from my understanding is this one under android.
By hack I mean a bypass versus your meaning of attacking the security and removing DRM, is there a reason you can't just use another chip or anything special its doing? Do you need the CPU and is the cryptography documented enough to make it easy or woth the effort? It may also be a passion project so I understand if you just want to do it to do it, and even share the information. If it is battery charging features if they're important are not special. The last 20% makes extra cycles and is the most stressful.
https://batteryuniversity.com/article/bu-409-charging-lithiu...
>Turn off the device or disconnect the load on charge to allow the current to drop unhindered during saturation. A parasitic load confuses the charger.
>Charge at a moderate temperature. Do not charge at freezing temperature. (See BU-410: Charging at High and Low Temperatures)
>Lithium-ion does not need to be fully charged; a partial charge is better. Not all chargers apply a full topping charge and the battery may not be fully charged when the “ready” signal appears; a 100 percent charge on a fuel gauge may be a lie.
>Discontinue using charger and/or battery if the battery gets excessively warm.
>Apply some charge to an empty battery before storing (40–50 percent SoC is ideal). (See BU-702: How to Store Batteries.)
It all helps, heat and fast charging are bad, charging to 100% and discharging to zero are also bad (100's of cycles vs thousands!).
I salvaged a BMS from a borked battery to fool the Bosch system into thinking that it has a 'legit' battery, and yes, you need that chip, the CAN-BUS communications do all kinds of stuff such as report state-of-charge to the display, enable the high voltage bus and so on. Without that the bike simply won't work.
The pack has enough capacity that range simply isn't a problem any more, just charge it up to 80% and go where ever you want that is within a reasonable distance (say 150 km).
I'm aware of battery university, I probably know the Lithium Ion page by heart now, you can quiz me :)
Can you explain how much of a difference it is from non state of the art equipment? I don’t know much about electronic vehicles, I assumed that it was just power regulators, and it could be done on hardware like charging through an advanced IC charger. Basically if you replace the chip with another one, what is the greatest cost?
Do you have that replacement might be mitigated through other means?
Do firmware updates matter? I know that there were projects to make a Bluetooth finder with non replaceable batteries not functional when the batteries were replaced, it was tile, it depended on waste, a replaceable battery that was locked, and became non functional to sell more product.
Do you see it being bricked in a forced update like the tiles? Are you sure it’s able to be tuned for the newer battery capacity, or do you see workarounds? I can see a switch that can change it to stock mAh cells to ensure the best compatible with the software, but you also lose efficiency through voltage lowering buck conversion.
The Bosch BMS is a little wonder of engineering, the packs less so. It has a 32 bit NXP CPU, a separate battery managing chip, a bunch of FETs, a DC DC convertor and a battery balancer and whole slew of safety measures (both sw and hw) in a 40 x 60 mm board.
It's one of the most, if not the most impressive BMS I've seen for its size. The packs are a different matter, the engineering of the rear carrier ones is mediocre, the frame mounted ones much better and the PowerTubes are much better still, but far less service friendly.
So far I have not found a way to fool the motor/controller into wanting to play ball with anything other than the genuine article on the other side of the CAN bus.
The battery firmware can be upgraded, but you don't really need to, it just woks. The higher range is not recognized (the battery still reports the Ah capacity of the battery type it shipped with), but the %age state-of-charge is accurate and that's enough to ride by without further monitoring (it's displayed separately, and you have to do a little bit of mental arithmetic to work out how many km you can still go).
There is no loss of efficiency, the batteries are at the same voltage as the originals (and that is something that would instantly cause the BMS to brick itself).