I had a cautionary discussion with an electrical engineer friend

The root of the challenge of upgrades and modifications to vehicles is proprietary computer code that car owners aren't allowed to have read/write access to...

This standard may help boost profits and patent rights for the car makers, but it stifles innovation, and most of the benefits we found with home computers and the internet have been because of open source computer coed like Linux, which is the basis upon which all our phones are coded... This means huge numbers of people can redo the code and it they come up with something really unique and valuable it's likely to get integrated into future iterations.

In the car world, Honda owners have a whole army of nerds who have reversed engineered the source code for decades, which is why most people who race Hondas have a laptop on board that's changing the settings in real time to optimize vehicle performance.

With Toyota however, there's not enough nerds over the decades to crack the code and only TRD modified Toyota's have the ability to get Toyota computer code re-written to optimize upgrades and mods. This means instead of changing code, we do spoofing, which means tricking the cars computers into recieving sensor data that it expects to see so it doesn't throw warning lights and shuts stuff down, which in the case of Prius is incredibly hard to avoid.

In other words, the Nexcell battery pack is designed to appear almost identical to what the sensors expect from NiMH OEM pack... But the 30 years of advancement in battery chemistry from LiFePo4 instead of NiMH means you get way better performance within the limits that Toyota's proprietary code allow.

Back in the Nexcell prototype days, which are well documented on PriusChat, we spent a great deal of time discussing what if any functions does the Prius battery ECU perform for an OEM pack that could be a problem for a lithium pack that's designed to match? The answer is we haven't found any issues other than the fact that Lithium packs are way less tolerant of being overcharged and can be damaged/lose capacity if they get charged too much.

We've learned that overcharging can happen if your pack is fully charged and the 12v battery is disconnected because it takes some miles of driving for the Prius to measure how charged up the battery pack is, so in some rare instances this can cause too many amps to go into a fully charged pack. The same problem also can happen in old Prius with corroded battery ECU terminals that will give bad readings of a discharged pack when the pack isn't discharged and ignoring this P3000 error code and clearing it and continuing to drive can also over charge the pack. However, Project Lithium is one step ahead of these problems and has refined the design of their modules in a way that limits overcharging if either of these problems arise.

So if your EE friend wants to have a more in-depth discussion about these details, Project Lithium is always interested in refining their near 8 years of testing and design work. But that requires more back and forth than just the EE's first reaction to what concerns might arise from the design.

 

They don't get it. Emulation without an emulator is next to impossible.