BMU firmware mods

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kolyandex

Member
Joined
Feb 5, 2022
Messages
7
Hi. I've started to reversing BMU firmware for able to increase real battery capacity in case of replacing battery unit from 48a/h to ~90a/h. Now i have correct data from BMU to vehicle CAN bus and diagnostics software. Flasher for BMU ECU also available.
If you're really interested for that awesome modification, contact me [email protected]. I need to research the market :D

hmudGPb.jpg

XOEebP6.jpg
 
I've achieved the same result with a cheap CAN bridge http://myimiev.com/forum/viewtopic.php?f=23&t=4983
As a bonus, can allow deeper discharges for new chemistry like NMC
 
Today we flashed our first iMiev with a repackaged battery (CATL 102Ah), it seems to work and even drive.

oxnTHeY.jpg
 
kolyandex said:
Today we flashed our first iMiev with a repackaged battery (CATL 102Ah), it seems to work and even drive.

oxnTHeY.jpg
Hi. Are the CATL 102Ah cells, NCM or LIFEPO4?. Grade A?.
 
Have you chatted to the Oz Electric Vehicles guys?

They're using a MITM module at the moment to achieve the same goal but reprogramming the BMU is a much cleaner solution

As a side thought, it would be safer/more durable to use LiFePO4, - if this was done could the car handle the lower terminal voltage/higher motor current?

So many questions once this part of the puzzle is unlocked
 
This is fascinating. How much does real driving range improve, and is there a flash back to stock capacity?
 
PV1 said:
This is fascinating.
Yes. I've dreamed of being able to do this.

How much does real driving range improve,
The title of the video ends with "after battery upgrade", so that depends on what capacity and health the replacement battery has. [ Edit: one would imagine that it would be of the order of 95/48x ≅ 2x the capacity of the factory new-car range, depending on several factors. ]

and is there a flash back to stock capacity?
I saw two file names ending in .bin; they had the same name except that one had "_95Ah" (or similar) and the other did not. So it looks like one is the original image as extracted somehow from the ECU, and the other is the patched or recompiled version that has 95 where the original had 48 (representing the battery capacity in amp·hours). So yes, I'd say he could have selected the other file, and replaced the firmware contents with the original.

95 Ah sounds familiar; I think that's the nominal capacity that the Oz DIY NMC cells use, which fit in much the same case as the originals. My guess is that Kolyandex or someone he knows is able to purchase these same NMC cells and perform the mechanical cell swap.

When I was looking into this, I got the impression that there was a limit to what value the firmware could store for the battery capacity. I can't recall now, but I think it happened to be pretty close to 95 Ah, by a lucky happenstance. But if battery technology improves much beyond that, it may not be possible to use this technique.

It would be interesting to know if he only changed the nominal capacity, or also modified the Soc versus cell voltage table. This post has a really rough auto-translation of the speech from the video; perhaps the answer is in there. It didn't leap out at me at a quick reading.
 
I don't think going beyond 95 Ah would be necessary for many owners. Doubling the original range makes the car a lot more useful, but for traveling further than that, I'd likely take something else anyway. The i-MiEV isn't the easiest car to drive on the highway. For comfort and aerodynamics, something like a Bolt or Model 3 are much better, not to mention the better charging networks. CHAdeMO is starting to become sparse here in the States.

This is a great way to extend the life of these vehicles, though, and is something I'll probably be looking into down the road.
 
Our guys here uses iMievs in taxi business here. It 5 times cheaper than gasoline cars and no requires to oil change and other service.
PS. sorry for bad english :D
 
No worries about the english, we are just grateful for the help to figure out these cars, and goggle translate works very well.

Do you have the factory MUT system, with the software package and the VCI unit, or is it a clone?

Do you think that MUT is necessary in order to make changes such as to increase the capacity value?
 
I use tactrix openport with MUT (with VCI-Lite emulator software). Need to use MUT for reset battery capacity after firmware update.
 
What is the purpose or reason for the firmware update? Are these custom firmware or from Mitsubishi?

Would it be correct to say that this is at least a 3-step process in that the firmware must be modified to allow or accept a larger cell capacity, then the Data Items List values must be written/stored in a memory somewhere, and then actually larger capacity cells must be installed.
 
It is quite amazing that you were able to figure out how to do this, you have knowledge and skills beyond our level.

i am helping another forum member, piev , replace his pack with the Samsung SDI cells, which are slightly larger than LEV, but hopefully they will fit. If they can fit, then we could sure use your help to make this happen.

[edit] worked on this yesterday and they won't fit. There are some dividers formed into the floor of the plastic battery pack tub--it is a custom tub made to fit only the Yuasa cells
 
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