[zorgzx]

So this topic has been beat to death, but bear with me.

So upgrading 20000USD batteries to go from 30-50km range is just plain stupid.

There should be aftermarket upgrades, but the only one I found is 8000USD. wich is nice but still just the same 7kw battery renewed.

If anyone knows someone that puts newer cells in old case please do post or write.

however I found the price of the LCI 2019+ modules is now below 1000eur. This means 6x packs is round 4-5K eur for complete raplacement to brand new 11kw pack.

My 2014 is 150Kkm. Most of my driving is in EV mode as it fits my commute so I've charged 2x day for 5 years and its still workable, if range have gone down a bit. No I dont really need it but I like my i8 and have spare cash.

So I'm looking to go forward with this with my local bmw shop. But before I do I'd like to hear if anyone know anyone that did it.

Did anyone put LCI modules in a Pre LCI car ? only post I can find says something about the fusebox or harness have to be swapped (its a 500eur part that says includes harness. But the post is very slim on details.

Anyone know anyone who did it, or know why it fails ?
As far as I can tell its the same voltage batteries so basicly the car should just charge longer and last longer.

Thanks for your time.

[stressdoc]

Great question.

Thankful I have a 2019 i8, that when stretched can go 40 miles on battery. With gas savings and environmental benefits -- averaging 59mpg. All the while having truly exciting near-supercar performance. And relaxed comfortable long distance cruising. On an upper-middle class budget.

Reminds me of why I fell in love with BMW long ago: a 2002tii that I bought for $2400 and lightened to 1890 lbs. Bilsteins, limited slip, Recaros, ... Sold it with 225k miles, in great condition.

My uncle had an Isetta. Phenomenal minimalist transportation.

Wish I had all three in my garage. They would all be competitive in the current global market. Timeless engineering marvels.

[avdept]

Its doable. I3s have aftermarket options to increase battery capacity much cheaper than it'd be factory solution. The reason there aren't many same options for i8 is simply because there are too few i8s around and even less folks would want to dismantle half of car to increase battery capacity.

[Budget M3]

Something else to consider for such a swap: the LCI cars have a different cooling setup than Pre-LCI. I.e. No hood scoop on LCI and direction of air underneath the car instead of through the hood scoop to cool the radiators. It is possible (and likely) that there are also software differences in the cooling setup for the two configurations. Before dropping in the higher capacity LiIon batteries, I’d recommend looking into how to keep them cool enough for reliable operation. The last thing you need is hotter-than-spec batteries.

[zorgzx]

Thanks for the input, I will look into it.

But I do not belive it will make any difference, the charge and discharge cycle should be the same, just longer as the engine, electrics and charger is the same. So I would not expect any heat related issues.
Perhaps the LCI can discharge a bit faster earlier or whatever, and require more cooling for that, but that would not change by swapping the batteries as cell count etc would be the same.

But thanks for the input. If I cant do the OE battery swap I will contact one of the shops doing non oe batteries and have all the individual cells replaced with higher spec ones, that should give even higher capacity.

I read somewhere that the i3 is possibile to upgrade to 56kwh from max 44 oe. by that same token the I8 should be in the 13kwh range.

[stressdoc]

Unless you have a lot of emotional investment in your current i8, I think it would be wiser to sell it and get an LCI.

[zorgzx]

Well, not really. I'm just a nerd that likes to tinker with how things are made. Allso I really like that car, and are soooo fed up talking to car dealers, car hustlers etc.

[stressdoc]

Tinkerers are cool.

[avdept]

Originally Posted by zorgzx

Thanks for the input, I will look into it.

But I do not belive it will make any difference, the charge and discharge cycle should be the same, just longer as the engine, electrics and charger is the same. So I would not expect any heat related issues.
Perhaps the LCI can discharge a bit faster earlier or whatever, and require more cooling for that, but that would not change by swapping the batteries as cell count etc would be the same.

But thanks for the input. If I cant do the OE battery swap I will contact one of the shops doing non oe batteries and have all the individual cells replaced with higher spec ones, that should give even higher capacity.

I read somewhere that the i3 is possibile to upgrade to 56kwh from max 44 oe. by that same token the I8 should be in the 13kwh range.

The easiest you could to - compare side by side cooling system parts for LCI and non LCI versions. Also worth to check if LCI has other charger, because it might be capable of taking more charge for bigger battery. But besides I don't think there's any difference in car. It's just facelift after all, not new version of car.
Looking forward for outcome. If you make I'll follow your route

[r10crw]

Love to see somone thinking like this. Ive worked with large battery vehicle and our latest gen cells are configured to use same charger etc just as you say. Its not rocket science just new cells and I suspect BMW may not be that different. Going down to the lowest cell voltages should make it straightforward to increase energy.

Im considering buying a complete battery on ebay and stripping it down just to evaluate potential gains.

[Flasher]

i'm in the process of swapping my 2015 BMW i8 20Ah cell packs with 34Ah cell packs from a damaged 2022 BMW 745e with only 20.000 km's - this requires fitting three extra NTC's per cell pack and making 6 adapter wiring looms to convert the single connector for the 745 CSC to the two CSC's per cell pack in my 2015 i8.
The i8 LCI versions would probably be much easier as they already have the one connector/ one CSC setup like the 745e , probably the wiring will be the same as the 745 packs for production efficiency reasons....
to keep things simple and avoid the need of the EOS test procedure i leave the rest of the electronic parts untouched, i just keep a record which serial number replaces which old cell pack....
of course you will need new gaskets and O-rings and a emptying/refilling session for the airco system ( there is already R1234yf refrigerant in my i8) - also check they use the correct oil (Sanden SP-A2 or equivalent) which is required for the i3/ i8 airco system....
after refitting the battery pack i will reset some learned parameters to force the sytem to learn the new charging times and mileage forecasts - time will tell if this all is doable or just a waist of my time and money....
if my attempt would fail i still have learned a lot from the technical setup of my i8 which is valuable too....
Fingers crossed, i will let you know if it was a succes or a bust !

[Coastali8]

Good luck.
Seems like a lot of trouble for an extra few miles of battery range.

[avdept]

Originally Posted by Flasher

i'm in the process of swapping my 2015 BMW i8 20Ah cell packs with 34Ah cell packs from a damaged 2022 BMW 745e with only 20.000 km's - this requires fitting three extra NTC's per cell pack and making 6 adapter wiring looms to convert the single connector for the 745 CSC to the two CSC's per cell pack in my 2015 i8.
The i8 LCI versions would probably be much easier as they already have the one connector/ one CSC setup like the 745e , probably the wiring will be the same as the 745 packs for production efficiency reasons....
to keep things simple and avoid the need of the EOS test procedure i leave the rest of the electronic parts untouched, i just keep a record which serial number replaces which old cell pack....
of course you will need new gaskets and O-rings and a emptying/refilling session for the airco system ( there is already R1234yf refrigerant in my i8) - also check they use the correct oil (Sanden SP-A2 or equivalent) which is required for the i3/ i8 airco system....
after refitting the battery pack i will reset some learned parameters to force the sytem to learn the new charging times and mileage forecasts - time will tell if this all is doable or just a waist of my time and money....
if my attempt would fail i still have learned a lot from the technical setup of my i8 which is valuable too....
Fingers crossed, i will let you know if it was a succes or a bust !

You most likely will need to charge/discharge it multiple times to allow system to learn new capacity, but besides, I think it should work. Good luck and keep us posted!

[MolarBear]

Edo Popken I believe has done this on the facebook forums, he has built a few racing cars from there and from memory has done a few upgrades including a battery upgrade. Might be worth dropping him a message. He might be in Switzerland based..

https://www.edopopken.com/edo-motors...orsport-parts/

[Flasher]

Thank you for your replies, after crawling under my car for 2,5 days i finally finished the upgrade from 20 Ah cell packs to 34Ah cell packs , the car runs both electric and combustion mode and charges by port and by Sport mode ....
Right now i'm having a look at the reset options , i don't want to mess up the result alfter my labour but it would be nice if i could tell the electronics it has to deals with 34Ah capacity from now on.....

[zorgzx]

Fantastic very interesting, please do write to us on how it performs, do you now have more range ? or does it stop using the battery when it reches old capacity ?

[Flasher]

i will have to do some test drives and charge sessions after the resets i just did, i will post the results but first impression is ok and i also start fresh with better 2022 batteries so more than 6 years younger...
The whole project has only cost me around 2600 euro which includes a extra bought new 20 Ah battery pack for initial research, 67v 5A pack charger , connectors, wiring, cable sleeving , 18 NTC's , high voltage and low voltage extension test cables , gaskets and O-rings , airco drainage and filling and an extra jack for lowering and lifting the battery.....
the 20Ah battery pack (unused, new in box, just investigated for wiring connections and NTC's) is for sale now (300 euro plus shipping costs) , might be interesting for someone who needs a replacement for a faulty cell pack.
the six replaced 20 Ah cell packs are still in good condition (47.000 km, max. 20.68 Ah. aging factor 0.80 which is normal. the first 20% disappear rather quickly but after that the aging flattens out and stays rather stable for quite some time....
I'm still not sure whether to use them for a home battery project for my solar system or sell them, just let me know when you are interested ......

[zorgzx]

Very interesting project could you share some photos of the process and did you need to reset anything to get the other batteries to work in the car ?

[Flasher]

i did not take much pictures in the process, here are just a few to get an impression...
the cell pack with the black wiring is from the original 20Ah pack, the one with the orange wiring is from the 34 Ah cell packs from the SP41 gen. 4 battery pack of the BMW 745e ( also used in other models)
the resets i did were done with Tool 32 using the SME_i01 sgbd file, all descriptions are visible in the job list.....

[Tazzie]

Very clever. You certainly know your stuff 👍

[zorgzx]

Im amazed I think youre the first person to do this, atleast that will write about it online. If you can find the time, could your please make a writeup of what you did, how the packs were different, how you solved it and some of your experiences with the software.

As it is now this is almost 100% non documented how to mess with the battery packs. I did some calculations on the polish? dudes that swaps out a old 22kw pack on the old i3 and puts newer cells (not oe) in filling the pack, they get up to 57kwh. Adding math to that would result in someting in the region of 13-15ish on the i8.

13-15kwh new for me would allmost quadruple the range. It's not economical, its not smart, its just for us tinkerers that like to play with our toys. And having owned mine for 5 years, I just like it more every year.

But for me the difficult point is just finding out how different the i3/i8 pacs are from eachother, charge controllers, harness, software etc.

so shedding a bit of light on this topic could help a lot of people.

Allso if anyone actually know of anyone that has done the non-oe battery upgrades to i3 I'd love to get in touch.

[Flasher]

the i3 has a different setup, they use 8 cell packs with 1 csc and 12 cells instead of 6 cell packs with 16 cells in the i8.....
that's why the pre-LCi i8 uses 2 CSC´s per cell pack, BMW used the same CSC´s from the i3 but to balance just 8 cells (half a cell pack) instead of 12.....
the LCI i8 has 6 CSC´s for balancing 16 cells with a 1 master- 5 slave configuration and a single CAN connection instead of double....
the cell total is 96 cells in both cars but the I3 cells are much wider and heavier hence the cell packs have other dimensions ....
the cell packs inside the SP41 batteries used in different models have the same dimensions as the packs in the (pre/ LCI i8, the gen3 versions have 26 Ah cells while the gen4 version have 34Ah cells.
the LCi cell packs are 0.9 kg heavier because of the higher energy density.
Depending on the car model the SP41 batteries can contain 5 or 6 cell packs so check the sticker to verify the cell pack number.....