BMW i3 Batteries

I'm considering purchasing the battery out of a low mileage BMW i3 for a project I'm planning (conversion of a Honda Pilot FL400 offroad buggy from petrol to electric) but can't find a huge amount of information about them either on here or elsewhere on the internet. What I've found so far and my assumptions:

- The battery pack contains 8 modules, each of which has 12 cells
- 60Ah battery
- I think they might be Samsung SDI NMC prismatic cells
- Total battery capacity 21KWh/22KWh (depending on which source of information you go by)
- Nominal battery voltage 355V
- I know the latest BMW i3 uses 94Ah Samsung prismatic cells

A couple of quite useful videos on YouTube of someone dismantling an i3 battery:
https://youtu.be/o7BhV0jqq_A
https://youtu.be/GoeyzXsovXA

Video of battery assembly in the factory:
https://youtu.be/iiJsKza5CF4

A few photos taken from various sources on the internet:

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Ebay Seller Description:



If anyone has any more information they can add that would be great. I'm really keen to find out what sort of constant current these cells can take and burst currents too.
Has anyone used the batteries from a BMW i3 for a project?

I think you have the key data for the batteries. Those look pretty easy to work with.

Stock i3 is rated for 125kW power. At nominal 360V, this would be about 350A. I'm sure you could get a little more out of them for short bursts.

What kind of motor are you thinking of using?

It sounds like if...the nominal voltage is 355V from 96 cells, then the whole pack is 1P?

spinningmagnets said:

It sounds like if...the nominal voltage is 350V from 96 cells, then the whole pack is 1P?

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Yes it is 1P pack. First 21.6 kWh pack (18.8 kWh usable) was made from 60 Ah cells. Actual 33 kWh pack (27.3 kWh usable) is made from 94 Ah cells. This year we are waiting for introduction of 42.6 kWh pack (cca 36kWh usable) with 120 Ah cells.

fechter said:

What kind of motor are you thinking of using?

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Early stages of my planning but possibly a Motenergy ME1616 coupled with a Sevcon GEN4 Size6 controller. Initial thoughts are 250A continuous & 500-600A bursts.

Cell manufacture video:

https://youtu.be/CDvxR3oNefk

12S of high-amp cells is VERY useful for a variety of applications. The website "DIY powerwalls" has been pressured into changing it's name, and they are now "second life storage". One of the hot topics is the fact that...as pure EV and hybrid cars reach an age where they no longer deliver the rated 80% of factory new WH, the old pack is likely to be sold on the open market. So...who would want an "old" pack that is only delivering 80% of their rated pack capacity?

if the price is right...a pack that can be broken down into modules that provide 12S / 13S / 14S...can then be easily configured to use mass-produced and available components to make a home "Tesla Powerwall". A new 18-kWH pack providing 'only' 14-kWH of power [after 8 years] in a power outage is still an awesome application for these "barely used" packs.

You can break down EV battery packs into smaller units and then reassemble them into any series group that you desire, but...12S per existing module as an option is pretty sweet. 12S at 350A? That sounds like a "Live for physics" 15,000W motorcycle pack...

I completely agree and my research into EV batteries for the use in my project has inadvertently led me to diy “power walls”. Not necessarily as useful here in the UK due to our weather but still something that has got me thinking.

For a car those packs sure look like there's a lot of wasted space...I know there trying to keep them safe and all but still...

I build a tiny 4s 12v 28cell mobile power wall. Easily keeps my laptop plugged in for say a full day and anything else that draws under 140w. It was fun to make but I can see the practicality of a 24v 7s system without the use of a buck converter and hooking that up to a solar charger.

I’m definitely subscribing to this thread. I spent about 12 years of my life dedicated to my FL350, FL400 and Drakart Formula Cross. Those cars and my motor home is where I had some of the best times of my life with Hoser and the gang from pilot odyssey dot com.

It will be really interesting to see what you come up with.

Tom

It might be a slow burner Tom but keep your eyes peeled as I’ll document it all on here. Hard to find them in the UK and they are expensive so it may take me a while to find one.

Out of interest, do you know any performance specs for a standard FL400? Top speed, horse power, 0-60 type of figures etc. I want to try and gauge what power to aim for with the motor, controller & batteries.

Stock Horsepower was about 40. Top speed was about 65 mph. 0 to 60 no clue. I had mine ported, polished, rev pipe, 39mm Mikuni carb, reeds, custom stuffer and a power bloc clutch. Bumped it up to 60/65hp and raised top speed to about 70. I could pull a wheelie for about 10 to 15 feet after the Hoser mod. Really loved that car till I got the Drakart Formula Cross. It was stock at 110hp and weighed in at a slim claimed 650 lbs. it was a rocket.

Tom

Ok, so 40HP = about 30KW.
So if I use two of these BMW modules in series it will be 24S & at 250A continuous that’s roughly 22KW. 500A bursts would be roughly 44KW.

I don’t think I could realistically match the performance of the tuned FL400 you had but stock should be doable.

What about weight? Any idea what the stock weight was?

Here's some detail on the Samsung battery:

https://insideevs.com/lets-look-at-the-specs-of-the-samsung-sdi-94-ah-battery/

cheers,
Michael

Thanks Michael, useful information. I wonder if one exists for the 60Ah version as that’s for the 94Ah.
The table seems to suggest a 5 second burst at 413A is as much as they can handle and that’s the 94Ah battery. The 60Ah is likely to be less. Maybe not good enough in a 1P configuration for my project. I’m also concerned about weight too.

Suggs said:

Ok, so 40HP = about 30KW.
So if I use two of these BMW modules in series it will be 24S & at 250A continuous that’s roughly 22KW. 500A bursts would be roughly 44KW.

I don’t think I could realistically match the performance of the tuned FL400 you had but stock should be doable.

What about weight? Any idea what the stock weight was?

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They were 600 lbs.

Tom

Hi, I am also looking at using some BMW i3 batteries in my electric forklift. I bought it last year with the aim of charging it up using solar and using it only in short bursts of 10 mins max once or twice a day. The original lead acid battery will not hold a charge.

I3 battery looks @ 48v maybe a good choice. What would I need to monitor and charge the i3 cells. I am new to battery monitoring systems. Is there a plug and play board I could use for this application?

BMS as any other, just choose good amps and that's it.

Suggs said:

Ok, so 40HP = about 30KW.
So if I use two of these BMW modules in series it will be 24S & at 250A continuous that’s roughly 22KW. 500A bursts would be roughly 44KW.

I don’t think I could realistically match the performance of the tuned FL400 you had but stock should be doable.

What about weight? Any idea what the stock weight was?

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I think about 110lb, I am tempted to go then,2 in series ,plan A was Chevy gen2, Chevy isaout 70lb
I have nd96850 and 8 kw qs hub motor