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Discussion Starter · #1 ·
While I still consider myself to be a Smart ED "newbie" I've done a fair bit of reading/research and think I have a decent handle on the whole debacle that is the Smart ED bricking issue.

As I understand it, the Smart ED battery will brick if the vehicle's been in an accident and the pyro-fuse has activated or the vehicle has been stored for an extended period of time and the 12 volt lead-acid battery has lost a portion of its charge. The latter example is far more common and my understanding is that it was an intentional design by Mercedes-Benz. The design feature, also known as "junkyard mode," was created so the HV battery would begin to self-discharge when the 12 volt source was depleted. The apparent logic was most wrecking yards pull the 12 volt lead acid battery when a vehicle arrives at their yard and having the HV battery self-discharge would eliminate a potential electrocution risk that conceivable could have lasted for years.

So here's the question: How much damage does the "average" bricked EV battery have? Said another way, of the 93 individual cells in the HV battery, how many of them are damaged to the point they can no longer be revived?

From what I've read a damaged lithium ion battery is often swelled and the swelling is the result of hydrogen gas that was created in the cell as part of the destruction process. Once a cell has swelled it can no longer be revived and unlike a car like the Nissan Leaf, the Smart ED battery does not provide an easy solution to swap out damaged cells.
 

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Think this is going to be a question on the minds of everyone when we all eventually have to move onto electric cars. In the UK we phase out new fueled cars by 2030, and then only new electric cars will be available. The problem of older electric cars of holding charge over the years from 100% when new, is down to 60% or 50% when 7 or 8 years old, or car in worst scenerio just bricking up, konking out, dead as a doo doo.

The problem is when the battery pack guarentee runs out (six or seven years down the line depending on car manufacturer) and if you brick up then the costs are yours to deal with.

On the Smart car similar to Tesla, you have to drop the battery pack from underneath, by unbolting the perimeter, then check which cells are finished and replace.

In the USA where the Toyota Prius electric car has been around a long time now, there are companies set up to exchange reconditioned battery packs, or just replace damaged cells. I assume more of these companies will set up as more and more older electric cars are on the road, in both UK and USA.

My personal gripe is the Smart EQ does not have a good range, so 'range worry' is the problem, and the other is Electric cars are way overpriced. I will be hanging on to my petrol (gas) 453 for a long time.

 

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The problem of older electric cars of holding charge over the years from 100% when new, is down to 60% or 50% when 7 or 8 years old ...
It is unlikely that an EV battery will degrade that fast. Based on the experiences here, maybe just 10 to 20 percent in 10 years is typical. And the prices of EV's are becoming pretty competitive with IC engine cars. In some US states, people are buying new Chevy Bolts for around $18K with various manufacturer and dealer discounts and government incentives.

Also, as far as I know, triggering the pyrofuse in a collision does not brick the battery pack. And, the bricking associated with a failed 12V battery being a deliberately designed "junkyard mode" is just conjecture. I know, because I am the author of that conjecture - a slightly sarcastic conjecture of how things go wrong when software "engineers" are allowed to think they are real engineers and try to design stuff.

As far as the conditions of the cells in a bricked pack (which have been discharges to just a half volt or less), normally a completely discharged lithium cell will have badly degraded capacity - especially power capacity. The traditional NiCo02 batteries were very prone to explosive fire if recharged from completely flat. The Smart cells are LiNiMnCoO2 and seem to be less prone to this hazard.

Those that have successfully revived their packs have never come back with a performance report.
 

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Discussion Starter · #4 ·
Think this is going to be a question on the minds of everyone when we all eventually have to move onto electric cars. In the UK we phase out new fueled cars by 2030, and then only new electric cars will be available. The problem of older electric cars of holding charge over the years from 100% when new, is down to 60% or 50% when 7 or 8 years old, or car in worst scenerio just bricking up, konking out, dead as a doo doo.
From my limited research at this point, I get the impression there's a thriving secondary market for EV batteries from vehicles that have either been totaled in a collision or simply reached the end of their useful life. As you pointed out there's a market for replacement Prius batteries and I've noticed there's a market for replacement Leaf batteries as well. I get the impression there won't be a market for replacement Smart batteries because too few vehicles were produced (limited demand) and the individual cells are difficult to remove and replace if one or more cells are damaged.
 

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Discussion Starter · #5 ·
Also, as far as I know, triggering the pyrofuse in a collision does not brick the battery pack. And, the bricking associated with a failed 12V battery being a deliberately designed "junkyard mode" is just conjecture. I know, because I am the author of that conjecture - a slightly sarcastic conjecture of how things go wrong when software "engineers" are allowed to think they are real engineers and try to design stuff.

As far as the conditions of the cells in a bricked pack (which have been discharges to just a half volt or less), normally a completely discharged lithium cell will have badly degraded capacity - especially power capacity. The traditional NiCo02 batteries were very prone to explosive fire if recharged from completely flat. The Smart cells are LiNiMnCoO2 and seem to be less prone to this hazard.

Those that have successfully revived their packs have never come back with a performance report.
Excellent post thanks for the information. :)

It's interesting to learn that "junkyard mode" is just conjecture - in some ways that's too bad because it made for a plausible explanation to what otherwise seems like a very poor design.

Concerning information about bricked Smart ED batteries that have been revived, I agree that there's not too much information available - that's mostly why I created this thread. There are two YouTube videos I've watched - in one case a YouTuber repurposed a Smart ED battery as a DIY Power Wall and ended up scrapping 9 of the 93 individual cells. His case, however, might be unique because the battery he bought had wires that had melted on the inside of the battery pack because the wrecking yard apparently ignored safety protocols and cut the orange power wires on the outside of the battery with a saw and created a dead short. (Interestingly, he was able to revive all 93 cells but had to scrap 9 of the cells because they self-discharged.)

In another video by a different YouTuber the video ends with an upbeat report that all 93 cells of the Smart ED battery took a charge - even those that were totally dead with 0.0 volts. There was never a follow-up video that I found but in reading the comments to the original video it appears the battery was eventually scrapped for parts. (I'm guessing he had the same self-discharging issue mentioned above and since individual cells/pouches are not readily available he just gave up and scrapped the battery for parts.)

On a final note, your comment about batteries that had their pyro fuse activated is interesting to me. I just assumed MB would apply the same "junkyard mode" logic and self-discharge the battery but to the extent "junkyard mode" is just conjecture I guess all bets are off?
 

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His case, however, might be unique because the battery he bought had wires that had melted on the inside of the battery pack because the wrecking yard apparently ignored safety protocols and cut the orange power wires on the outside of the battery with a saw and created a dead short.
That is probably not correct. Unless the car is switched on via the keyswitch and and the power train control unit finds that "all systems are go" then the two main power relays inside the battery pack are open and the orange cables are not energized.

But yes, salvaged Nissan LEAF modules are being used for a lot of garage projects.
 

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Discussion Starter · #7 ·
That is probably not correct. Unless the car is switched on via the keyswitch and and the power train control unit finds that "all systems are go" then the two main power relays inside the battery pack are open and the orange cables are not energized.
Interesting - thanks for the information.

Here's a link to the video (the portion relating to the wire damage starts at 4:25) -

I read through many of the comments that followed the video - some thought the wire damage was due to how the battery was removed from the vehicle and another thought it might be the result of flood damage. One person said the damage was related to the accident the donor vehicle was in and it was an intentional design. I'm not 100% sure how the pyro fuse works but I doubt there'd be that much damage to the inside of the battery if the pyro fuse had been activated.

But yes, salvaged Nissan LEAF modules are being used for a lot of garage projects.
I agree. In fact I'm intrigued by the market for repurposed EV batteries. Tesla battery cells are very plentiful on eBay - one seller even polishes the case and puts a Tesla logo on the cell for people who want to use it as a paperweight or conversation piece.

While I've only done limited research, it appears to me that the Smart ED battery is one of the poorest designs for people who either want to repair or repurpose the battery. It seems like most of other OEM EV batteries have cells that can be swapped out relatively easily. Between the Prius, Leaf, and Volts it appears there's a decent supply of cells for people who are either looking to get their car back on the road or want to repurpose the battery for another use.
 

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I'm not 100% sure how the pyro fuse works but I doubt there'd be that much damage to the inside of the battery if the pyro fuse had been activated.
The pyro fuse is licated under the driver's seat and is a simple job to replace, although finding one and clearing the code if you don't have MB's exclusive xentry syatem might be a challenge.
 

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There is a person in poland that for 500 us he will unbrick the BMS.
Fixing electric vehicle smart EQ BMS error part1

Broken EV Smart eq bms battery error part2



Refill the cooling battery and engine system of the smart 453 EQ

Smart 453 EQ fix part4
 

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The battery brick because one of the cells the voltage was off by 100 milivolts and the bms brick itself,I dont think he replace any cell.
Rollin
 

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Bricked hv batteries not a problem with 453 Smart EQ.

Smart ED hv batteries are not repairable in the same sense as Leaf, BMW, Ford c-Max, etc are. The cells are not unboltable but are Al to Al and Al to Cu pressed/soldered(?). Typically bricking means a few to several cells are dendrite-shorted so any charge given is lost overnight. You could leave these dead cells in place to avoid making a mess and just solder jumpers from the Cu lands atop each to effectively remove those cells from the pack. This of course will no doubt mess up the BMS operation but you might get some useful power thru your jumpers. The reduced-cell battery could also be used in solar or other EV projects. Lotsa luck!
 
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