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New life for a bricked HV battery

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sokoloff

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Discussion Starter · #1 ·
Y

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#2 · (Edited)
sokoloff said:
This is from the EU Facebook page. Just passing the info along.

www.eqpassion.de

EQpassion Blog - smart ED3 17.6kWh battery repair (feat.P18051C / bricked BMS)

What can you repair on the battery? How are you? Can you protect him preventively?
www.eqpassion.de www.eqpassion.de

Len
Click to expand...
So After I had been writing that the "junkyard mode" (deliberate bricking by design) was just speculation that I no longer think is correct, Moritz reports that it is correct. However, if removing the 12V battery triggers junkyard mode as I previously suspected, why is "Vincent Rapide" reporting successful cases of long term storage with the battery disconnected? So we still don't know for sure what triggers the bricking process - although keeping a small charger connected to the 12V battery during long term storage is the sure method to prevent it.

And, at least we now know how to fix it - which admittedly is still a difficult and expensive job - especially the sending of the BMS to Europe to get reset - although I presume it no longer has to go to that userous shop in the Ukraine.
 
Vincent Rapide

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#3 ·
I charge the hv battery one module at a time ie 120vdc per each of the 3 modules.
120v x3=360v. There is no need to do all 3 at once at such dangerous voltages.

This avoids any current flow thru the costly 'current sensor' since you are connecting directly to either end of each module, and you are doing one module at a time.

If the module is severely depleted you can start with a 65v cc/cv charger. Then when you get up to 65v then connect another similar charger (or a fixed 65v source) in series and slowly work up to 120v max.
--
 
Y

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#4 ·
Vincent Rapide said:
I charge the hv battery one module at a time ie 120vdc per each of the 3 modules.
120v x3=360v. There is no need to do all 3 at once at such dangerous voltages.

This avoids any current flow thru the costly 'current sensor' since you are connecting directly to either end of each module, and you are doing one module at a time.

If the module is severely depleted you can start with a 65v cc/cv charger. Then when you get up to 65v then connect another similar charger (or a fixed 65v source) in series and slowly work up to 120v max.
--
Click to expand...
But I assume you will still have to send the BMS to a potentially shady operator to get that P18051C disabling code removed, right?

How is a supposedly globally prestigious car manufacturer getting away with this glaring defect anyway??? Between this and the Volkswagen scandal, my opinion of both German engineering and German corporate governance is, let's just say, down there.
 
J

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#5 ·
It seems to me like the only way to get rid of the complete charge on the HV battery is to dump it through the DC-DC convertor and then into the 12V battery. This would be consistent with the reports of "it doesn't happen if the 12V battery is removed" (though that would also preclude some of the electronics running).

Anything else would almost surely show us something getting hot while the power is being dissipated. (You'd have a report if it was using the HVAC system to dump the power.)
 
Y

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#6 · (Edited)
jimsokoloff said:
It seems to me like the only way to get rid of the complete charge on the HV battery is to dump it through the DC-DC convertor and then into the 12V battery. This would be consistent with the reports of "it doesn't happen if the 12V battery is removed" (though that would also preclude some of the electronics running).

Anything else would almost surely show us something getting hot while the power is being dissipated. (You'd have a report if it was using the HVAC system to dump the power.)
Click to expand...
I presume the cell-balancing shunt circuits on the "supervisory boards" do it - about 3 watts per cell over 60 hours would do it. That's still 279 watts in a small enclosed space but the steel enclosure probably dissipates heat fairly well even if the cooling pump can't come on becase of the 12V battery is dead. Nobody has ever witnessed the bricking in action, and nobody knows how long the pack discharging actually takes. They would probably notice some warmth coming from the car's underside.
 
Jmk2020

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#7 ·
Yinzer said:
So After I had been writing that the "junkyard mode" (deliberate bricking by design) was just speculation that I no longer think is correct, Moritz reports that it is correct. However, if removing the 12V battery triggers junkyard mode as I previously suspected, why is "Vincent Rapide" reporting successful cases of long term storage with the battery disconnected? So we still don't know for sure what triggers the bricking process - although keeping a small charger connected to the 12V battery during long term storage is the sure method to prevent it.

And, at least we now know how to fix it - which admittedly is still a difficult and expensive job - especially the sending of the BMS to Europe to get reset - although I presume it no longer has to go to that userous shop in the Ukraine.
Click to expand...
So first of all Minecooky take you message and call it truth. So forget about the junkyard mode, as this is really nonsens and proven by measurement, internal documentation and reengineeing of the BMS firmware.
I just start a new post about giving some addition background knowledge from developer view.
Also the P18051C i addressed in the post. There are now colleagues around the world which could help you. Also the ukraine option is not too bad as he really knows (most times) what to do.
Eqpassion is just forwarding it to a other guy in Lithuania, who even fix it and switch of HV isolation measurement functions. This is just real dangerous and even not necessary if he would do the job right.

If you what to fix it in US or CAN i can link you locally.
Or i can tell you a European shop which can really fix it and not just reset the P18051C :) For reach to reset P18051C only you even do not need to open the BMS at all, if you really understand the BMS functions. I also checked the work of 5 different sources in meantime and can tell you which unit is done by who :cool: and what is done wrong.
 
Jo e Lefors

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Now 09 451 Passion Cabriolet Met Blue & Silver First 08 451 Passion Cabriolet Yellow & Black
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#13 ·
Stephen ONeal said:
I am willing to try but I am 73 and not very knowledgeable about battery / Electrict
Click to expand...
Welcome to SCoA forum Stephen.
Sorry to hear your ssmart has "Bricked"
Lack of electrical knowledge (since you brought it up) age doesn't bode well for you.
Without nationwide support You are pretty much on your own.
Good Luck
 
sokoloff

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Discussion Starter · #16 ·
I agree with Jo e, but also suggest you some exchanges of ideas with JMK2020 in Post #11. He may be able to save you. Selling a dead EV is going to be very difficult. Might end up having to almost give it away to a junk yard or just part it out yourself. Sorry to hear about your situation. BTW what is the status/age of your 12v battery?

Len
 
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D

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2014 Cabriolet bought in Sept 2016 with 6,470 mi
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#17 ·
Stephen ONeal said:
I will put her up for sale. Any suggestions?
Click to expand...
Contact Mercedes Benz USA and threaten to sue them for making a defective product. You probably will have to sue them at least in small claims court before they will settle with you, but you are much more likely to get somewhere near your money back this way than selling it.
 
D

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#19 ·
The Battery Management System (BMS) is defective. You cannot drive the car to the point that the traction battery will be unusable (bricked), but the BMS itself can and does do exactly that - run the traction battery completely out of power so that it becomes unusable.

M-B USA has never issued a notice, much less a recall or provided any kind of fix for it or ways to avoid it happening. Nor has there been one in Europe or anywhere else that we know of.

All the information that we have is from people who it has happened to and others who have looked into it.

Don't know how M-B has gotten away with it, but they have up to this point. If it happens to me I will sue if for no other reason than to find out what they knew and when they knew it and try to make sure it doesn't happen to anyone else.
 
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Yinzer
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