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Of course, it is ridiculous that I have to treat the workings of the Smart ED like some kind of mystery puzzle. Why tf can't I just call someone at Mercedes Benz who should refer me to an engineer who know all this s?
Money. Time. Proprietary competitive information.

Do other manufacturers have engineers who can chitchat with customers who are passionate about the product? Can I call up Apple and talk about my phone's engineering? Can I call up Ford and talk with an engineer about the sick 351 that I'm thinking about swapping from an old F150 into my Mustang? Or Intel about the latest hyperthreading information leak bug?

Though I agree that it would be helpful if more technical information were published, I don't think that a live conversation with a knowledgeable engineer on demand of any enthusiast is realistic.
 

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Discussion Starter #22 (Edited)
But they do have "customer service representatives" right? I am only asking questions that any service technician is supposed to know (or any mechanic knows about Ford V8's) - but apparently they don't. And if they can't answer a question they can elevate it.
 

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Discussion Starter #23
It just occurred to me that the the failure of the Smart ED's traction battery after a period of time with the 12V battery is removed or failed may not be a bug, but a feature!

It may the way that MB assures that the car in not shock, fire, and consequently a lawsuit, hazard after it goes to a junkyard. 12V batteries are the first thing to be removed from a car arriving in a junkyard becasue of the battery's lead content and recycling value. So, the MB engineers figured that this would be a good way to signal a "self-destruct" protocol in the BMS which then, over a few days, discharges the battery pack flat.

That is my idea for fwiw...
 

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Discussion Starter #24
Though I agree that it would be helpful if more technical information were published, I don't think that a live conversation with a knowledgeable engineer on demand of any enthusiast is realistic.
Enthusiast? The situation is not of an "enthusiast" - it is of an enraged person, who spent hard sweat-earned money or got in deep debt buying the only kind of electric car he/she/they could afford, because he wanted to "do the right thing" for future generations - only to see his/her/their investment rendered a brick that he/she/they then have to spend more money to haul away.

And also, if manufacturers are really using "propriety information" or "so-called "intellectual property" to prevent people from being able fix their cars that they spent so much money on, then, we are in serious need of laws to prevent such stuff. I understand that Massachusetts does have such a "right to repair" law.
 

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Close Call

It just occurred to me that the the failure of the Smart ED's traction battery after a period of time with the 12V battery is removed or failed may not be a bug, but a feature!

It may the way that MB assures that the car in not shock, fire, and consequently a lawsuit, hazard after it goes to a junkyard. 12V batteries are the first thing to be removed from a car arriving in a junkyard becasue of the battery's lead content and recycling value. So, the MB engineers figured that this would be a good way to signal a "self-destruct" protocol in the BMS which then, over a few days, discharges the battery pack flat.

That is my idea for fwiw...
Yikes, :eek: I once disconnected my 12V battery overnight to try to clear/reset the SAM, come to find out my problem was from removing the dash cluster and bumped the light switch while the dash was out and all HE!! broke loose. The car acted strange after putting it all together (Interior lights stayed lit on the PRND shift indicator over night.

Well I don't know how but my HV battery isn't a paperweight and somehow the car "fixed" itself.
 

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My 2 cents.

I did a simple 12v battery test and as all the earlier posts mention I agree that daily/ weekly use = NO problems
Storage = Huge heavy paperweight brick.

My 2015 ED 451:
After full charge, still plugged in sitting several hours. 12 volt at 12.27VDC
Turn on Ignition. 12 volt at 13.32VDC
After long drive, parked 2 hours unplugged. 12 volt at 12.52VDC
Plug in to charge HV. 12 volt at 13.37VDC

So as stated earlier the 12volt gets topped off and maintained while driving, plugged in only charges WHILE the HV is charging.

I agree storage REQUIRES a 12v battery tender 3A min.
Storage over inclement weather EVSE recommended also.
 

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Discussion Starter #28
Yikes, :eek: I once disconnected my 12V battery overnight to try to clear/reset the SAM...
Well I don't know how but my HV battery isn't a paperweight and somehow the car "fixed" itself.
The 12V battery probably needs to be out for several days - and then the internal discharging of the traction pack cells down to zero at a rate that would not burn something up takes a few days too. If you intervene at any time before the pack drops below 280 volts of so you are probably safe.

Absurd amounts of totally gratuitously complex IT controlling everything in cars these days...
 

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So as to not create panic, I’d recommend striking “quite” from the above sentence?

Although troubling, only “a few” ED’s with BRICKED HV batteries have been documented on SCoA. My SWAG is that we are seeing a BRICK rate of less than 3%?

Bear in mind that some may have knowingly bought an off-lease MBFS BRICK at a deep discount hoping that they could breathe life back into ED?

If ED doesn’t move under it’s own power and the dash won’t light up or displays multiple warnings - you are playing the ED LOTTO . . .
Mine just bricked itself due to a dead 12v so add me to your 3%...
 

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Sorry to hear that. What are your plans for it?

Len
2014 EV Coupe 20,000 miles
2014 EV Cabriolet 18,000 miles
 

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Not sure. might try to pull battery and recharge manually / send the BSM of to a foreign land for a mind wipe. I really wish we could figure out the BSM error fix are "shareware" it. Its bad enough the MB has us in this situation in the first place.
 

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Discussion Starter #33
Does disconnecting HV by use of under-dash switch throw any immobilizing codes?
VR
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That is a good question. The owner's manual warns the owner not to pull it. But I beleive it is supposed to be pulled to provide a safety lockout/tagout when servicing any HV components. It would be very annoying that this would result in codes that only a MB dealer or other shop with specialized equipment can clear.
 

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I can offer a second-hand account based on the 2014 ED I just bought last month. The person I bought it from was the second owner and had owned it since late 2016. He lives in Illinois and stored the car during winters. He was aware of the battery bricking issue and kept a battery tender on the 12v battery during storage. He had attached a couple of leads to the battery so that the tender could be plugged in just under the passenger footwell. He threw the battery tender in with the purchase. The car had about 7000 miles on it when he bought it and it has about 11500 miles on it now. The HV battery is in great condition, testing at around 51-52 amp-hrs. I don’t know what state of charge he kept it at while in storage, but whatever he did, it seems to have worked.
 

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I agree storage REQUIRES a 12v battery tender 3A min. [smart car]
He threw the battery tender in with the purchase. [VSAncona]
Basis for the '3 amp min' statement?

Photo or specs of your tender which seems to be doing its job successfully?

Until we discover exactly what is wrong inside our hv batteries that is causing all this grief, we can try to approach, thru the backdoor, techniques to mitigate its effect. Some techniques will be overkill, some will be inadequate but hopefully we can find the proper settings. This proper solution, once discovered, could point directly to the cause of the problem if enough genius is applied. Leakage vs 'operational failure' seem to be the choices here.
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Discussion Starter #37
Basis for the '3 amp min' statement?

Photo or specs of your tender which seems to be doing its job successfully?

Until we discover exactly what is wrong inside our hv batteries that is causing all this grief, we can try to approach, thru the backdoor, techniques to mitigate its effect. Some techniques will be overkill, some will be inadequate but hopefully we can find the proper settings. This proper solution, once discovered, could point directly to the cause of the problem if enough genius is applied. Leakage vs 'operational failure' seem to be the choices here.
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VSAncona is referring to a common 12 volt car battery charger. Since the battery only needs to be maintained, only a very small charger is needed - as long as it has an automatic float-maintenance setting.

I know from my measurements that the car's syatems drain the 12V battery at a rate of about 50-60 mA - this drains the battery in about 3 weeks. We know from too many anecdotal accounts that once the 12V battery dies, the HV battery gets drained by some mechanism. I have posited that this may be be an idiotic feature, not a bug, to assure the HV battery self-destructs for safety purposes if the car ends up in the junkyard. Note that lithium cells have near zero self-discharge.
 

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This seems to be the best existing thread to start Storage Histories for Smart EDs.

50 Days - car parked in garage unlocked with 12v battery DISconnected. 12v battery on float charger. 12v battery is original factory 5/2015, hence my concern! Upon arriving home (on 7sep2020) found hv battery to be at 50% level, presumably exactly where I left it 50 days ago. I say presumably because apparently I did not record this %; my guess is that it was at 50% and I should be able to remember such occurrence, and I vaguely do. Anyway, I was pleased to find it at 50% and I'm a believer in Li-Ions being half full for storage, what Tesla recommends. So very likely I did leave the hv battery at 50% and it did not lose any charge at all. The 12v battery responded well to the float charge and now is behaving 'like new' although I trust this as far as I can throw it. Today it greeted me: 12.4v / 13.8v / 14.3v as the dc-dc started up. I have a new LFP 12v battery to replace it with someday soon.
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Discussion Starter #40
This seems to be the best existing thread to start Storage Histories for Smart EDs.

50 Days - car parked in garage unlocked with 12v battery DISconnected. 12v battery on float charger. 12v battery is original factory 5/2015, hence my concern! Upon arriving home (on 7sep2020) found hv battery to be at 50% level, presumably exactly where I left it 50 days ago. I say presumably because apparently I did not record this %; my guess is that it was at 50% and I should be able to remember such occurrence, and I vaguely do. Anyway, I was pleased to find it at 50% and I'm a believer in Li-Ions being half full for storage, what Tesla recommends. So very likely I did leave the hv battery at 50% and it did not lose any charge at all. The 12v battery responded well to the float charge and now is behaving 'like new' although I trust this as far as I can throw it. Today it greeted me: 12.4v / 13.8v / 14.3v as the dc-dc started up. I have a new LFP 12v battery to replace it with someday soon.
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Note that if the battery had lost some SOC from self-discharge, the SOC gauge would not have detected it - all it does is count watt-hours in an out of the pack. But for lithium batteries, self-discharge is nil.

What is more interesting is that you disconnected the 12V battery during storage and had no problem. Our working hypothesis from other people accounts of HV battery failure during storage was that a disconnected, or dead 12 battery was what triggered the HV pack's self-destruct.
 
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