[BabyBumblebee]

I replaced the 12V battery in my 2014 Smart EV 451. The car didn’t like me doing that. Anyone else had this problem?

 

[Yinzer]

Does the car run?

Someone else reported this problem - although he or she attributed it to accidentally grounding out the positive terminal, causing a big spark, even though the negative terminal had been disconnected.

Available service informaiton indicates that the HV service disconnect (under the left side of the left footwell) is supposed to be pulled before 12V battery service - buy DIYers in this forum are afraid to pull it becasue it might trigger a software "disable" of the car and then can only be reset by towing it to a dealer. Go to page 50 of the "Introduction to Service for the Smart Electric" .pdf file in the sticky posts above.

I will put a question out if anyone has pulled the service connect what happened when they did.

 

[jzchen]

Hmm. If that is the case, pull the service disconnect, then disconnect the neg terminal of the 12 V battery. Let the car sit maybe 30 mins to let any capacitors discharge, reconnect the the 12 V, then the service plug, and hopefully she's happy...

Sent from my moto g(7) power using Tapatalk

 

[Yinzer]

Hmm. If that is the case, pull the service disconnect, then disconnect the neg terminal of the 12 V battery. Let the car sit maybe 30 mins to let any capacitors discharge, reconnect the the 12 V, then the service plug, and hopefully she's happy...

Sent from my moto g(7) power using Tapatalk

The point is that we are afraid of what the car's psychopathic gaslighting software will do to the car if it detects the service disconnect being pulled. The service primer refers to the cars syatem being de-energized first with the "DAS system", then the service disconnect is pulled.

No normal, physics-based mechanical or electrical assumptions can be relied on when working on a Smart ED.

 

[Vincent Rapide]

STOP, please, with the Service Disconnect. It is not necessary to do this before disconnecting the 12v battery. Just remove the neg terminal and tuck it out of the way so it wont jump up and accidentally contact the battery terminal. The car will not complain, show codes or anything.

If you reconnect at exactly 12 o'clock perhaps the dash clock will now be correct(?).
--

--

 

[jzchen]

The point is that we are afraid of what the car's psychopathic gaslighting software will do to the car if it detects the service disconnect being pulled. The service primer refers to the cars syatem being de-energized first with the "DAS system", then the service disconnect is pulled.

No normal, physics-based mechanical or electrical assumptions can be relied on when working on a Smart ED.

My interpretation from what I read was he kept the plug installed, changed the battery, and then got the "you're screwed" message after installing the new one. I figure it wouldn't hurt anymore to try the official route of disconnecting the plug, then simulating changing the battery, in the hopes that the ECU forgives him for not following the official instructions.

It may be a case of misery likes company, 12 V system has a failure and decides to take HV system down with it, and/or vice versa...

Sent from my moto g(7) power using Tapatalk

 

[jzchen]

Someone for goodness sake pay the piper the $60 and pull the startekinfo.com instructions for this.

Like I noted in another thread no Mercedes in my lifetime required any sort of fancy dance to replace the 12 V battery. BMW, Porsche, even Ford yes, but not Mercedes. Sadly, my suspicion is that something is failing along with the dead 12 V or HV battery. Something that possibly Mercedes/Smart warranty should be covering....

Even if you didn't program the new battery in all three model experience I had with Porsche, BMW, and the Ford the car still started up. It was more for longevity of the battery. Something else is breaking, maybe due to low voltage...

Sent from my moto g(7) power using Tapatalk

 

[sokoloff]

Here's a thread on DIY replacement of the battery.

DIY - replacing 12v battery (451)

Yesterday I replaced my original battery with a new OE one from Mercedes. The new battery is identical to the original battery in specs. Cost was $176. I couldn’t tell the manufacturer, but in the past, Varta made most Mercedes batteries. This new battery was identical in size to the...

www.smartcarofamerica.com

Len

 

[Yinzer]

Someone for goodness sake pay the piper the $60 and pull the startekinfo.com instructions for this.

Like I noted in another thread no Mercedes in my lifetime required any sort of fancy dance to replace the 12 V battery. BMW, Porsche, even Ford yes, but not Mercedes. Sadly, my suspicion is that something is failing along with the dead 12 V or HV battery. Something that possibly Mercedes/Smart warranty should be covering....

Even if you didn't program the new battery in all three model experience I had with Porsche, BMW, and the Ford the car still started up. It was more for longevity of the battery. Something else is breaking, maybe due to low voltage...

I suspect that the design team for the smart ED was a totally different group than the normal automotive engineers - they were probably recruited from the ranks of the IT engineering field and simply have no experience with the the conventions of automotive service and serviceability. Yes, I agree that something is going on regarding the association of dying 12V batteries and bricking HV batteries via their BMS. And the problem is almost certainly software, not hardware.

 

[Yinzer]

STOP, please, with the Service Disconnect. It is not necessary to do this before disconnecting the 12v battery. Just remove the neg terminal and tuck it out of the way so it wont jump up and accidentally contact the battery terminal. The car will not complain, show codes or anything.

If you reconnect at exactly 12 o'clock perhaps the dash clock will now be correct(?).
--

Available service information states that HV system de-energization, involving among other things, pulling the HV service disconnect, is to be performed for changing the 12V battery. Yes, I know some successfully replaced their 12V batteries without following this procedure, but this does not mean it will always work.

 

[Vincent Rapide]

Possiblity exists that hv battery might be better preserved long term if Service Disconnect is made before 12v battery is removed from car long term, compared to these sad sagas of Smart folklore. The pinhead Daimler engineers might have had something like this in mind when they wrote the docs sensing the unique failure mode might rear its ugly head but didn't want to spell it out in plain German. However this does not excite me sufficiently to run an experiment.
--

 

[jzchen]

Available service information states that HV system de-energization, involving among other things, pulling the HV service disconnect, is to be performed for changing the 12V battery. Yes, I know some successfully replaced their 12V batteries without following this procedure, but this does not mean it will always work.

Do you mean different software versions, because I can't see how it would affect different ones differently otherwise? So some are programmed to self destruct while others aren't? Still points to some kind of failure...

Essentially my point is this, empowered with the actual (updated) Mercedes/Smart service literature, we can know whether we or the car is to blame. It's just like the story of a lady (assumedly not knowledgeable in car service) gets ripped off, vs the less likely male, we are being taken advantage of when we don't know the proper procedure. Stories here are along the lines of "I bricked my smart", not "my smart broke down". I turned a maybe $500+ navigation update into a $250 one by getting the instructions and going to the parts department and asking politely if they'd allow me to install it on my own vs pay a technician hourly to babysit as the car downloaded the USB. My friend fearful a star machine was needed to restore his '14 E class after a needed battery change paid over $500, and more recently we swapped that one out in a a parking lot for the cost of the battery alone.

Don't give Smart/Mercedes an excuse to void any responsibility. At least tell them you replaced it properly. Len already changed his successfully just by swapping it out. Why wouldn't it work for others, unless something else went wrong with the car? Saying it may not work for others is begging the question.

Sent from my moto g(7) power using Tapatalk

 

[BabyBumblebee]

I’m not sure what caused the message but probably was pulling the hv disconnect. I did that once or twice before battery change and it didn’t give the hv->workshop message the first couple times. It seems to drain hv battery fairly quickly(20% overnight 40% to 20%) with the hv service plug pulled and the 12v battery negative pulled. I don’t understand, seems odd. The radio turns on when you hook the 12v battery up. Also seemed odd. I think this car would be more enjoyable within warranty and within 70 miles of a MB dealer that services them.

 

[jzchen]

I may just subscribe. I didn't complete my "manual" for the '12 E Class in the household. One day for $60 or 1 week for $160. Usually 1 day is not enough and exhausting to try... If I do I'll search for a '14 VIN and look up the 12 V instructions. Before Smart and Mercedes were on separate websites. I lost my smart in 2017 so I didn't need to pay smarttekinfo ever again, besides the fact I already got my smart manual. If the HV battery drains like that some sort of warning must be in the instructions...

Sent from my moto g(7) power using Tapatalk

 

[Vincent Rapide]

I replaced the 12V battery in my 2014 Smart EV 451. The car didn’t like me doing that. Anyone else had this problem? [OP]

So this was not the full story at all. Might be a good idea to give all the details; what you did and why you did it. You are getting bizarre results from your car.
--

 

[Yinzer]

I’m not sure what caused the message but probably was pulling the hv disconnect. I did that once or twice before battery change and it didn’t give the hv->workshop message the first couple times. It seems to drain hv battery fairly quickly(20% overnight 40% to 20%) with the hv service plug pulled and the 12v battery negative pulled. I don’t understand, seems odd.

Yes, it does seem very odd. It supports the hypothesis that the BMS has some kind of battery pack "suicide" bug, or deliberate stupid "safety suicide feature", that is activated by a combination of conditions. So you left the battery disconnected and the service plug pulled for 12 hours of so?

The car still drives and charges?

 

[Vincent Rapide]

Two threads here on the same issue, maybe combine them?
--

 

[jzchen]

12 V replacement instructions are in the owners manual. Ran across it in the '15 ED manual. No HV service disconnect mentioned.

Regarding care for the HV battery:

Don't leave it discharged or almost completely discharged for 14 days or longer, or was it over 14 days? Otherwise might be permanently damaged. Try not to charge it at 80% or higher, nor let it drop below 20% before recharging.

Sent from my moto g(7) power using Tapatalk

 

[RudyK]

Has anyone tried to remove the 12v battery from a 2018 Smart Fortwo? The space above the battery appears to be too small to accommodate the removal.
The 2017 Smart has a larger opening above the 12v, unlike the 2018.

 

[Jo e Lefors]

I know I have seen discussions about it on the forum recently. You may have to use the forums search feature, if you don't have an owners manual.
Good luck