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You need to check the voltage of the battery when the keyswitch is off.
When the key-switch is off AND the smart is not charging.
 

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Are you guys sure the 12V-thing for the cigaret lighter is worth it? The cigaret lighter is only activated, when the DCDC-converter is keeping the 12V circuit at about 14V. So it's never showing the voltage of the 12V-battery.
This is only mostly correct. My gauge will read battery voltage for the first 1-2 seconds the car is turned on. After that it reads the converter voltage. Specifically 11.2 - 12.1 volts when the car is turned on. Then 14.1 - 14.7 after the converter comes on.
 

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Couple things:

1. There should be no "hopefully" about the service they did on your Smart (especially for $540) you should have gotten a detailed statement on the work they did including the service campaign software update.

2. Since the cigarette lighter is only on when the car and the DC-DC converter (equivalent to the alternator in a IC engine car) is on, that 14.5 volts reading tells you nothing about the health of the battery. You need to check the voltage of the battery when the keyswitch is off. It should be at least 12.5 volts or so.
Thank you, ok make sense.

I contacted MB, apparently this update was already done but by the previous owner. Good thing!

For the voltage, thank you for this clarification, so my cigarette lighter thing is useless, at least for the smart electric... So I need to remove the carpet floor and the battery form every time I want to check... not cool... or find a way to have the cigarette lighter always connected, or simpler, have something like that
62362
always connected on the battery... but it will use energy (a bit) and drain the battery (if long time unused)... Probably a check every week will be the solution.
Thanks
 

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Thank you, ok make sense.

I contacted MB, apparently this update was already done but by the previous owner. Good thing!

For the voltage, thank you for this clarification, so my cigarette lighter thing is useless, at least for the smart electric... So I need to remove the carpet floor and the battery form every time I want to check... not cool... or find a way to have the cigarette lighter always connected, or simpler, have something like that View attachment 62362 always connected on the battery... but it will use energy (a bit) and drain the battery (if long time unused)... Probably a check every week will be the solution.
Thanks
This isn’t necessary. I get a read on the battery voltage every time I start the car using the meter plugged into my cigarette lighter. It takes 1-2 seconds for the converter to come on after I start the car - as I said in the post above.
 

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MY08 cabrio MY09 cabrio Brabus MY15 ED
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I just went to MB, (FYI it cost me $540 for the 40k/4y service) hopefully they did it.
$540 seems huge for an ED? Other than the desiccant cartridge what other high ticket part/service was done?

I ask only because my smart Center tried to sell me their flat rate Platinum “package” bundle which included an oil/filter change???
 

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This isn’t necessary. I get a read on the battery voltage every time I start the car using the meter plugged into my cigarette lighter. It takes 1-2 seconds for the converter to come on after I start the car - as I said in the post above.
Or alternatively, wires can be routed from the battery terminals to an more accessible check (and if necessary, charging) point under the service flap (aka the Smart's "hood"). That is what I did. And the voltage can be checked with an ordinary volt-ohm-multimeter which letoon does not seem to be aware exists. Boy - we are really seeing the effects of Radio Shack going out of business. A volt-ohmemter should be in everyone's toolbox if they have a toolbox at all.
 

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Or alternatively, wires can be routed from the battery terminals to an more accessible check (and if necessary, charging) point under the service flap (aka the Smart's "hood"). That is what I did. And the voltage can be checked with an ordinary volt-ohm-multimeter which letoon does not seem to be aware exists. Boy - we are really seeing the effects of Radio Shack going out of business. A volt-ohmemter should be in everyone's toolbox if they have a toolbox at all.
I miss Radio Shack. I find stuff on Amazon and only when I absolutely have to, Digikey(expensive). Where do you shop for your electronics?
 

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I have a voltmeter, thank you. I am simply looking for a way to check it daily/easily, without have to remove the carpet/form from the fortwo.
 

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$540 seems huge for an ED? Other than the desiccant cartridge what other high ticket part/service was done?

I ask only because my smart Center tried to sell me their flat rate Platinum “package” bundle which included an oil/filter change???
Agree, huge... but I just bought the car from Craigslist and want to be sure everything is ok. They changed the braking fluide also and the desiccant... still huge, agree. Anyway next time I will change the desiccant my self...
 

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I have a voltmeter, thank you. I am simply looking for a way to check it daily/easily, without have to remove the carpet/form from the fortwo.
I routed a pair of voltage check and charging wires from the terminals to under the service flap. An existing rubber wire harness gland near the steering column can be used to route the wires through the "firewall". The battery charging wires could prove invaluable if you find the battery dead with the car locked. The "manual" key lock on the driver's door is not actually a mechanical lock - it actuates a (battery dependent) switch(!).
 

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Discussion Starter #32
On my ICE cars I have never replaced a battery until it started having symptoms. Sometimes I'd go 10+ years with the same battery.

But do I need to change my thinking with the 12v battery in the EV's? We've got a couple of threads going now where leaving a dead 12v battery in the car might "brick" the HV battery and even though the HV battery might still be functional, there is no way anyone has come up with yet to put it back in service.

The 12v batteries on my two Smarts are each about five years old and reading 12.7v. I think they are both the originals, but here is an interesting note in the service record I got from the dealer before I bought the coupe.

"Radio left on by sales. Battery drained and had to be charged. Okay after charge."

Apparently that situation had no bearing on the HV battery.

Len
2014 EV Coupe 18,000 miles
2014 EV Cabriolet 12,000 miles
Okay, going back to my original post that started this thread. We now have two or three more cars where the HV battery is bricked or heading that way. Not sure if the battery update program that came out several years ago fixed this issue. Both of my cars have had the update. Unknown whether the cars "bricking" had the update or not.

So back to my original question. Is it wise to change the 12v battery after five or six years when there is no sign of a problem or do you wait for the 12v battery to give it up? I'm leaning to routine replacements.

Len
2014 EV Coupe 19,500 miles
2014 EV Cabriolet 17,000 miles
 

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My '09 is a gasser, so this may not apply. Since the battery in the 451 is not very accessible, I routinely change it about every four years. After the original, I have done two replacements and will be due again in a little over one more year. Maybe excessive, but I like the peace of mind.
 

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Discussion Starter #34
Thanks for your reply. If you lived closer, I'd take your four year old batteries and use them for several more years. :) Just kidding - we each need to do what makes us feel comfortable. Gas and diesels I drive until the battery tells me it's over, but there is no real downside to doing that. In the electrics though there seems to be a connection between the 12v battery going bad causing the $10,000 HV battery to brick itself. I think I may have convinced myself.

Len
2014 EV Coupe 19,500 miles
2014 EV Cabriolet 17,000 miles
 

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Thanks for your reply. If you lived closer, I'd take your four year old batteries and use them for several more years. :) Just kidding - we each need to do what makes us feel comfortable. Gas and diesels I drive until the battery tells me it's over, but there is no real downside to doing that. In the electrics though there seems to be a connection between the 12v battery going bad causing the $10,000 HV battery to brick itself. I think I may have convinced myself.
I am wondering also...I waited potential answer, I liked the idea of the update saved everything and didn't brick the battery... but if it's not true... My only idea is to keep an eye with the voltmeter weekly on the battery and check the voltage (I am handy, but I don't know anything about EVs...). What I know is my battery is from 2014 (never changed) and I should worry...
 

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Discussion Starter #36
Yeah, I'm due to service my coupe this spring and I'm leaning to just going ahead and replacing the original 12v battery. In these cars I guess maybe I need to think differently unless more info comes out about the update which I have had done on both of mine.

Len
2014 EV Coupe 19,500 miles
2014 EV Cabriolet 17,000 miles
 

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Car been sitting for a few days. Today cigar/voltmeter says: 12.0v . . 11.8v . . . 14.2v. Not good, time for direct action so hooked up tiny float charger thru passenger window. With luck this will maintain slowly dying 12v batt during my absence for a couple weeks.

63770



I had two different little float chargers on hand, both from Harbor Freight I believe. One has the usual long cord from the wall-wart to the device and its short clip leads. The other has only short leads; get the long leads. As seen above the 120vac plug/wall-wart is inside a juice bottle held onto the door handle with a hole punched & twistums. The 12v thin wires fit when window almost fully closed, still loose. So only low voltage inside car and the wind can't blow away.
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Discussion Starter #38
Living dangerously Vincent. Hope the chargers keep things alive until you replace that battery. Keep us posted.

Len
2014 EV Coupe 20,000 miles
2014 EV Cabriolet 18,500 miles
 

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I'm now thinking of not locking car in my absence so there will be no drain to run the Sentry system. Will that kill Sentry?
Any other power saving measures to take?
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I purchased a 2014 ED last December. It currently has around 30,000 miles. I’ve been reading a few threads like this one that talks about the 12v battery failing and bricking the HV battery. So today I decided to take a look my battery and it appears to be the original battery, with a date of 10/2014.

So now I have a couple of questions. As long as I replace it right away (within a day or two) is it okay just to wait until this battery dies? Or does it need to be replaced before it reaches that point?

Second question is how can I tell if my car has had the battery software update?
 
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