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I left the lights on and drained the battery. I tried to charge the 12 volt battery - can I now put the car on the EV charger or could this hurt the vehicle if the 12 battery is dead?
 

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What specifically do you mean by "tried to charge the 12 volt battery"?

Plugging the car to a charging station or adapter with a dead 12V battery will not hurt the car - it just won't charge until the 12V battery has been separately charged so it has enough voltage to turn on the control systems.

You need to get to the 12 volt battery connected a charger - or jump it from another car. As soon as the 12 volt battery is charged a bit, turn the key and the car should "turn on" and the battery will be charged the rest of the way from the traction pack and DC-DC converter. It is just like jumping an IC engine car, starting the engine, then letting the alternator charge the battery the rest of the way.
 

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What specifically do you mean by "tried to charge the 12 volt battery"?

Plugging the car to a charging station or adapter with a dead 12V battery will not hurt the car - it just won't charge until the 12V battery has been separately charged so it has enough voltage to turn on the control systems.

You need to get to the 12 volt battery connected a charger - or jump it from another car. As soon as the 12 volt battery is charged a bit, turn the key and the car should "turn on" and the battery will be charged the rest of the way from the traction pack and DC-DC converter. It is just like jumping an IC engine car, starting the engine, then letting the alternator charge the battery the rest of the way.
I used a small car jumper (Halo) after I opened the 12-volt battery compartment under the pass floorboard. I didn't get any indication that the electronics of the dashboard were getting power. I still don't know how it ran down the battery in the first place. The car was parked for a few days, the key was off, the car was locked, lights were possibly left on, but I don't think so. Could this be a fuse issue? IF so, how would I check that out? Thank you so much for your quick response!
John
 

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Step 1 is to put a test light or meter on the battery. If the test lamp glows brightly, it's a fair chance that the battery isn't the problem. (A meter showing over 12V is also an indication, but the battery could have an internal fault that might still allow a 12V reading without being able to provide enough current to run the car.)

Test light is better. Ground one end of it, and probe the positive post, then over any fusible link, then over to the fuse panel, etc.
 

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Check/replace the 12v battery. My 2014 ED had the 12v die after sitting for 3-4 days to the point of zero response or lights. I jump started it and got lots of error messages but car was drivable. Battery wouldn’t charge even after a 30-40 minute drive. Had to use jumper box to start car each time.

This happened with zero warning signs.


Sent from my iPad using Tapatalk
 

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Discussion Starter #7
Could this be a fuse?

I've tried to jump the 12V but I am not getting any dash lights to come on at all. Could there be a fuse that is preventing the power from reaching the control systems?
 

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I've tried to jump the 12V but I am not getting any dash lights to come on at all. Could there be a fuse that is preventing the power from reaching the control systems?
I had to look up what a "Halo" is. Its claimed "57,720 mWH" (i.e. thousanth-of-a-watt-hour) of power is in more plain language, 57 watt-hour or a minuscule 4 1/2 amp hour at 12.5 volts. That can't begin to charge a completely dead car battery which can be 50 to 100 amp-hr.

Sure, it might have the current capacity to provide the 150 amps for a few seconds to turn a car starter, but that does not mean it has the energy storage to charge a totally discharged car battery to any degree.

So....

Buy or borrow a voltmeter/multimeter and check the battery voltage. 13.5 or so is fully charged, but anything over 12 volts should be enough.

If voltage is low, try jumping it using ordinary jumper cables from another car. Watch the polarity! Leave them connected and the other car engine running for 10 minutes.

Alternatively, buy or borrow a 12 volt battery charger (a little few-amp one will do) and leave the charger connected until the battery is charged.

If the battery is dead and the car has been in below freezing temperatures then the electrolyte probably froze (it is plain water when 100% discharged.) and the battery is ruined.

I think I recall that the battery positive terminal has fuses? I doubt any fuse blew, and if it did, it indicates a bigger problem.

If the battery is good, then it could be a wiring harness fault. Smart ED's have a history of wire chafing and breakage problems in the right rear quarter panel area - behind the interior trim in front of the right tail lights - but we are nowhere near checking those more serious differential diagnoses yet.
 

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If the battery is good, then it could be a wiring harness fault. Smart ED's have a history of wire chafing and breakage problems in the right rear quarter panel area - behind the interior trim in front of the right tail lights - but we are nowhere near checking those more serious differential diagnoses yet.

@Yinzer:
Dang, how often does this happen? I have a 2014 ED, can I add some sheathing to the wiring at that point to protect it from that issue?



I used a small car jumper (Halo) after I opened the 12-volt battery compartment under the pass floorboard.
@Anyone:
Is there a way we can make a SEC(sp?) plug come from the battery to make it easier to access/charge during days of non-use?


What specifically do you mean by "tried to charge the 12 volt battery"?

Plugging the car to a charging station or adapter with a dead 12V battery will not hurt the car - it just won't charge until the 12V battery has been separately charged so it has enough voltage to turn on the control systems.

@Yinzer:
Do you know how many watts the traction battery will provide for charging the 12v battery?
 

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Discussion Starter #10
Got it started!

I've tried to jump the 12V but I am not getting any dash lights to come on at all. Could there be a fuse that is preventing the power from reaching the control systems?
I had to look up what a "Halo" is. Its claimed "57,720 mWH" (i.e. thousanth-of-a-watt-hour) of power is in more plain language, 57 watt-hour or a minuscule 4 1/2 amp hour at 12.5 volts. That can't begin to charge a completely dead car battery which can be 50 to 100 amp-hr.
Thanks, Zinzer for the info regarding the type of 'jump start' the 12-volt system needed. I thought that the small jump assist units out there, like the Halo I used, would do it, but no, they won't. So i followed your advice and jumped it from another car. That did it! Turns out I still had 65% in the main battery but drained the 12 volt. Even better news for me is that the 12-volt battery has come back to life and has not failed to hold a charge for 2 weeks now. Love this board!
 

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Foolios: "Do you know how many watts the traction battery will provide for charging the 12v battery?"
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No, it would be a good thing to know, though. If you are thinking about a high-draw accessory, you are limited by the fuse for whatever circuit you are connecting it to though. And most accessories in the Smart are controlled by the SAM - damaging that is a very expensive repair.

"Dang, how often does this happen? I have a 2014 ED, can I add some sheathing to the wiring at that point to protect it from that issue?"
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I think the wear problem is primarily in the rear quarter-panel area - near the charge receptacle behind the plastic interior trim panel in front of the taillight access panel. The drivetrain control unit, the wires to the onboard charger, and a several wire bundles are packed in this space and one or two wire bundles can wear on metal frame parts in this area. It was bad design.
 

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Thanks, Zinzer for the info regarding the type of 'jump start' the 12-volt system needed. I thought that the small jump assist units out there, like the Halo I used, would do it, but no, they won't.
Happy to see the ordinary jump worked!

Besides the Smart, I find it hard to believe that these Halos can actually crank an IC engine car if a battery is completely dead. One would think that once connected in parallel with a much larger capacity dead battery, their voltage would sag too much to turn the starter. They might work with a marginally low battery maybe, but not a completely dead one like when you leave a dome light on for a few days.

Until I see one work myself, I'll file them under "gimmick". They way they give their capacity in milliwatt-hours to make the number look more impressive was the hint I needed.
 

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Foolios: "Do you know how many watts the traction battery will provide for charging the 12v battery?"
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No, it would be a good thing to know, though. If you are thinking about a high-draw accessory, you are limited by the fuse for whatever circuit you are connecting it to though. And most accessories in the Smart are controlled by the SAM - damaging that is a very expensive repair.
Thanks for the info about the harness wires. I'ma gonna add some kind of protection around the wires.

Well, I was thinking of drawing directly from the battery via a separate fused load. I don't wanna draw through any other wiring or accessory. I was hoping I could find out how many watts the traction battery will provide to keep the 12v battery from running too low. But then now that you mention it, I wonder if there is a fuse from the traction battery to the 12v battery. If so, that would tell me what the max watts I could draw before blowing that fuse.
 

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Well, I was thinking of drawing directly from the battery via a separate fused load..... But then now that you mention it, I wonder if there is a fuse from the traction battery to the 12v battery. If so, that would tell me what the max watts I could draw before blowing that fuse.
According to page 21 of the ED General Service Information (see one of the stickys above) there is a 12V charging prefuse between the power electronics control unit (in the engine compartment) and the battery. The physical location of the fuse or its value, I don't know.
 
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