charging my i3 with extended cable 220volt

Hi, i got a question, in my garage sometimes my parking space is full, so the cable cannot reach the electrical outlet (220volt) , can i use extended cable 3-4 meters to extend the cable.. will it damage my battery? is it harmfull for the car , please help.. my car is 2015 i3 full electric version.. thank you

depechemode said:

Hi, i got a question, in my garage sometimes my parking space is full, so the cable cannot reach the electrical outlet (220volt) , can i use extended cable 3-4 meters to extend the cable.. will it damage my battery? is it harmful for the car

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Using an extension cord with your charging cable isn't recommended by BMW. However, doing so wouldn't damage your car's battery pack or your car directly. BMW's concern is that an extension cord could cause a fire which could damage more than your car.

To be safe, the extension cord should be high-quality and must be rated to conduct at least 25% more current that your charging cord delivers because it's doing so for several hours during which time it could become hot. If that's 10 amps, the extension cord should be rated to conduct at least 12.5 amps. The outlet into which you plug the extension cord should be in good condition (i.e., no corrosion or loose wires that could cause electrical resistance and thus heat). Don't coil the extension cord while in use because that could make it hotter. The first time you use a new extension cord, it would be wise to check it periodically to ensure that the plugs and wires aren't getting dangerously hot.

Many people use an extension cord as you are proposing by taking the appropriate precautions.

thanks for the answer!

You want one with the cable wire gauge of at least 12g and have good quality plug and receptacles.

Yea, don't just plug in a new setup and forget like i did and almost burn the house down.

justanotherdrunk said:

Yea, don't just plug in a new setup and forget like i did and almost burn the house down.

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is it the extention that burnt or the original cable, didnt get from the picture

gdepechemode said:

is it the extention that burnt or the original cable, didnt get from the picture

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Neither the extension cord nor the BMW charging cable burned. This is a photo of the North American electrical receptacle into which the extension cord or charging cable had been plugged. The receptacle had been removed from the wall revealing house wiring that had dangerously overheated after charging his i3 (I assume that the i3 owner had detected an overheating receptacle or smelled the burning wiring insulation). The problem was likely a loose or corroded connection of the house wiring to the receptacle that had not caused problems before charging because most electrical consumers plugged into this receptacle had not consumed as much electrical current continuously for such a long period. Because the current that flowed was less than the circuit breaker's rated value (likely 15 amps), the circuit breaker could not protect this wiring and receptacle from being damaged. This is why when using an electrical circuit for EV charging the first time, all electrical plugs, receptacle, and exposed cables should be checked frequently for overheating.

and i got another question , if i leave the 220v cable connected to the power outlet when charging complete... will it be a problem?
maybe an overcharge problem? or an battery heating problem ? or will it stop the charge and its ok?

im curious about leaving the cable on the car after charging complete...

I can't quite see the scale, but that sure looks like a standard American 110V outlet, no? And you somehow plugged a 220V "extended cable" into this? No wonder it melted!
BTW, for over a year I charged overnight with a 50' 110V 10-gauge extension cord, no problems.

i3an said:

I can't quite see the scale, but that sure looks like a standard American 110V outlet, no? And you somehow plugged a 220V "extended cable" into this? No wonder it melted!

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Ah, a misunderstanding! justanotherdrunk posted his photo of his American 120V outlet after it had been used to charge his i3 using his 120V American OUC as an example of what could happen if depechemode tried to charge his i3 using his 230V Turkish OUC if depechemode wasn't careful in his choice of outlet, charging circuit, extension cord, etc.

depechemode said:

and i got another question , if i leave the 220v cable connected to the power outlet when charging complete... will it be a problem?
maybe an overcharge problem? or an battery heating problem ? or will it stop the charge and its ok?

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As your battery pack nears full charge, your car will send a signal to your charging cable to decrease the charging current. When your battery pack reaches full charge (actually 97% of its theoretical maximum charge), your car will send a signal to stop charging. So even though your charging cable is still plugged in, it will not continue charging unless the car sends a signal to do so. This could happen if you have enabled battery pack or cabin preconditioning which would cause the battery pack's charge level to drop.

So leaving your charging cable connected won't overcharge or overheat your battery pack. However, many battery experts believe that leaving a Li-ion battery pack at high charge levels for extended periods of time could increase its degradation rate thus shortening its usable life. BMW has created a 3% charge level buffer above which the i3's battery pack cannot be charged, so there is some built-in protection against this degradation. BMW must feel that repeatedly charging and leaving an i3's battery pack full will not reduce the battery pack's capacity sufficiently during its warranty period to require a warranty replacement. For the U.S., the capacity is guaranteed not to degrade more than 30% during the 8 year/100,000 mile (160,000 km) warranty period.

Some of us who hope to keep our i3's past the battery warranty period try to treat our battery packs as kindly as possible to minimize degradation, so I fully charge only when I anticipate needing the full range. I try to complete my full charges as shortly before departing as possible to minimize the time period during which my battery pack is fully-charged. Understandably, many i3 owners don't want to bother with such considerations and charge their i3's like they charge their smartphones: charge every night so they are fully charged the following morning. It's too early to know for certain which approach might result in longer battery life.

One thing to consider, though, is that once the battery capacity does degrade enough to suggest a replacement, that replacement is likely to be MUCH higher capacity, and probably cost less. Given that, I don't worry about it. Tom's experience over 56K miles seems to indicate that it isn't a huge problem that needs to be addressed. It's nice to have the full capacity in the car when leaving in case your plans change along the way.

Note, though, that it is the car that adjusts how much current it wants, not the EVSE. The only two things coming out of the EVSE are power and the pilot signal that tells the vehicle the maximum it can draw, but it is the vehicle that then decides how much and when the power is applied...sort of like a lightbulb, even if only a 40W bulb, it still works with a 15A supply without damage. Think of the car's logic as having a dimmer circuit that can throttle back the max power from the EVSE into whatever it currently needs up to and including telling the EVSE to shut off the power.

A CCS unit, on the other hand, does need to adjust it's output as it's essentially going directly into the batteries, rather than the acv from the EVSE that is going into the vehicle's power supply. Another reason why it must cost lots more than an EVSE.