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I usually drive low-mileage runs and could easily charge an electric car at home.

But what happens when I go on holiday? I charge the car at home, drive to an airport, then leave the car in a car park for 2-3 weeks. Assume the airport is something like 50-100 miles from home, so the trip uses around a quarter or half of the battery capacity. (I’m deliberately not specifying a model, as I haven’t even decided to buy electric, yet.)

The car park operator will not charge the car just before I return. I did ask an off-airport company and they said they had ‘no plans to provide charging facilities’.

I would not like to return on a long flight only to find my car not ready to get me home. Even worse would be if the car would not even start.

Has anyone considered this problem? Are there any workarounds?

EDIT Thanks for the interesting answers

I am unable to mark an answer as 'correct', I haven't even decided on an EV. This is not to say the answers are not correct, just that I cannot accept. I have up-voted.

Regarding the comment about taxis, I am in UK. I have quotes for £40 in an offsite car park near Birmingham (BHX) for three weeks; and for a taxi (one-way) for £65.

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    This isn't the best response and I'm assuming you've already considered it, but I'll mention it anyways just in case. Why not take a taxi, or ask a friend if they can drive you to/from the airport? Everyone I know does the latter anyways, since airport parking is expensive. – Kitsunemimi Feb 4 '20 at 16:50
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    Its not the car that copes, its the owner. – Moab Feb 4 '20 at 16:53
  • Welcome to the site. I'm voting to close this as off topic because it's not a maintenance question but a planning question. In any case the batteries in an electric car hold their charge far longer than a lead acid battery, I'd suggest researching that. – GdD Feb 4 '20 at 17:32
  • @GdD i think this is on topic here keeping the car charged is maintenance and failing to keep the car charged will lead to the need for repair so it is on topic. – trond hansen Feb 4 '20 at 18:47
  • Seems like a good question about maintenance to me and has received a very nice answer from someone with what sounds like experience on the situation. – – narkeleptk Feb 4 '20 at 19:32
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As an electric vehicle owner for many years, I've found that the traction battery does not have problems with long duration idle state. If you top up the battery before heading to the airport, it will have depleted enough to be in a good storage/safe level. My current vehicle charges only to 80% by default, avoiding the problems associated with 100% charging. I'd expect that your choice of current EV will operate in a similar manner.

Your concern about not starting is the critical one. If my vehicle sits unused for more than a few weeks, the starting battery (12v) can deplete due to parasitic loads. Today's vehicles have their share. Wireless key fob electronics, alarm systems, radio/clock/8-track players all drain the battery over time.

The convenience outlet, formerly known as a cigarette lighter operates only when the vehicle is in ACC or Run mode, removing the ease of use of a purpose-built car charging solar panel that would connect via such a feature. Our vehicle has a rear mounted outlet which is active at all times, but not the best location for a solar battery tender. If you are comfortable with the possibility of theft, one could attach directly to the battery, a battery tender type of solar panel and leave it outside.

For our previous EV, I used such a device, but placed it on the dash and allowed the exposed cable to transit between the hood and passenger door. I believe there was efficiency loss due to the glass absorbing some energy.

If the car park has a 110v outlet (USA, which I suspect is not applicable for you) that can be used, every EV is shipped with a low-power EVSE that would keep your vehicle topped off and keep the starting battery charged. I'm not sure how the system works on the other side of the big pond.

Even if you use a ride service, the vehicle at home will have the battery deplete. A new vehicle with a new battery should tolerate three to four weeks, but that's not a certainty.

One could also remove the cable from the ground terminal to remove parasitic loads. In our current EV, this causes no complications other than slightly dirty hands and a brief delay. Some motor vehicles, EV or ICE, are not happy to have the supply interrupted.

  • Thanks, the idea of a solar panel had not occurred to me. – Peter Bill Feb 8 '20 at 15:47
  • The 12V battery is usually only recharged by the DC-DC converter when the electric drive system is on (the contactors are closed). If the parasitic draw appears to be critical, you may be able to activate your cars auxillary heating from whereever you are. While this would waste some battery capacity, it will also enable the HV system and should therefore recharge the 12V battery as well. My EV (VW e-Golf 2019) supports this over its own mobile internet connection, meaning I could turn it on from anywhere in the world. – towe Feb 12 '20 at 14:40
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Not an answer, but more just in addition to what fred_dot_u has already mentioned.

I couldn't say about your local airport, but some airports have EV charging stations in their long-term lots, so it could be the case that you can just hook up there.

Also consider how much energy the EV batteries hold. They are meant to support HUGE draw and voltage to support the motors. Yes, when factoring how much you drive each day, this may not last long (e.g. 200-500 miles of driving depending on environment). Now, consider the relatively TINY draw from things like computers and accessory systems. An Engine Control Module will be in the hundreds of mAh usually (when not in use), things like alarms are also quite low when not actively sounding horns, clocks take 10s of mAh or less I believe. Pretty much ALL of the non-drive systems in an EV use very small amounts of energy compared to the drive system.

Just as an example (and I realize this will change a lot depending on the vehicle), a 100 kWh batter (like the Tesla models) would power a 15A draw at 12 VDC for about 23 days (just sheers numbers to number, not a real word example).

Again based on sheer numbers, this would be equivalent to leaving the cabin heater and cabin comfort system (with each circuit hitting continuous max draw) on for about 3 weeks! I couldn't find exact numbers of actual amp draw that EVs use when they're "off" but I'd imagine it's probably somewhere in the low single-digit amp range or lower. Probably will spike up to a few amps if the alarm is tripped or something.

In any case, my point is just that the amount of energy used at rest should be pretty small when compared to driving levels of use, and the batteries should store fine for a few weeks. Even just putting a completed vehicle on a boat and shipping it over seas, the vehicle could sit, unused, for upward of 30 days.

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    it's important to note that many EVs do not pull parasitic power from the pack. Nissan Leaf and Tesla S both have "starting" batteries as do the legacy Rav4EV and contemporary (2012-2014) models. I'd expect most of the current build of EVs have separate 12v batteries, hence the caution. – fred_dot_u Feb 7 '20 at 14:24

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