I often joke with my wife that the only reason I keep her around is for her blood, (this is very-much a bad joke so please don’t get upset). Being Type O-Negative, she can donate to me in a pinch even though I can’t reciprocate with my inferior A-Negative blood. All this joking about blood-types got me thinking about a different type of “donation.” We are a mixed-car family. I, being the courageous eco-warrior that I am, drive an environmentally friendly all-electric (EV). She drives a gas-guzzling, earth-destroying SUV. It’s amazing that still we’re still a couple! Sarcasm notwithstanding (and this entire paragraph has been nothing but sarcasm, so far), I have often wondered what would happen if my EV ever ran out of juice at the wrong time. Could my lovely wife come to my rescue with her SUV and a pair of jumper cables and jumpstart my electric car?
The answer is: kind of.
See, electric cars contain two batteries and, by extension, two electrical systems. The first is the large, high-voltage battery pack that powers the motors that drive the car, and the second is a “standard” 12-volt electric battery much like the ones found in gas-powered vehicles. That smaller battery operates on its own circuit, and is used to keep electronic features such as clocks, seat positions, and remote door locks in a responsive state when the car is turned off. Critically, though, that 12-volt battery also powers the car’s ECU and CAN bus (a series of sensors and controllers throughout the car), and the car absolutely will not go without an “OK” from the ECU.
Now, if you run that main battery down by, say, driving the car until it’s out of juice, then no. No, you absolutely should not try to “jumpstart” an electric car whose high voltage system has been drained and “limp it home” or whatever. Not only is it nearly impossible to do without specialized equipment, it can be incredibly dangerous without the proper training. As such, if you drive your EV to “empty”, the only reasonable option available to you is calling roadside assistance. You should never Never NEVER adjust, connect anything to, or mess with the larger, high-voltage battery and its connections in any way. (You’ll die.)
That said, driving an EV to “E” isn’t the only way it can get immobilized. Let’s say, for example, you parked your car for the weekend with some usable range left in the high voltage system, but happened to leave one of the doors ajar or one of the map lights on over the weekend and the car won’t start when you come out to the garage on Monday morning. Those lights are powered by the 12-volt battery and are on the 12-volt circuit, and you CAN jumpstart the 12-volt system by using another, conventional ICE/hybrid car.
You’ll probably have to consult your car’s owner’s manual to find this battery in a modern EV, and it can be pretty hard to find because it won’t be located under the hood as it is in a traditional vehicle. You should also look to the EV’s owner’s manual for exact instructions on how to connect the jumper cables to the battery, but it’s straightforward enough. The first step is to make sure the EV is off. To repeat, the electric car must be fully OFF and UNPLUGGED from any wall socket or charger in order for this to ensure everyone’s safety. Once the cars are lined up and the 12-volt systems are connected, the gas-powered or hybrid car providing the jumpstart needs to be started first, before the EV is switched on.
Once the EV’s electronics come online and everything is communicating, the high-voltage system can get the OK it needs from the ECU to start and go– and (assuming everything is working as it should be) the going is what will charge the 12-volt system.
It’s important to note here that simply getting the car “on” and leaving it in your driveway won’t do the trick like it would in an older, conventional car. The 12-volt system is charged under load, and (in many cases) does not re-charge from being plugged into the wall so you’ll need to drive the car for a few minutes (15-30) in order to get some juice into the 12-volt. If you turn the car off with some good range left over in the high-voltage system and find that it won’t start again, even after several miles of normal driving, it might be because the 12-volt battery has been damaged, and you should contact your dealer or a qualified service station to test it and, if need be, replace it.
So, that’s what I mean by “Kind of.” And, if a life-partner with a traditional car is not available to help with a jumpstart when you find your EV stranded, there is still hope for stranded EV drivers. Since 2011, AAA has maintained a fleet of trucks capable of recharging both types of batteries found in standard EVs. These trucks carry a fast charger that can add around one mile per minute of charge to the main battery, as well as conventional 12-volt jumping systems. Early reports indicate that their trucks aren’t being used as much as their initial estimates predicted, because EV drivers tend to be more conscious of range than ICE drivers. I, myself, have never run out of charge (although I’ve come very, very close), but it is nice to know that I won’t be stranded forever if I ever do. What do our readers who own EVs think? Have you ever run out of juice on the side of the road? How did you get out of your predicament? We would love to hear your stories in the comments section below.
Source | Image: Original content from Enrg.io; AAA.