Jump starting an electric car

[Robert Atkinson 2Participant @robertatkinson2]

I went to the Thorpe Camp (Lincolnshire) Amateur Radio Rally yesterday. Bought an Enots 5D oil gun for the ML7.
I did have one “first” not related to model engineering:
I “jump-started” an EV. Not a Tesla, a Hyundai. Owned by the seller next to me. Somehow over 4-5 hours they discharged the 12V lead-acid auxillary battery. That meant they could not turn it on! The battery was down to 5V. I was in SWMBO’s Ford Focus (2l petrol). He asked for a jump start. I pointed out it was a bit risky but he said it was OK. Not that he knows about the car, he was looking for the alternator…
Not sure how the car lets you flatten the 12V battery when there is charge in the traction battery either. Sounds like a design flaw. Owner thought that the traction battery was 48V…. He did not appear to have any radio kit connected.
Anyway after 10-15 minutes of connection to my running car his battery was up to 12.6V. I disconnected the jump leads and they were able to turn the car on. Thete was plenty of charge in the traction battery.
Apparently if you let the Aux battery in some Teslas go flat the car has to a dealership for “repair”.

Robert.

[HopperParticipant @hopper]

Yes he was lucky it was not a Tesla. From what I have seen at YouTube University, you can’t unlock the doors, or even open the bonnet,  or do anything at all if the 12 volt battery goes flat. It required dismantling half the car to get to the battery to change/charge it.

[Pete RimmerParticipant @peterimmer30576]

The 12v battery is charged by an inverter when the vehicle is ‘running’ i.e. turned on and ready to drive. All the guy had to do was turn that vehicle on and make sure someone/something is in the driver’s seat and the traction battery would provide charging power for the 12v battery.

I leave my Toyota EV van standing for long periods and I have to do this because of the tracker and dashcam being permanently ‘on’. I dump a heavy bag on the seat and spend the time washing it.

[Chris GunnParticipant @chrisgunn36534]

That just happened to me with my Hyundai Santa Fe hybrid, put it to bed fully charged as I thought, 300 miles driven the previous week, in the morning nothing at all. Could not get in it, Hyundai rescue (the AA) jumped it for me, and I asked what he thought drained the battery, and he said it could have been trying to do an upgrade and constantly looking for a connection and this could flatten the battery. My wife reminded me that the day before BT installed an optical cable. With the new terminal box on the inside of the wall next to a power socket. Thus meant the router had to be moved to the window ledge, and the closest thing to this to it on the other side of the wall is the car, so was the AA man right?

If you are considering Voip, BT will want to site the new terminal box next to a socket, ours needs 3 sockets, 1 for the new terminal box, 1 for the router, and 1 for our phone base station, so bear this in mind, your sockets might not be where you want all the new stuff. On the bright side, the Internet is now much much faster.

Chris Gunn

[Hopper]

On Hopper Said:

Yes he was lucky it was not a Tesla. From what I have seen at YouTube University, you can’t unlock the doors, or even open the bonnet,  or do anything at all if the 12 volt battery goes flat. It required dismantling half the car to get to the battery to change/charge it.

The two most popular Tesla’s are the Model 3.

[Hopper]

On Hopper Said:

Yes he was lucky it was not a Tesla. From what I have seen at YouTube University, you can’t unlock the doors, or even open the bonnet,  or do anything at all if the 12 volt battery goes flat. It required dismantling half the car to get to the battery to change/charge it.

And the model Y.

[Hopper]

On Hopper Said:

Yes he was lucky it was not a Tesla. From what I have seen at YouTube University, you can’t unlock the doors, or even open the bonnet,  or do anything at all if the 12 volt battery goes flat. It required dismantling half the car to get to the battery to change/charge it.

There’s also the Model X.

 

[Hopper]

On Hopper Said:

Yes he was lucky it was not a Tesla. From what I have seen at YouTube University, you can’t unlock the doors, or even open the bonnet,  or do anything at all if the 12 volt battery goes flat. It required dismantling half the car to get to the battery to change/charge it.

Model S.

[HopperParticipant @hopper]

 

[HopperParticipant @hopper]

Tesla #1

[Pete Rimmer]

On Pete Rimmer Said:

The 12v battery is charged by an inverter when the vehicle is ‘running’ i.e. turned on and ready to drive. All the guy had to do was turn that vehicle on and make sure someone/something is in the driver’s seat and the traction battery would provide charging power for the 12v battery.

I leave my Toyota EV van standing for long periods and I have to do this because of the tracker and dashcam being permanently ‘on’. I dump a heavy bag on the seat and spend the time washing it.

I ask merely for elucidation, if you can’t get the doors open, how do you switch it on?

[Hopper]

On Hopper Said:

Tesla #1

So do you retract your statement that half the car needs to be dismantled to change the battery or not? Posting videos of other issues doesn’t cut it.

[Vic]

On Vic Said:

On Hopper Said:

Tesla #1

So do you retract your statement that half the car needs to be dismantled to change the battery or not? Posting videos of other issues doesn’t cut it.

Mmmm, nope.

[Ian McVickersParticipant @ianmcvickers56553]

I have an Ioniq and have had the flat battery issue a couple of times. Leaving the boot open while you clean the car is enough to kill the small battery. I now have a portable battery in the glove box just in case it happens again. Just for info if you need to jump start one then once the electronics have started you can disconnect the car from the jumper as its no longer required. All the small battery does is power the system and bring in the traction battery. Once its on it will happily power everything and recharge the small battery.

[V8EngParticipant @v8eng]

So a vehicle costing many thousands of pounds with a monster battery pack supplying several hundred volts needs a little separate battery to make it work!

[duncan webster 1]

On duncan webster 1 Said

I ask merely for elucidation, if you can’t get the doors open, how do you switch it on?

On my van you just put the key in the lock in the door and turn it just like any other car with door locks. Pop the bonnet and you get access to the service (12v) battery.

 

[duncan webster 1Participant @duncanwebster1]

According to Hopper with a Tesla, flat 12v means you can’t unlock the doors, hence my query.

[Michael GilliganParticipant @michaelgilligan61133]

https://youtu.be/mSPKP5C7CE0?feature=shared

https://www.youtube.com/watch?v=mSPKP5C7CE0

 

Grrr!! … still can’t work out how to embed the video !

Both of these should point to a $5 Fix

MichaelG.

Edit: __ sussed it … very easy, albeit counter-intuitive

 

.

[NealebParticipant @nealeb]

One of my local club members had the same problem, again due to leaving the boot lid open without noticing for the morning. Ended up calling the AA as he wasn’t sure about jump-start procedure. I believe he discovered this when he was sitting in the car, turned on the ignition, and nothing happened. Can’t remember now the make of car.

However, it does seem reasonable that, at least while the car is not in use, the traction battery is not used to top up the 12V battery. After all, if the car were left for a week or two, say, you could come back to it with not just the inconvenience of a flat auxiliary battery but a flat traction battery as well which would be a touch more problematic.

[Chris GunnParticipant @chrisgunn36534]

Ian, saw your post about the Ionic, I guess my problem could be the same, left the boot open while unloading some plants, and dragged the floor mat out a bit, when I pressed the blipper to shut the boot and walked away, it did not shut and opened again, unnoticed by me for several hours. I guess that could have done it. Anyway I would be interested to know what small battery you keep in the glove compartment, and how you deploy it. IE do you open the bonnet and jump the battery, then open the door with the key, or will the blipper work once the car is jumped?

Thanks Chris Gunn

[duncan webster 1]

On duncan webster 1 Said:

According to Hopper with a Tesla, flat 12v means you can’t unlock the doors, hence my query.

Oh I see. I don’t know about that. I drive a Toyota and was referring to a guy with a Hyundai. Not sure why you would ask me about how to open a Tesla.

[Ian McVickersParticipant @ianmcvickers56553]

Chris the battery pack is similar to a “Duracell 1100A Li-Ion Jump Starter”. Open the car then pop the bonnet. Clip the battery pack on to the battery then press the car start button. Once it powers on simply disconnect the battery pack. The small battery will be charged from the high voltage one. There was an issue with the ioniqs a while ago regarding the small battery discharging even when the car was properly locked, all door closed and all lights off. I believe the issue was with the car checking the small battery once every 24 hours then recharging it if needed. But as the car never really fully turns off power will still be drawn. Happened to me once. Enough power to unlock the car but nothing else. This was solved by Hyundai changing the software to check the battery several times per day and recharge it.

[Pete Rimmer]

On Pete Rimmer Said:

On duncan webster 1 Said:

According to Hopper with a Tesla, flat 12v means you can’t unlock the doors, hence my query.

[…]  Not sure why you would ask me about how to open a Tesla.

I suspect that Duncan was really asking the forum at large

… which is why I provided the answer.

MichaelG.

[Robert Atkinson 2Participant @robertatkinson2]

ISTR there was a similar problen with the early Porsche Boxsters. Rear engined the battery was in the front. The bonnet release was electrical. So if the battery went flat you coud not access it. I think the solution was taking the rear undertray off and connecting to the starter motor. Later versions had a manual release in the wheel well

[Chris GunnParticipant @chrisgunn36534]

Ian, thanks very much for the comprehensive info, just what I wanted to know. I will get this sorted out, as I would hate to be stranded over something so simple to fix.

Chris Gunn

[Author]

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