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Discussion Starter #1
Anyone have any idea on what to do. Thanks to lockdown I have an Eq with both batteries flat. I can get in the car using the hidden keyhole, in the passenger door and with a bit of a struggle I have got the charger cable out of the boot as my tethered cable won't reach the socket. Next problem is the charge socket flap is electrically released so that's a no no. I can get at the 12v battery and could trickle charge it. Should I disconnect the battery before connecting a charger, and will charging the 12v allow me to open the charge flap.
 

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Yes you should disconnect the 12v battery to charge. Seems a bit frustrating that there is not a manual override for the charge port flap!
 

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The car wont do anything with a flat 12v battery as you have discovered. Even if the traction battery was 100% it wouldnt do anything with a flat 12v battery. After a good charge of the 12v battery it should come back to life.

Best of luck !
 

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Yes you should disconnect the 12v battery to charge. Seems a bit frustrating that there is not a manual override for the charge port flap!
Why do you need to disconnect the 12v to charge it?
Thanks to lockdown I have an Eq with both batteries flat.
How do you know both batteries are flat? If you can't power the car up how are you reading the traction battery?
In my view of the world you could jump start the 12v from another car and then leave it on or run it around to charge the 12v like an ICE with a flat 12v.
The best solution is to charge the 12v with a decent charge conditioner like a CTEC for 48 hours, but it depends on the time and kit you have.
 

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Why do you need to disconnect the 12v to charge it?
More safety / assurance than anything... There could be a lot of variables which could cause damage to the electronics in the car from unknowns such as the quality / voltage of the charger, accidently reversing polarity etc. It's usually simple / easy to just disconnect the battery terminals.

'Jump starting' many modern cars is ill advised - filled with risks these days, and likely not recommended on an EV at all. I could not find any clear documentation from Smart around doing this, but as with the above potential to damage any sensitive electronics I would always err on the side of caution given that time is not a critical factor here.
 

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Safety first, always sensible unless you own an MG. :p
I missed the OP setting a timescale. If they have sufficient time then I can't argue against the slow approach.
 

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Discussion Starter #7
The car wont do anything with a flat 12v battery as you have discovered. Even if the traction battery was 100% it wouldn't do anything with a flat 12v battery. After a good charge of the 12v battery it should come back to life.

Best of luck !
Thanks G.a.r.y. and all others. Bit pigged off by it, been checking it on a regular basis, but not been on road for a month, looks as though the traction battery can't top up the auxiliary unless the cars in use. Not a point that is made amongst all the other warnings and cautions you get. I'll get my son the essential worker, to bring over the beefier charger, we only have a 12v trickle charger, Don't think it would stand the inrush current when it's connected.
 

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Discussion Starter #9
Yes you should disconnect the 12v battery to charge. Seems a bit frustrating that there is not a manual override for the charge port flap!
Thanks, there will be! It hadn't occurred to me that I wouldn't be able to see the charge state indicator without 12v power, or that it would only get charged when the car was switched on.
 

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we only have a 12v trickle charger, Don't think it would stand the inrush current when it's connected.
Trickle is the best option. Don't worry about the charger.
As @Tandy0 says the trickle charger will cope even with a completely flat battery, just get it on charge ASAP. If either charger has a "float charge" use that to help the battery recover. Even with just a trickle charger 24 hours on charge should be enough to allow the car to start and power up the traction battery to prove that is ok.
 

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Discussion Starter #12
As @Tandy0 says the trickle charger will cope even with a completely flat battery, just get it on charge ASAP. If either charger has a "float charge" use that to help the battery recover. Even with just a trickle charger 24 hours on charge should be enough to allow the car to start and power up the traction battery to prove that is ok.
I'm just puzzled how you charge your car normally if your tethered cable won't reach the charge socket.
That does need an explanation Jeff - If I'm intending to charge it I reverse up to the house 5m of cable is a comfortable reach, This time i'd put the car in nose first and a foot or so short of the reach by the tethered lead. Easy you say just roll the car forward, "Drats". it's in Park and the stick is locked until the car is powered up. It really does stitch you up if the 12V is not there. My son is an engineer at JLR, he's bringing a charged battery, set of jump leads and a trickle charger. Fortunately that plastic patch on it's snout comes off with a couple of prods with the key. We plan to disconnect the negative, put the trickle charger onto the battery and then charged battery onto the positive and disconnected negative lead. That way we should be able to open every thing and check the state of the traction battery.
Fortunately Son has gone through the electric conversion training and is now cleared to train and asses dealership mechanics, hence my desire to sort this without recourse to the dealers.
 

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Discussion Starter #13
As @Tandy0 says the trickle charger will cope even with a completely flat battery, just get it on charge ASAP. If either charger has a "float charge" use that to help the battery recover. Even with just a trickle charger 24 hours on charge should be enough to allow the car to start and power up the traction battery to prove that is ok.
Some progress, once 12v charged, all panel indications working, traction battery shows 49%. When switched on with key I get an overdue service notification, it's just gone over 12 months old, followed by "Stop - Turn off motor" As it drove OK to the point where it has been standing, it's unlikely to be a mechanical fault, Might something need re setting? I'll ring the dealers tomorrow.
 

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A low 12V battery can trigger all sorts of errors in other EVs, so it's probably the same with your's. Once it's charged back up, the errors should go away
 

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I would add you should never charge the battery without leaving it connected to the charge-state-monitoring dongle that's on it when fitted to the car. If that's what you've done, the car ECU now thinks the battery is totally flat, despite it not being flat. You'll have to reset the battery adaptation to allow it to reassess the battery state (or something, not something I've ever done).
 
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