Flat 12v battery

I have just joined in the hope of getting some help but I cannot find how to post my question.

I am in isolation and just found out my EQ for two battery is totally flat. The App said it was 98% charged. My problem is the central locking appears to be locked on preventing me from opening the charging port flap. I got into the car manually using the passenger manual opening but the central locking button seems to also work off the power so will not disengage the lock. I am a new driver of EQ so find it strange that everything locks and not opens when the battery goes flat. I seek someone’s advice on getting the flab open so I can charge the car. Many Thanks

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Welcome Gareth

Can you get to the 12V battery and either Jump Start it (slave itto another 12v battery) or take it out and charge it up. EV’s have very small 12v Batteries that soon go flat if the car is not used. Unfortunately having let the 12V battery go completely flat is will have again, but quicker. A another couple of time and you will need to replace it.

Do you know why it went flat, ie. left something on drawing a small amount of power for a while?

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yep like osbrook said its your 12v battery thats dead , mine expire on my smart ED just at the three year mark , the accessory batteries on all EV seem to be the weak point if they are not daily driven. The bonnet on my ED forfour is held in place by two plastic catches so access to the front is easy , two fabric straps stop the bonnet from falling off but need to be removed to fit the new battery. I disconnected the old battery for 30 minutes and then removed it and fitted the new one , i had no issues.

I had to buy a new battery because one of the cells was dead in my 12V battery , my local smart garage quoted a crazy price (£250) to replace and fit so i brought a battery from Halfords using my trade card.(£100)

Thank you very much. It was the 12 volt battery. It is surprising though that Smart have a all locked policy when this battery goes down. It’s definitely the weak spot as my electric car battery was 98%. Strange they do not direct some of the charge to charging the 12 volt battery when it goes low.

I charged the 12 volt. Ran the engine for an hour and then topped up the minor discharge on my electric car battery. Now all is fine.

Sorry I forgot to answer your question. I am in isolation so kept checking the electric car charge which was fine. I have to admit I did not realise there was a normal car battery as well.

How frequent and long should I run the engine as with lockdown I am going nowhere? Should I use a trickle charge from my charger?

Many Thanks

Gareth Don’t need to run it. But he main battery should be below 80% charged and 20% charged if you are leaving it standing. Obviously it is worth moving the car every few weeks to stop the ‘Square wheel’ syndrome.

The best bet is to put a trickle charger on the 12V battery for now.

im starting my ed one a week and moving it back and forwards for 10 minutes

Thanks. My drive slopes very slightly so I put a brick against the tyres and left the handbrake in off position. Is that ok? I have a trickle charger so thanks for suggesting that.

I wonder do you know the link to the user manual. I did not get one when I bought the car. When I search the user manual on the SMART site although the link says user manual it goes to sales.

handbrake off is smart , i never leave the handbrake on when any car is left over time.

i dont have an electronic version of the users manual.

Thanks. Found the user manual on the Mercedes app. No index though :). I have a 2018 EQ forTwo. Is the 12volt battery in a slot under the passenger side floor as the older Smarts?

i believe its in the passenger foot well , my forfour eq has it under the front bonnet.