Dead Battery and Won’t Charge!

okohll · Jan 15, 2025

Sam S said:
Hi, I got my car in February last year and have been loving it until today!

I set it to charge last night as it was just over 30% and this morning it is frozen up, stopped charging in the night at some point and is not responding. I assume the battery is now dead due to the cold, or needs to warm up before it can respond. I managed to unlock it and got in but the screen won’t come on so I can’t tell it to start charging and my charger won’t start again until the car responds……

Has anyone got any tips please on how I can get it charging? This has got me quite worried as it has been fantastic till now, but this is the first really cold spell since I got it and fortunately I don’t have to go anywhere this morning, but it should be ready any time to get in and go.

Thank you .

I can understand the 12V battery dying but during charging seems a strange time for it to happen. Isn't the car supposed to charge the 12V from the main battery during use or charging? I thought the most danger of a dead 12V would be from coming back to the car after it had been sitting idle for a while.

siteguru · Jan 15, 2025

My car is charging right now, and the app shows the 12V battery voltage as 14.3V. So yes, the 12V battery should be charged when the HV battery is charged.

dsimpkins · Jan 15, 2025

okohll said:
I can understand the 12V battery dying but during charging seems a strange time for it to happen. Isn't the car supposed to charge the 12V from the main battery during use or charging? I thought the most danger of a dead 12V would be from coming back to the car after it had been sitting idle for a while.

I believe that the car will not charge the 12V battery from the HV battery if the HV battery is below 50%. Quite a few people have been caught out by this from reading previous posts on the forum. I bought myself a battery booster and keep it under the passenger seat as a precaution against a low 12V battery.

Matt x power · Jan 15, 2025

I rarely let my HV battery Go below 50% also I sit in it for about 1/2 an hour before I start work.

Sam S · Jan 16, 2025

Lizibee said:
This has happened to me. I couldn’t get into my MG4 today. My son opened the car using the spare key. Need to jump start the car now after reading this post.

They don’t tell you this when they sell you the car

. I thought I’d really done my homework on the ins and outs of buying an electric car before deciding to get it. I even showed the MG salesperson where the speed limiter is, after being told it definitely does not have one.

We are away presently and I really hope my car starts when we return….. I’ll worry about it when we get back and will order a better battery jump starter for future

. Hope you got your car sorted.

Martinonline · Jan 16, 2025

I have posted about my travails when I found my 12V battery was below 12V and the battery charging warning icon came on. (HV battery at 80%.) I could not charge AC or DC until I boosted the 12V battery. (I've had no problems since.)

The original poster set a charge. When the charge started if 12V battery charging circuit failed to connect then the 12V battery would have drained and caused their problems.

Because the car is so dependent on the 12V battery it would be useful to have a notification if the charging circuit failed.

JonnyG · Jan 16, 2025

Martinonline said:
............Because the car is so dependent on the 12V battery it would be useful to have a notification if the charging circuit failed.

This 12v battery tester is on offer at Amazon at the moment and may be worth adding to the "emergncy kit". If you apply the 50% coupon discount (valid until 19th Jan) it comes out at just £9.99 with quick delivery for Prime members (usually around £39.99)

It can estimate the 12v battery's health as well if you input some battery info.

I think it's a mistake as they are offering a 50% discount on an already discounted price !

It comes with a nice zip case too !

https://www.amazon.co.uk/gp/product/B0CCTB8P9C/

okohll · Jan 16, 2025

dsimpkins said:
I believe that the car will not charge the 12V battery from the HV battery if the HV battery is below 50%. Quite a few people have been caught out by this from reading previous posts on the forum. I bought myself a battery booster and keep it under the passenger seat as a precaution against a low 12V battery.

Good to know that's the case even when charging I guess. A particularly stupid bit of coding if I may say but what can we do.

Dead Battery and Won’t Charge!

okohll

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siteguru

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dsimpkins

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Matt x power

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Sam S

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Martinonline

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JonnyG

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okohll

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