DCDC Charge Fault

[OrangeKayakTom]

Good afternoon all.
Long time lurker, first time poster.

I have a pre-facelift MG5 LR (excite) which I've had since new. (2022)

Last weekend my wife plugged it into our Hypervolt charger overnight. When she came to use the car the next day the charge hadn't finished and the car was giving a DCDC CHARGE FAULT on the dash.

I have tried disconnecting and charging the battery then reconnecting and resetting any fault codes. The fault remains.

I have checked both the 5A and 150A fuses listed as CCU in the manual and they both have continuity.

I have it booked in with a dealer next month but was wondering if anyone has any information/tales/advice about this fault. I've seen two threads on here which are very much a tale of woe but if anyone knows anything I would appreciate it if you could reply with your experiences.

 

[5teep]

Try it on another charger, both AC and DC, see if it's the car or your charger at fault.

 

[MickeySw]

Last weekend my wife plugged it into our Hypervolt charger overnight. When she came to use the car the next day the charge hadn't finished and the car was giving a DCDC CHARGE FAULT on the dash.

If real, this basically means all low voltage power is supplied by the 12V aux battery. To verify, check the voltage displayed on the dash or even better, measure it across the battery terminals when the car is READY.

Beware, the 12V battery is constantly drained while driving, once it’s voltage goes below a certain level, the car will simply shut down ..

 

[OrangeKayakTom]

Try it on another charger, both AC and DC, see if it's the car or your charger at fault.

I should have put in the original post that I have tried another 32Amp AC charger and have tried the low current 13amp 3 pin charger, neither of which charge the car.

 

[OrangeKayakTom]

If real, this basically means all low voltage power is supplied by the 12V aux battery. To verify, check the voltage displayed on the dash or even better, measure it across the battery terminals when the car is READY.

Beware, the 12V battery is constantly drained while driving, once it’s voltage goes below a certain level, the car will simply shut down ..

Yep. This is the case. Having charged the 12V battery whilst disconnected the voltage was around 12.8V. it is now around 11.7V so it is not being charged from the larger battery when the car is on.

 

[MickeySw]

Yep. This is the case. Having charged the 12v battery whilst disconnected the voltage was around 12.8v. it is now around 11.7v so it is not being charged from the larger battery when the car is on.

Looks like the CCU is faulty and needs replacing, The car may still DC charge and drive, provided you recharge your 12V aux battery externally.

 

[Coulomb]

I highly recommend charging the 12V battery with a standard 12V car battery charger. The longer it spends below about 12.0V, the shorter its life will be. It only has a 12 month warranty. If the 12V battery is healthy and full, it should be safe to drive the car to the dealer, assuming it's not too far (say a half hour drive, preferably less). Possibly via a fast charging station, but note that it still won't charge the 12V battery, as that's the CCU's job, even during a DC rapid charge.

 

[dragon2611]

I highly recommend charging the 12V battery with a standard 12V car battery charger. The longer it spends below about 12.0V, the shorter its life will be. It only has a 12 month warranty. If the 12V battery is healthy and full, it should be safe to drive the car to the dealer, assuming it's not too far (say a half hour drive, preferably less). Possibly via a fast charging station, but note that it still won't charge the 12V battery, as that's the CCU's job, even during a DC rapid charge.

Should probably try to minimise 12V loads as much as possible as well, so ideally no lights, fans/radio .etc (weather permitting)