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Linkhttps://evilution.co.uk/mod/hashtag-power-system-failure.htm Copy to ClipboardYou get into your car after it has sat around not being used for a while and you see this message on the speedo.
Time to panic right?
Usually no but possibly yes.
What Causes It?
More often than not, it’s a low 12 volt battery has issues closing the HV contactors.
And If It’s Not The 12v Battery?
This is when you hope and pray that you still have a warranty because there’s an increasing number of reports of the rear motor on dual motor cars (Brabus, Pulse etc) failing. It never seems to be the front motor.
Contact smart to claim on the warranty and make sure you get a courtesy car because some people have waited months for a repair.
Fixing The Low Voltage Battery Fault
You have some options.
1 – You can leave it and come back later. It usually happens when the temperature is cold which can bring the battery capacity down. Waiting until the weather warms up can give the car enough power to start.
2 – Disconnect the battery earth lead for a few minutes. This can help it recover enough since there’s no drain on the battery.
3 – Get yourself a battery booster such as the NOCO Boost X. This is the one I bought. You just connect it to the battery and it’ll start fine.
4 – You can get a jump start from another car but I recommend against it as ICE cars tend to have a dirty 12v signal.
Why Does It Happen?
This happens for 3 reasons.
1 – The battery used is the cheapest one that Geely could buy in bulk.
2 – The battery is woefully undersized for the car.
3 – The charging dynamic for the 12v battery is terrible!
Charging Dynamic
I warned smart directly about this back in 2024 but I don’t think they will bother fixing it. I’ll show you the graph and talk you through it.
A battery will normally be above 12 volts when the car isn’t driving. When the car is used, the car will syphon off some of the 400 volt battery and transform it down about 14 volts. This is used to charge the 12 volt battery.
Heading to the graph, you can see that as I left home, the battery was at 12.75 volts and as soon as I started driving, the car began to charge it at 14.25 volts. As you drive, it lowers the voltage sent to the battery in steps. This is because the battery doesn’t require full power all the time. As it charges, the supplied voltage should go down and down until it’s enough to keep the battery charged and power the car. Expect that to be about 13.6 volts.
When you stop the car, the battery voltage peaks because there’s no drain from the car’s electrics.
I then put the car on charge. This is where smart have made a big mistake. All the time the car is charging, the car is forcing a continuous 14.3 volts into the battery, if it needs it or not.
My drive to work was 30 minutes and you can see the voltage being sent to the battery was decreasing. So, what it didn’t need was over 3 hours of continuous full power charging.
When I left work, because the 12v battery was over charged, it didn’t need any charging for the full 30 minute drive home. It stayed at 13.6 volts.
Battery Abuse
Car batteries don’t take kindly to this kind of abuse. I warned smart that this would cause electrical errors long before they started showing up in customer’s cars. It will also cause the 12v battery to fail prematurely. However, I suspect they don’t care because cars will be out of warranty or it’ll be cheaper to replace a load of 12v batteries than it would to recall cars to recode the charging dynamic.