[six]

Yesterday I managed to trigger a ‘High Voltage System’ warning message on my 50e. Thought I’d share as it might help others who get this message/warning pop up.

I’d been out in the car and had my EcoFlow power bank with me which I was charging on the return to home journey with the 12v lighter cable plugged into the boot socket.

When I got home I put the X5 on charge and forgot the EcoFlow was in the boot. Back in my old 40i once the car was locked the boot socket shut down after ~ 10 min. However, it seems the 50e keeps the boot socket live while the car is charging up. This might be all or some of the time, but it turns out the socket was live long enough to finish topping my EcoFlow (12v charging at 8amps) which would have been quite a lot of charging!

I discovered the EcoFlow fully charged later but the X5 was giving the High-Voltage system warning, which was unnerving to say the least, first warning massage I’ve had knock on wood!

So it seems the EcoFlow pulling a load of charge from the 12v socket in the trunk had thrown the car, I guess it was struggling to maintain the charge in the 12v battery meanwhile charging the traction battery. Went for a drive and after a restart the warning cleared and all now normal

So be wary about leaving things charging in the car when the car it self is being charged. The EcoFlow is a bit of an edge case as it was drawing a load of energy and I guess a phone etc might well not encounter this issue… But worth noting that it seems power being pulled from the 12v sockets might upset the cars charge management system.

[krypttic]

I don’t think that’s the cause. Many of us have had a similar error, that also cleared on its own, without charging anything in the trunk.

[eelnoraa]

I don't think this is the cause as well. 12V socket is protected by fused, so the Ecoflow cannot pull more power than the fuse allows, which should be a safe limit. When the car is shut off, I think the 12V socket will cut power after 10-15 minutes, so it is not like the 12V battery is being draw all the time.

[six]

Originally Posted by eelnoraa

I don't think this is the cause as well. 12V socket is protected by fused, so the Ecoflow cannot pull more power than the fuse allows, which should be a safe limit. When the car is shut off, I think the 12V socket will cut power after 10-15 minutes, so it is not like the 12V battery is being draw all the time.

This is the point, the EcoFlow should have not charged as the power should have shut off, but it did fully charge so the power to the 12v socket wasn’t shut off, certainly we now know this 100% on the 50e, well mine at least. To get back to full it must have charged for over an hour or more, even once the car was locked.

So theory is, while the 50e is charging it’s not asleep like when shut and locked but not on charge.

[six]

Originally Posted by krypttic

I don’t think that’s the cause. Many of us have had a similar error, that also cleared on its own, without charging anything in the trunk.

Not saying it’s the only cause, in my case it was the most probable cause, on this occasion. I’d agree there are likely many other glitches that trigger the warning too. Just I’d avoid leaving anything more power hungry than a phone plugged in.

[BlkGS]

Hopefully you found a glitch, and not the beginnings of a more serious issue

[Scott Ayers]

The mild hybrid system is quite clever, actually. The alternator of the car ONLY charges the 48v battery located under the hood. The 12v battery in the rear is charged through a PCU (power control unit) that converts the 48v battery voltage to 12v, and vice versa, if necessary.

The 12v battery, being a critical system component, can draw down the 48v battery to a discharged state if a 12v draw is present for a long period of time without the engine running. Apparently, when a 12v aftermarket accessory draw is present after engine shutdown, the car does not go fully into sleep mode, and the 12v battery draws from the 48v battery until the 48v battery is too weak to provide power through the PCU to the 12v battery. After that, the 12v battery will continue to discharge. If the 12v battery does not fully discharge before the next engine start, the system will provide the "high voltage" error on restart because the 48v battery voltage is low. The engine start when cold is done by the mechanical starter motor, which uses the 12v battery. When warm, engine restarts are performed by the alternator/motor with 48v, driven through the accessory belt to the crankshaft. Even with a dead 48v battery, the engine can still be started if the 12v battery has enough charge, and the mild hybrid battery will recharge itself while driving..
I hope this helps.