Battery Cooling system

[ALANB]

Having a bit of a debate in another place about whether the same cooling system and hence refrigerant is shared between the battery, motors and passenger cabin? It was in my previous vehicle. Anyone know?

 

[Alb]

Although I've seen it contended, I've never come across any proof that the A/C system is used at all

 

[m4rmite]

Doesn't the manual say 4.2 litres and 4.8 litres of coolant is used for the battery cooling and for the ac system.
I took that as there's 2 systems

 

[ALANB]

Found this from Siemens...

Doesn't the manual say 4.2 litres and 4.8 litres of coolant is used for the battery cooling and for the ac system.
I took that as there's 2 systems

Coolant is different to refrigerant....the coolant is the liquid that flows whilst the refrigerant is the gas in the compressor...so I'm not clear. In my previous car Mitsubishi Outlander PHEV it was a big deal if the compressor wasn't working due to lack of refrigerant.

Doesn't the manual say 4.2 litres and 4.8 litres of coolant is used for the battery cooling and for the ac system.
I took that as there's 2 systems

This is getting more complicated....it appears there are three things getting cooled. The battery, the drive transmission and the air in the cabin. Both the first 2 use glycol being pumped around and the cabin air passes over a cold plate. The question is what cools the coolant, and via which radiator.

 

[Deep purple]

I have not yet managed to find a circuit diagram of the cooling/heating systems in the MG5 and trying to trace all the pipes and components is a real challenge.
Alan B sums it up that there are 2 circuits to cool the transmission and the battery which just transfer heat to the ambient air. Then there is the AC system for cabin cooling.
What is clear is that the systems are very basic and not designed for efficiency as there is no heat pump for heating which just uses direct electric elements, and the various sources of heat and cool are not integrated. The AC system obviously does use a standard heat pump setup like most ICE cars.
One of the reasons that Teslas have such high range is that they have a full integrated heating and cooling system with a heat pump so that no energy is wasted. The secret of this system is the Octovalve which basically diverts heating/cooling fluid to where it is needed or can be used. I won't try and explain it as it is fiendishly complicated. Sandy Munro has done some great videos about it, sample at the link, there are others by him.

For those of you who haven't watched Sandy's videos I commend them to you. He is an EV guru with a huge track record in the motor manufacturing industry who now runs a consultancy which advises manufacturers, including the Chinese.

 

[ALANB]

I have not yet managed to find a circuit diagram of the cooling/heating systems in the MG5 and trying to trace all the pipes and components is a real challenge.
Alan B sums it up that there are 2 circuits to cool the transmission and the battery which just transfer heat to the ambient air. Then there is the AC system for cabin cooling.
What is clear is that the systems are very basic and not designed for efficiency as there is no heat pump for heating which just uses direct electric elements, and the various sources of heat and cool are not integrated. The AC system obviously does use a standard heat pump setup like most ICE cars.
One of the reasons that Teslas have such high range is that they have a full integrated heating and cooling system with a heat pump so that no energy is wasted. The secret of this system is the Octovalve which basically diverts heating/cooling fluid to where it is needed or can be used. I won't try and explain it as it is fiendishly complicated. Sandy Munro has done some great videos about it, sample at the link, there are others by him.

For those of you who haven't watched Sandy's videos I commend them to you. He is an EV guru with a huge track record in the motor manufacturing industry who now runs a consultancy which advises manufacturers, including the Chinese.

I've contacted James Coates at Cleevely Electric Vehicles | Electrical Vehicles | Gloucestershire who confirms it is linked for cabin and batteries but not for transmission. It sort of explains why the EV aircon in the cabin struggles sometimes on hot days and high speed journeys as the refrigerant loop is working on both.

Here's a diagram for a Tesla M3 showing how it shares the same cooling refrigerant loop

 

[Deep purple]

All the green stuff in the Tesla diagram is refrigerant and the red stuff is ordinary coolant (water/antifreeze). Its an ingenious system which is very efficient with minimum number of components.
Cleevely's statement about the MG ( and they ought to know) is interesting and I would love to see the diagram for this arrangement and how all the conflicting demands are met when in winter the cabin will need heating when the battery may need cooling. Does battery heat in this case get used for the cabin?
Has anyone got access to a workshop manual for the car?

 

[ALANB]

All the green stuff in the Tesla diagram is refrigerant and the red stuff is ordinary coolant (water/antifreeze). Its an ingenious system which is very efficient with minimum number of components.
Cleevely's statement about the MG ( and they ought to know) is interesting and I would love to see the diagram for this arrangement and how all the conflicting demands are met when in winter the cabin will need heating when the battery may need cooling. Does battery heat in this case get used for the cabin?
Has anyone got access to a workshop manual for the car?

My view is that the cabin heating is pretty basic and separate. a heated filament after or before the fan, because it clears the windscreen so quickly in winter and also the smell you get as it burns off when used for the first time in a while, just like that on an old electric filament home heater as it burns off the dust.

Think I was right: Skyworks | Automotive - Electric Vehicle PTC Heaters

 

[Deep purple]

Agree about the filament but does the battery heat get re-used in the cabin heating to help reduce the load from the filament? It would increase range if it did, and that is effectively what Tesla does (although Teslas have a heat pump not a filament for heating.) But it would be more complex so probably not done in view of build cost.

 

[ALANB]

I think MG is built to a budget, lol

Now had Brighton MG confirm that the systems share same cooling system, in the case of battery and the cabin. The compressor circuit has an evaporator for air for the cabin and a chiller plate for the glycol battery coolant. The transmission coolant is air cooled on a separate glycol circuit.

 

[snowyy]

all i know is it apparently needs flushing out on the second service hence the increase in cost!

 

[ALANB]

all i know is it apparently needs flushing out on the second service hence the increase in cost!

No this is on service number 5...it is not the second service.