Reversing in neutral?

[OriginalBigAl]

I have a short uphill stretch (50m) to my parking place in front of the house. In an ice car to reverse out I leave it in neutral and let it roll backwards out of the property on to a very quiet lane, controlling it on the brakes. With the MG4 on the flat putting it in D or R and letting the brake off, it starts to roll without touching the throttle, ie some power is going through the drivetrain. So if I put it in reverse and go backwards downhill the brakes will have to do more work and control would be more problematic. Would I cause potential damage by using the ice method of descending the short distance then carrying on as normal. I have seen the other posts on this but they did not answer this particular question as does the user manual.

 

[Ian Key]

Putting it in R and using the brakes to control your speed shouldn't cause any problems and you will have re-gen and caliper braking. Using neutral all the braking will be with the caliper brakes.

 

[siteguru]

I'm not sure regen braking works in reverse?

And anyway - if you're in neutral then by definition the motor is "disengaged" so no regen would be possible; in either direction.

 

[Ian Key]

I'm not sure regen braking works in reverse?

And anyway - if you're in neutral then by definition the motor is "disengaged" so no regen would be possible; in either direction.

You're probably right and thinking about it re-gen doesn't kick in at low speeds.

 

[OriginalBigAl]

The manual does say re-gen is not available in reverse, and also if the car breaks down it cannot be towed in neutral , hence the query. But putting it in reverse lets it creep and this added to Mr Newtons discoveries means the breaking has to be better controlled. In neutral the creep is eliminated, but there must be a reason why MG and others ,even the AA and RAC say moving the car in neutral is not a good idea. I have no idea why this is ,as I assume the same as Siteguru that neutral means the power is disengaged. I tried this question last night on EV speak and got lots of angry men shouting obscenities at each other, mostly Americans and strangely, no Scots!( if you know what I mean)

 

[tsedge]

The towing relates to the car being moved while unpowered - there's no problem using neutral when the car is on.

 

[siteguru]

That's why I used double quotes when I said the motor was "disengaged" - it isn't actually (as it's fixed to the gearbox and axle) but it presents minimum resistance to the car free-wheeling. This is fine when the car is powered on, but can cause issues when the car is being towed when powered off, as the generated power (the motor turns into a generator*) has nowhere to go except as dissipated heat, which could cause damage if left running long enough.

* Yes, I know that this is what happens with regen. But when the car is powered and being driven, the power expended far outweighs the power regened so there's always somewhere for the regen power to go - (relatively) little of it is dissipated as heat.

 

[OriginalBigAl]

Cheers guys , I think I,ve got my head around that now.