Remote heating while plugged in

[Abitinga]

I was lead to believe that if you pre heat the car, while plugged into the mains, it would draw power from the house not the car. Yet since using the pre heat this winter I get in the car afterwards and find the charge reduced. Have I been mis informed. And why is the car not charging back up after the pre heat has completed.

To give an example I put my car on to defrost windows at 0440 for 10 minutes while it is plugged in, I then go to the car at 0540 to go to work and my battery is still not fully charged. I have my car charging times on 24/7

Any advice.

 

[geoffshep69]

The preheating will take the majority of power from the mains, but my understanding is that the heater draws more power than the mains can supply, so it does also draw a small amount of power from the main traction battery.

Others will give you the specific figures, but the drain from your battery is relatively small, and a 20 minute pre heat shouldn’t impact your EV range by more than a mile or two. Clearly it is still far more efficient to preheat and lose a mile or two rather than get into a cold car, and fire up the heater (and probably the ICE as well) as soon as you drive off.

Not sure about the recharging, I’d have assumed that once pre-heat is finished it would start to charge again.

Incidentally, why do you have the preheat on an hour before you go to the car ? All the heat will be lost by the time you get in the car, why don’t you set it so that it comes on 20 minutes before you leave so that you can get in a warm car and don’t need to operate the heater at all ? That is more efficient than attempting to have a full battery but then needing to turn on the heater straight away.

 

[anko]

Not sure about the recharging, I’d have assumed that once pre-heat is finished it would start to charge again.

It should. But some have reported that this is not the case when a charge timer is set. This same charge timer may also cause the full pre-heating cycle to be powered fro the battery, not the mains.

 

[Muddywheels]

I'm sure I read the draw on 3 pin plug charger is more than it can supply and will drain battery - I'm using dedicated tethered chargemaster unit at home and battery is still showing full after 20 mins pre heat although symbol shows charging on dash :?

 

[anko]

On a 16 amps (or 32 amps for that matter) dedicated charger the car will take max 3.3 - 3.4 kW from the grid during charging and / or during pre heating. The heater can draw up to 4800 watt. This means you loose approx. 1400 watts per hour of pre heating. After 20 mins, this will be approx. 450 watts, or 2 miles max.

I don't think the battery gauge will reflect this, having only 14 bars.

 

[NightPHEVer]

My 2014 PHEV, plugged in to a Rolec 32amp charger in my garage will click (actually more of a 'thunk' than a click) back to 'green' (green 'charging' indicator light on the charger as opposed to blue 'not charging' light) when the pre-heater has just been on. Don't know if the Rolec clicks to 'green' as soon as the pre-heater has come on 'cos I've never been there to see it (Exciting update! Mon.9th Jan: Actually, now I have and the green 'charging' light does indeed come on the charger as soon as the pre-heater switches on). I have the pre-heater (set via PHEV dash touch screen) running for 10 minutes before I get into the car. If the charger is not plugged in, but the batteries are fully charged, when the pre-heater has run the in-car blue battery charge strip indicator does sometimes have a small 'used a bit of power' gap at the top.

 

[anko]

10 minutes of pre-heating while not plugged in translates to a 'loss' of 800 watts. Almost double the amount compared to 20 minutes while plugged in. I think it makes sense that the gauge does show this loss and not the other.