Front / Rear heated screens

[clarkeehull]

Just recently because of the cold weather... I've noticed when I put the front and rear screens on together it zaps a lot of power from the engine. The lights dim, and the car is sluggish.

This is the first Ford I've owned and used in the cold weather. It's a 2003 1.6 Focus. Is this normal? Or could the battery be on its way out??

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[Russ]

The front screen is a huge drain on the battery itself, although if the battery is original it will be 'well by its Best Buy date'

[clarkeehull]

The front screen is a huge drain on the battery itself, although if the battery is original it will be 'well by its Best Buy date'

Hi Russ.

The battery looks fairly new. Bought the car in September with 70k and had it serviced. It's been pretty cold these passed few days and it's started no problem, just when I use the front screen it seems to struggle a bit.

I just wondered if it was common on this age of Focus.

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[Micro]

The lights dim on my newer Focus when both screens are on, I don't notice a lot of power drop (the lights come back to normal intensity), but it may depend on how big the alternator is that is fitted.

[artscot79]

ideally you shouldn't use both together front screen is 75amp add the rear 100amp add lights etc as well that's why its best to use the front for the least time necessary before driving off allowing the battery to charge up on the drive home

[Incontro]

2 hours ago, artscot79 said:

ideally you shouldn't use both together front screen is 75amp add the rear 100amp add lights etc as well that's why its best to use the front for the least time necessary before driving off allowing the battery to charge up on the drive home

Surely the front is a higher wattage element? The front seems to zap more power than the rear on mine (so much so that when you switch it on, you can hear the high pressure fuel pump whine).

[v530anh]

I think that is why my front heater automatically switches off after a few mins and the rear just stays on. Makes sense.

[clarkeehull]

That sounds sensible. Mine shuts off after a short while too. Considering its an 03, it's still pretty effective.

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[mjt]

3 hours ago, artscot79 said:

ideally you shouldn't use both together

On both the cars we've owned with full electronic climate control the demist button puts both screens on, the blower to maximum and turns on the aircon so evidently the system is designed to cope with this load, at least for a short time. As mentioned the front screen turns itself off quite quickly.

 

1 hour ago, Incontro said:

Surely the front is a higher wattage element?

I think you misinterpreted what Arthur said - he meant with both screens on the total would be around 100 Amps, i.e. 25 for the rear.

[TitXlover]

I used to have the same thing on my Mk1 Focus. Tried not to use both together as it does drain the battery. Used to find when really cold the radio would turn off to save power too.

[artscot79]

yeah sorry 75amp front 25rear front only stays on 5 minutes before it switches off remember some batteries charge at say 75-80amp per hour as said aircon is about 35amp add it all up you can drain a battery quickly

[isetta]

front uses tons of power which is why it is wired to only come on if engine is running. on my wife's 2001 focus when switching on it made the revs drop momentarily and the lights would dim slightly but go brighter again if you increased the revs slightly. I would imagine on tickover it is using more power than the alternator is putting back in the battery, hence it goes off after a certain amount of time as stated above.

I don't think any of this would make the car sluggish though. If there wasn't enough electrical power for the engine then sluggishness would not be the result, it would be something worse, like it cutting out. 

[DJ_Andy_M]

On 12/6/2016 at 8:41 PM, Incontro said:

Surely the front is a higher wattage element? The front seems to zap more power than the rear on mine (so much so that when you switch it on, you can hear the high pressure fuel pump whine).

You'd be correct. I think it was just a typo. The rear one will operate with the engine off. The front one won't and on an auto start stop car the car won't shut down with the front one on.