I don't have any Haynes manual to hand to check the figures but my gut feeling is that a 25A heated windscreen would be a bad idea on a BEC (2003
5PW R1) with a bike battery?
I've already had a couple of stator failures.
Would you get away with running it without headlights or cooling fan on I wonder?
Anyone else running a heated windscreen on a BEC?
It's my Fury so an S3 Elan screen. Existing one is cracked so needs replacing anyway.
My gut feeling is also that there not 25A spare in a BEC alternator. And the time you need to heat the windscreen you probably also need the lights on
Great demand for screen heating in Barbados Dave?
It was a bit nippy a few weeks ago, dropped below 25 deg C late night / early morning for the first time in ages!
However the car is in the UK not out here 
Just copied this from the 5pw service manual...
Charging system
System type AC magneto ----
Model (manufacturer) F4T471 (MITSUBISHI) ----
Normal output 14 V/32 A at 5,000 r/min ----
Stator coil resistance/color 0.19 ~ 0.23 Ω at 20 °C (68 °F)/W–W ----
Rectifier/regulator
Regulator type Semi conductor short circuit ----
Model (manufacturer) FH001 (SHINDENGEN) ----
No-load regulated voltage 14.1 ~ 14.9 V ----
Rectifier capacity 35 A ----
Withstand voltage 200 V ----
I'd say with an output of 32A and with the known stator problems, you'd be pushing it drawing 25A just for the screen. Not done the maths
but I guess you'd be drawing close to the max even without fan and lights on.
To be honest you only need a heated screen to defrost in the morning
De misting is a different problem and needs vents
If you ran a heated screen you could link a battery booster at home or run a heater matrix and blowers
Does seem to be strange idea though
Adi,
Yeah thought so.
Daft thing is that currently a heated screen is cheaper than a normal one as unless I want to wait 2 months+ for the next batch to arrive the normal
screens are made to order.
quote:
Originally posted by hobbsy
Adi,
Yeah thought so.
Daft thing is that currently a heated screen is cheaper than a normal one as unless I want to wait 2 months+ for the next batch to arrive the normal screens are made to order.
Yeah that is the temptation. If I ever sell it a future buyer could weigh it down with a car battery i suppose...
quote:
Originally posted by twybrow
quote:
Originally posted by hobbsy
Adi,
Yeah thought so.
Daft thing is that currently a heated screen is cheaper than a normal one as unless I want to wait 2 months+ for the next batch to arrive the normal screens are made to order.
So just buy one of the heated ones - and then decide whether to plug it in!