In general solar panels are rated for their maximum output in full
direct sunlight. If the solar panel was not directly angled to the
sun, output will be less. If the panel isn't directly in the sun,
output will be less, etc. etc.

The only real advantage to a lower rated solar panel is that you
usually don't have to worry about overcharging your battery, i.e. you
don't need a cutoff circuit.

Sorry, but the smallest panels I have is 6 watts. 1.8 watts is barely
enough to turn a fan.

On Mar 26, 2007, at 8:16 PM, Martin Jagersand wrote:

> Hi,
>
> Before leaving for Europe last fall I bought a 1.8W solar panel
> trickle
> charger and put it on my '82 Westy inside the windshield and facing
> straight southward.
>
> http://www.canadiantire.com/browse/product_detail.jsp?FOLDER%3C%
> 3Efolder_id=1408474396672503&bmUID=1174953995011&PRODUCT%3C%
> 3Eprd_id=845524443275941&assortment=primary&fromSearch=true
> *
> Product #*11-1880-2
>
> Fast forward 5 months. I'm back in Canada for a month in March
> (digging
> though
> 2 boxes of accumulated mail etc...)
>
> To my disappointment the battery on the '82 Westy is almost completely
> discharged. Trying to find a reason I measured the output of the
> charger
> at two times: 1pm under full Alberta sun: 40mA,  at 4pm 10mA.
> That makes only 480mW and 120mW. Far from the advertized 1.8W.
>
> Has anyone else tried to buy these chargers? Is the Watt rating pure
> nonsense in general? Or is it worthwhile to bring it back and try
> another
> one?
>
> Martin