# reasonable prices

Discussion in 'Electrical Systems' started by lazeyjack, Jun 7, 2007.

1. ### lazeyjackGuest

2. Joined: Oct 2006
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Location: London UK

### TrevlynsSenior Citizen/Member

LJ, I’m definitely out of my depth here (as far as electricals are concerned) But when I see it is “For use in conjunction with a 12v 110 ah Leisure battery” and “Ideal for powering camping, caravan, low voltage household lighting, charging mobile phone batteries, lap tops, 12v kettles etc”, have a look at this solar trickle charger at a fraction of the cost.

3. Joined: May 2005
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Location: Pensacola, Florida

### BillyDocSenior Member

It's the cost per watt that you need to look at. A "trickle charger" at 8.99 pounds (sorry, I don't have the "pound" symbol on this keyboard) is roughly 6 pounds per watt, the more substantial solar panel pointed to by Lazeyjack at 245 pounds for 80 watts is actually only 3 pounds per watt . . . half the price!

Watts are a measure of power and are determined by multiplying the voltage times the amperage if we're talking about electricity. So, for example, a 100 watt light bulb could be one designed for 120 volts and 0.833 amps, like in the US, or 220 volts and 0.454 amps as in most of Europe, or 12 volts and 8.333 amps as on most of our boats. All will put out roughly the same amount of light, because all use the same power, that is, Watts.

The other common measure of power is, of course, the Horsepower, which is directly equivalent to the Watt and an interchangeable unit of power. That 100 Watt lightbulb (or any of them) could also be described as a 0.134 Horsepower lightbulb, because one Horsepower is equivalent to 746 Watts (100/746=0.134).

I used to sail with a 0.0335 Horsepower masthead light, but I hated the way it ate my battery . . . so in my next boat I plan on using the new 0.00402 Horsepower LEDs instead. I'll have to use three of them for the tricolor, of course, but that's still only 0.0121 Horsepower. The battery should last almost three times as long! And no more climbing the pole to replace a burnt out bulb either.

BillyDoc

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