Not quite. Your math is good for the for the parallel case, but not for the series case. P=I*V. In parallel there is three times the current and in series there is three times the voltage. Either way the power output is 15W. Of course you do want to set it up for the correct voltage for you application.
I don’t ever want to hear you saying that again.
You are half right though. The efficiency does go down, and that’s because the resistivity of the semiconductor goes up (phonon scattering). But, the flux photons far out weights the heating effect, so a photovoltaics will always produce more electricity in sunnier areas.
great price… just can’t figure out a use for one given my current needs. That, and i really can’t afford to buy a whole mess of 'em.
Yeah well that’s why low humidity and lots of sunlight are a good mixture for solar panels and they suck here near the gulf. The electrons tend to bump into each other in a chaotic way with increased heat which actually impedes the current flow. Shit during the sunny months in Alaska, the thing would be superconducting like crazy.
uhh… yeah, what he said…and don’t you forget it…
Ok sir! 
Interesting information, thanks 
I love to learn stuff like that!
I’m in for 3, for a test…
Walmart carries the black cased 4 watt version of this unit for I believe around $50. I’ve got a portable workbench that was made out of an old coleman popup camper, and these would keep the batteries topped off nicely if they work (plus, I have a huge flat roof that they would mount nicely to…) - I run a sound system and some inverted stuff off of 4 800ah car batteries (that are charged normally via a honda 2000watt gen…
Soo, if they work, what a deal - if not, ehh, we’ll see… I’ll let people know here once I get them…
… also, as for the people who said they had one of these and it didn’t work - they (here) come with a 5 year warranty… That’s not an overly bad deal considering the price, even if it’s a bit of a gamble…
The output of these panels is basd on 5 hours of sun per day; they should more than keep up with the parasitic drain on a boat with unless it has a a lot of accessories that run constantly.
I love these, in for 3… have a few 1 watt units I use to supplement my modified solar outdoor accent lighting, a single AA cell just does not cut it, using 3 AA works well for me, using track light type cables that the lights attach to, and also provides the voltage to recharge the batteries…
Plus the panels can be placed in an area to charge the units that would not normally get enough sun to recharge the battery as well as others, plus you can mount your sidewalk markers where you want plus a few wall sconces and the UPS guy does not call me dirty names when the time changes and he is still delivering after dark…
I also use a unit to keep my battery booster/air pump charged, seems to keep me from having to recharge the unit so often, and since I started using one, I have not had a dead booster when I needed it… when I remember I do make sure it is charged, but if I forget at least I feel it is getting a trickle charge close to what is being lost…
Hey, the concept does work, if it did not, School Zones would not use them- here in Texas anyway…
Plus many Ranches use them to keep the battery charged for their electric gates, where it is not feasible to run AC to…
Hunters use .5 watt units to keep their 6volt deer feeder batteries charged also…
Try one, at this price, I don’t know if it can be beat, my first 5 watt unit cost me over a bill a few years back, and that was on clearance at WallyWorld…
Nothing has to be switched on for a battery to self-drain (that’s why the term is “self-drain”). Lead-acid batteries self drain pretty fast, the more expensive gel and AGM batteries do not self-drain nearly as fast (but they cost 3 - 4 times what comparable lead acid batteries cost.)
Three in parallel would be 15W @ 15V or series 5W @ 45V
http://www.partsonsale.com/learnwiring.htm
Nope I’m right. The second important rule to remember about series circuits is that the current or amperage in a series circuit stays the same. Did you look at the link I provided. I have a degree in this trust me.
Am I right in assuming that wiring up three of these in parallel is simple to do?
"Three in parallel would be 15W @ 15V or series 5W @ 45V "
Uh wrong.
Three in par. would be 15W (15V x 1 amp)
three in series would be 15 watts (45V x 350 mAmps)
where do I mail in for that degree?
I have to disagree.
Series
45 volts @ 350 mAmps
Parallel
15 volts @ 1050 mAmps
Either way you get a power output of P=3IV= 15W
Oh yeah forgot to mention … about that website… Even its says :
Remember: In a series circuit the current stays the same but the voltage is additive. In a parallel circuit the voltage stays the same but the current is additive.
YEAY!!! someone else gets it
Not in the winter.
A popular boating store sells another brand of solar trickle chargers…
SE-150: 150mA, 2.25W, 15.5" x 5" x .75", Cars, small boats, RV’s
SE-500: 500mA, 7.5W, 14.8" x 14.2" x 1", Medium sized boats, RV’s
for $44.99 and $99.99 respectively.
I’ve been debating getting trickle chargers for my boat, but I always assumed I’d need two, one for each battery. The potential $100-200 price point was kind of hard to swallow when I could just bring them home from the marina and top 'em off in my garage
This seems like a good deal as far as I can tell, two shipped from woot for cheaper than just one I was looking at with lesser specs. I guess I’ll take the gamble.
Is there any chance these could somehow damage the batteries?
Someone needs to tell E-Bay that degrees go for more than $10.