posted on Sep, 16 2009 @ 03:31 AM
Stay away, looks cheesy to me . . .
It appears to be a run-of-the-mill 2000va (~1800 watts) UPS system (battery backup you would use for a large workstation or server) hooked up to a 90w
solar panel for charging.
The solar panel is maybe worth $500
Notice it doesn't say anything on there about how long this "solar generator" lasts on a full charge. A typical 2000va UPS system will run about
7-10 minutes at full load (1800 watts). 1800 watts will *maybe* run your fridge and a few lamps.
Based on the unit's size I wouldn't bet much more than 10 minutes or so at full load, maybe 25 minutes at half load. It's not much bigger than a
breadbox and with existing battery technology you just can't store very much power in that size container.
Your "generator" (i.e. battery pack) can produce 1800 watts but your charging capacity is only a single 90 watt solar panel. You are using up power
20 times faster than you can produce it. Once the battery runs out you have a 90w solar panel for electricity. Maybe enough for a small radio,
provided it's sunny outside.
Now here's where it starts to really suck . . . (sorry my nerdy side is about to show)
So let's say it uses two 12v, 18ah (amp-hour) batteries (pretty typical for your average UPS system).
To charge the batteries:
18ah 12v battery needs 12v @ 18amps for one hour to fully charge
x2 -- two batteries means 2 hours @ 18 amps to charge
Total amp-hours needed to charge is 36ah @ 12v
Solar panel output:
90 watts, assumed to be 12 volts = 7.5 amps
So, with 36 amp-hours needed to charge your batteries, your solar panel @ 7.5 amps would take 4.8 hours to recharge the "generator" so you could get
another 10 minutes of 1800w power. Keep in mind that's 4.8 DIRECT SUNLIGHT hours, and to be safe I'd add 20% to account for innefficiencies in the
system, so probably more like 5.5 hours or so.
Sorry for the long technical post -- just want folks to realize solar panels, while very cool and all, really don't produce very much power per their
cost. So many websites out there selling them like you can plop a couple panels on your roof and save 20% on your electricity bill -- it's just not
true. You need a HUGE investment to produce enough power to run 20% of your house. Typical solar installations don't "pay themselves off" with
electricity savings for 10 years or more.