Dillon Nichols wrote:Hi Bryan,
I would suggest you go ahead and get a kill-a-watt or equiv. Mine tend to die fairly promptly, which is annoying, but I haven't found anything comparable to use instead, and they're pretty handy.
A solar panel this size will not be powering your fridge... If you find a panel that fits the full window, it might be rated at 40W peak output. Your actual output will be lower; among other things, you will be limited in your angle options, and the glass will take a bit of a toll. Beware of shading the panel, it can take a disproportionate toll on output.
If the fridge is key, you might consider a larger battery bank than your solar panel can reasonably recharge; charge the bank off of an AC-powered charger when AC is available, then use the solar to maintain the bank until needed, and to slow the draining of the bank. Recharge when power comes back.
You can likely power your laptop/phone/modem and some basic lighting, preferably 12V, from even cheap car batteries, although you shouldn't expect very long life or runtimes from this sort of battery. Figure out the total combined wattage you need for these items, and determine if your current 12V-230V converters are adequate. I would only ever advise use of a quality pure sine inverter, but you can experiment with modified sine/step wave units if you aren't overly attached to your devices. Decide if you want to accommodate the fridge before buying...
The 'some sort of power converter/charger for it all' you mention is a solar charge controller. Readily available in all sorts of prices and quality levels. An 'MPPT' controller will get you a bit more power out of your panel vs a 'PWM' controller. Again, I'm not a fan of the cheaper options, but they sure are cheap.
For the solar panel itself, for your situation getting the best possible fit for the window is pretty much the primary concern here.
I'd suggest getting everything up and running with the best of the batteries you have, and upgrade the batteries after that.
Steve Farmer wrote:1) You're on a budget
2) You're got some soldering kit
3) You've got special requirements regards matching panel size to window size
4) You're indoors so don't need professionally made weather hardened solar panels
So.. buy some solar cells from ebay, which will cost you about a third of the price per watt compared to a ready made panel, and custom make your own panel(s).
The main thing as you learn is to be very very careful how you handle the solar cells, they are extremely fragile. If you handle them carefully when moving, soldering and securing to a backing panel, then you will be OK.
On the batteries, technically yes you can use car batteries for light use but don't let them discharge more than 10%. ie keep them at 90% charged or higher, otherwise you will kill them.
However, don't use car batteries indoors because when you are charging they give off hydrogen gas and in certain circumstances lead and sulphur compounds. Maybe you have a balcony or roof space which can house a battery enclosure?
For any given power, Voltage is inversely proportional to current. And higher current gives higher losses in the cabling. So at low voltages eg 12, 24V, losses in cables are high. Keep your cable runs as short as possible and use good thick cables for any runs that have to be longer than a few metres.
Post some pics on here and let us know how you get on.
Dillon Nichols wrote:One died while monitoring some pretty heavy loads a couple months after I bought it; another when I'd had it a year and had only used it a handful of times... I am assuming the deaths are down to crappy manufacturing/QC, but a brief postmortem showed no terribly obvious causes of failure beyond that.
So, unfortunately not really anything to learn here except 'cheap chinese gadget is built to cheap chinese quality standards'... Last time I looked there really wasn't much in the way of alternatives though.