Simple Solar Setup

A few months back, I bought myself a starter solar setup, consisting of:

20W panel (this was on sale when I bought it for $60)
18Ah UB12180 battery
10 amp charge controller

This will not power the whole house!! In fact, it turns out that even my laptop is a little too much for the panel to maintain - but that's what the battery is for. I am typing on my laptop, connected to the battery via a 12V Dell power supply from ebay (because converting DC to AC to DC is crazy - it's inefficient).

Controller, battery, 12V plug and laptop power

When I start the laptop up, the very simple charge controller's charge display (3 LEDs!) drops from full to 2 lights on immediately. If it's full sun out, it will pretty much stay like that all day. The laptop and battery stay fully charged if the laptop is put to sleep. If I plugged the laptop in with less than full charge, it would suck the battery level down pretty quickly though.

So I'm guessing that, in full sun, the inefficiencies of the panel and the cheapo charge controller mean it's probably only putting out 12-15 watts, where my laptop is pulling 15-25.

It's pretty cool. This laptop has a 3g card in it, so I can be totally 'off grid' if I want. I could use the laptop for 3-4 hours a day, and keep the battery and the laptop fully charged, at a guess.

Is this cost effective? No. The whole lot cost me $100 or just over. If it saves me 0.1kWh a day, every day, it would only save me roughly $7 a year - and it is very unlikely to do that much! A 15 year payback!!

But, it's cool. If we go camping, I can bring it along. The battery is neither large nor heavy. The panel is large relative to the size of an 80W panel (amorphous technology I guess) - meaning that, while the 80W panel IS larger, it's far far from 4 times larger!

We've also got solar powered food, but that's another story!