Solar Power For Apartment Dwellers

David Trammel's picture

We have often had comments that go like, "I'd love to lower my dependability on the electric company BUT I live in an apartment." Here is a very detailed article over on Lowtech Magazine's website, where the editor tries to power their office with a solar system placed on his apartment's window sill.

I'll leave it to those who are fimiliar with the nuts and bolts of such systems to comment on his numbers.

He also has a discussion on the merits of staying DC. Solar panels generate 12 volt DC current that is then converted to AC current by and inverter. Most appliances reconvert that 120 volt AC current back into DC internally. You have approximately a 20% loss from such a DC/AC/DC system.

In larger system you could shrug off such a loss, but for a smaller system like this, used in a apartment might it make more sense to connect only DC powered appliances and lights?

Blueberry's picture

So you start with 12 volts dc and you want to charge your phone or tablet or run a LED light. Most of the chargers converts are of a type call linear voltage reg. The parts are very cheap to buy you can buy what you need to make a unit up for under 2 dollars USD. So your output is 5 volts at 1 amp (7805) this will charge a phone or tablet or run a LED light also make the math easy for the next step. Your input 12 volts at 1 amp output is 5 volts at 1 amp. 12 watts of power in 5 watts of power out so what about the difference 7 watts. this gets converted to heat!!!! So much for being green. There are other devices on the market that cost a lot more to buy or build. If your total power system is under 200 watts stay with 12 volts dc.

On the battery side of a solar system best to stay 12 volt or 24 volt. I like a 12 volt battery bank can get replacement parts at the local auto parts house. If you are building a big system say total daily output above 2000 watt consider 24 volts. If you go to a 48 volts dc system the stuff gets expensive and a 48 volt system can KILL YOU RIGHT NOW! I think 48 volts dc is more of a hazard than 120 volts ac.