Small backup energy storage

[Shmel]

Hello,

After last 2.5 days power outage I became concerned about small backup system.

I have a basic emergency set, which includes 2 LED lanterns, fed from D batteries (bought a pack of 50 of them back in 2003, and they still last). I keep several ice packs in my freezer. They take space, but do a good job during power outages keeping fridge cool for a couple of days. So, one day of outage was no problem, but the second day made me dull. My cell phone discharged. Tried to recharge it from computer UPS unit, and killed the battery. It became rather hot and uncomfortable without a fan.

I started thinking, where can I get some power during such outages? I live in an apartment, so generator is out of question. I think, during a couple of days I can be comfortable with ~500Wh battery and 1kW of peak AC power (chargers, fan, emergency lights and some electronics). I am not allowed to rewire anything in the apartment. The system should work from the AC wall outlet.

I found several all-in-one packs on solar sites, which include a small solar panel (nice option, but not really necessary). All of them lack quality, overpriced, non-expandable, non-reparable, and reviews say, if something brakes, manufacturers refuse to refund. Same solar sites offer a wide range of equipment which suites my needs for decent price. In going DIY route there are some issues. Max DC current can be ~80A, so proper wires and fuses are needed. Besides, everything should be enclosed accurately and safely in some box or cabinet. I do not want to scatter electrical devices around the apartment.

Do anybody have experience in small scale backup systems? Any plug-and-play packages on the market or DIY kits which I overlooked? Any DIY success stories? Please, share.

[Sunking]

Unless all you want is to charge a cell phone, run a laptop and a few LED lights you are pretty much SOL in an apartment. You cannot keep your fridge going.

First your apartment would have to face due solar south with space to put up a panel or panels

Let me give you an idea.

A 100 watt panel = $250
10 amp charge controller $50
100 AH 12 volt battery $200

Assuming you have a south facing apartment will generate about 300 to 500 watt hours per day in summer, and far less in winter.. That is enough to run your laptop 5 or 6 hours per day, and a few LED lights. Fridge is out of the question

[Shmel]

Unless all you want is to charge a cell phone, run a laptop and a few LED lights you are pretty much SOL in an apartment. You cannot keep your fridge going.

First your apartment would have to face due solar south with space to put up a panel or panels

Let me give you an idea.

A 100 watt panel = $250
10 amp charge controller $50
100 AH 12 volt battery $200

Assuming you have a south facing apartment will generate about 300 to 500 watt hours per day in summer, and far less in winter.. That is enough to run your laptop 5 or 6 hours per day, and a few LED lights. Fridge is out of the question

My apartment actually faces south, and I have a patio in front of my window where I could place a portable solar panel during outages. But this is not a highest priority option. I think about charging ~50AH battery from the grid when the grid is available and using it during outages for running small appliances. Just similar to computer UPS, but with bigger battery. I am not going to run a fridge or electric tea kettle or microwave, of course. Duracel and Xantrex offer plug and play packs of this scale, but they have too many negative reviews.

[Mike90250]

This isn't "small" but it's rugged and semi-moveable. I call it the Solar Monolith. Simple instruction photos here

http://www.facebook.com/album.php?aid=2074858&id=1196643274&l=7e66e96c3c

You can place 2 batteries on the bottom, which act as ballast, and the shelf holds chargers and other goodies.

I used 60W flexible amorphous panel, but using a poly or mono panel, you can get higher efficiencies, with the
risk of breaking the glass.

Mono_2005_CS_056.JPG

You can gather the pieces, and wire them up, without the chassis, or

get a panel, and an automotive "jump start pack" and use the solar panel to recharge it. (if you have sun) I use a model from PEAK to power my CPAP for outages.

Mike

solar: http://tinyurl.com/LMR-Solar

[Shmel]

WOW! This looks cool. Thanks for info and some questions.

1. How safe is it to keep all system in a wooden enclosure in terms of fire hazard?

2. What kind of fuses do you use between battery and charger/inverter (if any)?

3. What do you think about combined inverters/chargers vs stand alone units?

4. Do I really need a pure sine wave inverter to run a laptop charger or portable TV? What type of inverter do computer UPS units typically have?

Thanks again!

[inetdog]

4. Do I really need a pure sine wave inverter to run a laptop charger or portable TV? What type of inverter do computer UPS units typically have?

Thanks again!

Computer (and other) UPS units are almost always pure sine wave. Anything else is too uncertain to be marketed to a general audience.
Your laptop charger and TV may work fine on Modified Square Wave, or they may not. It is a matter of how their particular power supply is designed, and the best way to be sure is to try it. (Borrow an MSW inverter or take your laptop and charger to a friend or a store that will let you test.)

[Sunking]

Computer (and other) UPS units are almost always pure sine wave.

I respectively disagree with that. If you go to the box store and pay $200 for a UPS it is a Standby Inverter with a small battery and even smaller charger with a MSW vibrator inverter. To get into Interactive and Dual conversion you gotta spend 4 digits and up to 7 or 8.

[daveb]

I'm confused. Why did my comment get deleted here? All I did was thank Mike for the ideas contained in the Solar Monolith. Was that against the rules? Anyways thanks again Mike.

[Mike90250]

@ Daveb - I see your comment:

Shmel

WOW! This looks cool. Thanks for info and some questions.

1. How safe is it to keep all system in a wooden enclosure in terms of fire hazard?

2. What kind of fuses do you use between battery and charger/inverter (if any)?

3. What do you think about combined inverters/chargers vs stand alone units?

4. Do I really need a pure sine wave inverter to run a laptop charger or portable TV? What type of inverter do computer UPS units typically have?

Wood is not the fire hazard, overloaded wires are.
no fuse at charge controller, but there are fuses for the loads
combined inverters/chargers are expensive, and not needed if you are charging with solar

[Shmel]

@ Daveb - I see your comment:


Wood is not the fire hazard, overloaded wires are.
no fuse at charge controller, but there are fuses for the loads
combined inverters/chargers are expensive, and not needed if you are charging with solar

Thanks!