My Solar Apartment

Some results

noreply@blogger.com (Dog Saucy) — Thu, 12 Jun 2008 14:00:00 +0000

After a few months of working out how to use solar power in my apartment, I'm ready to share some results. I'm hoping that some conservation plus offsetting some grid use with stored electricity (my battery) will reduce my grid usage and electric bill. Check out the simple graph that's reported on my ConEd bill.

There's definitely a downward trend. That may be explained by the dramatic decrease in temperature and less AC/fan usage from the end of Summer to the beginning of Spring. But look at the difference between Jan 08 and May 08.

During May, New York's temperature is significantly warmer than January. But I actually reduced my grid usage by 22%. This exercise is having a positive effect. But it will take a full year to really get a good comparison. So stick around.

Reverse current leakage

noreply@blogger.com (Dog Saucy) — Tue, 27 May 2008 15:52:00 +0000

Not a bedwetting condition, reverse current leakage can drain a solar charging system's batteries at night or when the solar panel is shaded. I don't know the details, but I understand the absence or even partial shading of sunlight actually causes the electrical flow to reverse. This would explain why my solar panel was not effective when placed on my AC unit. There's occasional shading and of course a good amount of nighttime to deal with.

One solution is to use a blocking diode to allow the current to flow in only one direction.

Most charge controllers provide this protection as well. A while ago I purchased a Morningstar SS-6 charge controller for $44.00. Rather than wire up a blocking diode, I decided to introduce the charge controller into my mini-system.

Here's where I made a big mistake.

I previously followed the Xantrex manual's instructions and wired a DC connector to my 6 watt panel and plugged it into the AC charger input.

Thinking about, it seems strange that this would work....DC to AC? But it works just like the manual says it does.

Following this logic I clipped off the connector with enough lead wire to connect it to the battery connections on the charge controller.

I then wired the solar panel to the charge controller.

Plugging it into the Powerpack did nothing.

No charge...no indications.

Apparently the AC input on the Powerpack cannot handle the DC current coming from the charge controller. This makes obvious sense. But because I had successfully wired up the solar panel to the AC input, I gave this method a shot.

The correct way to do this is to use the DC/DC charging cable that ships with the Powerpack.

I clipped off one end...

...and wired it to the charge controller. The wire connected to the center terminal is the positive connector. When connecting to the battery connections of the charge controller, this connector should be wired to the positive terminal. My cable had white printing on the positive wire and no printing on the negative wire.

I then plugged the DC charging cable into the Powerpack at its DC power socket. The Xantrex manual states that recharging the Powerpack via DC will not light the charging status light. This was inconvenient considering I wasn't too confident I was doing this correctly. However, after draining the battery to 90%, I set it up to charge on my roof. After a half day in the sun, the battery was back to 100%. I'm assuming the charging setup was done correctly. I'm going to use it like this for a few days to make sure.

A hole in my bucket

noreply@blogger.com (Dog Saucy) — Sun, 18 May 2008 16:01:00 +0000

After two weeks on my window AC unit, I'm sad to report my little panel has not collected enough juice to fill up my Powerpack. The week before I placed the 6 watt panel and Powerpack on my roof. It took 3 sunny days to get a full tank. So this weekend I abandoned the AC unit and returned the team to the roof.

I liked the AC solution because it was so convenient. Just plug in the panel in the morning. Unplug at night. The only thing with the placement....there's a tree and streetlight nearby that eventually cast shadows on the panel around midday. The shadows must be cutting down the efficiency.

After moving the setup to the roof I realized this process is very similar to collecting rainwater for use in an apartment. Sure, you've got a tap that delivers more water in a one minute than you could collect in a week. But efficient collection plus conservation could significantly cut into how frequently you hit the tap. Now it's just a matter of where I place my buckets.

Dirty, dirty, dirty

noreply@blogger.com (Dog Saucy) — Sat, 10 May 2008 16:49:00 +0000

After three days of good sun this week I was disappointed my battery was still registering an empty status. I've noticed this pack reports only four capacity states, 0% (empty), 80%, 90%, and 100%. But I'm not even getting an 80%. Checking out the panel on Wednesday, I noticed a layer of pollen, dust and other gunk had collected on the surface. Surely this sooty crap has a negative effect on the panel's wattage.

Today I pulled in the panel, gave it good wipe down and set it back out. You can see in the pic the grossness that came off the surface. And this was after a full day of heavy rain!

I'm wondering how people in houses with panels on the roof deal with debris, pollen, bird poo and other detriment that builds up on their panels. Please leave a comment with some insight. Meanwhile, I'll be fishing my panel in and out of my window for some regular cleanings.

No sun = no fun

noreply@blogger.com (Dog Saucy) — Sat, 03 May 2008 15:19:00 +0000

The weather has been pretty crappy this week with only two somewhat sunny days. My mood and my battery are both running real low. But that's the thing with solar power. No sun, no fun.

So I'm on-grid at the moment contemplating how to scale up so I'm storing more power in a shorter amount of time. Any suggestions or comments are welcome....

Here comes the sun....in about three years

noreply@blogger.com (Dog Saucy) — Fri, 02 May 2008 13:02:00 +0000

While I've been dinking around with my little apartment panel and powerpack trying to squeak out a wee bit of solar power, researchers in Tel Aviv and Silicon Valley are claiming big advances in solar cell development. From what they say, the cost and efficiency of solar power will challenge typical utilities in about three years. Check it out below.

Start-up: Affordable solar power possible in a year

Researchers claim photovoltaic cell advance

Pulled from Engadget

AC piggyback ride

noreply@blogger.com (Dog Saucy) — Wed, 30 Apr 2008 17:26:00 +0000

Not that I mind carrying batteries up stairs....but I after some looking around my place I found a much more convenient (if not ironic) place for my panel. Pushing to the side the shutters on my window AC unit, I was able fit the panel through the unit's frame and place it up against the window. A screw on top of the AC unit was placed in a great spot to help support the bottom of the panel.

Once in place, I pulled the cable tight and ran it across the unit's length and down the side.

I also used cable mounts to nail the cable to the sill. The cable continued to the floor and plugged into my power pack.

The panel has eye holes along its length. I may pull the panel back inside, run some wire that allows me to anchor the panel on both sides, and re-install it. Meanwhile, I've saved myself a trip up the stairs on this sunny day.

A short solar afternoon

noreply@blogger.com (Dog Saucy) — Sun, 27 Apr 2008 22:06:00 +0000

BEEEEEEP!

The juice ran out almost exactly at noon. So it seems I powered my system for about 3 hours. Not bad. But if I want a full weekend of up time, I'm going to need more batteries.

What's nice is that I can just set the Powerpack back out in the sun for another charge. So maybe two batteries would make sense. While one is powering the system the other is charging. And during the week they could both charge.

The other option is to daisy chain some AGM batteries to the Powerpack. We'll see.

First solar morning

noreply@blogger.com (Dog Saucy) — Sat, 26 Apr 2008 14:37:00 +0000

Here it is....my first morning using stored power. I would say stored solar power if I hadn't charged the Powerpack off my wall. Xantrex is really adamant about fully charging the pack for 48 hours before using it. But next week, it's all sun baby.

One nice thing about this Powerpack is its portability. I have roof access with only one flight of stairs. On Friday it was super sunny in NYC. I carried the pack and solar panel to the roof and let the rays pour in. Yes, the pack was already charged. But it felt good to top it off solarly(?).

If you're a soccer fan you'll know this was a crucial morning in the Premiership. Chelsea v Man Utd kicked off at 7:45 AM EST. There's no way the pack would last powering my TV. And I'm too hungover to trek to a bar this early. But not too hungover to figure out P2PTV.

Peer to Peer TV allows users to view TV programs broadcast all over the world. I'm not sure how it works and have yet to really read this article. But it does work. I downloaded the TVUPlayer to my laptop and was good to go. Kind of wished I hadn't cause Chelsea took the game 2-1 in the last 10 minutes. BOOOOO!!!

But that tragedy aside, P2PTV is a great solution for solar powered TV entertainment. I'm not sure of the legalities involved. Be sure to check your country's policies regarding P2PTV.

Using my Dell laptop meant I deviated from my planned system. However, the pack reported I was drawing 70 watts throughout the game....very similar to my Mac mini system. I watched half the game (45 minutes) on the laptop's batteries and half on the Powerpack. The pack powered my speakers the entire match.

I'm currently writing this entry on the pack as well...so I've got a way to go. The pack should sound an alarm when it's time to turn off.

It's a bit sunny today. So after I hear that nasty ringing, I'll take another trip to the roof.

Powerpack

noreply@blogger.com (Dog Saucy) — Sun, 20 Apr 2008 19:43:00 +0000

After taking a few weeks off, I'm back on this project.

On my return, I found a great battery solution for a micro-solar system. The Xantrex XPower PowerPack 600HD is both a 28 amp hour battery and a 600 watt inverter. With a little modification, you can connect any solar panel under 30 watts directly to the unit. This negates the need for a charge controller or inverter. At $182.98, the Xantrex battery is a great value and will help keep my overall costs down.

The catch...I needed to solder a Size L Coaxial DC Power Plug to the end of my panel's cables. The plug connects the panel to the battery pack via the AC charger input socket. Normally, you would plug in AC adapter and charge up the battery pack via a wall socket. Instead, I'll plug in my solar panel and let it charge the pack during the week.

"Solder" is a scary word. Before today I didn't know anything about soldering. But this link to the EPE "Basic Soldering Guide" was a big help.

I used a wire stripper to expose the positive and negative leads.

One problem, the hole in the casing for the plug is too narrow to accept both wires. I had to widen it slightly using a drill.

Once I slid the casing on the wires, I used a multi-clamp to position the wires against the plug's contacts. The center contact is positive and takes the red wire. The outer contact is negative and takes the black contact.

If you don't have three hands, using a multi-clamp is important. You'll drive yourself crazy without one.

After the solder cooled, I slip the casing on and plugged it in the AC charger input socket.

Placing the panel in the sun caused the "Charging Status" light to glow green. The battery was collecting my first bits of solar energy.

The next thing to do is hook up my computer system to the fully charged battery and test how long I can keep things running.

Mistake = Good news

noreply@blogger.com (Dog Saucy) — Tue, 01 Apr 2008 02:06:00 +0000

Taking the advice of some postings, I purchased a Kill A Watt to get a more accurate measurement of the watts my computer system pulls. When using my system, the following components draw power.

Mac mini (1.5 GHz Intel Core Duo)
Mac 20" display
Lacie 500GB external hard drive
JBL Duet 2.0 speakers

These components pull 75 watts of power.

Airport
Cable modem

These components pull 5 watts of power.

So instead 197 watts like I previously thought, I'm only looking at 80 watts. This is great news. I only need to collect 320 watt hours of solar power to run my computer system for 4 hours over the weekend.

Research - Part 3

noreply@blogger.com (Dog Saucy) — Sat, 29 Mar 2008 16:10:00 +0000

In part 2 of my research I learned I need to collect 65.6 amp hours (788 watt hours) of electricity over 5 days if I'm going to power my current computer setup. I currently can't place a solar panel on my roof. The only other place is on the sill of my front window. It's 4.5 feet wide and 5.5 feet tall and has 8 inches of window sill to place solar panels.

There are a few options for this situation.

Global Solar makes some folding solar panels that might work. Only problem is that they are too wide (the most narrow is 9 inches wide) to fit on my sill. I also want to tilt these toward the sun. These don't seem ridged enough to do that.

They do make a 9 inch wide, ridged panel called the GSE Module 6W. This is the panel I've chosen to go with.

My sofa backs up against the window with the back extending a few inches above the sill. This panel can be placed on the sill and lean against the sofa back for the tilt. As a smaller panel, I have some more options if this setup doesn't quite work out. It's also not too expensive and an easy way to jump in and figure this stuff out.

So I picked up this panel ($67.50) at the Alternative Energy Store. It arrived a few days ago and is now sitting in my window. I also went to Radio Shack and picked up a 29-Range Digital Multimeter ($29.99) to measure how much electricity I'm picking up from the panel.

This panel is rated at 6 watts. It's open circuit voltage is rated at 23 volts. It's short circuit current is .45 amps. I went up to my roof and took a measurement and sure enough, it's hitting close to these levels.

Sitting inside in my window at 12 noon on this sunny day, it's measuring 18.48 volts and .17 amps. This means the window is knocking down its efficiency quite a bit. I'm betting it will only collect 50% of its rated power inside my apartment.

I'm going to take measurements every hour for the rest of the day.

11 am (19v - .19 A)

12 noon (18.48v - .17 A)

1 pm (18.48v - .19 A)

2 pm (18.3v - .22 A)

3 pm (17.8v - .16A)

4 pm (8.4v - .01A)

I didn't measure at 10 am but will assume I had basically the same sun as 11 am. This means with one panel I can collect good sun for 6 hours a day and operate at about 50% of the panel's rating...meaning on a sunny day I can generate 3 watts for 6 hours or 18 watt hours per day.

Let's say we get an average of 3 sunny days during the week. That means with one panel I'll collect an average of 54 watt hours by Friday night.

On my sill I can fit 3 panels. So with an investment of 2 more panels I'll be at 162 watt hours.

Remember I needed to generate 788 watt hours to run my current computer setup over the weekend. Looks like I have a problem. I either need to get more solar panels or reconsider what I'll power with the 162 watt hours I'll store.

Research - Part 2

noreply@blogger.com (Dog Saucy) — Wed, 26 Mar 2008 16:50:00 +0000

I learned from Part 1 of my research that I need to generate and store 788 watt hours of electricity to power my current computer setup for four hours. Part 2 of my research concerns how to store that electricity. The answer: batteries. Big batteries.

Batteries most commonly used in solar setups are either "Flood Lead Acid" or "Sealed AGM" batteries. Because I'm living in an apartment (ie. no garage, hardwood floors) and am not around much during the week, Sealed AGM batteries are the way to go. Because they are sealed, they won't spill acid which could eat through my floor and drip on my downstairs neighbor. They also don't require much maintenance. They just sit there and do what they are supposed to do.

A battery's storage capacity is measured in "amp hours". To figure out how many amp hours I need to power my setup, I follow this formula.

Watt hours / Battery volts = Amp hours

In my case this means....

788 watt hours / 12 volts = 65.6 Amp hours

The batteries we're talking about are 12V DC batteries...much like a car battery. If you've ever picked up a car battery you know it's heavy. I don't like carrying car batteries. And I certainly don't want to pay to ship these things. So I found the closest battery distributor to my apartment ( Interstate Batteries ) and checked out their inventory.

There are plenty of AGMs to choose from. Which one depends on how many I can stand to carry to my apartment. It also depends on how much time I've got to fill them up. Remember I want to collect electricity during the week to use on the weekend. That means I've got five days to fill up 65.6 Amp hours.

How I'll fill up the batteries will of course have some influence on exactly the batteries I purchase. I live in an apartment. There's a chance my landlord would let me place a big solar panel on the roof...but that's doubtful. So my solar panel choices are limited...meaning I'm limited on how fast I can collect solar energy....let's hope Research - Part 3 will hold the answers on the solar panels I need thus helping me decide on batteries.

Research - Part 1

noreply@blogger.com (Dog Saucy) — Tue, 25 Mar 2008 16:24:00 +0000

I've completed my first round of research and am happy to say that this project IS possible to pull off. And it may not even be very expensive.

The first site I found on DIY solar was this one from treehugger.com.

Inexpensive DIY Solar Power - The $600 Kit : TreeHugger

It's a concise plan for a cheap solar solution that could be scaled up to accommodate more demand over time. Thing is, I didn't recognize a thing in the list of items to buy besides what sounded like a car battery.

That's when I found these guys.

The Alternative Energy Store

They provide great descriptions of the necessary components and even have a section dedicated to learning the basics of setting up a solar system. If you're like me and don't know much about electricity, this is a great place to start. You can even call them with questions if you're still a bit confused.

These are the components to a basic DIY solar system.

Solar panel

Charge controller

Battery

Inverter

I now know the first step in creating a solar system is to figure out how much power you'll need to collect and store. Remember, my goal is to power my computer system on the weekends.

Here's my system. I double-checked the watts per component online. You can also purchase a watt meter to get average watt usage over time.

Mac mini (110 watts)

Mac 20" display (65 watts)

JBL Duet 2.0 speakers (22 watts)

Assuming the above watt indications are the average operating levels, this system requires the following power.

110 + 65 + 22 = 197 watts

So if I want to run my computer setup for at least four hours over Saturday and Sunday, I need to figure out how to store 197 watts X 4 hours or 788 watt hours of electricity.

How to do that will be Research - Part 2.....

The beginning

noreply@blogger.com (Dog Saucy) — Thu, 20 Mar 2008 17:35:00 +0000

Last summer I moved from a tiny studio in Manhattan to a spacious one-bedroom in Brooklyn. I expected to gain space. What I didn't expect to gain was the sunshine. My front windows get full exposure for at least 4 hours a day. That's what got me thinking.

I'm never at home during the week when all this is happening. It seems possible that I could collect the solar energy, store it as electricity and use it on the weekend when I'm home most of the day. Maybe I could even use a little at night during the week.

I also think it's a good idea have some backup power in case of a blackout. I don't see the summers getting any cooler. And I don't see oil, gas or electricity getting any cheaper. Come July when we're all cranking our AC from the Bronx to Coney Island, I'll have something to depend on when the lights go out.

So this blog will document my attempt to setup a solar electric system in my apartment. The goal of the system is to collect and store electricity during the week for use on the weekend. At minimum it should power my home computer setup. It should also be easily scalable.

I plan to include all the steps from research, to equipment, costs, setup challenges, etc.. My hope is that I can create a relatively cheap system that other apartment dwellers can copy.

Please stay tuned.