Solar Backup Generator

[Flufreak]

Re: Solar Backup Generator

http://www.costco.com/Browse/Product.aspx?Prodid=11298162&search=solar&Mo=26&cm_re=1_en-_-Top_Left_Nav-_-Top_search&lang=en-US&Nr=P_CatalogName:BC&Sp=S&N=5000043&whse=BC&Dx=mode+matchallpartial&Ntk=Text_Search&Dr=P_CatalogName:BC&Ne=4000000&D=solar&Ntt=solar&No=9&Ntx=mode+matchallpartial&Nty=1&topnav=&s=1

$320 gets you a 60W Coleman setup at Costco, only a 150W inverter though.

For low power dc only, Costco has a $100 setup (2.5W charge, 7.5W output ) that includes a Lithium ion battery:

http://www.costco.com/Browse/Product.aspx?Prodid=11467546&search=solar&Mo=26&cm_re=1_en-_-Top_Left_Nav-_-Top_search&lang=en-US&Nr=P_CatalogName:BC&Sp=S&N=5000043&whse=BC&Dx=mode+matchallpartial&Ntk=Text_Search&Dr=P_CatalogName:BC&Ne=4000000&D=solar&Ntt=solar&No=7&Ntx=mode+matchallpartial&Nty=1&topnav=&s=1

[Alwaysprepared]

Re: Solar Backup Generator

I wanted to give a quick update on my solar backup generator. I've had no problem at all getting a panel. I actually got one locally through a discount tool wholesale place. Apparently it is normally used by craftsmen to recharge their cordless drills. It's a more modern solar panel, so a charge controller was not necessary (but still recommended). I also ordered a backup solar panel, which was the very same device, and this took several weeks to arrive.

The battery is a deep cycle marine battery from a local store. I also have a backup battery which is currently in use as a backup for my sump pump. I really believe in redundancy.

I purchased the wires and most of the wire nuts and wire numbers from a local hardware store. The battery box was purchased at an automotive store.

It was not at all difficult to put it together. The solar panel came with clips to attach it to the battery across the voltage terminals. You can also attach it more securely and permanently with lugs.

The inverter was purchased at the same tool wholesaler outlet. I have also found them for about the same price at my local electronics store. Inverters come in ascending prices based upon the amount of watts that you need. Ultimately there a real limit to how many watts you can pull based upon the number of deep cycle batteries you are using. Look that particular part up in the links I showed earlier. If you had many solar panels and many batteries, you could really power a lot of devices. My setup is very small scale, just enough for emergency use.

It's not at all difficult to build this. I feel much better now that I made it. I would highly recommend making one for peace of mind.

What kind of inverter and wires do you use? Thanks.

[Zac]

Re: Solar Backup Generator

Systems runs more efficiently with a higher voltage because the current (amps) required to deliver a given amount of power (watts) is lower. For example, a 240 watt load would draw 20A at 12V, but only 10A at 24V or 5A at 48V. This reduces the resistive losses (turned into heat) in the wiring among other things.

There are also DC-DC converter that can convert from the battery (12/24/48V or whatever) to the voltage you need for your load without going through an inverter. This is more efficient, but may not be practical for some devices. Devices that use a wall adapter that supplies a single DC voltage are the easiest to use in this way.

I have a number of the ICT and Lind brand DC-DC converters and have found them to be well built and durable. There are many commercial ready-to-use dc-dc converter models intended for use with forklifts (48V), commercial vehicles (24V), and military/aerospace (28V) that may be suitable and available inexpensively in the surplus market or on ebay. If you're willing to do some soldering and mate heatsinks/fans with the dc-dc converter then there are many more choices. Searching on ebay for vicor will bring up some of those.

Keep in mind that most (if not all) dc-dc converter consume a small amount of power like most inverters even when the load is not turned on. So, it is best to switch them off or disconnect them when not in use. As much as possible, I try to get devices that can directly use the battery directly, avoiding both inverters and dc-dc converters, for the highest efficiency.

[Zac]

Re: Solar Backup Generator

Here's some stuff I wrote up on another forum that may be of interest:

In response to how much solar capacity is needed to run a refrigerator:

I have a small solar system that produces about 8 kwh/day in the summer (about 1/2 that in the winter). My 8 year old maytag freezer-on-top 25 cuft refrigerator consumes 1.8 kwh/day. The inverter consumes about 30 watts with no load so the daily (24 hour) power consumption including the inverter is about 2.5 kwh. I don't know the exact cost for my solar system as I got the components over a few years, mostly from ebay and craigslist.

At current prices, the cost for a small system that could run a full size refrigerator is about $6K:

(1) 8 GC2 6V @ 220 Ah golf cart batteries @ $90/each, $720 (available at costco and sam's club)

(2) solar panels with 1500 watt rated production, $3/watt, $4500 (might be able to get cheaper surplus panels and could use less capacity, but would run risk of having insufficient production in the winter)

(3) mppt charge controller, $600 (Apollo T80)

(4) 1.2+ kw inverter, $200 (surplus sine wave model from ebay)

(5) cables, hardware, breaker(s), misc, $200

---

My 8 year maytag front loading washing machine required a peak of 850 watts and consumed 0.2 kwh per load (according to the kill-a-watt meter) of towels using the extra rinse option. Also, an energy star compliant 7 year old 25 cuft. refrigerator consumes 1.8 kwh/day.

---

I ordered a set of 8 of the Surrette S530's for a 48V@400Ah (19.2 kwh) battery bank. Cost was $2838 including sales tax, but I have to go pick them up myself. (cost before sales tax was $320 per 6V@400Ah battery)

Surrette's spec on the S530 capacity is 400Ah @ 20 hour discharge rate, but that actually rises to 530Ah @ 100 hour discharge rate, but they don't mention anything about the charging rate or its effect on life or capacity. (I would want to rapid charge them when running a generator to conserve fuel.)

I checked out the latest shipment of GC2 golf cart batteries (6V @ 220 Ah) at costco today. They increased the price to $80 (+9 core charge) and reduced the warranty to 12 months (6 months non-prorated).

Also, some new model MPPT charge controllers such as the Apollo T100 and Xantrex XW support a higher PV input voltage which allows smaller wiring and potentially more efficient operation. I like the Apollo T100 which allows up to a 160V operating voltage with 200V open circuit. The Xantrex XW allows 140V operating, but only 150V open circuit. The Apollo models also support an external current shunt that does net current metering to/from the batteries and has a bigger LCD display. (The older Apollo T80 allows 112V operating and 140V open circuit.)

[Possibilities]

Re: Solar Backup Generator

I wanted to give a quick update on my solar backup generator. I've had no problem at all getting a panel. I actually got one locally through a discount tool wholesale place. Apparently it is normally used by craftsmen to recharge their cordless drills. It's a more modern solar panel, so a charge controller was not necessary (but still recommended). I also ordered a backup solar panel, which was the very same device, and this took several weeks to arrive.

The battery is a deep cycle marine battery from a local store. I also have a backup battery which is currently in use as a backup for my sump pump. I really believe in redundancy.

I purchased the wires and most of the wire nuts and wire numbers from a local hardware store. The battery box was purchased at an automotive store.

It was not at all difficult to put it together. The solar panel came with clips to attach it to the battery across the voltage terminals. You can also attach it more securely and permanently with lugs.

The inverter was purchased at the same tool wholesaler outlet. I have also found them for about the same price at my local electronics store. Inverters come in ascending prices based upon the amount of watts that you need. Ultimately there a real limit to how many watts you can pull based upon the number of deep cycle batteries you are using. Look that particular part up in the links I showed earlier. If you had many solar panels and many batteries, you could really power a lot of devices. My setup is very small scale, just enough for emergency use.

It's not at all difficult to build this. I feel much better now that I made it. I would highly recommend making one for peace of mind.

[Possibilities]

Re: Solar Backup Generator

Here's a website which gives a clear schematic. Don't be nervous, almost anyone can do this.

http://www.grandpappy.info/wsolar.htm

[Possibilities]

Re: Solar Backup Generator

Here is a website which details FREE plans on how to build a variety of do it yourself solar projects. I am listing it here since many companies are asking folks to pay for plans, and it simply is not necessary.

http://www.builditsolar.com/index.htm

[Possibilities]

Here's what I am planning to do for a solar backup generator. I looked lots of places, and it's really quite simple as this gentleman has illustrated in his video. The big problems is finding a solar panel at this late date. I calculate spending around $300 for the charge controller, battery, solar panel, battery box, inverter, voltmeter, and misc connections.

Here is a video which details how to put one together YOURSELF. Anyone who takes some practical safety precautions can make one of these. The video does not attempt to sell you anything, it is only a demonstration of how simple it is to cobble one together using inexpensive parts.

http://www.youtube.com/watch?v=ROyER7YT4DM

The majority of the components can be purchased locally except for the solar cell in most cases. You can google backup solar generator in order to find FREE plans. There's no need to buy a ready made one, nor pay for plans.

Here is a website that has free plans though you should watch the video above to see how to hook up everything.

http://www.rain.org/~philfear/how2solar.html

This is a copy of a post that I made yesterday 04/30/2009 in another part of the forum. I was able to purchase my solar panel and charge controller at Harbor Freight Tools. You may be able to find something similar in your own home town. This is not an endorsement of Harbor Freight by the way.

I am using a dc to ac inverter (rated at 400watts) in order to recharge my cell phones, rechargeable batteries for flashlights, AM/FM radio that receives TV (but no screen) and receives NOAA. [I'm betting that they would use the NOAA channel to send out public emergency information in the event of a severe pandemic.] You could buy a larger inverter i.e more watts, but it's going to drain the deep cycle battery quickly. You are not going to power up any large devices.

I am also going to charge my laptop since it contains multiple pdfs for home schooling my children. I also have stored several documents from diverse places like the Hesperian Foundation's ebook, "When there is Doctor". I am putting the documents directly on my internal hard drive instead of a backup hard drive since it would put an additional energy drain on the laptop. You can greatly increase the total time you can use your laptop by turning off your wireless card, and by turning down the screen brightness.

I seriously thought about buying a generator but decided against it. Where would I store the diesel fuel? Generators are LOUD, and I imagine that people might fight over them later. Having one makes you a target. What would I need one for since it's Springtime? If It was winter, I might consider it.

I have two propane tanks for emergency cooking on cloudless days. I plan on eating simply heating my food with a solar oven if need be. Really it's more about the comfort that comes from eating hot food. I plan on being practical and eating from the refrigerator and other perishables first, followed by what's in my freezer, then canned goods.

For emergency lighting, I purchased an inexpensive lamp that burns paraffin oil. The lamp is enclosed, which will assist with preventing fires. Open candles burn too quickly and will be dangerous with my inquisitive children. I noticed today that there were no matches to be found in my large local Meijers. Hmmm. Bought a couple large butane lighters instead. From what I read in Bosnia matches were extremely hard to find later.

Without revealing too much, I grew up very poor, and then later when I went back to school, I lived in extreme poverty. There were times I didn't have enough to eat, and literally ate a tablespoon of peanut butter and water for a meal. Sure it's nice to have lots of money, diverse foods to eat, cold AC when it's hot, and heat when it's freezing. It's nice to lights on all over the house for convenience. We can manage just fine being very judicious about turning on the flashlight, and being careful about having on the radio.

If the Pandemic doesn't progress too quickly, and I can manage to build one, I am considering making an Earth battery close to the house. Here is a link to how to make one:

http://peswiki.com/index.php/PowerPedia:Earth_battery

The Earth batteries were used long ago to power up telegraph stations.
Here is a link showing a demonstration:

http://www.youtube.com/watch?v=eztcSWZpfJg&feature=related

I am looking for a good link which demonstrates a cheap way to do this. It would probably never power up an AC device, but it might be used as a trickle charge for a dc battery.



Good luck everyone.