Wondering about a great new energy-saving device
you found on the Internet? Then CLICK HERE!
Sorry. Jeff no longer answers questions online.
This will remain as a searchable
resource for all BHM website visitors.
Archive for the ‘Housing’ Category
Monday, June 22nd, 2009
I recently purchased a small 600 square foot cabin that is wired for 12 volt dc. It has eight small florescent lights, a car radio and I also plug in a 19 inch 12 volt TV occasionally. In addition I purchased a used refrigerator Nova Kool model 3800 24volt DC for this cabin.
I am currently carrying two 6 volt golf cart batteries back and forth (for recharging) when I stay at the cabin on the weekends. I would like to make this process easier and am considering purchasing a Suntech 175W 24V Solar Panel, a charge controller, two more golf cart batteries and a power converter 24 volt DC to 12 volt DC. I plan to keep the lighting and power outlets at 12 volt DC and have 24 volt DC to power the fridge.
Am I on the right track? Do you know if Suntech solar panels are good quality or not? Can you recommend a charge controller and power converter for this application? Any other advice you might have for me?
The solar module you are considering is a 24 volt module, and cannot be connected to a 12 volt battery system unless you purchase a $400+ MPPT solar charge controller that allows a higher voltage solar array to charge a lower voltage battery. If you use a standard charge controller, it will force the solar module to operate at half its normal voltage which cut its watts output in half.
Although I do not buy or install any solar hardware made in China for more reasons than I can discuss here, I will say that SunTech is one of the oldest and best respected solar manufacturers in China, but I was not pleased with workmanship on the few that I have purchased.
If you stay with a 24 volt battery to match the 24 volt solar module, you will need four (4) golf cart batteries, and I think you will find the lower cost voltage converters to be very light-duty for this application. We have had several fail when loaded near their advertised ratings.
Since this is a small cabin, I would keep the batteries and all wiring 12 volts DC as you can find almost anything in an RV or boating supply store that will operate on 12 volts DC. You cannot find much of anything to run directly from 24 volts DC unless you use the voltage converter, but then if it fails you lose everything.
Good Luck and buy a good LED flashlight!
Friday, May 22nd, 2009
Do you have any experience with propane refrigerators? If so, what model small refrigerator do you recommend for a small cabin that will be used year-round?
Thanks so much,
We have included propane refrigerators and freezers on many solar off-grid homes, but since most are based on heating a gas to cause the cooling cycle, I would not use them in an application where the home is not occupied for many parts of the year like a typical weekend cabin. After the first few years there are some maintenance issues that you need to take care of to keep them operating properly, and they do use a lot of propane.
We have switched to the 12/24 VDC small 50 liter refrigerator or the larger 8 cu.ft. top load freezer by SunDanzer that operate from solar charged battery. They require very little solar power to operate due to their very heavy wall insulation, and do not use a flame like the propane units. I think if properly installed they are a much safer and offer a longer life solution, although they are more expensive.
Thank you for your quick reply
If you do not mind another question, I am wondering what brand of 50 liter refrigerator would you recommend? And, pardon my ignorance, but what does the “V” in VDC mean? Does it mean voltage?
You can see I am at the beginning of the learning curve relative to using solar energy/alternative energy sources to achieve energy independence for a small cabin.
SunFrost and SunDanzer both make really great super-efficient DC refrigerators and freezers. All SunFrost models are stand-up designs, and all SunDanzer models are top load. You may like the stand up version better, but they are pricey.
I have worked with both for almost 15 years and each has their advantages. Up until this year, the SunDanzer units were in the 8 cu.ft. range which is fairly large. This spring they came out with a 50 liter unit which I found to be perfect for a week-end cabin type application due to the small size and very small battery usage. However, it’s a top load and must be ordered either as a freezer or a refrigerator, but not both.
When we say “VDC” we mean “volts DC”.
Click Here for ome other useful solar terms
Hope that helps.
Wednesday, March 25th, 2009
I have a situation not completely unlike Blake McKinney’s cabin (issue 83) in that I am planning an off grid cabin that will only be used once in awhile — in northern Wisconsin! Was considering solar hot water (closed glycol system) that might be able to be integrated into a radiant infloor (also with glycol) system to keep the house/plumbing from freezing when no one there. Do you think this is reasonable? Electric to run the pump would be from PV modules/battery bank. Would you still recommend a propane wall heater as backup?
We would use a high efficiency wood stove to heat home when occupied.
Our solar exposure is considerably better than the McKinney place.
Also, do you know of any remote monitoring system for house temperature, etc that could use cell phone signal to communicate info back to us at our main residence 90 miles away? :)
Finally, is it generally recommended to NOT let your propane generator automatically switch on to recharge the batteries when no one is around?
Thanks a bunch,
That’s a lot of questions!
I would not recommend trying to heat a home with an active solar system for long periods of the winter when nobody is home. There are too many little things that can turn into big things when nobody is there to correct. For example, a big snow can cover the solar array for days if nobody is there to clear them off. A pump could fail, or the system could leak. Even a small leak of a sealed antifreeze system will cause makeup water to enter and could cause the now antifreeze in the loop to freeze.
I would deal with this in one of two ways. Either design a passive solar home that has enough thermal mass to keep from freezing at night, or design all the plumbing to slope to 2 or 3 low points where you can completely drain all the piping before you leave. Blankets and sheets on beds and clothing in closets will become “musty” under these conditions so I would strip the beds and remove anything that could be damaged from the cold and/or dampness.
I would not leave a generator on automatic start if I was going to be gone longer than a weekend as a simple control glitch or battery problem could cause the generator to run until it ran the tank dry.
There are now all kinds of remote Internet and wireless phone based controls to allow monitoring of remote homes and businesses. We have inverters that will send an email to the installer if there is a problem, and there are Internet based cameras that will send you live video of inside your home if the alarm is activated or there is a water leak.
I suggest that you keep it simple. If the pipes are dry and you remove anything that can be damaged from the cold, why spend all that money to heat someplace you will not be for months at a time.
Thursday, March 5th, 2009
I am looking for sources, info, anything that will help concerning building an energy efficient retirement home, off the grid if possible, east of Dallas, Texas. Prefab companies, plans, books, anything to help me get started.
We have had numerous articles about solar system design, solar system types, how solar works, etc. Many can be read online. And the Backwoods Home Bookstore has two good books on solar systems including one I reviewed in the last issue. Order the back issues on CD if you no longer have these issues.
Thursday, February 19th, 2009
My 1928 stucco frame house has I believe no insulation in the walls. I do have blown insulation in the attic. I’ve done some research on installing expandable foam in the walls so as not to have to remove the interior plaster walls. It’s going to be expensive and the payback is about 6-7 years. Any comments on the foam issue?
Yes, older homes are a real problem to heat, but on any home the most heat loss is usually out the roof and air infiltration. Wall heat losses are far less if you can seal up all the cracks around windows, doors, wall outlets, and anywhere else the wind blows. In other words, I would first put the most money in insulation for the attic and sealing all the cracks. We did tons of computer energy modeling that showed it made sense to install thermal windows in new construction, but the high cost to retrofit them in an existing older home with many other problems was not worth the high cost.
As far as spray in foam insulation, its a great insulator, but if not done right, you can get voids if the mixture is too little, and you can blow off the siding if the mixture is too much. They also have to drill lots of holes around the exterior walls and I am not sure how well those can be patched to look good after.
Saturday, January 17th, 2009
I live in Wisconsin, which is prone to ice storms similar to what shut down the power grid in the Northeast and across Indiana this winter.
I am considering a battery backup system using four golf cart batteries wired to 12v and a 1500-2000 watt inverter to power lights, fridge, gas furnace, or wood stove blower [separately, of course].
Since I don’t have the budget yet for solar or wind, I was wondering if using my Honda Odyssey’s alternator with a battery isolator installed to recharge the battery bank would be a good idea. Any thoughts would be appreciated.
Thank you in advance,
We have many projects with batteries and inverter for emergency power that did not include solar. However, I would not use the car to re-charge the batteries as this will be a major load on the small alternator and will use more gas than you think as you will probably need about 3 hours of charge time per day which is like driving 200 miles each day.
Keep your idea, but buy a generator. Most high quality inverters will include a high capacity battery charger which will allow re-charging for about 1 or 2 gallons per day. The only caution is you need a good quality generator in the 6 kW or larger size range, and having a good voltage regulator. Low cost generators drop their peak to peak voltage as they get loaded up and any battery charger will stop charging altogether when this happens.
Thursday, January 15th, 2009
My name is Bruno Enzler. I live in the Netherlands and I have a question about independent energy.
First of all thank you for your website information. I’m reading through it.
I’m trying to figure out if I can start a business in Solar Energy and a lot of ideas go through my mind.
One of these ideas I would like to ask you about.
Is it possible to provide a bungalow recreation park or a similar location with solar panels on the roofs of the bungalows and to centralize the energy to a powerhouse or a large battery bank in order to make the park independent from a energy company?
If I need to make my question clearer please let me know.
Thank you so much for your reply.
Best regards and best wishes for 2009.
There have been many successful off-grid solar powered rental units on islands and in areas without grid power, with each unit having its own solar system. There have also been central systems with one large solar array and battery bank used to supply separate cottages surrounding this central system. It really comes down to cost if this is worth doing as the equipment is easily available.
Unless you are in a very unusual location, if you can easily connect to the power grid its very hard to justify the high cost in a rental type application.
Good luck with your venture!
Tuesday, January 6th, 2009
We live in a condominium apartment and a good part of the year we receive a lot of wind. We also have several south facing windows and a deck with good exposure to the sun. With condominium rules and regulations, we’re not able to put solar panels on the roof. Is there a solution to energy independence when you live in a condominium like this one?
Yes, been there, done that. My big concern would be reducing my electric loads and emergency power. When we lived a year in an apartment complex in the middle of a large city during the construction of our solar home, there were several power outages. Although this never affected us due to the emergency preparations listed below, we got a big laugh watching everyone bail out of the complex 5 minutes after the power went out and head for Mom’s house or a hotel. I still can’t believe how un-prepared most apartment and condo dwellers are.
First, reduce your energy usage. What difference does it make if you save 500 watts by reducing your electric loads by 500 watts, or keep the loads the same and install a 500 watt solar system – your bill still goes down the same amount, and you didn’t spend $5000 for a small solar system you aren’t allowed to install anyway.
Replace every light, and I mean every light, with compact fluorescent lamps or halogen. Buy the “warm” color fluorescent lights, which may require going to a lighting store. For most applications, a 15 to 25 watt compact fluorescent lamp will work where you had a 75 to 100 watt incandescent bulb. Anywhere you need really good color quality like a bathroom mirror or kitchen, replace with halogen. A 45 watt halogen bulb is blinding and has great color. It can replace an incandescent bulb 2 to 3 times its wattage.
Most likely your next biggest load is your refrigerator, and if it is over 10 years old it was built before major changes were made in the Federal energy guidelines. Also, if it came with the condo, it probably was “spec” quality, which is at the low end of efficiency even if its newer. You can replace this energy hog without the permission of the condo association. Finally, if you do not have one already, replace the standard wall thermostat with a good quality programmable unit, also something you can do without permission and this can really save if you are gone most of the day.
Next, be prepared. Since you have limited storage space take one small closet or under one bed and make that your emergency storage room. Build up a pantry in the upper half with foods that will store a long time and require minimum preparation. Buy a canned heat camping stove. These fold up and take very little room, yet easily heats a pan of water to prepare rice, instant heat-and-serve meals, etc. Add a few gallons of bottled water and 2 or 3 LED type flashlights. Extra batteries is a must have. Add a small battery radio and extra trash bags, paper plates, plastic utensils, and you are ready for anything!
There have been many past articles in Backwoods Home on how to make an emergency pantry and what you should have on hand at all times. I suggest reading these back issues for more ideas.