John B's posts

lol Ken,

Don't be too hard on him. And I'm sure James will sell him a package system if he really wants it, as they do carry those Sunwize package deals.

But if he can figure out why is it that one 256 watt system costs $3676.86, while for only $15 more he could get a 460 watt system, then he will be well on his way to understanding.
http://store.altenergystore.com/Kits-and-Package-Deals/Off-Grid-Systems-Cabin-Systems/c466/

Michael,

You're probably not going to like this, but you need to go back and read some more. Decide (ie measure) how much power you need, and then decide if you need/want a sine wave inverter or if a modified sine wave will do, and then how much (battery) storage you want.

I spent six months reading and researching before I placed an order with the Alternative Energy Store. Having a badly broken leg that had me in a chair for the last three months with leg elevated and unable to work probably helped a lot during that period.

I started correspondence with about one dozen companies and slowly eliminated most of them because of high prices or low knowledge. I corresponded with the solarkits.com company that you gave the link to. They seem to have several companies that operate under the partsonsale.com umbrella. In the end they were only able to offer to beat anybody's price on Mitsubishi modules. If you scroll down that link that you gave you will come across "New for 2005" which does not give me a lot of faith that they can deliver anything at the advertised price. In fact most of their other sites like to use "Prices too low to list - call for details".

Here are a few other sites that you can look at if you're just looking for the lowest possible price:
http://www.scsolar.com/index.html
http://www.wholesalesolar.com/index.html
http://solar4me.com/
http://www.directpower.com/index.html
http://www.discountpv.com/allitems
http://www.alphasolar.com/
http://store.solar-electric.com/
http://www.affordable-solar.com/

Generally speaking, I found the people working in Arizona and New Mexico to be the most knowledgeable about what they were selling. In the end it came down to Affordable Solar and the Alternative Energy Store. Pricing was very close, but I wanted to purchase everything from a single supplier so I choose AES.

Don,

That's correct, and if you have that same cable then you're good to go.

Don,

Just a follow-up clarification on the 30 amp circuit.

Your inverter does not need 30 amps to operate. That is the maximum or rated power of the inverter. With a 30 amp input at 120V you have 30x120 or 3600 watts of power coming in that can be redistributed at 12V. That would be 3600/12 or 300amps at 12V to be divided amongst all of your appliances to be used simultaneously.

If you use the 20 amp circuit from your generator your power is limited to the previously mentioned 2400 watts. If all of your appliances add up to less than 2400 watts you are OK with the single 20 amp circuit.

It is standard practice to have equipment such as inverters rated higher than the maximum load, so I think you will probably be just fine using a single 20amp receptacle. And it's always good to know your loads so you don't try to run the microwave and hairdryer at the same time.

Don,

Your best answer would come from the manual that came with your generator or from the manufacture.

Receptacles in your house are commonly 15 or 20 amps as stipulated by the National Electrical Code and they would have 15 or 20 amp breakers in the panel box that would trip if the current went above a certain level. I suspect that your generator would also have some sort of internal breaker that limits each receptacle to 20 amps.

On the L14-20 the "L" indicates "locking" and the "20" part of the code indicates 20 amps so that would be restricted also.

If your generator is placed in a position relative to your trailer where it is unlikely that anyone or anything will walk or fall across the cord then you can use the cheaper household type 120V plugs.

Remember that a gasoline engine will produce carbon monoxide in the exhaust so place it downwind and as far away from trailer windows as possible.

DON'T EVER RUN THE GENERATOR INSIDE THE TRAILER. That should go without saying, but far too many supposedly smart people have died from running generators inside their homes and trailers in the wake of power losses caused by hurricanes and other natural disasters.

Don,

I don't think you're going to find any sort of adapter that will allow you to switch between 20 and 30 amps. The easiest solution is to make up a short cable for that.

I'm working on the assumption here that your travel trailer's 30 amp connection is 120V as well. I've never "plugged in" at a camping location so I don't know. If it is 240V then you have a different kettle of fish all together. You would then have two 120V legs with 15 amps on each. Double-check that before you do anything!!!!!!!!!

The L14-20 is a locking type 20 amp plug that can be purchased in the electrical section of your local Lowes or Home Depot. This is better than the standard 120V plugs because it locks in place to prevent accidental unplugging after you insert it and give it a small twist.

If your travel trailer inverter converts 120V AC to 12V DC for internal use then this should work for you.

At the same store you should also be able to purchase a 30 amp receptacle of the same type that you currently plug your power cable into. Put these two items on each end of a short cable and you should be good to go. I would use 10awg wire minimum, 8awg preferably.

It may be worth noting here that even though you have a 5000 watt generator you can only get 2400 watts (20A x 120V) from either of the receptacles in your generator.

I will leave it to your imagination on how you could make up a short extension cord with two plugs and one receptacle since I've already said enough for someone to start asking questions about my Electrician's License.

Lawerence,

You have to look at Power and not Voltage alone. A 200ah battery will give you 200 amps for 1 hour, or 20 amps for 10 hours, or 16.67 amps for 12 hours. Power = Volts X Amps.

A 200 watt load will draw 16.67 amps at 12 volts. Therefore a 200 watt load will discharge a 200ah battery by 50% after 6 hours.

While you may be able to draw some inference about the state of a battery by measuring its voltage, remember that an almost dead battery will still measure about 12 volts.

John

Joe,

I did a search and found more information on it here:
http://www.synergex.co.nz/solarventi.shtml

And here:
http://www.users.bigpond.net.au/ges/solarventi/solarventi.html

It's a bit of a stretch to call it an air conditioner, and it can't work for me.

John

Jarred,

You really haven't made it clear what is connected and what isn't, but here goes:

14V from your PV is good. 17V from your battery is highly unlikely. That looks more like what I would expect from a charge controller trying to charge a dead battery. You can see the same thing in your car after you first start it. The alternator output shows a high voltage that falls as the battery is recharged.

The question that I need to ask is the load connected or disconnected when you get the 5.5V reading?

If you're reading 5.5V without the load connected then the output of your charge controller is bad. If it drops from 12V to 5.5V AFTER you connect the load then it is most likely to be a problem on your router board that is dragging the voltage down. However there is still the small possibility that the charge controller cannot take any load whatsoever without a severe voltage drop.


John

Thanks Tom.

I've invested a lot in insulation and double glazed windows so my home is fairly energy efficient. We slept without the AC last night and will probably only use it a few times between now and May next year. However, from June through August when the temperature and humidity are both in the 90's there isn't a source of cool air anywhere, not even at night. Having been born here I'm acclimatized to it but others have a difficult time adjusting and just run their AC units all year round.

John

Hi Lee,

I'm sure the good folks here will steer you in the right direction, but here are my two cents. Actually its probably nearer to a dollar. First let me say that I have never installed a solar panel in my life. I am anxiously awaiting the arrival of my order, but I have done a lot of reading in the past six months and maybe, just maybe, I might have slept in a Holiday Inn Express during that period.

I looked at the Kaneka panels and put them in the category of "high voltage grid-tie without battery backup". I think you're better off going with a nominal 12V PV module rather than a 60+V module and then depending on your charge controller to bring the voltage down. I can't say for certain, but I would think that you can get a much cheaper MPPT Charge Controller if it only has to operate at 12V.

I considered passive trackers and found that they added about 50% to the cost of the array, and would increase the output by about 30%. Unless you have a shortage of space, put the tracker money into more modules and leave them in a fixed position. Also, I've never come across anything that moves that wouldn't require maintenance.

As far as the pump goes, my instincts tell me that you would be better off with the 12V model and run it directly from the batteries. I just don't know if 240 Watts of PV power is going to be enough to run your pump alone, much less supply some power in a barn. Again, more experienced heads can tell you much better than I can.


John

Air-conditioning accounts for the major portion of my electricity usage during the summer months. Since evaporative cooling is ineffective due to the high humidity, I was wondering if anyone had any first-hand experience with solar air conditioning of any sorts.

I've been sort of keeping track of the unit manufactured by GPM and now distributed by SolCool since the first announcement quite a while ago. Prices have only fallen from around $7K down to around $6K which leads me to believe that sales are not going that well. It would be nice to hear an independent opinion since I am a bit skeptical about anything that SolCool might have to say after reading this:
http://www.solcool.net/fms.htm

A study carried out by the California Energy Commission seems to think that it is feasible. However, it doesn't appear as if WorkSmart Energy Enterprises have had any success with a commercial product either.
http://www.energy.ca.gov/reports/2004-10-20_500-04-062.PDF

Move the fulcrum point nearer the center of your array. Of course this might be much easier said than done as it depends on the design of your rack, but as your fulcrum point (ie hinges) approach the center of balance the force required to lift the back of the array will approach zero.

Now if I can just get the good folks at this store to ship my order out then I can start to experiment with some of my own advice. :-)