John B's posts

Posted by John B on May 6, 2008 06:49 pm

#61 -  Renewable Energy > Technical Discussion: Other > Re: Freetricity.com
Rich,

That sounds great, I noticed your website up this morning with a page from the freetricity website.

First, to answer your battery questions, maybe you should have a read from Xantrex who made your C-35 controller.
http://www.xantrex.com/support/readfaq.asp?did=267&p=590

This is another good source for learning about batteries:
http://www.batteryuniversity.com/

Generally speaking, you do not want to discharge your batteries more than 50%, and 20% (or 80% charged) is much better if you want them to last you a few years.

I am somewhat confused by the information that you have given. You have a 24V system, (and qty 4 times 6V batteries) but you give me a measurement of 12.56V for your battery when charged. Huh? where is that coming from?

You also say that you get 1 full day of use out of 2 days charging time. How does that translate into kilowatt hours? i.e. what is the model number/capacity of your batteries?

What sort of cycles are you running? Can't you just let the system charge the batteries continuously as you are using them instead of charging and discharging the batteries? What's the rated capacity of your Aims 24V inverter? Do you have any means of measuring (say a watt meter) how many kilowatt hours you are getting from the batteries so that you don't over discharge them?

John
 

Posted by John B on Apr 6, 2008 10:59 am

#62 -  Renewable Energy > Technical Discussion: Other > Re: Connecting batteries up
Here's a taster! I live in the UK so the sums about 110v are not relevant, while I understand what was implied. Our mains electricity is 230v @ 50 Hz (usa = 60hz, I beleive).

Steve, it is really a power issue so the same rules will apply. Now remember Power = Volts x Amps.

Most houses in North America will have two 110V (actually anywhere from 110V up to 130V) feeders into the mains panel. These 110V feeds are 180 degrees out of phase with each other, so 220V is available by going across the two phases.

For large loads in the 5000 watt range, like big air conditioners or electric ranges, it is normal for them to be wired for 220V operation, thus reducing the current and wire size.

If you have a 5000 watt 12V/230V inverter, the current at 230V is 5000/230 or 21.7 amps which can be carried by normal household wiring. But assuming that the inverter is working at full capacity, 5000 watts at 12V requires 5000/12 or 416 amps of current flow from the batteries.

Ignoring for the moment that such a current flow would quickly destroy most batteries, it would require a very large guage wire for the connection between the inverter and batteries.

An inverter greater than 3000 watts at 12V is quite unusual, so you might want to take another look at the specs on your inverter.

Some cheap inverters, with no disrespect to your inverter, will be advertised as 2000 watts in very large letters on the packaging. But on closer examination, and in much smaller lettering, it says rated at 1000 watts continuous power, and further explains that it can operate at 2000 watts for 5 seconds.
 

Posted by John B on Apr 5, 2008 12:59 pm

#63 -  Renewable Energy > Technical Discussion: Other > Re: Connecting batteries up
Steve,

It doesn't matter. Once they are connected in parallel, every positive point is electrically the same as the other. Same for the negatives. Also, don't forget to ground the negative. It will work without it, but if you have a problem then you want the current to flow through the ground wire and not you!

John
 

Posted by John B on Apr 3, 2008 05:43 pm

#64 -  Renewable Energy > Technical Discussion: Other > Re: AGM Batteries - Do They Vent?

I'm I gonna go boom? :-)



Probably not.
http://batteryuniversity.com/
 

Posted by John B on Apr 3, 2008 12:24 pm

#65 -  Renewable Energy > Technical Discussion: Other > Re: Wire for connecting panels to controller
Quick question, what is the best type of wire to use to connect panels to the charge controller?

Solid wire or multi-strand?

Multi-strand. However, I must caution you that the answers to these questions are not a simple as you may think. If you just want to hook up a few panels to charge a battery as mentioned in your previous posts then we can help, but it you want to take it further then you should consult an electrician.

The insulation on any common wire that you purchase will deteriorate in the sunlight so it should be run in a conduit from the panels to the controller. You can purchase wire that can be exposed to the sunlight, but that is much more expensive. An example of that would be the MC connector cables that come attached to the PV panels.

Once you have decided on the guage (size) wire that you will be using (more on this below) then you will have to consult the NEC code manual to see how many wires you can put in a conduit. Once you know how many wires you have, then you can determine what size conduit you will need.

Quote
Also is there any effect if there is a long run of wire between the panel and controller

Yes. There will be a voltage drop on the conductor. ie the wire. The larger (and more expensive) the wire, the smaller the voltage drop. Again the NEC code tables will give you ampacity for the wires so you can calculate the voltage drop that you can live with as well as the ampacity that you must have.

Ampacity refers the amount of current that the wire can safely carry. Once you know how much current your panels will be generating then you match that with the correct wire size.

As an interesting aside, I find it best to wire panels for the highest possible voltage thus giving the lowest possible current since your power losses are due to current flow. Also, a lower current means you can get by with smaller, and cheaper, wire.

If the distance between the controller and panels is quite long, then you may want to consider putting a combiner box near the panels and then use just two large wires to carry the aggregate current from the combiner box to the controller.

The combiner box would have the individual fuses or breakers for each PV, as you need those to protect both the panels and the controller or whatever equipment you have them attached to.

If you are just doing some tinkering then we can help you, but if you want to do more then you need to seek help from a professional. Give us the details on everything that you have, including specs on the panels and controller, and we can probably figure out wire and conduit sizes for you, but I repeat, if you want more then seek professional help or do a lot more reading.

John
 

Posted by John B on Apr 1, 2008 11:40 am

#66 -  Renewable Energy > RE General Discussion > Re: Successful Systems
do not put a wind turbine on a moving vehicle.  that is crazy.

But you have to admit that it's pretty damned funny. I can just picture some company that will remain nameless coming out with a roof-mounted version for your car.
 

Posted by John B on Mar 31, 2008 09:33 pm

#67 -  Renewable Energy > Technical Discussion: Other > Re: Polarity sensitive DC circuit breakers
Connect the + of the breaker to the + of the battery.
 

Posted by John B on Mar 20, 2008 04:37 pm

#68 -  Renewable Energy > RE General Discussion > Re: How many batteries will support it?
If, my AC consumption is 1000Watts, run 4 hours, that would be 4000watts dividing 12v, the quotient is require AH = 334. So, I needed 10 of PVX-340T batteries to support it.

10 batteries would only barely do the job and to completely discharge them would probably ruin the batteries after a few cycles. 24 batteries would give you a few years before you have to replace the batteries, but here are a few questions to ask yourself:

1. What are you going to use to recharge the batteries?
2. Why not use that power source to run the A/C?

Batteries are only about 70% efficient if you discharge them to 50% of capacity. That means that every time you suck 4 kilowatt hours from your battery bank, you will probably have to input 6 kilowatt hours from another source to completely recharge the batteries.

It would probably work out cheaper to run the A/C on a small portable generator.

If you want to use solar to power the A/C, then about 1000 watts of PV power is the minimum that you will require and that means you have nothing left over for anything else after running the A/C.


John
 

Posted by John B on Mar 13, 2008 11:07 am

#69 -  Renewable Energy > Technical Discussion: Other > Re: Freetricity.com
Rich,

I see your website is still awaiting upload. Have you received the WindMaster from Freetricity yet and can you let us know how it is working for you?


John
 

Posted by John B on Feb 18, 2008 04:41 pm

#70 -  Renewable Energy > Technical Discussion: Other > Re: Inverter sparking
Beverly,

I suspect that your manual transfer switch is a "Make-Before-Break" type which is causing the output of your inverter and the grid to be connected together momentarily, and the sparking occurs because they are not in phase.

You will need a "Break-Before-Make" type switch, which means that computers, TV's, and other sensitive electrical equipment might switch OFF during the brief period that it takes for you to throw the switch.

John
 

Posted by John B on Feb 18, 2008 12:26 pm

#71 -  Renewable Energy > Technical Discussion: Other > Re: Solar well pump prodject
Richard,

A 1HP pump consumes around 1200 watts while running, and something higher than that at start up. Your motor says 9.6A max at 230V so it should go much higher than 2200 watts, but I would be careful just the same as it might be enough to trip a 1500 watt inverter.

The next thing that we need to know is how often and for how long is your well pump run?

A 50W panel and 5 hours of sunshine will give you 250 watt hours of energy, or 15,000 watt minutes of energy. Your panel will therefore supply enough energy to run your pump for about 12 minutes each day.

Not knowing how your well pump is used its hard for me to say, but if comes on and off several times during the day to pressurise a water tank then it would work fine if the total run time does not exceed say 10 minutes per day on average.

In the above scenario your system should work fine if you get a 1500 watt inverter with a surge rating of 2500 watts.

John
 

Posted by John B on Feb 18, 2008 09:03 am

#72 -  Renewable Energy > Technical Discussion: Other > Re: Solar powered Low voltage lighting.
I will have a total of 1,000 watts of lights.

This looks like an ideal situation to go with LED bulbs. LED's are expensive, but you could probably get the same amount of lumens of light using only a tenth of the power, and with a longer life span they would pay for themselves in less than five years. The electric grid, wherever it is available, will always be much cheaper than a solar solution, so don't look to solar as a cost-effective solution to any power requirements.
 

Posted by John B on Feb 8, 2008 03:25 pm

#73 -  Renewable Energy > Technical Discussion: Other > Re: Freetricity.com
That's great Rich. I hope everything works well for you, but here are a couple of things that you might wish to take into consideration.

One of the fundamental laws of physics, written down by Sir Isaac Newton hundreds of years ago, states that for every action there is an equal and opposite reaction. One of the ways this manifested itself in your recent visit would be that the drill press used to turn the blades of the windmill consumed about twice the power when it was turning the larger motor delivering 31 amps, than when it was turning the smaller motor delivering 15 amps. Remember there is no such thing as a free lunch, or free "tricity" for that matter.

Of course with a nice large drill press you would not notice this, but in the real world those blades are turned by the wind and hence the power developed is dependent on the speed of the wind and the swept area of the blade.

There are several variables involved in determining how much torque a windmill will generate, and hence the amount of power (ie size of motor) it can deliver, but if anyone tells you that all you need is to change to a bigger motor for more power then its very likely that they don't know what they are talking about. Here is a good starting point for reading up on wind power:
http://www.otherpower.com/windbasics1.html

If you put a 10 watt permanent magnet motor in the windmill then a wind speed of say 8mph will turn the blades quite rapidly as there is little resistance (from Newton's Law) from the 10 watt motor. However, if you place a 500 watt permanent magnet motor in the windmill then those blades will have to develop a considerable amount of torque to turn those blades, and in all likelyhood would not even begin to turn in wind speeds below 10mpg.

In the real world you might be faced with deciding between a 5 watt motor which allows the blades to spin freely and rapidly, (and nice for the viewer who has no way of measuring the power output) or a 500 watt motor that provides so much resistance that the blades cannot turn at all.

Like I said, I wish you the best of luck, but you would have been much better off to see a unit producing 500 watts of power using nothing but the wind to turn those blades.
 

Posted by John B on Feb 8, 2008 02:35 pm

#74 -  Renewable Energy > Technical Discussion: Other > Re: Determine Charge Controller Watt Rating at Nom Batt Voltage
They are specificed. For the C35 it is 35 amps, for the C40 it is 40 amps, and for the C60 it is 60 amps.

The maximum power handling capacity of a C35 at 12V nominal battery voltage would be 35I x 12V or 420 watts. If you have your system configured for a 24V nominal battery bank then the C35 is capable of handling 24V x 35I or 840 watts of PV power.

Power handling capacity for the C40 and C60 would be calculated as above.
 

Posted by John B on Feb 8, 2008 10:38 am

#75 -  Renewable Energy > Technical Discussion: Other > Re: Determine Charge Controller Watt Rating at Nom Batt Voltage
Unfortunately, MANY charge controllers merely list maximum output (or load) current and acceptable system voltages.  How can we tell from this information what the maximum CC Watt rating is?

Watts = Volts x Amps. Most charge controllers are limited by the amount of current (Amps) that can flow through them. For the MX-60 that value is around 60 Amps. Therefore 12 x 60 gives you 800 watts at 12V and 24 x 60 gives 1600 watts at 24V etc.

The other charge controller that you gave the link for is rated at 25 amps for 12V therefore that is 25 x 12 or 300 watts at 12V.

You are not always going to get the full rated power from your panels, and a measure of safety is usually built into the products, so that is why they say their 300 watt rated charge controller can accept 350 watts of "input" power from the panels.
 

Posted by John B on Feb 5, 2008 10:54 am

#76 -  Renewable Energy > Technical Discussion: Other > Re: LONG RUN CABLE in AC or DC?
Do the longest run with the highest voltage that you have available. You are effectively transferring power (V x I), but the current (I) portion determines the size, or ampacity, of the cable that you will have to use and that will probably be your greatest cost. The lower the current being transferred the smaller, and hence cheaper, cable you can deploy. This is why power utilities transfer power from their main generation plants to the sub-stations with voltages in the kilovolt range. The low current minimizes the loss of power in the cables.
 

Posted by John B on Jan 25, 2008 12:08 pm

#77 -  Renewable Energy > Technical Discussion: Other > Re: Solaroll water heater
3M 5200 marine sealant is good. I've never tried it with any hot water systems but it works great anywhere that I have ever used it, and 3M claims it will work in temperatures from -40F to 190F.
 

Posted by John B on Jan 14, 2008 09:14 am

#78 -  Renewable Energy > Technical Discussion: Other > Re: Off-Grid Solar Project - 2KW+ - Request for Feedback
If it’s a 24V/170W panel, it would be $765/ea (@ $4.50/Watt) – that would be about 14 panels – For a 48V/2200W array = 24 panels. . .  that’s like $11,000 – $22,000 (24V vs. 48V)             
Even though the 48V system may be more efficient to invert to 110, that’s twice the up-front cost in the array. . . 

Jack,

Power (measured in watts) = Voltage x Amperage, so two 170W panels (24V/7A) will give you 340 watts whether they are connect in parallel producing 14A at 24V or in series producing 7A at 48V. However, there is a lot more to putting a system together than just selecting the panels. You will need to read some more on the basics of electricity and PV system design. This is probably a good place to start.
http://howto.altenergystore.com/

 

Posted by John B on Jan 13, 2008 11:03 am

#79 -  Renewable Energy > Technical Discussion: Other > Re: OutBack FlexMax 80
The "80" in FlexMax80 refers to the maximum current that it can handle, just like "60" in the MX60.

You are correct in your calculation that it will only handle 7 Kyocera 130 watt 12V panels if they are all in parallel, or perhaps 8 taking inefficiencies into consideration. However, it can handle four time that amount if you wire them in series for 48V.

The beauty of the FlexMax80, like the MX60, is that you can wire your panels for 48V or higher even if your battery bank is 12V since the controller will handle the step-down conversion.

I started reading Outback documentation about two years ago when I started the research for my system and I can say that is has gotten progressively worse since that time. They are probably using the engineers and developers (to whom it all makes sense) to write the documentation instead of hiring someone who could write it from the average person's perspective. Your best bet for understanding Outback products is to put your questions up on their user forum.
http://www.outbackpower.com/forum/
 

Posted by John B on Jan 12, 2008 01:11 pm

#80 -  Renewable Energy > Technical Discussion: Other > Re: Help with small system sizing!
Judging from the size of the pumps and the number of hours run, I was guessing this to be some sort of community pool.
 

Posted by John B on Jan 12, 2008 09:16 am

#81 -  Renewable Energy > Technical Discussion: Other > Re: Help with small system sizing!
Hey guys. I am trying to size a small PV system for a battery bank to power my 2 pool pumps. I have never sized a battery bank and need some help.

Here are my loads:

Pump 1-      1 1/2 HP  230V 12A
daily operating time 10 hrs.

Pump 2-      1 HP  230 V 12 A
daily operating time 6hrs.

That is quite a large system. Here is how you can start. 1HP = 745 watts, but the HP rating on motors can be quite nominal sometimes. My 1HP pool pump runs at a measured 1200 watts, so lets use 1800 watts for your 1.5HP pump.

1800 watts for 10 hours is 18 kilowatt hours per day. Now add on another 8 kilowatt hours for your 1HP pump. To get that from a 12V battery you will need 24000/12 or 2000 amp hours of battery life. That would be 20 batteries of 100AH capacity each, but since you don't want to discharge your batteries more than 50% then you need 40 batteries. That then becomes 80 batteries if you want reserve power for 2 days.

I would estimate that you will need around 10kilowatts of PV power to run that system.
 

Posted by John B on Jan 11, 2008 04:11 pm

#82 -  Renewable Energy > Technical Discussion: Other > Re: Freetricity.com
The California Attorney General might be your best bet to get your money back since their website offers franchise areas. I found this from the TopGolf BBB report.

"On November 26, 2001, we verified that this company is not registered with the California Attorney General to offer a business opportunity. If a company charges more than a $500.00 investment within a six month period, the company may be required to register with the California Attorney General. You may choose to verify registration requirements as a Seller Assisted Marketing Plan by calling 619 645 2051."
http://www.labbb.org/BBBWeb/Forms/Business/CompanyReportExtensionPage.aspx?CompanyID=13147769&sm=

They may not be the same person, but the same rule above should apply.
 

Posted by John B on Jan 11, 2008 03:42 pm

#83 -  Renewable Energy > Technical Discussion: Other > Re: Freetricity.com
But you have to admire the way he defends his product (whatever it happens to be at the time), and proudly signs his name (whatever it happens to be at the time). lol.

http://www.frauds.org/read.html?postid=23&replies=0

http://www.frauds.org/read.html?postid=27&replies=0
 

Posted by John B on Jan 11, 2008 03:21 pm

#84 -  Renewable Energy > Technical Discussion: Other > Re: Freetricity.com
As for Steve being Carl I think that is correct but even that is wrong Carl Vetts is really Carl Vettes.

And who knows how long that will last.
http://www.frauds.org/read.html?postid=29&replies=0
 

Posted by John B on Jan 11, 2008 09:29 am

#85 -  Renewable Energy > Technical Discussion: Other > Re: Off-Grid Solar Project - 2KW+ - Request for Feedback
Lots of problems here, so its difficult to decide where to start, but perhaps we can begin by looking at problems associated with using lots of small wattage panels instead of a few large wattage panels.

Each 15 watt panel has a dimension of approximately 3 square feet, therefore 2000 watts of panels will require a minimum of 400 square feet. Do you have that amount of space available on the south-facing side of your roof? If you place them side-by-side on the ground they will stretch for 150 feet or more.

You probably cannot put more that 4 of those panels in a "series" string, so that means you would have about 35 parallel strings going into a controller. That means 35 dc breakers at around $10 each for every string.

You may only get 10 watts or even less from the "cheap" and supposedly 15 watt panel that you purchased, whereas the manufacturer of a UL listed brand name PV panel will stand behind their warranty for 25 years with a guaranteed minimum output.

The system that you have shown will probably act quite nicely in carrying out its intended purpose of trickle charging a 12V battery, but I suspect you will have lots of problems if you try to extrapolate that into a 2kw off-grid power system.
 

Posted by John B on Jan 10, 2008 09:08 pm

#86 -  Renewable Energy > Technical Discussion: Other > Re: PV powered circulator pump for AET solar hot water system undersized PV panel
I think the AET systems come with them standard.
 

Posted by John B on Jan 10, 2008 04:51 pm

#87 -  Renewable Energy > Technical Discussion: Other > Re: PV powered circulator pump for AET solar hot water system undersized PV pane
probably wont cook the pump, but has potential to cool already heated watter off.  by increasing pv size, you increase the likelyhood that the pump runs before the collector is hot enough to heat the water that is already warm in the house in its tank. 

I use an El Cid 5w pump in my system that I tested by putting it on a 12V car battery. The only thing that it did was pump a whole lot faster that what it does on the 5W solar panel. I suspect the March pump is the same and will not draw any more current than it can handle, provided the PV panel is still a nominal 12V.

Early startup should not be a problem if he has a temperature differential switch controlling the pump, which I suspect he would. My setup is very simple (no freeze to worry about) and it pumps as soon as the sun comes up and continues pumping until the sun goes down. I'm considering purchasing one of those temperature differential switches myself now that the temperatures have been dropping down to the low 70's at night. lol.
 

Posted by John B on Jan 9, 2008 10:00 am

#88 -  Renewable Energy > Technical Discussion: Other > Re: What to charge for solar installations?
I couldn't afford to go to Harvard (and temporarily ignoring the fact that they wouldn't have accepted me even if I had the money) but I know someone who went to Harvard Business School and he says "Charge as much as the market with bear"!
 

Posted by John B on Jan 4, 2008 10:14 am

#89 -  Renewable Energy > RE General Discussion > Re: Successful Systems
Steve,

The folks here at AES (and their competitors as well!) can put together a packaged deal for you. A great way to start is to look at a packaged deal like this one and make sure you understand the purpose of every item in the package.
http://store.altenergystore.com/Kits-and-Package-Deals/Grid-Tied-with-Battery-Backup/Grid-Tied-w-Battery-Backup-Package-1/p6075/

Places like these below can help you with that.
http://www.nrel.gov/
http://www.sandia.gov/Renewable_Energy/renewable.htm
http://www.awea.org/
http://www.energy.ca.gov/

Once you understand the reason for everything in that package and how they all integrate then you can start to put together your own package. I too looked at having a small wind generator and in the end decided that it was not worth the trouble. Wind looks really good on initial price/performance, but if you have anything less than a steady 15 knots available to you every day then you are likely to end up with a wind generator producing about 20 percent of its rated capacity.

John
 

Posted by John B on Jan 3, 2008 11:48 am

#90 -  Renewable Energy > Rebate Programs and Net Metering regulations > Re: Introduction to Rebate Programs and Net Metering
I'm planning to store power in batteries at night, and use that power during the day when electric rates are high. 

I've always worked with a figure of 80% for battery efficiency, but this study from Sandia Labs seems to indicate that it is below 50% for a fully charged battery.
http://photovoltaics.sandia.gov/docs/PDF/batpapsteve.pdf

Figure that your inverter is only about 90 to 95 percent efficient, and each charge and discharge shortens the life of the battery, then electricity rates need to be at least three times more expensive during the day for you to break even.

If your utility allows for grid-tie, then that would be the best bet for making the best use of all the energy that you generate.

My utility does not allow for grid-tie as yet so I have a similar problem to yours. I have 3200W of solar power and many days I generate more power than I need when the sun is shining. The charge controller just shuts down the excess power from the arrays after the batteries are fully charged, and on some cloudy days my batteries fall far below a healthy state of charge since I have to transfer the loads manually between the grid and my solar output.
 

Disclaimer and Disclosure

The Alternative Energy Store, Inc reserves the right, within its sole discretion, to refuse or delete any posting or portion thereof, or terminate or block the access to this forum.

The opinions and statements posted on this forum are the opinions and statements of the person posting same, and do not constitute the opinion or act of the Alternative Energy Store, Inc (AltE). The Alternative Energy Store, Inc does not endorse or subscribe to any particular posting. No posting shall be construed as the act or opinion of the Alternative Energy Store, Inc.

Click here for BBB Business Review

McAfee SECURE sites help keep you safe from identity theft, credit card fraud, spyware, spam, viruses and online scams
Desktop Website | Mobile Website

Share

Click on an icon to share! If you don't see the method you want, hover over the orange "+".

Feedback

What can we do to help you?

Please enter a summary
Sorry, the copyright must be in the template.
Please notify this forum's administrator that this site is using an ILLEGAL copy of SMF!
Copyright removed!!