Living offgrid with small solar system(s)

[Muhendis]

Mine is 7 phase. Or rather, it will be when I finally get the time to put it all together. What comes out will effectively be slightly bumpy DC. My sympathies to all users of Hummer. The electronics to make DC from the turbine would be quite substantial. The piggott design uses no slip rings so you would need to untwist the down lead occasionally. There are no yaw bearings because they would be too easy to move in the slightest breeze. I will not be spending time carving wood for the blades but instead will be using ten inch plastic pipe cut to suit. My earlier scale model leads me to this. We don't have so much wind here in Thailand. Possibly about 40% of the year but it seems such a shame that it should go to waste.

[Jing Joe]

Mine is 7 phase. Or rather, it will be when I finally get the time to put it all together. What comes out will effectively be slightly bumpy DC. My sympathies to all users of Hummer. The electronics to make DC from the turbine would be quite substantial. The piggott design uses no slip rings so you would need to untwist the down lead occasionally. There are no yaw bearings because they would be too easy to move in the slightest breeze. I will not be spending time carving wood for the blades but instead will be using ten inch plastic pipe cut to suit. My earlier scale model leads me to this. We don't have so much wind here in Thailand. Possibly about 40% of the year but it seems such a shame that it should go to waste.

I don't see how "the electronics to make DC from the W/T would be quite substantial". I assume the Hummer? Generally, it only needs a suitable bridge rectifier and they have come down in price over the years and their ratings have been going up. I assume this regulator/inverter has at least a 50 to 60 amp bridge for its 60 volt working conditions. (AC comes down the lead). Probably less expense than 7 bridge rectifiers total in a comparable size W/G? But for sure, go for anything but single phase design. Not just for the noise my Hummer has but the cogging effect that resists start up in light winds.

Good to see you have confidence in the cut-pipe blades. At the other end of the efficiency scale/design, I once used a 400W 48v AIR brand like for yachts. Its blades were computer designed and moulded and as such were supposed to harvest max energy. W/G power out is proportional partly to velocity cubed I think, and they claimed to have just about done this to the max. Its speed was phenomenal and the tips were designed to distort instead of over-revving into self destruction. The breaking of the sound barrier effect was waking the dead so I took it down. Even wooden single blade W/G blades in the 1930's had some nice aerofoil shapes. If you don't have much wind, why not put the extra effort into shaping the blades because as you said "shame that it should go to waste" ? and there's good instructions on that web site you gave us.

Re wind levels, where are you in Thailand?

Edited March 9, 2016 by Jing Joe

[Muhendis]

The electronics for a single phase (Hummer) I describe as substantial because a full wave rectified sine wave of a 60v p-p sine wave would give you +/- 30v half wave voltage. That is to say each half wave would start at zero and rise following the sine rule to it's maximum of +30v and then decay back to zero. A ripple voltage of 30v. To convert this to a smooth DC voltage requires a filter of some magnitude designed to handle both the current and the variations in frequency. A multiphase design requires a much simpler filter (possible none at all) and the rectifier on each phase need not be a bridge rec. Full wave rectification will be quite adequate. Assuming, once again, a 7 phase, 60v 8A output, the voltage seen by the charge controller will have a ripple voltage of about 1v which would require negligible filtering. I would assume that the Hummer controller has all the required filtering inside so the costs of the filtering would be hidden within the overall cost of the unit. Besides, the term I use "substantial" is not so great in terms of actual cost but more in terms of relative component cost. I have short arms and deep pockets.

The aerodynamics of a pipe cut blade complete with 4 degree twist and taper are just as good as a well carpentered wooden blade. But there is a huge difference in the cost measured in manhours and weight. As you mentioned. The startup in low wind is important. a plastic blade will be far lighter than a wooden one and with less mass, it will present less torque for the wind force to push around. As you probably know, a half decent blade will have lift which will make it go round faster than the wind can push it. The downside of the plastic pipe blade is it's weakness where it is joined to the turbine and the effects of UV light on the plastic. These are of concern to me and I will be paying close attention to them in the design.

I am in Buriram province. When the wind blows trees fall down. When the wind doesn't blow we roast.

[George Harmony]

Think that @naam will laugh....

I bought two mini usb fans, one for my planned work desk and one for next to my bed.

Ive tested yesterday with a small powerbank and it runs till morning and i could still charge my hp.

Think i dont have to use my big table fan again.

Here a review by someone: https://m.youtube.com/watch?v=OLIPT7ibYVQ

[Naam]

@the @only @thing @i @laugh @is @your @using @the @sign.

[George Harmony]

I use "@" cause naam = in dutch name...so your name=name ?

[George Harmony]

I was sitting about 3 meters away from this mini usb fan and i still felt the breeze.....really amazing

[George Harmony]

Does anyone know. If i have a gadget with adapater ac to 5volt BUT I connect that gadget to a 6volt battery will it go "kaput" ??? Its a musicbox with fm radio. If that gadget can handle that 6volt also in the long term i dont have to use a step down module.

[Muhendis]

That all depends on the specification of the "music box". Frequently these gadgets will run ok out of spec. but may run a little hot. Is there a rating plate on the gadget which states the range of input voltages it will work at? I suspect the answer will be "no" in which case there is only one way to find out without any converter..............

Something you could try is to add a couple of schottky diodes in series with the supply to the gadget. This will get rid of an unwanted volt or maybe use a standard silicon diode which will get rid of 0.7 volt. Both solutions will probably be a fine and permanent fix.

[George Harmony]

Adapter=5volt 600ma

[George Harmony]

Adapter=5volt 600ma

Diode solution is a good tip..thanks

[Muhendis]

As I thought. That information is not helpful for what you want to do. I guess there is no information on the musicbox with fm radio so you're left with the diode idea or take the risk and run the musicbox with fm radio off of 6V. By the way. If you go for the diode idea, a silicon diode of 1 amp capability (1N4007) should only cost a few Baht and are readily available from any electronic component shop.

[George Harmony]

If you go for the diode idea, a silicon diode of 1 amp capability (1N4007) should only cost a few Baht and are readily available from any electronic component shop.

Thanks...i will look for this diode.

[Crossy]

If you go for the diode idea, a silicon diode of 1 amp capability (1N4007) should only cost a few Baht and are readily available from any electronic component shop.

Thanks...i will look for this diode.

Any 1N400X (X= 1-7) will do, the end without the band goes to the + of the power supply, the end with the band goes to the + of your radio.

I would start with two in series (about 1.2V drop) and check what voltage you have at the radio, if less then about 4.5V then take out a diode.

They look like this http://www.mynpe.com/mynpe/more.php?data=263301014007 0.32 Baht each

I have a big bag of 1N4007s drop me a PM with an address and I'll bang a few in the post if you can't get them locally.

[George Harmony]

Thanks for your offer. Think i can get it here....

[Jing Joe]

The electronics for a single phase (Hummer) I describe as substantial because a full wave rectified sine wave of a 60v p-p sine wave would give you +/- 30v half wave voltage. That is to say each half wave would start at zero and rise following the sine rule to it's maximum of +30v and then decay back to zero. A ripple voltage of 30v. To convert this to a smooth DC voltage requires a filter of some magnitude designed to handle both the current and the variations in frequency. A multiphase design requires a much simpler filter (possible none at all) and the rectifier on each phase need not be a bridge rec. Full wave rectification will be quite adequate. Assuming, once again, a 7 phase, 60v 8A output, the voltage seen by the charge controller will have a ripple voltage of about 1v which would require negligible filtering. I would assume that the Hummer controller has all the required filtering inside so the costs of the filtering would be hidden within the overall cost of the unit. Besides, the term I use "substantial" is not so great in terms of actual cost but more in terms of relative component cost. I have short arms and deep pockets.

The aerodynamics of a pipe cut blade complete with 4 degree twist and taper are just as good as a well carpentered wooden blade. But there is a huge difference in the cost measured in manhours and weight. As you mentioned. The startup in low wind is important. a plastic blade will be far lighter than a wooden one and with less mass, it will present less torque for the wind force to push around. As you probably know, a half decent blade will have lift which will make it go round faster than the wind can push it. The downside of the plastic pipe blade is it's weakness where it is joined to the turbine and the effects of UV light on the plastic. These are of concern to me and I will be paying close attention to them in the design.

I am in Buriram province. When the wind blows trees fall down. When the wind doesn't blow we roast.

Thanks M for reply. Looked up Buriram Provence. Sound similar to that proverbial place somewhere were;- "it never rains then it pours".

Not quite agree about your AC theory M re W/G. It is actually a 21v sine wave that has a 30V peak. (1.414 x RMS = peak) and peak V is mostly relevant after rectification (half or full wave) if a filter capacitor is in circuit for it to charge to that peak V (and assuming no load). Not going into charge(Q) capacitance© and Voltage(V) versus drain here. The circuit on P21 of your upcoming W/G has 4 x full-wave bridge rectifiers. If your regulator is going to have a storage capacitor and charges/regulates from there, maybe you might be interested in smoothing any ripple with capacitance (and choke?) but maybe only to satisfy some features of the regulators electronics.

With my Hummer regulator/inverter, its different approach regulates by dumping 20 x 100W halogen lamps across its output when that V equals 65V, from memory. They are 120V lamps so at only 60 volts applied and with assumed negative co-eff of resistance, it could be effectively more than nominal 2000W (20 x 100W).

I don't think there is a filter capacitor nor do I see the need in this design. There will only be charge current from that area of the rectified pulses that exceed the battery V up to the peak V value. And because of the zener effect of the battery combined with its hopefully low internal resistance, there may only be a very marginal ripple of the battery voltage. Optimistically the repeated charge pulses we know then chemically converts the battery to steadily increase its voltage, and in turn the W/G needs just that bit more speed to rise to the occasion so to speak. Any capacitor in this design would surely have to be massive to achieve a comparative smoothing effect compared to the zener and internal resistance effect I mentioned. Today my W/G speed is frustratingly just under the "bar" and the simple Hummer regulator is not a tracking design like my solar regulator..

Re the cut-pipe blades, all the best and may I share my experience with white 90mm rainwater PVC pipes in the sun. 30+ years ago I painted some with what turned out to be a good quality water based paint and recently re-arranged part of them. Some parts not exposed to the direct sun had only scratchy brush marks originally, and in between them the PVC had eroded/etched about 1mm deep.

Re the blade where it joins the hub, no doubt you will be curving the shape to reduce discontinuity for strength (where there is little wind action/gain anyway) so how about also applying pressure pack construction foam to fill that ineffective part of the root of the blade? Any extra rigidity could help? It would need painting also, with water based paint.

BTW. I've been amazed at the insects(?) that have caused minor erosions/collisions of the leading edge of blades during my living with W/G about 38 years now.

[gk10002000]

Don't need cooling for meat. Keep a few chickens. Fresh kill and eat. raise some rabbits, fresh kill and eat as needed. Get some guinea pigs like they do in South America. One dog is a decent meal. I am a believer that goats could do well in Thailand but they don't seem to have a large following

[Jing Joe]

Thanks for your offer. Think i can get it here....

Don't let it stop at just two diodes for any other applications George.

I've used up to about 8 in series for other applications and their total surface area is safely proportional.

Keep in mind the knee of the conductive part of their curve has more slope than Zener diodes so you could get more than 0.6V drop depending on how much current your device needs. Use how many that suits the device. It can go up to 1.0 V per diode but still a good cheap suggestion posted. The 10A ratings of small cheap diodes these days is marvelous.

If in doubt, with larger voltage drops needed, buy a series Zener instead with appropriate voltage/current / power ratings.

P.S. don't dismiss any radio/TV/ DVD/VCR appliance as junk. There are lots of diodes in them. Even the small 240v power packs (especially with the transformers) usually have 4 diodes and they mainly fail because of open circuit primary windings.

If you are lucky the diode part number is visible and look up their rating. Probably 10A anyway. If one starts getting too hot in your usage, they more often go short circuit than open so watch out then for too much voltage on your device.

Edited March 11, 2016 by Jing Joe

[Muhendis]

The electronics for a single phase (Hummer) I describe as substantial because a full wave rectified sine wave of a 60v p-p sine wave would give you +/- 30v half wave voltage. That is to say each half wave would start at zero and rise following the sine rule to it's maximum of +30v and then decay back to zero. A ripple voltage of 30v. To convert this to a smooth DC voltage requires a filter of some magnitude designed to handle both the current and the variations in frequency. A multiphase design requires a much simpler filter (possible none at all) and the rectifier on each phase need not be a bridge rec. Full wave rectification will be quite adequate. Assuming, once again, a 7 phase, 60v 8A output, the voltage seen by the charge controller will have a ripple voltage of about 1v which would require negligible filtering. I would assume that the Hummer controller has all the required filtering inside so the costs of the filtering would be hidden within the overall cost of the unit. Besides, the term I use "substantial" is not so great in terms of actual cost but more in terms of relative component cost. I have short arms and deep pockets.

The aerodynamics of a pipe cut blade complete with 4 degree twist and taper are just as good as a well carpentered wooden blade. But there is a huge difference in the cost measured in manhours and weight. As you mentioned. The startup in low wind is important. a plastic blade will be far lighter than a wooden one and with less mass, it will present less torque for the wind force to push around. As you probably know, a half decent blade will have lift which will make it go round faster than the wind can push it. The downside of the plastic pipe blade is it's weakness where it is joined to the turbine and the effects of UV light on the plastic. These are of concern to me and I will be paying close attention to them in the design.

I am in Buriram province. When the wind blows trees fall down. When the wind doesn't blow we roast.

Thanks M for reply. Looked up Buriram Provence. Sound similar to that proverbial place somewhere were;- "it never rains then it pours".

Not quite agree about your AC theory M re W/G. It is actually a 21v sine wave that has a 30V peak. (1.414 x RMS = peak) and peak V is mostly relevant after rectification (half or full wave) if a filter capacitor is in circuit for it to charge to that peak V (and assuming no load). Not going into charge(Q) capacitance© and Voltage(V) versus drain here. The circuit on P21 of your upcoming W/G has 4 x full-wave bridge rectifiers. If your regulator is going to have a storage capacitor and charges/regulates from there, maybe you might be interested in smoothing any ripple with capacitance (and choke?) but maybe only to satisfy some features of the regulators electronics.

With my Hummer regulator/inverter, its different approach regulates by dumping 20 x 100W halogen lamps across its output when that V equals 65V, from memory. They are 120V lamps so at only 60 volts applied and with assumed negative co-eff of resistance, it could be effectively more than nominal 2000W (20 x 100W).

I don't think there is a filter capacitor nor do I see the need in this design. There will only be charge current from that area of the rectified pulses that exceed the battery V up to the peak V value. And because of the zener effect of the battery combined with its hopefully low internal resistance, there may only be a very marginal ripple of the battery voltage. Optimistically the repeated charge pulses we know then chemically converts the battery to steadily increase its voltage, and in turn the W/G needs just that bit more speed to rise to the occasion so to speak. Any capacitor in this design would surely have to be massive to achieve a comparative smoothing effect compared to the zener and internal resistance effect I mentioned. Today my W/G speed is frustratingly just under the "bar" and the simple Hummer regulator is not a tracking design like my solar regulator..

Re the cut-pipe blades, all the best and may I share my experience with white 90mm rainwater PVC pipes in the sun. 30+ years ago I painted some with what turned out to be a good quality water based paint and recently re-arranged part of them. Some parts not exposed to the direct sun had only scratchy brush marks originally, and in between them the PVC had eroded/etched about 1mm deep.

Re the blade where it joins the hub, no doubt you will be curving the shape to reduce discontinuity for strength (where there is little wind action/gain anyway) so how about also applying pressure pack construction foam to fill that ineffective part of the root of the blade? Any extra rigidity could help? It would need painting also, with water based paint.

BTW. I've been amazed at the insects(?) that have caused minor erosions/collisions of the leading edge of blades during my living with W/G about 38 years now.

I agree with you entirely re. the requirement for big expensive inductances and capacitors for the full wave rectified output of the W/T. My thinking was that you were converting to dc first for the charge controler. People have been successfully charging batteries for years with rectified mains. It's only fairly recently that 3 stage charging has come to the fore.

Your info. re. plastic experiences is well received and yes at the bottom end of the blade there will be a flared section to catch low startup wind and it's this section which I shall beef up to a stronger joint onto the hub and to blend it in as much as possible.

[Jing Joe]

Thanks for your offer. Think i can get it here....

Don't let it stop at just two diodes for any other applications George.

I've used up to about 8 in series for other applications and their total surface area is safely proportional.

Keep in mind the knee of the conductive part of their curve has more slope than Zener diodes so you could get more than 0.6V drop depending on how much current your device needs. Use how many that suits the device. It can go up to 1.0 V per diode but still a good cheap suggestion posted. The 10A ratings of small cheap diodes these days is marvelous.

If in doubt, with larger voltage drops needed, buy a series Zener instead with appropriate voltage/current / power ratings.

P.S. don't dismiss any radio/TV/ DVD/VCR appliance as junk. There are lots of diodes in them. Even the small 240v power packs (especially with the transformers) usually have 4 diodes and they mainly fail because of open circuit primary windings.

If you are lucky the diode part number is visible and look up their rating. Probably 10A anyway. If one starts getting too hot in your usage, they more often go short circuit than open so watch out then for too much voltage on your device.

ADDITIONAL NOTE. However many diodes you end up using, install/disguise them in say the positive leg of the device lead, and put a sleeve of heat shrink tubing over the diodes and then even a second one over that part of the double wire lead. There is heat shrink now with double the shrink capability (and double wall thickness to boot) to conveniently slip over the end plug.

Additional note above

[George Harmony]

Don't need cooling for meat. Keep a few chickens. Fresh kill and eat. raise some rabbits, fresh kill and eat as needed. Get some guinea pigs like they do in South America. One dog is a decent meal. I am a believer that goats could do well in Thailand but they don't seem to have a large following

Thought the same till i need a cold beer. Extra small coolspace for meat, milk products and rest food is then welcome if i later can connect a fridge to my offgrid system.

[George Harmony]

Till now i did not know that there are also 12volt fridge/freezers which look like the ac models. According to the description they consume 45-65watt depending on the model.

Im wondering if such 12volt compressor fridges also need a higher wattage as they start???

Pitty that i cant find such 12v models in the city where i am now. Camping model compressor and peltier models easy to get here.

[Naam]

Im wondering if such 12volt compressor fridges also need a higher wattage as they start???

yes, they do.

[IMHO]

Till now i did not know that there are also 12volt fridge/freezers which look like the ac models. According to the description they consume 45-65watt depending on the model.

Im wondering if such 12volt compressor fridges also need a higher wattage as they start???

Pitty that i cant find such 12v models in the city where i am now. Camping model compressor and peltier models easy to get here.

The answer is: depends

If a 12VDC motor is just hooked directly up to 12VDC, yes - it still has a higher startup draw than what it needs to run. However, low wattage motors might also have a speed controller, which can negate the startup current demand by doing a programmed 'soft start'. Think radio controlled cars..

Would a 12VDC fridge have such sophisticated electronics though? Unlikely, given that fridges normally need to run 24/7, so are not candidates for pure PV-only power - i.e. the designer would assume there's battery power available, and that it could handle the startup demand - especially given that such fridges probably take several hours to reach target temperature inside.

Edited March 11, 2016 by IMHO

[Muhendis]

One day we might have inverter fridges and freezers............Now, there's an idea for a startup.

[IMHO]

One day we might have inverter fridges and freezers............Now, there's an idea for a startup.

Errm, not sure if that was a joke, but there are plenty of them already that doesn't mean they current-limit startup though - just that they run the compressor at a variable speed once started. Ditto for inverter air con, inverter pumps and inverter washing machines.

Edited March 12, 2016 by IMHO

[George Harmony]

If a 12VDC motor is just hooked directly up to 12VDC, yes - it still has a higher startup draw than what it needs to run.

How much higer?? Can someone gives an estimated startup wattage. Cant find it in th description of above product.

Typical marketing/advertising mistakes ref above picture.....who put such fruits in a fridge???? Marketeers probably hahahahahha

[Muhendis]

Not too sure about eating cold bananas but the rest of the fruit is great cold.

Startup current for a motor under normal load can be anything from x5 to x9 you will need to calculate your own wattage from that.

[gk10002000]

Don't need cooling for meat. Keep a few chickens. Fresh kill and eat. raise some rabbits, fresh kill and eat as needed. Get some guinea pigs like they do in South America. One dog is a decent meal. I am a believer that goats could do well in Thailand but they don't seem to have a large following

Thought the same till i need a cold beer. Extra small coolspace for meat, milk products and rest food is then welcome if i later can connect a fridge to my offgrid system.

I know. I really didn't mean to suggest going back and living like the old days. But there are some pretty decent DC refrigerators that if well insulated can be powered on during the day and will keep cool through the night, not to mention propane powered refrigerators that many RVs have. Think like you are on a Boat or a RV. May tickle some thoughts

[George Harmony]

But there are some pretty decent DC refrigerators that if well insulated can be powered on during the day and will keep cool through the night, not to mention propane powered refrigerators that many RVs have.

Exactly my thoughts also. One poster gave a tip of adding extra insulation. Only during peak hours running a fridge/freezer solar powered can be totally free without draining the battery so much, only for startup.

Propane absorbs a lot.

Edited March 12, 2016 by George Harmony