Author Topic: We have no bananas today... (Read 3552 times)

DamonHD · « **on:** August 14, 2007, 09:16:01 PM »

No off-grid time for my laptop/server today. Bv<

I have set the system to only 'scrape' the excess power for my laptop/server at the moment, and today has been a dull and rainy day, and I do have my office light running happily from PV right now, so it's all working to plan, if slightly frustrating.

However, as the battery should be full, I hope that even if we have more heavy cloud that I'll get a little off-grid time.

Of course, this is just egging me on for the next system design (430W of Sanyo HIT, 400+Ah@12V battery, Outback MX60..., + possible small wind turbine) purely for taking the laptop off-grid even in mid-winter...

Rgds

Damon

ghurd · « **Reply #1 on:** August 14, 2007, 04:26:29 PM »

Possibly the voltage or hysteresis set points are off for the optimal performance of the system? I expect the hysteresis is too high.

In a very small system, a micro-sized wind turbine will make more difference than most people expect, in winter.

G-

AbyssUnderground · « **Reply #2 on:** August 15, 2007, 02:56:46 AM »

It was dull all day here too which meant I got about 1.5Ah total of power. It didn't go much above 200-240mA all day. Currently at 12.92v with no charge. What a useless place Britain is. :-)

DamonHD · « **Reply #3 on:** August 15, 2007, 06:20:36 AM »

Hi,

I've fiddled with the hysteresis points quite a lot to (a) reserve plenty of juice for lighting and (b) cut down on oscillation, which was quite bad and is only just about 'OK' now. I think that my battery and wiring resistance is high for the DC-DC converter inrush current.

On the bigger system I'm planning there will be very different set-points, and a drop-out delay, and better wiring, not to mention 10x the battery capacity and thus much lower resistance.

Rgds

Damon

PS. I am off-grid right now in fact, which is good.

DamonHD · « **Reply #4 on:** August 15, 2007, 06:22:51 AM »

On balance, I much prefer some cloudiness to 40C+ days and/or poisonous critters, especially having a very young child.

Slightly damp and dull and safe... B^>

But just wait until I fill my old wooden toolshed with large lead-acid batteries...

Rgds

Damon

DamonHD · « **Reply #5 on:** August 15, 2007, 06:24:58 AM »

BTW, I really am thinking of adding a Rutland 503 later in the year unless someone can suggest a small cheap and effective VAWT as an alternative. System power draw is 20W continuous, so covering a significant chunk of that in winter with wind, even close to a house in a built-up area, should be doable.

Rgds

Damon

gotwind2 · « **Reply #6 on:** August 15, 2007, 10:28:17 AM »

Hi Damon.

I would seriously re-consider buying a Rutland 503, I bought it's bigger brother, the 903 and it performed poorly inland, these little marine gens are best suited to the open sea gales imho - they do look nice though...

My experience here

http://www.gotwind.org/rutland_913.htm

Ben.

DamonHD · « **Reply #7 on:** August 15, 2007, 10:47:44 AM »

I'd trying to get something small and safe* and that can push a few watts into a 12V battery...

I really don't have a better alternative at the moment... The money is mentally on the table for an alternative, since specing the solar PV to cope with midwinter is so expensive...

Rgds

Damon

* That I can mount on a 2m washing-line pole in my tiny back garden, that won't chop up small birds or drop on my toddler's head, or madden my neighbours with noise.

rippersoftware · « **Reply #8 on:** August 15, 2007, 12:11:16 PM »

If you can build a VAWT yourself and have access to a small DC servo motor (Ametek, etc), some pulleys or sprocket and chain, then try a PVC VAWT.

http://www.fieldlines.com/story/2007/5/2/155245/1038

Warm and sunny in Iowa.... RipperSoftware

ghurd · « **Reply #9 on:** August 15, 2007, 01:19:31 PM »

Have you tried your hand at AC conversions?

Fairly easy to get an amp or 2. Cheap too.

This monstrosity broke an amp, but usually about 0.2A. The motor had every reason not to choose it, so naturally I did.

http://www.otherpower.com/images/scimages/2050/ugly20.jpg

This was a 3 phase 3600RPM (3000 RPM on your side of the pond). Many reasons not to choose this one either, so again, I did. Makes over 3A. Hard drive magnets.

http://www.otherpower.com/images/scimages/2050/3phHD.jpg

This was a single phase vent fan motor with 6 coils and 4 magnets. Converted it to 3-ph output. Still not finished, but over 3A no problem with a hand drill. I believe these have more potential than has yet been exploited. A 220VAC version may need the individual coils separated (easy).

http://www.otherpower.com/images/scimages/2050/VentMtrGuts.jpg

Same idea as this box fan motor, but bigger...

http://www.fieldlines.com/story/2005/7/4/34446/17324

I am not saying those are good. They are not. I'm saying they show how easy it is to cheaply get a bit of power in the yard at 7' high.

And my sister moved to Saint Louis, on purpose! 40C+, poison critters and creepy-crawlies, tornadoes... Then she had a baby. She now lets a wild (non-poisonous) snake live in the garage to eat the creepy-crawlies, a win-win situation.

They are all doing fine.

DamonHD · « **Reply #10 on:** August 15, 2007, 02:33:02 PM »

I really feel unconfident to try motor conversion etc.

I can wield a small soldering iron and screwdriver, and a tenon saw and a drill.

Generally my DIY work is more on the software end.

I'm also happy with the electronics design work (and still learning of course!).

But really I'd rather buy the hardware bits premade and concentrate on the system design, software, etc.

Coward, me? Yep!

Rgds

Damon

gotwind2 · « **Reply #11 on:** August 16, 2007, 02:44:47 AM »

Yes, that's one of my failed attempts in the link above - I wouldn't advise that.

Vawt's need to be big to get any decent power.

Ben.

Bruce S · « **Reply #12 on:** August 16, 2007, 09:12:16 AM »

G-;

St. Louis ain't that BAD!! :-D. Okay so we broke 2 heat records in a row, it took 70+ years to do it. The best part is that the humidity finally burnt off now just.. H O T.

Another item worth working with. Can be setup as a H or V is the blower fans found in autos and can be had for next to nuthin'.

They make for a good learning lesson, are PM motors and have great bearings and mostly setup for 12Vdc already.

Sure they will need a high RPM to get real power out of them but still very useable and easy to work with. Minor soldering at best.

Also , those front grill fans are PM motors as well but need 4x the speed of the squirrel cage fans to get an out put.

Both of these, if left mostly intact, could always be truned back into cooling fans if the charging isn't worth the time.

Thoughts?

Bruce S

PS we're having a cool wave now it only 93F ;-D

ghurd · « **Reply #13 on:** August 16, 2007, 09:38:20 AM »

From time to time I look for 24V fan motors. No luck finding one here, but they seem more common in England!

Car 12V fan motors. Your luck must have been better than mine. My 12V motors would be good for 6V charging, so the 24V may be good for 12V charging.

I still want to get a blown up Cadillac variable speed heat-A/C fan. Too expensive new, but they seem like an ECM right down to the brains blowing up when used as they were designed. Should make a dandy small windmill without any effort?

My bro-in-law, cutting the lawn in sandals, in the middle of a housing development, accidentally cut up a copperhead. St. L. is not the place for me.

Bruce S · « **Reply #14 on:** August 16, 2007, 10:05:53 AM »

G-

Copper head? haven't seen one in the city in years. 3 foot 1/2m, garden snakes with a field mouse ? sure good for them.

I should've been more clear, you are correct about the volatge, but a couple nice little ones would be just fine as a back up for the solar.

A voltage doubler would do just fine to bring one up to volatge size. Nice heavy current too.

Thoughts?

Bruce S

DamonHD · « **Reply #15 on:** August 16, 2007, 10:58:16 AM »

Wow! Thanks for the ideas!

(And, yes, nasty snakes in the grass is what I want to avoid in life: cat sh*t is quite bad enough, even if it's my cat's...)

OK, a car fan of some sort sounds interesting electrically, but then I'd have to chose sensible blades and a swivel/furl mechanism, which I don't even reach 'clueless' level on!

And, of course, a charge controller, with a nasty inductive input.

Another reason for liking the cut of the 503's jib is that it comes with a matched controller...

Rgds

Damon

Bruce S · « **Reply #16 on:** August 16, 2007, 12:28:12 PM »

Damon;

Cats:-) nice animals, trainable even. Ours knocks on the door to be let in :-D hunts squirrels to let us know they're "on-the-job:.

Using the car fan; if you get the ones with a squirrel fan ( nice lead in huh:-O) you can use it's mountings to add taller Vawt blades. This has been done a bunch, here and in Mother-Earth-New mags.

The output that G- remeined me of, is where you'll need to watch. The 12V ones will be lower than the 12V needed but they should also have a good current level where they can be useable.

You can make taller blades out of most anything, small buckets come to mind, There was/is a video of one in the files that shows how well buckets do.

Poster of that file;> forgive the memory loss but chime in here if you will with a link to it :-))

Charge controller? should be more than a few around here, could even use a simple LM317 circuit to limit output. It's input is wide enough .

Most parts can be had mostly for free ( fan, buckets, and such) elecrtonics , you might have to dig into old TVs , monitors and stuff .

With all that you've done already; you should have no problem with this other stuff

Best of all the hunt and build is pretty free and so much fun!! plus you'll be doing your part to help one less thing to go into the rubbish.

Cheers and have fun!

Bruce S

ghurd · « **Reply #17 on:** August 16, 2007, 12:48:35 PM »

You might find a 24V fan from a lorry. I guess that's a truck with the steering wheel on the wrong side. eBay often has them with the price listed in £.

I don't think the blades would be a big deal. Probably small enough not to need furling. I'm usually wrong on these matters. Blades like these is what I'd try.

http://www.fieldlines.com/story/2007/4/23/184051/462

Bruce is correct about high current. My 12V auto fan motors would do like 3A at 6V no problem. They just wouldn't hit 12V and 150ma in a hurricane. That's why I think a 24V lorry heater fan motor might be OK.

The charge controller for systems of this scale won't be a big deal anymore. Soon. And cheap too. Like £7 ~ 8 delivered, even to places that use £.

Somehow "haven't seen one in the city in years" doesn't make me feel any better.

I refuse to live in fear of things I don't understand, so I pull out my lawfully carried concealed handgun and shoot creatures I do not understand. Like copper heads, if we were cursed with them. I don't understand cats either. Kidding. :-)

DamonHD · « **Reply #18 on:** August 16, 2007, 01:08:11 PM »

Well, my request present for my 40th birthday (only 2 days away: bah!) is a home-made anemometer to get some idea of the possibilities.

For unrelated reasons we have a garden full of decorative spinning children's fans, and they are often moving, which gives me some hope.

Anyway, no one's talked me out of the 503 yet! I might pony up some chunk of the 503's cash to someone on the board if you want to build me a safe and quiet mill + controller for a 12V system! It's really not get to let huge voltage spikes through that might fry my laptop though... B^>

Rgds

Damon

Bruce S · « **Reply #19 on:** August 16, 2007, 01:37:54 PM »

Damon;

That is a very nice unit , kinda pricey tho. I took a look at the output and you might want to look at something else.

This ones built for boats and it'll be llooking for high winds to do anything real.

19 knots = about 22mph or around 36Kph and that's a bit high for around the homestead.

I don't know the price of this unit but you might want to look at other. except of course they may not be a pretty. It is tough to beat a package deal.

Depending on where you located there are other package deals going for around the $800USD and these are landbased.

Your call.

Which ever you choose have fun;

And let us know, especially if you go with a package deal, so others can benifit..

Bruce S

timmy · « **Reply #20 on:** August 16, 2007, 02:01:46 PM »

cute looking little gen for sure!

If I was to go by my area average wind speed (5.6-6.4mph or roughly 5-6 knots), it would produce zero in the way of energy unfortunately.

Does the UK have somthing similar to www.awea.org? or more specifically

http://www.awea.org/faq/usresource.html

interesting graph here

http://www.windtrap.co.uk/Wind_Turbines/Rutland_503_Wind_Charger.htm

online knot to mph here

http://www.militaryfactory.com/conversioncalculators/speed_knots_to_miles_per_hour.asp

fungus · « **Reply #21 on:** August 16, 2007, 02:05:28 PM »

Another interesting one would be the turbines sold at navitron.org.uk ...pretty big but will put out good power for a cheap price... otherwise a small ametek motor wind turbine with pvc blades doesnt need too much work..

ghurd · « **Reply #22 on:** August 16, 2007, 02:46:49 PM »

(Angus- Your email is bouncing)

fungus · « **Reply #23 on:** August 16, 2007, 02:59:52 PM »

ghurd,

try my other email address... (aicchalmers at btinternet dot com / info at reenergy dot co dot uk)... sent you an email too...

hiker · « **Reply #24 on:** August 16, 2007, 03:06:44 PM »

you could rewire one of those 12v heater motors--when you open one up--youl see that theres a lot of space for lighter gauge wire...

Bruce S · « **Reply #25 on:** August 16, 2007, 03:52:37 PM »

Hiker;

Thanks for the pic!!

This is the same that has the Squirrel cage fan on it right?

I my neck of the woods , we can't put up anything that even comes close to putting out enough power to trickle charge with a 'mill, but these I've worked with in the past and they spin up so easily.

Never ahd the chance to open one up, will give it a look see again.

Cheers

Bruce S

Bruce S · « **Reply #26 on:** August 16, 2007, 03:58:47 PM »

Ben;

That one looks so nice, I wouldn't care if it put out even a 1/2 volt.:-D

Using the wood on the bottom of that, would it be possible for you to attach it to one of the squirrel cage blower motors and see if it'll do somethin'?

Could be worth a shot

even if it put out only 6 volts, the current these have are more than enough to throw it to a doubler and get a few watts out of it.

Thoughts?

Bruce S

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Author Topic: We have no bananas today... (Read 3552 times)