Sunday, April 19, 2020

Wind Turbine Pt 4 (or 5 or 6 or 7 or 8)

Somebody asked me the other day why I was building a wind turbine and what it would power. The answer is that I had the turbine generator that I'd bought off eBay some years ago and never had used. Having all this free time, I can use some for experimentation. The turbine generator is alleged to produce 12v. I have yet to see 12v from it. Turning the turbine blades by hand I got 6v but I wasn't turning them all that fast. Thus I've wired a 12V LED light directly to the turbine. That actually lights up at around 8V. I'm expecting some strong winds over the next day or so so I've sat the turbine outside in sight of a window. That way I can see if it's producing sufficient power to make it worthwhile in this form.

A possible change would be to build it into a water turbine though currently I lack an adequate water source to test that.

Thus far I have to say I probably get far more still days than windy days and those days with a breeze, the wind speed is too slow to do anything - even to flutter leaves on a tree. Watch this space for developments. The goal is - if this experiment works - to turn it into a wind generator for my bus.

Here you can see clearly the LED. It's not an LED I'll be using in the bus. It gets very hot and to my mind that's no advantage over my halogen bulbs. I have plenty halogen bulbs. The whole argument in favor of LEDs is very sketchy.

LEDs are supposed to last a long time. Not my experience. LED flashlights don't last much longer than the batteries. LED 120v bulbs don't last as long as the implied warranty. I've never had one last more than a year and frequently they don't last more than a month or two. The failure rate for a device claimed to last around 7-10 years has been about 95%.

LEDs are supposed to be very bright - sure they are if you like being dazzled by very directional light that's hard on the eyes.

LEDs are supposed to be very cool as opposed to incandescent lights. Not really - some of them are but most have great big cooling vanes (or like this one, no cooling vane) and get really hot.

To cap it all, I paid $5 for ten halogen bulbs and LED bulbs are $5 each. LEDs are not cheaper to buy. They're not cheaper to run (because of the extraordinarily high failure rate) and they're worse for the environment (all those that have to be thrown away). I can't say anything about carbon dioxide as my lighting is solar powered so whether they're LED or halogen, no fuel is burned to produce the electricity.

As regular readers are aware, I'm unhappy with the performance of my twin 35AH AGM batteries. Everything else in the system is top notch. The batteries are the weakest link. I've heard choruses of buy this and buy that. No. Not doing it. The problem with AGM batteries is that they're inherently a terrible design. I looked into Lithium batteries and found there were several major issues. First the ready built batteries are obscenely expensive. Secondly they're not well made.

I looked into lithium batteries and found the cheapest place to get the standard 18650 cell is from Aliexpress. The cheapest place to get holders for the cells is also Aliexpress. In fact the same that I'd paid for protected 18650 cells is less than I'd pay on eBay for unprotected unknown brand 18650s. Thus, I ordered some 18650s and holders.

The 18650s I ordered are button top which means they look just like an AA battery but bigger. There are no solder tabs. The holders I ordered are the kind of holder but bigger you'd expect to put AA cells into. The point is that in the event of a single cell failure, I can just pull that cell out and replace it without any soldering.

As far as capacity, the cells are reportedly 3400Mah. With the 5 holders holding 4 each that should be around 17AH though I'll regard it as a success if I have 10AH. The existing underbus battery holders should be fine. I'll have to make battery housings but that's no problem. I'll probably (since 18650s don't take up much space) use vinyl planking to build the housings. That's fairly swift and painless as well as well insulated against heat, cold and water. It also means I don't have to modify my existing battery holders. I might even add some thermal fuses or thermal cutouts. Maybe set them at 60C (150F) so if the battery compartment rises above that, it goes cold. I'm just having a Dickens of a job finding self-resetting thermal breakers that will cut off at 50 or 60C.

Aliexpress is one of those China inc websites. Alibaba is the wholesale version. Both are as sketchy as eBay and Amazon. Ages ago I used to live in a town in Britain called Swansea. There were several pubs there where you could go to buy your own stolen hubcaps back. All of these online places mentioned seem to be the kind of place where you can buy things cheap as long as you don't ask where they came from!

Buying from eBay can be fraught. Several times the bank has called me and asked to verify transactions. Sometimes the transaction has apparently been from a country not listed on the description. I've bought something advertised as being in the USA but it has been billed from China. In that instance there's dishonesty so I and the bank decline that transaction. I had one the other day. I bought a respirator due to the Coronavirus epidemic. The bank didn't even call me but declined the transaction. The seller tried to bully me into paying and I told them straight that the bank declined the transaction so they must be flagged as a crook. They sure did pester me until I finally had a note from eBay saying that I needed to remember to pay next time. Remember to pay, my arse - the transaction was declined by the bank twice!

Today on Aliexpress I had issues too. I got around them using Paypal and buying direct but I'll have to see what if anything arrives since the lead time is extraordinarily long. Two months in one instance. Thank heavens it's only two suppliers and one product per supplier.

I'm still not getting down to fixing the back door despite the leak is rotting some of my OSB flooring. I need to get down to that.


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