Help with battery bank for mini wind turbine

Joined
Dec 24, 2015
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Hi folks

It's very windy where I live - there are two huge offshore windfarms and the hills are studded with turbines. S0 I thought I'd make a small wind turbine for experimentation.

I have 36 18650 cells that are rejects from my ebike battery pack build because they only have 900-1400mAh capacity left, but that's enough to build a 12v 12A 3s12p battery bank to connect to a wind turbine.

The turbine I am building will use a small permanent magnet dc motor from a Ryobi 18v cordless drill if it proves suitable after some testing to see what volts it outputs at various rpms.

What electronics do I need to connect the turbine to the battery pack - would it be best to employ balance charging?
 
What you will need are things like:

If you want a 12vish pack, the a 4s pack, not a 3s pack. (4.2v fully charged is really 3.7 or 3.6 nominal.) Drill motors at full voltage spin fast. My guess is you wont be able to get the drill motor spinning fast enough to get 12v too often, so consider less series in you pack for experimentation. Once you got the turbine built, test it in the wind with a volt meter to see what voltage you can expect to be working with.

Voltage regulator
Dummy load, resistor
large blocking diode
A way to balance the cells when not in use.

All the things normally found in a wind turbine setup plus a balancing setup which could be as simple as connecting all the positive leads together and all the negative leads together to self balance the cells.

An inexpensive step down or buck dc converter from eBay might work, depending on the volts and amps from you drill motor.

Oddly enough eBay has this page: http://www.ebay.com/gds/Wind-Turbin...-Controllers-Part-1-/10000000006308446/g.html

eBay also has cheap step down and step up regulators you could use for experimentation. Again, build the turbine and test the output to see what you might be able to use.

Also, these guys have great information on diy wind turbines.
http://www.otherpower.com/bottom_line.html

:D
 
Cheers, that's very useful.

I intend to make the blades and hub and mount, then put the motor I have together and see what the output in various wind states is before I buy any electronics to hook up to it to see if this motor is going to do the job. If not, I'll try a different motor, not that I have any others lying around, but there are a ton of cheap motors of various kinds on ebay.

I just bought a 9 cell laptop battery on ebay, it's not an OEM one, so it is made from cheaper Chinese cells. I took them out and tested them with my Imax B6 - instead of the 2200 or 2400mAh they should be, 8 are in the 1000-1100mAh range and one is a pathetic 300, so they will be used for experiments rather than go into my ebike pack. Oh well, I only paid 5.99 inc postage for 9 cells, so not a big loss.
 
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