New Battery Pack and Stall ?

[valterra]

Thanks to Norm's great idea to use tubing to make a battery pack, I assembled a new pack out of 50 NiCads.  

Ingredients:

50. NiCad batteries
    
1. 10' length of 1/2" PVC ($0.89 on sale!)
   
10. PVC end caps
    
10. small bolts with matching nuts and washers
    
1. length of copper grounding strap (got some years ago for grounding my Ham station - a project I never got around to).
   
   

I basically assembled 5 individual 12v tubes (10 batteries apiece) and then bolted them in parallel with the copper banding.  I can take pictures if you like.  Not too complicated, but I joked with my wife about how it looked a little "spooky."

I poked some extra holes in the strapping, so I can add more "cells" later.  I also made some smaller ones just large enough for the leads of my DVM to squeeze into.  Man, I HATED trying to attach my voltmeter to stuff all the time.  Problem solved now.

I also bolted on some wires for 12v stuff to run off the battery pack.

So today was a nice windy day, and I learned some new lessons with my new battery pack.

First, I learned about how batteries really will regulate the voltage down to their level until they get full.  I'd hooked my generator up to a single 12v "cell" before, and it didn't do much to keep the voltage low.  I think it was because the batteries were already fully-charged.  Unloaded voltage on this thing sometimes spikes up to 30 volts and higher, but usually is in the high teens.  The battery pack held the voltage down around 12-14 volts.  

When it started to climb above 14 on a regular basis, I plugged in a small 12v white tail-light (which I understand is about 30 watts) and watched the voltage slowly drop - drop - drop on my voltmeter.

When it got low enough where the light wasn't lit very brightly (9 volts or so), I unhooked it and watched the batteries charge again.  It was a neat process.  Very hands-on and interactive.  So I believe I have a good understanding of the Dump Load concept now.  If your generator is still up there whirlin' around and your batteries are full, flip on a light!  :-)  

I also learned a bit about Stall, having originally hooked the light bulb DIRECTLY to the genny.  My thoughts:  As it approaches 12 volts, the light will slowly come on.  But to my dismay it completely stalled my genny.  My only question is WHAT is stalled?  Is it the blades or the motor itself?  Longer blades would be more powerful, but spin slower (not enough voltage on these Ameteks), but would a WIDER blade be more powerful?  In other words, could the RIGHT blade actually power this light, or is it that my Ametek motor itself cannot produce the energy?

My little wooden blades are working like a charm, but are a little scary at 400+ rpm.  I'm wondering it it'd be better to build a 4-blade system that would spin slower but start up in lower winds than my 2-blader.  And I have another Ametek to use, so I could put up a second Genny.  Build 4 foot (8 foot diameter) blades instead of 2 foot, so they'd spin half as fast.  Then hook the two gennies up in Parallel.

I know technically they wouldn't be working that hard, but I'm thinking the larger blades would extract more power from the wind, and therefore be better able to handle a load?  Also, an Ametek spinning at 200 RPM has just GOT to last longer than one spinning at 400?  I'm not worried about the expense - the motors are already bought, and the mounting is cheap and easy.  But am I wrong in trying to spin these a little slower with longer blades, or should I be trying to pump them as fast as possible?

Any thoughts are welcome!  If you want pictures of anything, just ask!!

[ghurd]

Only 50 NiCds?

Stall.  

Check the 'real' ohms of the bulb with a meter.  When it's cold (off) the ohms are very low. The resistance of the motor may be more.  A cold bulb is like a short.

A shorted windmill won't turn fast enough to make any power.

Blades have to be turning pretty fast to make power.  

Try to get power below about 6 or 7 MPH, and it is like a 747 trying to take off at 20 MPH.

Try to get power with a shorted windmill, and it is like a 747 trying to take off straight up. Like a Harrier Jump Jet.

I don't believe longer than 4' is a good idea for an Ametek.  

Seriesing them is a very bad idea.

The 200RPM should last longer than 400RPM.  But.  The amp-hours produced by the 400RPM will be a lot more than the 200RPM.

Spin it at 50RPM, it will make no power at all, and it will still wear out.

Wondering about the blades.  The 2-blade deal with the fancy pait job?

How well are they balanced?  Much vibration?

G-

[Tballer2]

Hi, I just came accross your post, I have an amtech motor, 2 1/2 hp and I have been experimenting with it, check my diary, I went with 4 blades 4' long, and a ring gear and starter motor gear to get the rpm's up on the motor, I think it may go, waiting for the wind to tell me, I have pics on photobucket, its in my diary, check it out let me know what you think, thanks, Tony

[valterra]

The are actually VERY well-balanced.  Inside the shop, they'll stay at whatever position I rotate them to.  And when they really get going, the don't shake much at all.  That's why I went with the 2-blade idear.  I'm afraid that 3 blades would be way off-balance.

The big problem I have with the 3-blade designs is how to get the circular hub for mounting.  I don't have money to spare now (recent change), and building 2 blades out of a single piece of wood seems like an elegant solution.

But, from my understanding, 3 blades would spin up at a slower speed, right?  But 2 blades are faster once they get going?  

With the longer blades I just thought I'd be extracting more power from the wind.  After all, everyone says that it's the swept area that is most important.  Unfortunately, a very powerful 150 rpm rotor simply won't "power" an Ametek motor.  That's the issue, isn't it?  When everyone says to have your blades match your alternator?  I need a different motor (or build a PMA) that requires lower speed and higher torque, and then I can use bigger blades, run them slower (rpm-wise) and get MORE energy out of them?

My little, very-lightweight blades spin up very quickly, and they DO make that motor generate the right voltage.  But for some reason, I feel like longer blades would pull more out of the wind, albeit at a lower RPM.  That's right, isn't it?

[valterra]

TBaller - I cannot find your albums on Photobucket

[ghurd]

My attempts at 2 blades were failures.  Even when static balanced, they shake your teeth out at speed.  3 or 4 blades balance a lot easier, even if the layout isn't perfect.  At least that's how it goes for me.

The RPM of the motor is what will determine the output.

Longer slower blades are able to collect more power, if they are matched to the generator.  10' blades on an Ametek will be a flop.

Blade design is not my strong point (obviously worse than my spelling).  A 2 blade can be designed to run slower than a 4 blade, or a 3 blade faster than a 2 blade.

That's where some people spend so much effort.  I'm just concerned if it works, and what the main problem is.  I can't leave a tiny 10W windmill up very long here, and only one small 100W one at a time (60 miles from here).

G-

[Tballer2]

try this I hope it works http://s275.photobucket.com/albums/jj304/arfab1/windmill/

[valterra]

I was actually surprised when these worked okay!  :-)  

Maybe I'm asking too much?  I mean, these blades DO spin up nicely.  But I'm just thinking that if I made wider ones, or something BETTER, I could get better performance from them.

[ghurd]

Have you seen Alton Moore's calculator?

Pick # of blades, TSR, and click calculate.

Big Fun!

And a nice little website too.

http://www.alton-moore.net/wind_calculations.html

G-

[Norm]

Have you ever thought about seeing how those

batteries would charge a 6,12,18 or 24 volt

battery? I make my battery packs 6 volt 'sticks'

(5 cells in each stick), this way I can hook them

in series or series-parallel or whatever.

Maybe your combination of blade,generator and wind

speed would be better suited to charging at 6 volts with a larger blade or 18 volts with a

smaller faster blade.

Ah, With only a 6.5 amp/hr battery pack...it's

much simpler to hook the Ametec up to pedal-power

...run it with a 10 speed bike select the right

ratio for the job. ( I haven't done this yet

but I have the stuff and the potential for it)

 

[valterra]

I have a 20v Ametek that already has the small rubber wheel on it to make a bike generator.  Just need the funds, or the wherewithall, to mount the bicycle to something!  That's all that I'm missing.   Well, a couple good diodes, too.

As for charging 6v, that's kinda what I was thinking when I said I thought of hooking 2 together.  6 + 6 = 12 and all.  Charging 6v is a good idea, but you're talking about plugging and unplugging them from the wind powered "battery charger" and using them on other applications?

For example, have a bunch of 6v packs all hooked up and charged.  Then remove 2 of them, hook them up in series, and use them to power a 12v appliance?  I just thought that'd be a lot more work is all.  :-)

But YES - you are absolutely right that it does exceed 6v more than 12.  Although I have been very surprised just how often these blades turn that motor well over the 12 volt line.

[Norm]

For example, have a bunch of 6v packs all

 hooked up and charged.  Then remove 2 of them,

 hook them up in series, and use them to power

 a 12v appliance?

 A bunch of 6 volt battery packs in parallel

being charged all at the same time...

 Later on one of

Ghurds load dumps to a 12 volt lightbulb.

would make it all automatic.

 The 12 volt appliance would have a place to

plug in 2 of your 6 volt battery packs...

integral circuit would hook them in series to

make 12 volts

Just like plugging in fresh battery packs to a

cordless drill in fact there are some drills

now that take 2 battery packs...

BTW Send a pic of your battery packs....

Was that $.89 for a 10 ft. pvc pipe?

[valterra]

I see - I just didn't know you could simultaneously have them hooked up parallel (6v) and in series (12v to run an appliance).  I thought I'd seen that pretty thoroughly discussed on here before.

Here is a link to the battery pack.  I put the pegboard up yesterday.  I guess now that I have one of those boards on the wall with stuff hanging off of it, that I'm one step closer to being a real-life wind / solar power nut!   :-)

There's a magnifying glass icon on there, where you can look at the picture full-size.  

[valterra]

The 5 foot sections were $0.99, and the 10 foot sections were on sale for $0.89.  That was a tough decision to make, lol.

[Norm]

Well no you can't feasibly have them hooked up

in parallel and hooked up to a load in series at the same time.

Here are a couple of my 6volt sticks.....





these are C size cells ...originally they are 3

sticks glued together and hooked in series to make an 18v. pack.

I take 2 18v packs and unglue them disconnect

the connecting straps take 4 of them so the +

are all on one end and glue them together.

 Those white loops are vinyl strips from some old

blinds with an oval piece of wood glued in...add

silver thumbtacks on the ends poked thru a strip

of aluminum or copper strip like you have.

...and you have a 5.2 amp/hr 6v. battery pack

I hook 2 of these in series and charge them with

a 12 volt VW solar panel and use each one on

some 6volt LED lights that last about a month.

between charges.

BTW What size are your NiCads?

[coldspot]

tballer2-

 That might be a "Amtech"

(tread mill motor, looks like to me)

 But its not the same as a "AMETEK"

(TDM or Tape Drive Motor)

(low RPM DC motor)

 On my 30 volt Ametek, for blades I'm playing with

3 blades at a little less than 4 foot.

 And it does take a bit of wind to get above 12 volts.

$0.02

[valterra]

try 4 foot DIAMETER (about 24 inches apiece).  Mine spin like nuts.  Pretty scary, actually.  You wouldn't want to try to stop it with your hand.

[valterra]

Okay, so you're talking about unhooking them when they're not being charged.  Just like you'd take your AA batteries out of the charger, use them, then put them back in the charger?

My NiCads are AAs.  At 700mAH, I figured I'm good for 3.5AH.  Nothing heavy-duty.  But I think it works for now.  I can power some small electronics, even a CFL bulb (using an inverter), and my generator isn't exactly loading them with KWs either.  I got the batteries at a very good price.  Eventually, I'll use a real sealed lead acid battery pack.  :-)  Or I'll just keep collecting NiCADs and NiMHs!

[coldspot]

valterra-

 By 4 foot, I was just guessing

 after looking it up, 33" diameter blade span.

 I'm using-

 "ITEM 93666-1VGA"

"RODENT CHASER WINDMILL"

 Harbor Freight junk item, but the hub and blades

I've modded with three dollar store foam glider wings.(22" wing span)

 I glued the three left side wings to the back side of the wooden blades, getting a lifting blade instead of just a pusher blade.(foam glued from root to tip, getting a larger root area)

 I know its not what people here would call a real blade set but when you have a nice little hub and some blades from a junk item you bought that fell apart in less than half a days worth of wind you sometimes try something new.

 I'm still working on my Dump load so this Ametek 30 is just lighting up a 12 volt trailer marker light, (161 or 1161 bulb I think), and three Red LEDS modded to run from 12 volts, (proper resistor inline).

 Today when I was out there, wind speed was 9-10 mph and the bulb was very bright in day light.

 The other day I put a Voltmeter on it, with the three LEDS in only 5-7 mph winds and voltage was from 5 to 9 Volts thats when I added the trailer light to help load it down.

[Norm]

Exactly, I charge my AA NiCads to 1.35v average

anything higher than that is a waste of time,

as far as I'm concerned. If you do charge them

any higher they quickly drop to about 1.35

anyway, from there they take twice as long to

drop to 1.3v.

Stick with NiCads, NiMHs may be 2 or 3 times

the capacity in the beginning but they only have

about 1/20th the life of a NiCad....they are a

lot cheaper in the long run....NiCads that is.

My setup for AAs is similar except I use paper

tubes for the cylinders and wooden plugs from

short pieces of dowel instead of caps for the

end pieces( I've never run across $.89 for 10ft.)

more like $.89 per ft. here....lucky you !

[valterra]

REALLY?  Where the heck are you?  The 5 feet for $0.89 is regular price.  So if you want me to buy some and cut it up and ship it, I can do that - as long as I get reimbursed.  It's not very heavy.

I did notice that this stuff has a thinner wall than the other 1/2" stuff that I have.

[Bruce S]

Hello Norm;

 Those packs are looking good. On using some of them myself for the e-bike, I have found that the 6v packs also seem to have a better load sharing ability.

I took your idea awhile back, except that I solder directly to the tabs, and used this to evenly build the packs. Your idea of charging the packs ALL together for a set amount of time and then measuring the voltage is a good one, helps with even load balancing.

I use my cute little 45W "ghurd dump load enhanced" HF panel/controller setup to charge them up.

The e-bike uses 48Vdc and I can pack a bunch of these 6V packs in to make up the 16Ahrs. I haven't gotten to the making of the packs with the thumb tacks, but can see how much easier that will be to do too.

One thing that would worry me. Using a 'mill if you take off all the packs, then there is the possibilty of the 'mill getting away in a wind.

I can't say just yet, city is always on me even when I just "try" to put a little VAWT out there.

I'm thinking a knife switch would be good to have so it could dump to the light when changing packs.

Hello Valterra:

  I like the thin PVC for use with the AAs, it a little lose, which is good for venting purposes.

Saw the pics, nice setup..

Cheers

Bruce S

[valterra]

The venting is what I thought, too!  :-)  

I keep reading about not allowing the mills to "spin free" without batteries, etc.  But I've also read (and observed) that charging batteries seems to have zero effect on the speed of the mill.  Seems to me that charging batteries doesn't load it down.

For example, today's a really windy day, and I have my 12v radio hooked up to the batteries and blaring.  The batteries show 13.8, and that mill is spinning completely nutso - it does NOT appear to be hampered or "working" in any way.  

Maybe I'm not giving it enough credit?  Or maybe there's a difference in the reactions of PMAs versus DC Motor-type mills like mine?

[Bruce S]

Windstuff Ed and Flux are 1000 years ahead of me on the 'mill loading ( others are too but they came to mind first ;-]).

I'll put up what I believe to me the "possible" idea of the mill loading versus battery state.

Again remember, me no have a mill, city bounded;-))

The mill can be affected by the battery charge state, this would be for the batteries to need a charge. The lower they are the more the mill will be able to charge them, until you get to a point of full charge or nearly full, at this point the mill must either generate a higher output ( faster wind perhaps) otherwise the batteries will not accept any further charge.

This is where a dump load controller would be handy. Once the batteries reach a voltage level , in your case 1.35Vdc per AA, the dump load controller would then read that voltage level and start dumping power off to where ever you had it set for and would stay in that mode until either the mill slowed down or the batteries once again needed a charge.

GHURDS little unit is perfect for this. The kit comes with everything you need, I'm not saying this just to try HELP sell them, I use them too. This is how I use one and have built 5 others for neighbors and they are pretty much the same way, BUT we have small Solar PVS. Works like a charm, the ole set it a forget it, (well almost) you would need to check on it at least once in a while.

For a windmill, Ghurd would need to chime in , Woofer has done much more than I have, he's got a real nice setup, even has LEDs in a remote spot :-).

For mine, I have a small 400watt invertor that is hooked up to a small car battery ( It was free) this battery just sits there and takes the dump from the controller once the NiCds are full.

I use the 400 watter to charge my portable drills, our mobile phones, and various other stuff . Once the power goes out in the house, it's used to light the house, so the nay sayers on our block can see :-))

One other thing, do not let the NiCds get any charge over 1.42V/cell for more than a very short period, this is the breaking point of them and is also the cut off point for ALL rapid chargers, they will get very hot and could vent out the top.

At 1.35 max/cell I've not had any burn up.

Hope this helps!!

Cheers

Bruce S

[ghurd]

The controller doesn't care if the batteries are charged wind, solar, hydro.

Works the same.

The batteries are holding the blade speed down.

G-

[Norm]

Hi Bruce,

city is always on me even when I just "try" to put a little VAWT out there.

How come Jay Leno can put a VAWT on top of his garage? Probably it's the money? or location??

http://www.pacwind.net/

[valterra]

doesn't sound like the "city."  Sounds like neighbors.