Author Topic: power furling?  (Read 6823 times)

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kitestrings

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power furling?
« on: February 25, 2014, 12:22:17 PM »
So I've been contemplating something on our turbine.  Right now we have a hand-winch that allows us to manually furl the machine; pics and description here:

http://www.fieldlines.com/index.php/topic,148058.0.html

I have never envisioned this as being the primary means of control, rather as a means to intervene for any number of reasons:

1) right now, things are new and I've pretty much been able to closed her down when I'm away
2) imbalance due to icing
3) Hurricane Irene predictions and the like
4) maintenance

It is, however, soft, simple and seemingly pretty effective.  There also are days where we have ample solar output to meet our needs, and unless we're diverting for something useful, I don't see the value of running it.  Weekdays, summers we may well have it "off-line".

What I was considering was to possibly replace the hand winch with a small ATV/motorcycle/portable winch (or operator); wireless remote.  The ideal thing might be to have it close down the turbine when the batteries have dropped into float.  Perhaps this could be triggered off one of the aux relays on the Classic.  I think Chris, maybe others(?) does something like this with electro-braking (shorting phases, latching for a duration, etc.) during prolonged wind events.

On the one hand it adds complexity to an otherwise simple system.  With the right amount of diversion - we're short there now - it might not be needed.  On the other hand, this thing will be 100' in the air by the end of the summer.  Operating it even by hand will have some added details.  I'd be interested in ideas, and merits of the idea as a whole.

Thanks, ~kitestrings

Flux

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Re: power furling?
« Reply #1 on: February 25, 2014, 12:43:28 PM »
Yes this is perfectly possible. You have the basic manual shut down so you can automate it with a small winch.

It does add complexity and the possibility of things going wrong but you can always go back to manual operation. If a hurricane comes when you are not there you have a better chance with the auto shut down and if it fails you are no worse off.

What I don't like is any complex control used as basic protection with no manual means of avoiding disaster.

I once built a machine that refused to furl ( I now know it was too little offset). It had manual furling like yours and it ran for several years with  car wiper motor operating a small home made winch. An anemometer operated the motor via a speed sensor using a 2917 tacho chip.

It worked perfectly well but seemed too risky as a basic control. If someone was there during a storm to manually operate the tail all was well but if it happened when no one was there and the control circuit failed then it would have been disaster.

When the furling problem was sorted the winch remained as a convenient remote shut down and could easily have been linked to state of charge or anything else if desierd.

Flux

clockmanFRA

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Re: power furling?
« Reply #2 on: February 25, 2014, 01:04:26 PM »
Sun has been out recently and I have just posted in CONTROLLS section about my PV back feed problem.

But, I am thinking about Chris taking his Turbines off line/shut down and allowing the PV to be master might be a way forward.

I am thinking that shorting a phase then all phases might be certainly worth thinking about, especially after loosing a Mk 1 blade on No 2 turbine in those horrendous storm winds over Christmas.

Also Kitestrings, as you can see from my other post, shutting my turbines down when windy and sunny and batteries full would possibly stop my PV back feed to the turbine dump loads.
Everything is possible, just give me time.

OzInverter man. Normandy France.

3off Hugh P's 3.7m Wind T's (9 years).  .. 5kW PV on 3 Trackers, (5 yrs) .. 9kW PV AC coupled Used/SH GTI's, on my OzInverter created Grid, and back charging with AC Coupling to the OzInverter to my 48v 1300ah batteries.

midwoud1

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Re: power furling?
« Reply #3 on: February 26, 2014, 05:41:40 AM »
Powerfurl can save your windturbine.
The LM 2917 tachochip. Glad to see Flux made it before.
In combination with a micro-controller it is a reliable programmable RPM switch.
Basic manual furling is a must,and automatic, can both work good.
I have it for a different app. And I sleep well during a heavy storm.
Instead of a winch and a spool , I think on a lineair actuator to pull the furl-line.
( Sat dish . long stroke lineair with limit switches )
Not a complex design.
 - Frans -

kitestrings

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Re: power furling?
« Reply #4 on: February 26, 2014, 10:20:44 AM »
Thanks for the feedback.  It's clear others with both wind and PV have to balance things in some fashion.  We have quite a bit of chicken and egg kind of things to work through in our case.  My preference is to always have the turbine loaded and doing something positive with the energy - charging batteries & pre-heating water our case.  On a sunless day, or evenings this is easy and we want all the wind output we can get.  On a prolonged sunny, windy period (like we start getting this time of year) it is more of a challenge – we don’t currently have 7-8 kW of readily available, sustainable diversion – and it can be hard to predict when the sun is going to burn through the clouds on a given day.

The idea of a motor operator makes sense.  The motion is a limited range of travel, and this would presumably have integrated travel limit switches.  I’m thinking it could even go at the base of the tower, connected via the Dyneema line.  I question using rpm as the mode of control and whether it needs to be independent of the charge controller(s).  Again, on a sunless day we want the full range of rpm to match the available wind.  I think one the Aux settings can be the means of control.  I’m not sure as it can be tied to charge stage, but I wonder if it could be as simple as setting it on input voltage (PV high limit).  When the batteries are full and/or the diversion is satisfied, that’s when the input voltage heads north.  Why couldn’t the force-furl occur whenever the input voltage exceeds say 180V?

Here's the hand winch & pulley if it helps to see it:



clockmanFRA

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Re: power furling?
« Reply #5 on: February 27, 2014, 05:22:04 AM »
Not sure about a mechanical furling system as a solution, especially a motor driven assembly.

 That means running a supply cable to your actuator motor at the base of the turbine. ?

More complications means more things that can go wrong. I use heavy duty actuators with in built limit switches and 24v motors on my Solar PV Trackers, and after many years of modifications, new bearings, new waterproofing, new grease nipples, motor modifications etc etc to the manufacturers spec, I now have something reasonably reliable.





What about Chris's concepts of loading/shorting out a phase then all phases.? At least that can be done at the Control station with some sort of relay arrangement.
Everything is possible, just give me time.

OzInverter man. Normandy France.

3off Hugh P's 3.7m Wind T's (9 years).  .. 5kW PV on 3 Trackers, (5 yrs) .. 9kW PV AC coupled Used/SH GTI's, on my OzInverter created Grid, and back charging with AC Coupling to the OzInverter to my 48v 1300ah batteries.

kitestrings

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Re: power furling?
« Reply #6 on: February 27, 2014, 06:37:00 AM »
Quote
What about Chris's concepts of loading/shorting out a phase then all phases.? At least that can be done at the Control station with some sort of relay arrangement.

Well, there are lots of ways to skin a cat.  (And it'd be pretty dull here if we did everything the same way ;D)  Fundamentally, what I don't like about shorting the windings is that IMO it is pretty harsh.  It dumps energy, & heat, into the stator where we've otherwise designed to avoid it.  In this case we're looking at taking a turbine likely operating in high winds, and potentially high output, and braking to a stop.  If you compare this to manually furling or Fran's variable pitch rotor, they are much more passive approaches.

We have this crowbar method now, but only because I haven't built a load box and I'm anxious to get away from it. We have a manual 'parking brake', but this is really the same thing - shorting the phase leads - just at a location more convenient for servicing the turbine.


I do agree with your thoughts on the added complexity.  If the actuator had spring return it could be a simple 'close contact/signal'; signal from CC (thru relay) which furls the turbine.  When the voltage drops and the contact opens, gravity returns the tail to the normal position.  Much like it works now with manual intervention.

~kitestrings 

kitestrings

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Re: power furling?
« Reply #7 on: February 27, 2014, 06:41:33 AM »
Yes, supply power for the actuator would have to go to the base.  I will have a spare set of field winding wires available when the Sencenbaugh comes down.

What brand/makes of actuators have worked well for you?  What modifications?


clockmanFRA

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Re: power furling?
« Reply #8 on: February 27, 2014, 10:50:31 AM »
In my opinion, LINAK are very good, but I need 22inches of travel so the LINAK become prohibitively expensive, so I have gone for a 24inch Heavy Duty satellite dish actuator.

http://www.satellitesuperstore.co.uk/satellite_diseqc_motors_36_volt_motors.htm#24inchh

Over the past 2 years I have tested, repaired and modified this particular actuator and things seem to be satisfactory.

Faults.
1. They are not waterproof, they say they are but after a year water was getting into the Motor brushes and the thrust bearings. So I fit a 5.00 size inner tube as per Photo.



2. The ally casting is reasonable quality and is sufficiently sturdy for the nylon reduction gear box. But lubrication nipples are required for the thrust bearing, one of mine just disintegrated, (bad bearing).
Pic as my previous post.

3.  The extending arm swivel joint is poorly made and can just fall out, so re-riveting is required, and on the 12mm dia bolt that passes through I fit safety washers, so the arm can not completely fail.





4.  The dc motor is 36v but I run it at 24v no problem and draws max 1.8 amp when loaded, ( me swinging on the tracker corner). However inside the motor is 2 half circle magnets that are just glued to the inside casing and these just drop off, so further attachment is necessary.



Everything is possible, just give me time.

OzInverter man. Normandy France.

3off Hugh P's 3.7m Wind T's (9 years).  .. 5kW PV on 3 Trackers, (5 yrs) .. 9kW PV AC coupled Used/SH GTI's, on my OzInverter created Grid, and back charging with AC Coupling to the OzInverter to my 48v 1300ah batteries.

SparWeb

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Re: power furling?
« Reply #9 on: February 27, 2014, 12:27:46 PM »
Clockman,
Getting the replacement bushing to stay in - what you've done looks like "staking", as in hammering around the edge of the hole to peen over the lip.  It'll never come out now!

Have the limit switches ever given you trouble?
No one believes the theory except the one who developed it.  Everyone believes the experiment except the one who ran it.

System spec: 135w BP multicrystalline panels, regulated by Xantrex C40, DIY 8ft diameter wind turbine, regulated by Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024

clockmanFRA

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Re: power furling?
« Reply #10 on: February 27, 2014, 01:31:45 PM »
Funny that SparWeb, the limit switches are actually good quality Micro switches and the assembly is very robust and easily adjusted for accurate/ precision distance for the actuator arm stopping.



This actuator arm had to be welded over as the peening was just not possible, as there was insufficient material to form over the bush.





Everything is possible, just give me time.

OzInverter man. Normandy France.

3off Hugh P's 3.7m Wind T's (9 years).  .. 5kW PV on 3 Trackers, (5 yrs) .. 9kW PV AC coupled Used/SH GTI's, on my OzInverter created Grid, and back charging with AC Coupling to the OzInverter to my 48v 1300ah batteries.

ChrisOlson

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Re: power furling?
« Reply #11 on: February 27, 2014, 03:32:06 PM »
Perhaps this could be triggered off one of the aux relays on the Classic.  I think Chris, maybe others(?) does something like this with electro-braking (shorting phases, latching for a duration, etc.) during prolonged wind events.

kitestrings, that's correct.  I use Classic AUX and dump the turbine power into a medium resistance three-phase AC load to start bringing under control when the power is not needed.  I set a few tenths of a volt below the solar charge points so the turbine will start cutting out as Batt V comes up to absorb, then it totally shuts the turbine down when the solar takes the Batt V all the way to absorb.

Our system has undergone some changes and we have a quite accurate measurement system on the net DC current to the battery so it can exit absorb at precisely the right time and take better care of the battery.  The wind turbine does not play nicely with that system because its output is too variable for decent battery charging.

So I have become a strong believer in that if you don't need the turbine power and the solar can handle it, shut down and save the wear and tear on it.  I use the stator braking into the resistance load to stall it.  Simply shorting phases is too violent and hard on stuff.  Dissipating the power into a resistance load brings it to gradual stop even in very strong wind.  Resistance loads are nice for that because they absorb and dissipate power in direct relation to how much voltage the turbine is producing on a MPPT system.  The higher the voltage goes the more power a resistance load draws.  Stator failures and burnouts are a thing of the past with MPPT so using it for dynamic braking doesn't put any undo load on it.  But a power furled tail should work fine too.

kitestrings

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Re: power furling?
« Reply #12 on: February 27, 2014, 07:14:32 PM »
Clockman,

I hope they're real cheap because unless I read it wrong, it sounds like they're not well protected, the bearing and lubrication sucks, the swivel arm has to be rebuilt to be reliable, and there are internal motor components that fall off.  Did I miss anything?  Yah, I'm all over that.  I assume these things don't all happen at once, and it may be a bit of "the devil you know...", but when you say this all out loud it is not very compelling why you wouldn't want to find more durable product.  I do know they can get pricey.

Welcome back Chris.  I hope the sailing was smooth, or invigorating.  I'm not sure what a sailor wishes for, maybe both?

So adding a power resistor load bank is high on my remaining 'to do' list, but as you've described here, and before, there's no sense running the turbine and cycling the resistors if the power isn't needed.  The Classic has two Aux relays, but I'm curious how you're getting what sounds like two stages of control, and still (I assume) diverting with one of the Aux outputs?

~ks


ChrisOlson

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Re: power furling?
« Reply #13 on: February 27, 2014, 07:44:37 PM »
Welcome back Chris.  I hope the sailing was smooth, or invigorating.  I'm not sure what a sailor wishes for, maybe both?

Well, relaxing is a better term.  We're waiting for the weather to get a little better and then heading down to the Gulf of Mexico to continue cruising.  Hopefully in March sometime.

Quote
So adding a power resistor load bank is high on my remaining 'to do' list, but as you've described here, and before, there's no sense running the turbine and cycling the resistors if the power isn't needed.  The Classic has two Aux relays, but I'm curious how you're getting what sounds like two stages of control, and still (I assume) diverting with one of the Aux outputs?

There's no diversion going on.  When the turbine gets to charge stage set point voltage the Classic simply unloads it and lets it free-spin.  If it goes over-voltage (Classic input V) the Classic's AUX1 turns on the brake with a mechanical relay.  Kind of a neat thing - the Classic's absorb voltage is like 0.5V (I'd have to check the exact setting) below actual absorb voltage set in the solar controllers.  So the turbine helps get the battery up to absorb then the Classic starts unloading it.  When the solar takes the BATT V up to actual absorb V the Classic thinks the system is way over-voltage.  The turbine is free-spinning at that point and doing nothing.  If the voltage goes up to the input limit the Classic turns on the brake and leaves it on until the Batt V falls back down to the Classic's absorb setting, then it lets the turbine go again.  The result is that it automatically shuts the turbine down during absorb and lets the solar do it's thing.

The function I am using is PV V High in the AUX1 menu.

I didn't know that it did that until I was playing with it one day, trying to get it to play nice with the solar controllers so they can properly measure the batt amps during absorb.   I had tweaked the Classic's Absorb V down a little and it happened.  And I go WTF?  So I tested it some more and it works every time.  So I tweaked the Classic's Absorb V down a couple more tenths and it's worked ever since.  It's really cool.

kitestrings

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Re: power furling?
« Reply #14 on: February 28, 2014, 08:52:07 AM »
Okay, I think I've got it.  I'd thought you were diverting to dhw water heating with one of the Aux outputs.

We're currently using Aux1 on "Waste Not Hi" for preheating water (this is small and on the DC load-side), and Aux2 is on the homemade clipper using PV High.  I forget, does the Aux1 have a delay setting also so that it is not cycling?  I could picture a day where a it is sunny & windy.  The wind assists getting to absorb, and the brake actuates when the voltage shoots up, but now say a cloud rolls by.  Wouldn't the turbine race back into action?

~ks

ChrisOlson

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Re: power furling?
« Reply #15 on: February 28, 2014, 10:28:16 AM »
Our system has undergone a few changes and the XW system now controls water heating, as it can log kWh sent to the water heaters (Conext ComBox) and I sort of like to know that.

On the turbine side, yes - if the solar drops out for some reason, or a heavy inverter load comes in that causes system voltage to "sag" out of absorb, it lets the turbine go and it helps out or carries the load until things return back to absorb again.  The AUX1 has adjustments for delay time and hold time on PV V High, as well as voltage ON and voltage OFF.  So you can custom set that to prevent repeated cycling of a mechanical relay.  If you set the jumper right inside the Classic you can make AUX1 put out 12V to operate one of those little ice cube relays with a 12V coil in it.  That's what I use for a pilot relay.  The pilot turns on the coil in a 200A SquareD three-pole contactor that connects the turbine's three-phase output (ahead of the rectifier) to the three-phase AC braking resistor.

The braking resistor assembly is outside (although inside a box) on the turbine power panels.  It's a fire hazard because it can get extremely hot in windy conditions when the system voltage rises to what absorb is set at in the Classics, using repeated braking to keep the turbine under control.  My latest one has three wye-wired garage door springs in it for resistors and the turbine will turn those springs glowing red in really windy conditions.  The steel box it's in gets up to 250-300 degrees and I got big fins welded on it to help it to get rid of the heat.  I got a wire cage around it so nobody can accidentally touch it when it's braking.  Not exactly something you want to have in the utility room but it has never burnt out with those big springs in it.  The springs are like 3/16" diameter or so wire, and wired wye it has about 3.7 ohm resistance.

clockmanFRA

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Re: power furling?
« Reply #16 on: March 01, 2014, 03:36:15 AM »
“I hope they're real cheap because unless I read it wrong, it sounds like they're not well protected, the bearing and lubrication sucks, the swivel arm has to be rebuilt to be reliable, and there are internal motor components that fall off.  Did I miss anything?  Yah, I'm all over that.  I assume these things don't all happen at once, and it may be a bit of "the devil you know...", but when you say this all out loud it is not very compelling why you wouldn't want to find more durable product.  I do know they can get pricey”.

In this day and age and most stuff coming from China, I expect failures, and here and now I am more than happy to give heads up to folk, so at least they know the pitfalls of particular products.
The main components of this particular actuator are in general well designed and well made, but as I said before some individual components need attention.
 
I have a limited budget and limited time, so in my opinion £124 for this and a quick re-build and mods seems a fair price against a LINAK at about £480 plus taxes.

I love my Hugh Piggott’s design, they are SIMPLE, VERY ROBUST, and COST EFFECTIVE, and  surely the Holy Grail of any Machine.
 
Yet on a cost effectiveness concept,  I can now make a simple, robust and cost effective 2kW double Axis PV Solar Tracker, at less cost for generated output than my beloved Hugh Piggott 3.7m (12 footer) diameter Wind Turbine.
 
Materials for a 12 footer  WT are about £1,100,  my materials for a 2kW Tracker  are about  £680, including actuator and sun tracking circuit, and £1280 for 2kW (8off)  good quality YINGLI  Mono PV Panels. I even get about 10% output from my Mono panels in murky/ambient light.
 
And yes, if you are in High  Northern or Southern latitude’s then perhaps a Wind turbine still makes sense.

Thanks Chris for your descriptions and your empirical evidence.   Obviously your turbines are putting out more than I reckoned, so I will re-think my dump load arrangements.
 
So Love’d your Garage door springs heating element arrangement for braking……..   ;D
Everything is possible, just give me time.

OzInverter man. Normandy France.

3off Hugh P's 3.7m Wind T's (9 years).  .. 5kW PV on 3 Trackers, (5 yrs) .. 9kW PV AC coupled Used/SH GTI's, on my OzInverter created Grid, and back charging with AC Coupling to the OzInverter to my 48v 1300ah batteries.

ChrisOlson

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Re: power furling?
« Reply #17 on: March 01, 2014, 07:58:11 AM »
So Love’d your Garage door springs heating element arrangement for braking……..   ;D

In my experience regular old coil stretch springs make pretty good resistors.  They seem to be able to be heated red hot repeatedly and not burn out.  The only thing that's a little strange is that when they get hot their resistance goes up quite a bit more than a regular heating element.  Not exactly sure what the difference is in heating element springs as compared to garage door springs.  But if you use regular springs you have to compensate for that a bit and plan on having the resistance approximately double when it gets red hot.

kitestrings

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Re: power furling?
« Reply #18 on: March 19, 2014, 11:43:01 AM »
Quote
So Love’d your Garage door springs heating element arrangement for braking……

Me too.  So Chris, I was looking at this a bit closer.  My original load bank was looking to be 3.4 ohms per phase (2 - 6.8 ohm in parallel), 6 resistors total.

      (2 in II, 6.8 ohms)         
Vline   Vph   R, ohms   I   watts (tot)watts (per resistor)
80   46.2   3.4   13.58   1,882   314
90   52.0   3.4   15.28   2,382   397
100   57.7   3.4   16.98   2,941   490
110   63.5   3.4   18.68   3,559   593
120   69.3   3.4   20.38   4,235   706
130   75.1   3.4   22.08   4,970   828
140   80.8   3.4   23.77   5,765   961
150   86.6   3.4   25.47   6,617   1,103


But, they're pricey buggers (~$120/ea).  I've been watching for something on e-bay, but hard to find the right qty, resistance & ratings.  At 3.7 ohms (higher with temp noted), it might be a good fit.

A few questions:
1)  I assume you are meaning the normal residential style springs as apposed to the torsion wound found on larger doors?
2)  You stretch them a bit to separate the coils?
3)  How did you make terminal connections?

BTW I owe you a thanks on describing the PV High function for the Classic Aux.  I had been using Waste Not for diversion (preheating dhw), but found when there was sun, and the wind was fluctuating it wasn't triggering soon enough.  With PV High I can catch any voltage increase above my preset, and tell it when to turn off.  the PV generally is handling the battery needs.  Slick.  I'm still playing with the settings (currently I'm on at ~75 or 80V and off maybe 65V), but it is working much better.

Regards, ~ks

ChrisOlson

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Re: power furling?
« Reply #19 on: March 19, 2014, 12:06:38 PM »

A few questions:
1)  I assume you are meaning the normal residential style springs as apposed to the torsion wound found on larger doors?
2)  You stretch them a bit to separate the coils?
3)  How did you make terminal connections?

Yep.  I went to the hardware store and bought three springs.  You have to stretch them out so the coils aren't touching or they just short out and it makes the resistance lower in them.  I put three of those white glass corner post insulators that you use for electric fencing in there.  Those insulators have a hole in the middle and you can bolt them to the back of the box with like 5/16" bolts.  Then I hooked all the springs together and hooked them over the insulators.  Then I spotted on a little steel tang at each joint where the springs are hooked together with the MIG.  I hook the wires from the turbine to the steel tangs with eyelet connectors on the end of the wire.

Those springs are made of a pretty good grade of spring steel so they got high electrical resistance (which you can adjust by changing the length of the spring).  And they seem to be able to take glowing red with no problem.  When I first got the idea of using a spring for a resistor I hooked one to a 12V deep cycle battery to see what it would take.  She instantly turned red, burnt the galvanizing off the spring, and to my surprise it continued to draw a fairly constant current glowing red and it never burned out.  Although it did lose all its "springyness" from getting red hot.  But it held its shape fine.  So I go, "hmmmph - no reason this won't work......"

Those springs are only about 4 bucks each.

kitestrings

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Re: power furling?
« Reply #20 on: March 19, 2014, 07:40:48 PM »
Thanks.  I might well give this a try.  The price is right, and they seem durable.

Reminds me a bit of a procedure I messed with years ago aimed at releasing sulfation from batteries that'd sat too long.  It was something outlined in a book by a guy named Michael Hackleman (Hackelman, sp?).  He wrote a few books - mid-seventies - on homebuilt wind, remote water systems, and the like.  Anyhow, I just remember cycling a bunch of batteries per this "recipe", and the load was basically a length of baler wire.  I don't know if they use that in other areas - it's mostly twine and wrapped round bales here now - but just across the border, Canadian hay regularly came in bales no one could lift wrapped with the stuff.

You measured it out, and then spiraled it around a broom handle.  If the goal was to put a serious load to the thing, yah it sure did that.  Not sure as we ever 'saved' any batteries that didn't just need a good wake-up, but learned a few things about Ohms & Murphy's laws.

Thanks for the feedback.  ~ks