Solar Install; the on-going saga

She's ready for some wires and a mast.



Front




Rear




Hub (anti-clockwise rotation :rolleyes:)




Yaw

Yup I cheaped out on the yaw bearing! That's a modified swivel caster. 2 squid does not buy you good bearings. It's exposed to the elements has an ABEC of about -5 and rattles like an LDV. I'll swap it after it drives me crackt, 'twill do for now.

The furling system is entirely experimental. I had a look at a few techniques and formula and wasn't bothered. There's no reports of any cyclist melting a dynohub open circuit, loaded or souped up as far as I can find. And I've found reports of people doing >50mph.

I took the wry eye with a pencil behind the ear approach and dead hung it on a hinge with a larger than standard swept area and no offset.
The theory is based on the VIRYA vane (that does work but uses maths, moments, and all sorts of Greek letters) the vane is balanced to lift away from the yaw in high wind and maintain nominal RPM with furling up to 30m/s.
I just crossed that with the Rutland approach which is; get a stick and poke it if you don't fancy taking it down. :pac:

I've spec-ed this as a 15watt generator because it's traditional to over-inflate the output of a wind turbine in the industry. From what I've seen and tested it'll be hard get more than 10W from this and that's before the circuit losses. I think a nominal 5w is reasonable. Doesn't sound like much but that's potentially twice what I'd get from solar in the heart of Winter after flying for 12 hours, which in theory is enough to offset the shortfall to when I'd be passing a hook-up.

My circuit is entirely the wrong way of doing things . Reason for this is I'm not making another hole in my roof or adding another 2 cores of cable the length of the vessel for a 10W generator.
I'm going to forego the dump load controller and just not fly it unless I'm >25Ah in the red...easy!...There's no way it can cook the batteries in my sleep then, even at full tilt it's too feeble.

Circuit Diagram

Bridge rectifier is all schottkys (low voltage drop)...not that it needs to be...only the forward biased ones are important. High voltage though because I'm running the dynohub in PWM solar control mode, so they need to withstand the OC voltage (~50v fast as I could get it).
Same goes for the low ESR capacitor.
The boost regulator is the Shenzhen market's finest :pac: 'nuff said.
The added C/O relay is because diodes suck on low-voltage generators and I'm not putting one in series with the solar module if I can help it. I need a diode to prevent the turbine powering the solar module at night-time, so the turbine has to power the relay coil instead...eh! I think it works better so. Feel free to suggest a better solution.

R2 could maybe be lost if R1 can do it's job (relay coil suppression and voltage limit).

[Edit]: Missed a component; +1 schottky diode, needed on the boost reg output to prevent the solar module powering the wrong end of it...hmmm perhaps make that a 17v reg.
[Edit 2]: Zener diode added in parallel with boost reg. primary side as a basic over-voltage protection (boost reg. max in. 30v).

I found the source of bother with the TriMetric. Turns out my ghost load is 63mA not 300mA. Which makes a bit more sense as I always thought 100mA was higher than spec. for the Tristar and the TM.

There's three signal wires running to the shunt for measurement of current based on resistance. Two wires twisted pair run to the load side and one runs to the battery side. The TM references the voltage drop on the cable wiring by comparing what is being sent and returned to the load side connections. It then uses this to calculate the differential between the load side and the battery side to calculate current.
I repurposed 7 core trailer wire to serve this loom (+2 cores for battery #1 voltage and battery #2 voltage). As it turned out one of the cores I was using to the load side was crispified from it's former incarnation, giving it a resistance ~1.2Ω higher than it's partner. I swapped both cores for the two spares I had left aside as they were closest to each other in resistance (0.15Ω difference). Hey presto meter is now within 30mA of my (internally shunted) DMM.
At which point I had to stop myself being a pedant and ripping out a 7 meter loom as the chicken flys for the sake of 1 amp hour accuracy every day and a half.

So given that the apparent constant load was previously 237mA out * 24hours * 21 days = 119.5Ah down between complete charges...pretty much in and around what I was griping over.

Meter your meters folks! So far I've 6 voltmeters and 4 current meters and any two of them might agree on a good day but not about the same things! :pac:

Those DC MCB's I keep recommending; ~10mA self consumption in the on position...I still reckon they're better conductors than fuses for switching power supply efficiency. Just remember to turn them off if they're sitting idle.

moodrater

moodrater wrote: »

...will I actually use this to which the answer is...

....Analogue variable power supply for the lekytronics lab

Boost reg. arrived, it's a neat little do-fer. About 92% efficient outputting 16v from between 7v to 12v and highly stable at that. It drops out below 7v and the output starts to bell curve. Not a huge problem hopefully as it's quite easy spin up to 7v with a 5W load on. Not so much with a 10 watt load I'll see how it does on a battery once I replace the trim-pot that lasted all of 6 hours...ah Chinese crap :rolleyes:, new trim-pot's gonna cost me almost half what I paid for the regulator. :pac:

Bittov an impasse at the moment. I replaced the 50kΩ trimpot with a 100kΩ because that was all that was in stock around the corner. Preset it to 25kΩ and re-mounted it. I reckon I set the wrong side though because I blew the snot outtov an SMD mosfet about 5 seconds later :rolleyes:
So now I've ordered an new mosfet and another dodgey Chineese reg.
I've already started to scavenge what's left of the reg.

Here's the board layout for the bridge rectifier, filters, over-voltage deterrent and boost reg.

Those were the smallest low ESR caps I could find nearby with a hefty voltage threshold.
...Well I could have gotten smaller but they were the same price.




30A relay with 2 schottkys mounted to the rear.
Relay holders make pretty good heat sinks.




Front of relay with RC coil suppressor attached.

The relay coil runs at 150mA which I'm not hugely happy about...I could get a smaller relay I suppose or a solid state if I come across one.

When I say this is the entirely wrong way of doing things; traditionally you connect the turbine straight to the batteries and regulate the battery by switching loads on and off in order to keep the turbine from over-spinning resulting in mechanical failure or open circuit generation resulting in electronic failure.
I put a fuse on this for tradition's sake but I may just take it out again. The dynohub will never threaten overloading the cable and electronics generally break faster than fuses, it may just be a liability to open circuit the dynohub.
The zener diode is the open circuit over-voltage protection that dissipates energy as heat after a threshold (25v). The one I picked is only a 5W and it's too small to do the job in a strong wind which in turn will cause a cascade failure of components if it goes. I expect it to be adequate coupled with the capacitors to handle the PWM absorption. Normally you'd use a series resister to assuage the thermal breakdown but then I'd lose watts generated too. Also once a zener is on it stays on until the voltage reaches ground reference so it wastes useful power in certain circumstances.
In essence it's a very simple load controller upstream of the batteries referencing the OC voltage as a switch.

All of these reservations while valid are not an issue as long as the turbine is under constant load ie; batteries are low.
I'm going to babysit it for a while as is to get some figures from the field before I start upgrading the parts. I can go with a 10W - 15W stud zener heat-sinked to my ali-frame, or get some mega-resisters, or even do it right and run separate cores and a robust controller, these're are all kinda expensive solutions and I think I'd rather know what to expect before I commit to any.

What could possibly go wrong?

moodrater

Sir Liamalot wrote: »

Bittov an impasse at the moment. I replaced the 50kΩ trimpot with a 100kΩ because that was all that was in stock around the corner. Preset it to 25kΩ and re-mounted it. I reckon I set the wrong side though because I blew the snot outtov an SMD mosfet about 5 seconds later :rolleyes:
So now I've ordered an new mosfet and another dodgey Chineese reg.
I've already started to scavenge what's left of the reg.

Here's the board layout for the bridge rectifier, filters, over-voltage deterrent and boost reg.

Those were the smallest low ESR caps I could find nearby with a hefty voltage threshold.
...Well I could have gotten smaller but they were the same price.




30A relay with 2 schottkys mounted to the rear.
Relay holders make pretty good heat sinks.




Front of relay with RC coil suppressor attached.

The relay coil runs at 150mA which I'm not hugely happy about...I could get a smaller relay I suppose or a solid state if I come across one.

When I say this is the entirely wrong way of doing things; traditionally you connect the turbine straight to the batteries and regulate the battery by switching loads on and off in order to keep the turbine from over-spinning resulting in mechanical failure or open circuit generation resulting in electronic failure.
I put a fuse on this for tradition's sake but I may just take it out again. The dynohub will never threaten overloading the cable and electronics generally break faster than fuses, it may just be a liability to open circuit the dynohub.
The zener diode is the open circuit over-voltage protection that dissipates energy as heat after a threshold (25v). The one I picked is only a 5W and it's too small to do the job in a strong wind which in turn will cause a cascade failure of components if it goes. I expect it to be adequate coupled with the capacitors to handle the PWM absorption. Normally you'd use a series resister to assuage the thermal breakdown but then I'd lose watts generated too. Also once a zener is on it stays on until the voltage reaches ground reference so it wastes useful power in certain circumstances.
In essence it's a very simple load controller upstream of the batteries referencing the OC voltage as a switch.

All of these reservations while valid are not an issue as long as the turbine is under constant load ie; batteries are low.
I'm going to babysit it for a while as is to get some figures from the field before I start upgrading the parts. I can go with a 10W - 15W stud zener heat-sinked to my ali-frame, or get some mega-resisters, or even do it right and run separate cores and a robust controller, these're are all kinda expensive solutions and I think I'd rather know what to expect before I commit to any.

What could possibly go wrong?

For low ESR you can just parallel up cheap/scrap capacitors.

Was it using the trimpot as both halve pf a voltage divider.

I don't like recycling electrolytics when ESR is a factor. Thanks for the tip though, it'll come in handy I'm sure. The wiper and one side are tied to ground I'm just an eejit for confusing them.

Solved the zener over-voltage protection conundrum from salvage. Zener, triggers transistor, switches on parallel load. Manually stall turbine to reset zener. Diode downstream so it won't waste anything it's not generating.

I'm tempted to use LED's to light the blades and tail as the dump...but it'll probably look naff, so maybe not.

Zener regulation works a treat, the only way I can spin the hub fast enough to activate it is wrap a rope around it and give it a chain-saw start.
I'm using series 12v bulbs at the moment to make a 10watt 24v dump load (easier see it's doing it's job). I'll probably change for a mega resistor further down the line, they're more reliable than pulsing tungsten filaments.

I reckon I'll be losing 25% to 55% of what's being generated to charge and control losses...ouch.

I can't for the life of me figure out a way to dump that C/O relay, other than manual cross-plugging (6% - 20% loss right there on the coil). I am not putting a permanent series diode on the panel, it'll cost more in voltage drop than it saves. Hrmmm, maybe an axial quick connect diode might work best. ...maybe eventually I'll learn to program microcontrollers.

moodrater

Sir Liamalot wrote: »

Zener regulation works a treat, the only way I can spin the hub fast enough to activate it is wrap a rope around it and give it a chain-saw start.
I'm using series 12v bulbs at the moment to make a 10watt 24v dump load (easier see it's doing it's job). I'll probably change for a mega resistor further down the line, they're more reliable than pulsing tungsten filaments.

I reckon I'll be losing 25% to 55% of what's being generated to charge and control losses...ouch.

I can't for the life of me figure out a way to dump that C/O relay, other than manual cross-plugging (6% - 20% loss right there on the coil). I am not putting a permanent series diode on the panel, it'll cost more in voltage drop than it saves. Hrmmm, maybe an axial quick connect diode might work best. ...maybe eventually I'll learn to program microcontrollers.

http://www.ebay.co.uk/itm/Durite-Relay-Latching-25-amps-12-volt-Cd1-0-728-02-/360538864184?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item53f1ca7a38

You'll just have to bite the bullet and get programming microcontrollers.

Actually something to consider.. an ideal diode controller with for each and ditch the rest 150uA operating current:

http://www.linear.com/product/LTC4359

moodrater

moodrater wrote: »

Actually something to consider.. an ideal diode controller...

Nice price tag...

Actually I think I can live with the schottkys and dump the relay and resistor gubbins.

Just tested it there:
0.1v drop @ 9A
0.07v drop @ 4.9A

I'll link through it when I fly the windy and bypass it when I'm taking it down. K.I.S.S.

moodrater

Sir Liamalot wrote: »

Just tested it there:
0.1v drop @ 9A
0.07v drop @ 4.9A

Something wrong there for a start I would say those values are impossible and secondly the only way you'll get a really low vf is where the junction temperature is really high.

Quite possibly, I'll double check later...im off galavantin'. I was thinking it was low because it's a 30A diode so not stressed. Although I was testing it without a heat-sink on 5A cable that was melting away while I was swapping meter leads.

moodrater

Sir Liamalot wrote: »

Quite possibly, I'll double check later...im off galavantin'. I was thinking it was low because it's a 30A diode so not stressed. Although I was testing it without a heat-sink on 5A cable that was melting away while I was swapping meter leads.

That diode is only rated for 3w dissipation.

Heat dissapation normally being Vf x I?
Oops!

@10A

I was testing running the fridge on Electric yesterday. It runs far far better off the inverter than 12v.
Set to 12v: it runs @10A
AC fridge (highest setting) + inverter: run @ 10.3A
Inverter idle: 0.7A

However because the AC element has a thermostat it's off when it doesn't need to run so cools for a lot less power. It's easy keep up with it on a cool sunny day 16Ah it ran for yesterday including the fans round back.

I think it's time I integrated the AC ring with the inverter ring on a changeover.

I pulled this out of curiosity. I've been out of port a week and try hard as I could I can't discharge my new batteries more than 20% DOD even if I fall asleep with the lights on and laptop running. :cool:

Daily Ah

The huge 100Ah spike was alternator assisted with the fridge running for ~4 hours followed by a really sunny day with the fridge on the inverter and the module tilted...most days after that were wholly or partially overcast and flat mount, there's about 2A coming in now in the rain with a white sky. You actually get more with a flat mount when light's this diffused. I can set the logger to watch specific time windows if I could be bothered.

Everything before the 100Ah spike is the system idle; flat panel with shading after about 18:00.
It's me just turning the panel on and off every few days to stop my starter battery sulphating. I might eventually put a micro-controller in here to automate the task while preventing short-cycling.

The system can do a lot better with better weather, exposure, panel angle and deeper discharges.

moodrater

Sir Liamalot wrote: »

I pulled this out of curiosity. I've been out of port a week and try hard as I could I can't discharge my new batteries more than 20% DOD even if I fall asleep with the lights on and laptop running. :cool:

Daily Ah

The huge 100Ah spike was alternator assisted with the fridge running for ~4 hours followed by a really sunny day with the fridge on the inverter and the module tilted...most days after that were wholly or partially overcast and flat mount, there's about 2A coming in now in the rain with a white sky. You actually get more with a flat mount when light's this diffused. I can set the logger to watch specific time windows if I could be bothered.

Everything before the 100Ah spike is the system idle; flat panel with shading after about 18:00.
It's me just turning the panel on and off every few days to stop my starter battery sulphating. I might eventually put a micro-controller in here to automate the task while preventing short-cycling.

The system can do a lot better with better weather, exposure, panel angle and deeper discharges.

Huzzah you have finally arrived. It should be easy to do an automatic tilter with a universal window regulator and a couple of ldrs or photodiodes :pac:

I'm not there yet M. My target is 3 - 6 weeks autonomy, but I'll settle for 52 if it's not that much more effort. I'm debating building an automatic split charge relay driver. The windies are for October onwards when demand increases and photons are scarce. Iirc I was getting 3-5Ah from photons on a good day last Winter. I dunno if I'll bother with automatic tilting, or even button controlled. It's rare enough I tilt it, clamp meter and me schtick work fine...I need to remake the stealth box this Summer too. I'm going to redo the lips in birch ply with a DPM over the grain. Wood's going soft from water ingress on the exposed edges. I also need to shoe-horn and restrain two dismembered turbines under the module.
I have a starter motor from a Peugeot 106, I'm toying with the idea of turning it into a bed winch, that could do the tilting too if I'm bored enough and change my mind.

I'm not having much luck with this windy.
I tried fixing that boost reg with another mostly similar mosfet and the 100K pot and let the smoke out of it so that's scrap now. The second reg. arrived for about the same price of a mosfet and a trimpot posted from China that's on the board now. It's rather underwhelming attached to a battery though. It's using an awful lot of power dropping out. Turning it on the bench the final output (without the relay because otherwise there just isn't any ) is 1.86W and raising the battery voltage by 3mV.
If I cut out most of the electronics and just use the bridge rectifier I can get 3.5W with the battery raising 12mV and far less drag on the hub.
Either way it's nowhere near the required 0.3V above the battery voltage to get it to accept charge.
Maybe a good breeze could do better than I can so I'll cobble it together to fly it but I might abandon the notion altogether at this rate.

Vf with a heat sink on that diode is 0.6V @ 9A.

Mwahaha! New record set. 156.5W from my year old 150W module (300mA load running). It's flashed 170W with edging, happily holding 155W though.

Meanwhile, there's no wind...anywhere. I swapped the yaw bearing on the Mark 2 windy for one from and expired angle-grinder. Attaching it to the van is stupidly vibratey, need a free standing new mast, maybe.

The Mark 2 will start up with no load in 3.5 m/s. Haven't seen anything stronger in the last 2 weeks. It'll find the wind in 1 m/s though.

Mark 1 has cobwebs on the blades, and doesn't get out of bed for less than a gale I reckon.

moodrater

Nice one well worth it so. Nice windmill mounts are the ones you park on top of tyre isolates vibration you'd probably need to guy or tie at roof level too via rubber bushing or whatever.

Yeah, seen 'em, being lazy at the mo and making do with plank. I've a few skate board bushings and rubber pads to reduce the vibration but it rattles the be-jaysus outtov the roof rack either way.

I've being thinking of stealing your wind-surfing mast idea for a telescopic pole, can't seem to find rigid metal conduit anywhere. I can live with the rattles until I see some electrons coming outtov the thing. Mr Piggott has a new manual out with ferrite magnets....worth a look if all else fails.

Some respectable wind forecasted for Thurs/Fri I believe.

Aidan_M_M

Liam , something I meant to ask , did you ever figure out why even numbers of blades are supposed to be noisier than odd numbered amounts of blades? Any why do most larger turbines in use have 3 blades? as opposed to 5 , or 7?

Resonance I think, even blades are balanced on the tower so shake more, odd blades are out of phase so to speak so make less noise. It's a little like having two axles on a trailer (odd blades) versus one (even).

As to why three is the popular number. The less blades you have the higher rotational speed you can achieve at the expense of start up torque. Given the cost of low rev. generators speed is preferred. One blade or two would be better except the moments will tear the tower apart. You get a lower wind-speed start up with more blades and a slight increase in efficiency but it doesn't out-weigh the expense of the added materials after three unless you're in a low wind site.

Aidan_M_M

Sir Liamalot wrote: »

Resonance I think, even blades are balanced on the tower so shake more, odd blades are out of phase so to speak so make less noise. It's a little like having two axles on a trailer (odd blades) versus one (even).

As to why three is the popular number. The less blades you have the higher rotational speed you can achieve at the expense of start up torque. Given the cost of low rev. generators speed is preferred. One blade or two would be better except the moments will tear the tower apart. You get a lower wind-speed start up with more blades and a slight increase in efficiency but it doesn't out-weigh the expense of the added materials after three unless you're in a low wind site.

Thanks. I have zero spare time, but sometime I WILL get around to building a wind turbine. . .

Hugh Piggott's ferrous magnet edition. No corrosion, cheaper than Neo magnets.

Aidan_M_M

there goes my evening!! < :

It works!




Max Gen.
The turbine spins faster but no more electrons come out. (60v open circuit before I stopped being so brave....wasn't worth finding out after that.)
(6.8 m/s is the only relevant reading on the dispay-o-meter dofer...that's been my alarm clock the last few days...
...I can set it to chime at a certain windspeed in case I had to get up and take a reading )

Numbers for the nerds:

Cut in: 4.8 m/s
Cut out: 3.1m/s
Rating: 7W
Max generation @ >7m/s: 7.3W

Nominal @ 4 m/s: ...not much :rolleyes: ~2W give or take
Nominal @ 5m/s: ~3.5W
Survival speed:

Furling system results inconclusive...not worth the noise, I'm fixing the tail to the body....rattles. Well everything rattles, rumbles, hums, shakes and vibrates. Free-standing pole is a must. Cheap fix: ear pugs!

So as to my 10W target...I need two of them or devise a contra-flow double alternator :pac: ...I'm not going to bother. The Mk-3 is going to be a serious 800W machine...non-portable or three.

The boost regulator gubbins is a waste of time, it just bamboozles the leckytrons...I get about 500% more output with just the basic Schottky full wave bridge rectifier straight to battery. Plus I mighta killed the zener...the dump load didn't make it to the gig on time.
Now maybe that figure is just the cap's charging, so it's not really lost but I'm over it, less stuff to go wrong without it.

Noise control, cable, find a home it won't get in the way and bother me next, she's a keeper.

Is it worth it?...hahaha...nah, probably not, your call. It'll run two MR16 LEDs at night in the Winter when solar's doing eff all, as are most campers...
...if you're on the side of a mountain, and fancy setting it up and packing it again in the morning.

In fairness it has better low end, real world potential than the off the shelf competition for 1/4 the price (not including learning curve expenses), and definitely not compensating for solar module loss of generation due to shading. :P

From another perspective; this is a 15W bird dunnit! Turbine shadow is half the module by the way.

Moral of the story; if there's gears or iron in the windings it's not worth the bother.
Actually the true moral is: Not enough PV? More PV so...

Aidan_M_M

Hey Liam , that's a great result , well done.