Help. VAWT Voltage generated but no Amps/Watts?

[Hannah Dawson]

Hi,

We're completely new to wind and sourced a wind turbine from a local supplier thinking it was locally designed (live and learn) who I actually think get from China (https://shdgpower.en.made-in-china.com/product/mKsxoOkdLrUX/China-Small-Vertical-Axis-Wind-Turbine-500W-24-48V-Speed-11m-S-500-Watts-Wind-Turbine.html) . We have the 48 V 500 watt turbine. Max 11A. We have a 400 Amp/hour Lead acid 48 V battery bank.

We've had it installed a few days now and live in a really windy area. The typical backround wind is 5 m/s on a quiet day up to about 10 m/s on a avergae day, lots of gusts though and we live in a valley where the wind roars through. The turbine has been spinning and we've been hearing a hum which our supplier says is it generating power (though it more sounds like a fast click as it turns).

Checked that the cable thickness we used isn't causing loss. Had a sparky do the wiring at the battery bank side, we wired into the turbine.

The problem is, there seems to be heaps of volts showing on the charge controller but no amps or watts showing up. We were told there had to be wind for 30 seconds or so greater than the cut in (24 V, not sure what it is in m/s). From what we can tell thats when the noise starts suggesting power is generating however we're still not seeing any reflection of actual power going into our battery bank.

Is it that we still just don't have enough wind for long enough for the turbine to actually send power down? Somethings not adding up and we're not sure what it is. Will chat to supplier too but would like other thoughts.

Thanks,

[Hannah Dawson]

There is some developments if anyone has thoughts. The controller seems to have a brief change in amps and wattage every few minutes (i've been told this happens typically when batterys are charged and they don't want to draw power)or so when above cut in speed at 60 V it generated 68 watts, it should be 500 watts. Also the controller despite having a 60 V max went to 105 V in a gust. Its as if its not acknowledging it needs to charge the batterys. Is this suggestive of a controller fault?

Suppliers away on holiday so i'd like to get my head around it before talking to them more.

[Rob Beckers]

Hi Hannah,

Your turbine looks cute!
When it comes to most Chinese wind turbines, there are lies, damned lies, and turbine specs... The design of this turbine is essentially a Savonius type (a class of vertical-axis turbines), and those have very poor efficiency to start with. The general problem with vertical-axis turbines is that they are more in the category of "yard art" than serious energy producers. There have been exceptions, but none of those were Savonius-type and they had their own issues.

With battery-charging turbines you need to keep in mind that they don't charge when the batteries are full. Have a look at Amps when the battery Voltage is low enough that the turbine should be charging (on a windy day). You mention 105 Volt, I assume this is on the input side of the charge controller? The output side would just be your battery Voltage and that should remain pretty steady. If not then you likely have a bad connection. Lead-acid batteries would have their absorb Voltage set around 60 Volt (for the flooded variety), the amount of current the controller would produce will taper to zero at that stage. Depending on the design of the controller and how well the turbine is kept under control when the batteries are no longer being charged the input Voltage (from the turbine) can vary a great deal.

If you regularly see 5 - 10 m/s wind speed you certainly have the wind to make a small turbine worthwhile! If you can't resolve things with this one, I would have a look at regular horizontal-axis types, such as a Primus AIR. They are not the greatest turbines, but they are affordable, work reasonably well, and are reasonably reliable (plus you can get parts when stuff breaks).

-RoB-

[Bill von]

There is some developments if anyone has thoughts. The controller seems to have a brief change in amps and wattage every few minutes (i've been told this happens typically when batterys are charged and they don't want to draw power)or so when above cut in speed at 60 V it generated 68 watts, it should be 500 watts. Also the controller despite having a 60 V max went to 105 V in a gust. Its as if its not acknowledging it needs to charge the batterys. Is this suggestive of a controller fault?

Maybe. If the input voltage is high and the battery voltage is low (specifically below the controller's setpoint for voltage) and it's not charging then the controller has a problem. You could try replacing it with one of the wind-capable controllers out there if it never works, but that of course is $$.

[Hannah Dawson]

Thanks both of you for your reply. We looked at that one Rob but decided on this (even knowing the low output) because of our location (very gusty/irratic) and requring consent ffrom council to mount one greater than 3 m high :/. Expectation wise we were expecting to only ever get max 200 watts out even with it being a 500 watt turbine so didn't sell ourselves short there. What gets me is that theres no output at all.

Battery bank hasn't been charged when we've been looking and all the settings have appeared 'normal'. Controller is reading the batterys fine with the voltage matching our PV inverter voltage so the contacts have been rulled out. Its really looking like a setup or controller problem.

As it turns out, the sparkys have supplied us with the wrong cable. Despite requesting 3 phase 4 mm cable from them they supplied 3 core 4 mm cable (earth being 2.5 mm). The supplier thinks this could cause the issue but now sparkys are disagreing. Seems with this turbine that the three cables (pair between cable one and two and pair between cable one and three read voltage OK but pair two and three do not). Supplier in New Zealand has said that one of the cables is the reverse magnetism and feeds back to the turbine. Thats potentially been wired in as the 2.5 mm cable and could be causing the problem. The feed back along ,may not be matching up OK (or so i'm told). Cable length is only 22 m so our sparkys are disagreeing. We get charge briefly with gusts and volts over 40 but it only holds for a second or two even when wind is constand and remains above our cut in voltage (24V).

This turbine makes a clicking sound too, similar to a plane engine starting up and at times theres a sound similar to a CD disk getting stuck. Apparently the sounds aren't normal so it again could be the feed back along the cable is off.

Thats where we are at anyway, do you guys have any thoughts on if this is a realstic concern?

[Rob Beckers]

Turbines like yours are really simple devices: The alternator produces 3-phase Voltage/current when they spin, that goes through a bridge rectifier turning it into DC, and then charges the batteries. The dump load is there to divert power when those batteries are full. If the input Voltage is there, and the batteries are empty enough, it should charge when it spins. To put another way, any time the DC Voltage coming from the rectifier is higher than the battery Voltage it will charge. When the batteries are full it either diverts current to the dump load, or switches the entire turbine over to the dump load. Possibly the charge controller is broken, or thinks it's a 24V battery bank and so believes the batteries are already full?

If you're handy you can just take a 3-phase bridge rectifier, hook up the turbine, make DC, and connect that straight to the battery bank (with a fuse of some sort in case of a short!). If the alternator works it will charge, and a cheap/simple clamp Amp meter would tell what's going through the lines (or the battery Voltage, since it will go up when it's charging). Keep in mind that to charge a 48V battery bank you need 58V+.

If the problem turns out to be the charge controller, you could get something else, like a Morningstar TriStar, and connect it in diversion mode to the batteries with the dump load you have. The charge controller is just there to prevent overcharging of the batteries. Since you mentioned measuring 105V AC while no charging was happening seems to indicate an issue with the charge controller: For a simple one like this the AC Voltage wouldn't normally exceed the battery Voltage (because the moment it gets higher it will send current to the batteries, and even a small Voltage difference would send lots of current to the batteries, slowing down the turbine and keeping the input AC Voltage under control that way).

If this is all black magic to you (and by the sound of it, to your electrician for sure), find someone local that actually understand wind turbines and measure through this thing. It really shouldn't be all that hard to find out what's going on, an hour tops with the right tools.

-RoB-

[Hannah Dawson]

Hi again,

Thanks for that reply, it's beginning to make a bit more sense. Unfortunately there's no one in my area, I had to go to a different city to get this. I'm sure there's someone who doesn't publicly advertise but no one who offers a service. I really appreciate your replys. I'd have to fly someone in :(.

Is it odd that I've been told cutin volts where charge is supplied to the batteries is 24 V and it's a 48 V battery bank ( where it needs 55 V plus?) or are we talking two different volts? And input generated voltage and the output voltage?

Cheers,

[Rob Beckers]

You can fly me in! Always wanted to visit New Zealand! :cool:

Cut-in Voltage really is just the point where the turbine starts charging the batteries. For a 48V battery bank that would be around 56 Volt or so (and above) for a 48V battery bank. Before that there's no current flowing, and the turbine is just free-wheeling.

Normally the AC Voltage of the turbine is a bit less, because rectifying 3-phase AC gives you a higher DC Voltage, by a factor of about 1.35 (roughly).

There is a class of charge controller called MPPT controllers (for Maximum Power Point Tracking), and those would work at a higher input Voltage vs. the battery bank Voltage. MPPT controllers can convert the Voltage downward. I highly doubt that's what you got with your turbine though. They are a much more complex and expensive beast. Most of them simply work by rectifying 3-phase AC into DC, and going straight into the battery bank from there. The charge controller either disconnects the turbine from the batteries when they are full (and to a dump load) or it has the turbine permanently connected to the batteries and switches on a dump load to divert current when the batteries are full.

-RoB-

[Hannah Dawson]

Haha I'd love too but a single income family with two kids and one of the way....dreaming!;). Though don't let that put you off visiting here.

Ahh it is an MPPT one, no dump load as such as it just goes back up the turbine (apparently?). Do they convert voltage upwards? or is that a silly question....

I just don't understand how we could be told the charge/cut in voltage is 24 V for this unit when they knew it was all a 48 V system. It was all supose to be a 48 V system but i know they have other turbines so i'm beggiing to wonder if we have been supplied the wrong one.

[Rob Beckers]

The picture on the Web site you pointed to in your original post shows a dump load. Guess you got something different from what they show.

What's the brand and type of the charge controller? Possibly I can find a manual or spec sheet. All the MPPT charge controllers I've seen can only convert the Voltage downward from input (wind or solar) to output (batteries).

MPPT controllers for wind turbines need to be loaded with the proper "MPPT table" for that specific wind turbine. Without an MPPT table they won't do anything. If yours is an MPPT one the manufacturer of the turbine would have to load it before shipping (hopefully).

-RoB-

[Hannah Dawson]

All resolved, turns out the sparky didn't wire everything into the controller properly so we only had two of the cables connected, the third needed a few extra twists of the screw to tighten it and it fixed. Sound stopped too.

Now for some wind! We've hit a very quiet wind time, and low fog/mist so no PV or wind.

Now to start saving for micro hydro for next year and hopefully have a robust all around system.

[Rob Beckers]

Glad to hear it's working Hannah!
It's one of those "if you want to get something done you got to do it yourself"... Annoying though if you pay good money to someone to do a job and they botch it.

I'd be interested to hear back in a while how the turbine is performing! Meanwhile, I wish you many windy days!

-RoB-

[Shawn tal]

Maybe. If the input voltage is high and the battery voltage is low (specifically below the controller's setpoint for voltage) and it's not charging then the controller has a problem. You could try replacing it with one of the wind-capable controllers out there if it never works, but that of course is $$.

That's what I thought

[Hannah Dawson]

A bit of an update. Its taking me a year to want to even look at the thing again after dealing with our supplier.

Rob- First off its still not working and if it is working and its just our turbulent wind that causes it not to work, I'd not touch one again if someone paid me to.

I had a baby and family stuff happening so we parked this as it was causing a bit to much stress. Also after we discovered it still wasn't working we were unable to find any sparkys (professional or even people with a remote interest/skills) to come and see the thing.

The update- We believed it was working, after our sparky came back to fix the bad wiring job (on a sunny day with full batteries from the PV system ) we saw the wind charge controller register some amps/watts for a few seconds and then disconnect/cut off supplying charge. It is suppose to do this when batteries are charged. When we were still on talking terms with the supplier, they told us that every few minutes the charge controller would check to see if charge was required and allow it or not allow it (pending battery voltage) . Anyway, all looked good and like it was working.

That's all the turbine has ever done though, it doesn't seem to actually supply any charge to the batteries. Leaves two options that we can think of (nb. wiring is OK from the turbine to controller and battery bank to controller).

1) wiring inside the turbine got damaged and needs fixing.
2) charge controller is faulty.

Leaves us to a process of elimination, first is to go inside the turbine and see if we can work out if its OK. However we have no spec diagrams for inside the turbine. We've asked the supplier who says they will send them and never does.

At this point, theres no harm in us disconnecting it and playing around with it, its an expensive ornament currently. If anything we can learn a bit more about the mechanics inside.

Two questions, is there some generic documentation/references online that someone can point me to so we know what the inner workings of these turbines are suppose to look like?

Second, Even though these turbines are notoriously unreliable, is it unheard of for it to not generate a single bit of usable power? I've observed it rain, hail and shine and theres nothing registering on the charge controller to the battery banks.

I'll add, we've even had our local university renewable resource department come and look on site and they can't work it out either.

Thanks!

[Rob Beckers]

Hi Hannah,

Congrats on the baby! That would keep you out of trouble and away from wind turbine projects for a while...

I have to say, every time you call an electrician a "sparky" it cracks me up. I would think electricians want to avoid sparks at all costs. Any time they do spark it will likely be their last one. :eek:

Back to the wind turbine: Yes, there is a way to trouble-shoot this. The spinning part is just the alternator and blades. It produces 3-phase AC, and the Voltage will vary depending on how fast it spins (and if it's connected to a battery). So with that, you can measure if it's producing any Voltage when it's spinning.

The 3-phase goes gets rectified to DC, and then goes into the charge controller (both those things are likely in the same box, separate from the actual turbine). If you can figure out enough to tell what's what you can measure on the DC side of the rectifier what's going on there.

Ultimately you probably don't need their charge controller (in case that's faulty). Since you mention it's spinning, just not producing, it makes me think that the controller is not doing anything to actively keep the turbine under control. Also, for the type you have they tend to spin with an RPM that's more or less linear with the wind speed, so they have build-in over-speed protection in a way.

You could also connect the turbine via a 3-phase bridge rectifier and a sufficiently sized fuse or breaker to the batteries, and measure if it's producing any current (with sufficient wind). For testing that completely takes the charge controller out of the picture, telling you if the turbine is capable of charging at all. While this should charge the batteries, it doesn't protect them from over-charging, so it's for testing only. It would tell you what works and what doesn't though. Please note the mention of a fuse or breaker between the batteries and the rectifier! That part is important (as in "let's not burn the house down").

Overall it sounds like electrical things may not be your thing. If that is the case it may make more sense to cultivate a local geek friend that knows a bit about electronics, and have him/her help out (and keep things from sparking too much)...

-RoB-

[Hannah Dawson]

Hi Rob, Thanks, third one to join us so I've got my hands full (all under four).

Haha, can you imagine a thick Kiwi accent while saying it, its pretty shocking.
I think they call themselves that here more than anyone else, though now you mention it, I can't imagine why.

The cultivation is underway, we're new to our city but I think I've found a retired electrician I can get to help. You are correct though, I have an understanding of electrics from a theory end but not the practical side. My husband is starting to delve into that part but it all takes time ;). I'm doing my PhD so enough to learn.

Re the charge controller. It is registering volts as it spins (that part of the controller works). The cut in voltage is 24 volts, I see it reach this easily and build up in volts and then drop back down a little (still over 24) as the MPPT kicks on (so the supplier said). It maintain the volts required and RPM but the controllers wattage gauge doesn't change which is where the assumption comes in that its not actually charging our batteries (It may actually be). The wattage changes for a second or two when there are really large gusts (showing as over 100 RPM, typically 75 Hz on the controller), and then goes back to zero. Your suggestion is good, thank you. I'll see if the electrician can come and do that, at least we know then if its charging.

Yes we've had enough close calls with fires. Last winter we discovered a rat got into our rodent proof battery house and made a nest ~1 m long and 20 cm deep in it. I think we had a lucky escape there. I've tried attaching evidence.

Will post an update when we have one. Thanks again.

[Hannah Dawson]

Good news I think/hope.

I phoned the supplier again today they are sending a new wind only charge controller. The charge controller supplied is wind/solar hybrid. Turns out (they weren't aware, but have been for over one year), that the hybrid charger they were supplying people with there wind turbine wouldn't work unless solar was also attached. The MPPT function wouldn't kick in.

I had wondered if it was the MPPT function, as we only had an occasional trickle over 50 (ish) V for a few seconds at a time (we have a 48V battery bank).

I had spoken to the supplier a few times over the last year and they've not once mentioned it until today. Fingers crossed this is the end and we will have many windy days.