Question about AMP reading from wind AC wind turbine

[Jim Acheson]

I wanted to reach out to the community for some experienced help with a question that I have been trying to answer about my wind generator relating to energy flow to the batteries. Let me say from the start that my interest for now with solar and wind is entry level and borders on the “hobby” level. The question I have is probably a basic one for many, so this is why I am reaching out. I have a 1600 watt wind turbine kit complete with wiring, rectifier, cables and 2 batteries (with all the fuses and shut off). I recently added 2 100-watt solar panels to round it out, and the solar itself keeps the batteries charged for my needs. I love the set up and I’ve had a good time installing and testing. The wind generator has spiked a lot of interest from all my do-it-yourself buddies. I have an AMP meter set up on my solar and it accurately reads the AMP flow from the panels to the batteries. The question I have is the AMP meter on the wind generator. We’ve had lots of wind this spring with consistent wind speeds of 15 to 20 mph and a few days with gusts as high as 35-40 mph (I saw a 55 mph gust). I have an anemometer installed by the control panel that I have been watching like a kid in a candy store window. I have the wind generator AMP meter in series with the negative lead coming from the rectifier (DC side) and only rarely do I see it spike up to about 5-8 AMPS with high gusts. It’s just a quick spike and then returns to 0. So is this normal? Does the energy only flow if the voltage from the wind generator is higher than the battery voltage? The solar sends energy constantly no matter what the batteries read (yes, I have a dump load). Is it different with the wind generator? Does the rectifier (going from AC to DC) alter the fact that the battery voltage level affects the energy flow unlike the solar panels? I’m trying to wrap my head around this. I just want to make sure there isn’t an issue with my install. I’ve seen the videos on YouTube where AMP readings are constant with wind generators in wind, but these were DC wind kits. Since mine is 3-phase to a rectifier, is that the difference? Thanks for your help!

[Rob Beckers]

Hi Jim,

What's the charge controller setup? Normally solar uses an charge controller between panels and batteries, tapering down the charge current as needed as the batteries get full. Wind turbines have two schemes for charge controllers, about equally common; some have a similar setup as solar panels, with a charge controller between turbine and batteries, regulating current based on the battery Voltage, others use a 'diversion controller', in that case the wind turbine is hooked up directly to the batteries (after a bridge rectifier) and a (separate) charge controller is connected to those batteries on one side, and a dump load on the other. In that scenario the charge controller 'diverts' current from the batteries to the dumpload to make the batteries follow the proper Voltage profile for charging and prevent overcharging.

You mention dump load, and constant Amp reading for the solar panels, which would suggest you have a diversion controller scenario, where solar and wind constantly 'charge', and excess is funnelled to the dump load via the diversion controller. Is that what you have?

If so, then yes, the wind turbine should show Amps going into the batteries regardless of their state-of-charge, as long as there is wind.

There will however only be current flowing from the wind turbine when the Voltage coming from it (after rectifying) is above the battery Voltage. What is the battery bank Voltage? Could it be that you are using a 12V wind turbine to charge a 24V battery bank?

-RoB-

[Jim Acheson]

Thanks Rob for taking the time to answer my question. I posted a picture under my profile of the control panel, it’s sideways so you might have to tilt your head to see it.
This is a Missouri Wind and Solar kit with two 12 volt batteries wired in parallel. I believe they make their own version of charge controller. If you can see my photo the charge controller has posts for the solar and PMG to control the batteries for overcharge (same controller does both solar and wind). The wind turbine is a 1600-watt Freedom, 12 volt. It has a 600-watt resister bank for the power dump. You asked if I have a “diversion controller scenario,” and I believe that is what I have.
The Amp shunt is coming off the negative lead from the rectifier. My batteries were extremely low before I got the solar added, we had 40mph winds over 2 days with gusts of 45 common. The PMG was spinning like mad. The switch was on “run” and not brake or free spin. A week later we had some more spring time storms with more winds that were in the 45 mph range (I have an anemometer) and I saw the Amp meter spike to about 5 amps briefly and then drop to 0. This happened about 3 times in the course of an hour. Today I redid the splice coming out of the PMG case just in case I messed up there, but there has been no wind to test this, but I doubt that is the problem. Just wanted to cover myself.
In your last 2 paragraphs you mentioned “the wind turbine should show Amps going to the batteries regardless of their state of charge with wind.” (that is my understanding of how it should work). Then you mentioned there will only be current if the voltage from the rectifier is above the battery voltage. If the batteries were low (say 11.9 volts), I would think a 40-mph wind would show some AMP flow. This has me stumped, so any suggestions or advice would be greatly appreciated, or ways to test.
I’ve had no problems with Missouri Wind and Solar, so this isn’t a slam on them. I live close to their warehouse and have been there several times, they don’t seem to be able to explain why this happens.

[Rob Beckers]

Hi Jim,

OK, that sheds a little more light on it... Missouri Wind & Solar has a reputation of, shall we say, stretching the truth a bit (or a lot). It's not that their turbines don't work, but if they claim 1600 Watt from their turbine you should picture the inside of a tornado with your house being removed at the same time, that's when you'll see those 1600 Watt being produced (however briefly). In reality people in high-wind areas report 200 - 400 Watt output on a good and very windy day.

If you can, measure the AC Voltage going into the alternator while it's spinning, in a decent wind. Would be interesting to find out what the alternator is producing. It would have to exceed the battery Voltage before it gets through the rectifier though.

-RoB-

[Jim Acheson]

Thanks, I'll do some wind voltage tests and get back to you. No wind today, hopefully later next week with some storms coming (and hopefully some rain).

[Jim Acheson]

Just wanted to add that I think you answered my original confusion. The solar dumps amps to the batteries and is readable on the amp meter (the charge controller shuts off the flow to regulate the battery voltage). However the PMG has the rectifier in-between it and the batteries/and controller. If I understand correctly amps will only flow from the PMG past the rectifier when the voltage is higher then the batteries. I guess I could set up a test with a spare battery that is very low and go from the rectifier to the battery with the amp meter in between. I'll monitor the voltage and amps to check output. Am I on the right track?

[Rob Beckers]

The rectifier is like a valve: Pressure (Voltage) has to be higher on the input side vs. the other (battery) side before there will be any flow (current).

That said, an empty battery isn't going to help. The differential is pretty small: An utterly empty battery is 11V, a fully charged one in float is around 14V.

It may be worthwhile to check if the rectifier is actually in good shape. One or more of the diodes could have failed (a Youtube video about your turbine mentioned that as a frequent occurrence). You'll have to educate yourself on how to test diodes, lots of videos out there.

-RoB-

[Jim Acheson]

Ok that makes more sense. A couple of weeks ago I bought a new rectifier and wired it to the battery with the amp meter by-passing the controller and there was no amp flow even with a 20 mph wind (PMG spinning pretty fast).
I tested the original rectifier and it tested like it's supposed too (with diode tester on volt/olm meter).
I guess I could read the DC volts off the DC volt side of the rectifier and see what it's putting out with wind and disconnected from battery, knowing it has to be greater than the battery voltage helps me understand. We have a week of warm weather here, not much wind, so it might be a week before we get storms so I can test.
Thanks again for answering my questions, I'll let you know as soon as I get some results.