Replacing a Wind Generator Charge Controller With a Simple Rectifier ?

[Fluenta]

Originally Posted by Jim Cate

Fluenta you've never mentioned what chemistry your big battery bank employs. If they are FLA, I'd say you have absolutely no worries about damaging them with unregulated output from your wind turbine. With the near continuous loads from all your systems combined with the vagaries of wind strength, it is unlikely that you will ever experience a full charge let alone harm the bank by extended overcharging. Brief periods of ~15-16 volts is very similar to the recommended equalizing charge regime for FLA, and will not harm things. Maintaining normal water replacement should be obvious practice!

Don't over think this issue!

Jim

"Don't over think the issue" - but I'm an engineer ...


Yes, our batteries are old school FLA - 980 Amp-Hrs at 12V composed of eight Trojan T-125 6V batteries. As we are living aboard full time as a family of five the batteries are rarely at risk of being full charged let alone being overcharged. With extensive solar and the wind gen plus an old water towed generator on passage we do keep a reasonably good charge but once a month we use the Honda 2000 to do a 100% charge and then every six months an equalisation charge.



The biggest risk from overcharging would be during long motoring like on the recent passage from Fiji to the Marshall Islands where we had to transit the South Pacific Convergence Zone and the Intertropical Convergence Zone with the MJO in full force. Lots of motoring in those cases and our two big house bank alternators (we also have a start bank alternator) charge up the bank pretty quick. On the passage towards Alaska the potential overcharging while motoring should be mitigated with our SOP's. We have a little 7" chartplotter now and one of the data items we leave on it is voltage so the on-watch can keep half an eye on the battery state so that should help as well.


I think the biggest risk is burning out the wind generator as it is rated for 400W which is only approx 27 amps at 12V. According to the Silentwind documentation this roughly equates to 27 kts so we need to be careful with squalls. It will be shame to miss out on the potential wind power generation on the windward legs but better than melting the wind generator windings - we seem to have spent lots of time this season going to windward with the TWS in the 20's.

[GILow]

For a temporary solution, I for one would be very comfortable using a simple bridge gate rectifier for a battery bank that size. Add a simple kitchen timer for when you notice the battery bank getting close to full charge as a backup to remind you to tether/brake the wind generator to prevent over charging.

FIWI, I gave up trying to find a wind generator regulator that did all that I wanted for my system and made my own. Not hard to do if you have time later on. Plenty of DIY primers on the Internet to get you going.

[Fluenta]

Originally Posted by GILow

For a temporary solution, I for one would be very comfortable using a simple bridge gate rectifier for a battery bank that size. Add a simple kitchen timer for when you notice the battery bank getting close to full charge as a backup to remind you to tether/brake the wind generator to prevent over charging.

FIWI, I gave up trying to find a wind generator regulator that did all that I wanted for my system and made my own. Not hard to do if you have time later on. Plenty of DIY primers on the Internet to get you going.

That would be pretty cool to make a regulator. I cannot imagine taking the time at the moment as plenty busy just keeping the boat operating (oh, and playing with our toys and keeping on the move). Maybe when go static for a a bit in Canada.

[GILow]

Originally Posted by Fluenta

I think the biggest risk is burning out the wind generator as it is rated for 400W which is only approx 27 amps at 12V. According to the Silentwind documentation this roughly equates to 27 kts so we need to be careful with squalls.

I would be surprised if this was a problem. My understanding (and I am happy to be corrected) is that the power rating is a practical limit imposed by blade area and efficiency limitations. I don't think internal resistance is going to be high enough to cause heat problems until well beyond that figure in a well constructed device, which I assume is the case with the Silentwind, particularly as breaking is provided by the controller, and generally this is done by some form of electrical shorting.

Also, 400 watts is 33 amps at 12 volts, and only 29 amps when the battery bank is at full voltage, but yes, I see SilentWind claim this output at 27 knots, which is good if true. (Thought I also note they talk about wind tunnel testing, which is likely to be more efficient wind than the stirred up nonsense you around boats.)

Full disclosure, I did once ignore the instructions with my Aerogen 6 and left it untethered and electrically braked. And of course there was an almighty storm with 50+ knot wind gusts. The end result was that the brushes in the pivot overheated and melted out of their sockets, subsequently leaving the generator unbraked, at which point it over-revved and blew the diode pack which had a reverse voltage rating of 500 V which is kinda scary really. Repair costs were trivial, but I have taken the lesson seriously.

[GILow]

Originally Posted by Fluenta

That would be pretty cool to make a regulator. I cannot imagine taking the time at the moment as plenty busy just keeping the boat operating (oh, and playing with our toys and keeping on the move). Maybe when go static for a a bit in Canada.

Yes, definitely a "spare time" project.

When I am happy with mine I will post the circuit and code here on C.F. It just has not had enough real world testing to be credible yet. But I built in a few features like rolling power production counters (24 hours/7 days) and adjustable cutoff threshholds. I am currently trying to get it to work nicely with the solar controllers' smart charging algorithm, that WOULD be good if I can do it. Currently it just bails out during absorption and leaves the final bit to the solar.

[Jim Cate]

Well, in periods of long motoring and worries about overcharging, simply killing the field excitation to the alternator will stop that source from contributing. In strong winds, can you not set up a means of shorting out the wind gen? That should essentially stop it and will limit the output to near zero. It is what we do with our Air-X and is recommended by the vendor. Blades rotate slowly and no harm is done.

And the old "turn it sideways to the wind and tie it off" ploy will surely stop it. Some human intervention can reduce the dependence upon electronic wizardry (an unreliable form of magic).

Jim

[Fluenta]

Originally Posted by Jim Cate

Well, in periods of long motoring and worries about overcharging, simply killing the field excitation to the alternator will stop that source from contributing. In strong winds, can you not set up a means of shorting out the wind gen? That should essentially stop it and will limit the output to near zero. It is what we do with our Air-X and is recommended by the vendor. Blades rotate slowly and no harm is done.

And the old "turn it sideways to the wind and tie it off" ploy will surely stop it. Some human intervention can reduce the dependence upon electronic wizardry (an unreliable form of magic).

Jim

Sorry I should have been clearer (writing replies as quick breaks between boat jobs and squalls). I have installed a switch to short the three phase output which "brakes" the rotors or at least only lets them turn slowly. Easy for the on-watch to do.


We also have a line attached to allow us to turn the vane perpendicular to the wind. That is a little more exciting at sea especially during a squall but of course doable.

[fxykty]

Fluenta already has a wind generator so this doesn’t help him or some of the other contributors but it may help someone looking to buy a wind generator.

Superwind 350 is specifically designed for unattended use and does not need braking or any other manual intervention for strong winds, and when paired with the SCR 12 Marine regulator does not need any intervention for fully charged batteries. Whether it’s worth the money?????

But believe me, you don’t want a solution that requires you to manually do something at a certain wind speed or at a certain battery charge - that’s a certain recipe for a mishap. There’s enough things to think about when the trade wind gusts 40+ and stopping the wind generator surely isn’t in the top 10.

[Fluenta]

Originally Posted by fxykty

Fluenta already has a wind generator so this doesn’t help him or some of the other contributors but it may help someone looking to buy a wind generator.

Superwind 350 is specifically designed for unattended use and does not need braking or any other manual intervention for strong winds, and when paired with the SCR 12 Marine regulator does not need any intervention for fully charged batteries. Whether it’s worth the money?????

But believe me, you don’t want a solution that requires you to manually do something at a certain wind speed or at a certain battery charge - that’s a certain recipe for a mishap. There’s enough things to think about when the trade wind gusts 40+ and stopping the wind generator surely isn’t in the top 10.

and to clarify, this is not intended to be our long term solution. There is not a lot of regulators to buy in the Marshall Islands so this is a temporary solution to get us to Alaska.

[RaymondR]

Originally Posted by Jim Cate

Fluenta you've never mentioned what chemistry your big battery bank employs. If they are FLA, I'd say you have absolutely no worries about damaging them with unregulated output from your wind turbine. With the near continuous loads from all your systems combined with the vagaries of wind strength, it is unlikely that you will ever experience a full charge let alone harm the bank by extended overcharging. Brief periods of ~15-16 volts is very similar to the recommended equalizing charge regime for FLA, and will not harm things. Maintaining normal water replacement should be obvious practice!

Don't over think this issue!

Jim

There was only one time when I forgot to tie mine off when high winds were predicted. I was woken when a front came through and whilst the shunt was switched in the wind was strong enough to generate enough amps to overheat the gen and the over temp circuit unloaded the gen and it went into screaming freewheel mode. I switched out the shunt and switched on all the DC loads in the boat and watched TV whilst the front worked through and the wind moderated a bit and I was able to switch the shunt back in.

One of the items I found very handy was a large 4" meter which I had expanded the voltage indication to 10 to 16 volts using a 10V zener diode. One becomes accustomed to glancing at it all the time and from the position of the pointer and without having to think about the actual voltage be aware of the battery charge state.

[kungfoo]

That's not a bad idea. You could use a large Zener (or TVS) diode with a heat exchanger to guard against dangerous over-voltage scenarios which might otherwise damage the electronics.

[Fluenta]

Originally Posted by GILow

I would be surprised if this was a problem. My understanding (and I am happy to be corrected) is that the power rating is a practical limit imposed by blade area and efficiency limitations. I don't think internal resistance is going to be high enough to cause heat problems until well beyond that figure in a well constructed device, which I assume is the case with the Silentwind, particularly as breaking is provided by the controller, and generally this is done by some form of electrical shorting.

Also, 400 watts is 33 amps at 12 volts, and only 29 amps when the battery bank is at full voltage, but yes, I see SilentWind claim this output at 27 knots, which is good if true. (Thought I also note they talk about wind tunnel testing, which is likely to be more efficient wind than the stirred up nonsense you around boats.)

Interesting point. One of the settings on the Silentwind charge controller is the maximum amperage which the manual suggests to calculate based on the maximum 400W divided by the battery voltage (max 14.8V for a Trojan T-125 at 25C). I calculated the max allowable amperage based on the charging volts of 14.4V (we are averaging over 30C here) as rarely to never are the batteries actually at 12V.


Looking at the power curve and the experience with the unit over the last seven years, I am quite sure it "can" develop more than 400W but ... at a cost of its lifespan. Having just replaced much the wiring inside the generator itself I would not want to test the theory that it can sustain more than 400W.

[GILow]

Originally Posted by Fluenta

... Having just replaced much the wiring inside the generator itself I would not want to test the theory that it can sustain more than 400W.

Ouch! Yes, point taken.

Clearly a much higher performance device than my old Aerogen 6, which is built like the proverbial brick s--t-house, but produces a lot less power, 360 Watts theoretical max, but that is in a LOT of wind, about 45+ knots. I rarely see 200 Watts from it in normal operation, mostly around 100 Watts.

Thankfully the bulk of my power comes from the solar, but it is nice to have the wind generator for cloudy days and night time sailing.

Good luck with your passage, at least you've got options for power generation.

[Fluenta]

A quick follow up to say it went well on the passage (SV FLUENTA: Marshalls to Alaska Day 26: Sunday again ... and LANDFALL Dutch Harbor). 3700 nm sailed over 27 days and, while hard to quantify, the wind gen with its simple rectifier provided a lot of our power.



Having to turn off the brake switch manually was a bit awkward in the squalls but usually one of the kids could be detailed to turn off the wind gen as the apparent wind approaches the mid 20's.

[missourisailor]

Originally Posted by Locquatious

The bridge rectifier will work but as mentioned it is hard on the batteries in high winds. It is very hard to anticipate wind gusts and the wind generator will give 15+ voltages into a charged battery. A simple rectifier is not a good idea for gel cell, lithium, or AGM batteries.

You can create an electronic braking system using an old battery combiner to drive a DPST/DT relay. Just wire the relay such that all three phases are combined when the battery combiner, set for battery float voltage, turns the relay on. We used that system for years until eventually the relay contacts developed corrosion resistance and failed to stop the wind generator fully.

The Kiss Extractor™ can control a Silent Wind or any 12V 3-phase wind generator with max output below 45 amps. It stops the wind generator for ~90 seconds whenever the battery voltage gets to a setpoint (12.8V, 13.2V, 13.6V, or 14.4V). The shut-off is solid state so there are no contacts to corrode. It will also get more power out of the wind generator at low wind speeds. And it has circuitry that prevents the wind generator from overheating.

I want to second the "Kiss Extractor".

https://www.seabournesolutions.com/K...model-4.10.htm

Although the Bridge Rectifier (stock Kiss regulator) works, it will over charge the battery during prolong winds.
The Kiss Extractor is a true regulator and acts as one!

Kinda pricy at $375. But still worth it.