Replacing a Wind Generator Charge Controller With a Simple Rectifier ?

[Fluenta]

We are getting ready to head out an approx 30 day passage and thr recently arrived and much anticipated replacement wind generator charge controller appears to not work. Does anyone have any experience using a simple three phase to DC rectifier instead (like this: https://www.amazon.com/SODIAL-1000V-.../dp/B00HZY4NRA)


I have tested it with my Silentwind and it seems to work fine. I will add a DPST switch so anyone can brake the wind generator if we want it to stop.


The Silentwind outputs three phase AC.



Thinking the SOP's will be to brake the generator if:


- Apparent wind speed greater than 27kts (which is a shame as we get great charging on long upwind legs).

- Motoring
- Shore power (which is funny since we haven't seen shore power in long time).
- Boat not attended.
- Batteries fully charged (pretty rare unless a long motoring trip).


Any insights ?

[Jim Cate]

this has been done and written about here on CF, so a Google search should find the thread(s) with the info. As I recall, it was a simple bridge rectifier and worked well.

Jim

[Fluenta]

Much thanks. I will do another search. I did not find it in my first one but perhaps I did not go back far enough.

[kungfoo]

No personal experience, but first-principals would suggest using a proper charge controller as a primary, and saving the $10 diode rectifier to be the backup for when it fails mid-crossing:

1) potentially damaging to the cells: Wind generators can have pretty high peak voltages, and when voltages get too high on lead-acid batteries they tend to turn into little electrolysis vats. I'm guessing you have the 27kt braking SOP to address this failure mode.

2) less efficient charge: MPPT exists for a reason

3) less efficient transfer: gonna go out on a limb and guess that it's a silicon diode system with a fwd voltage bias of 0.7V. Any given current path has to go through at least two of them for a total of a 1.4V drop.

[Fluenta]

Originally Posted by kungfoo

No personal experience, but first-principals would suggest using a proper charge controller as a primary, and saving the $10 diode rectifier to be the backup for when it fails mid-crossing:

1) potentially damaging to the cells: Wind generators can have pretty high peak voltages, and when voltages get too high on lead-acid batteries they tend to turn into little electrolysis vats. I'm guessing you have the 27kt braking SOP to address this failure mode.

2) less efficient charge: MPPT exists for a reason

3) less efficient transfer: gonna go out on a limb and guess that it's a silicon diode system with a fwd voltage bias of 0.7V. Any given current path has to go through at least two of them for a total of a 1.4V drop.

All good points. Thanks.


Yes, if I had access to a "proper" charge controller I would use it but not a lot of shopping here in the Micronesia. It would take a few more weeks for another replacement to arrive.


1. Yes, I would rather like to avoid the vats of molten battery. With a 980 amp-hr battery bank it at least takes some time to raise the voltage too high. On passage with a big autopilot, electronics and our old fridge/freezer there usually is a big load on the system. On passage it is rare for use to use the motor solely for charging as we have a pretty good solar array, a wind generator and an old school water towed generator (which we rarely use as it gets in the way of fishing). On the passage to Alaska I expect the solar is not going to help us as much. When we get to Alaska and can figure out a shipping address I'll get a new charge controller.



2. The $US700+ one we just bought is not MPTT.


3. Good point. I wonder what is in the expensive charge controller.

[kungfoo]

I actually *just* finished designing my first DC/DC charge controller for a measly 10A system with only a 15V peak and the BOM cost was something like $45. Granted, I was using really nice linear-tech ICs, but still...

Mostly, though, I would guess it's the magic smoke that requires an EE wizard to put back into the circuit :-)

[fxykty]

We’ve got a Superwind 350. Love that it automatically slows itself down in very high winds and keeps generating in over 35 knots - great for windy passages around NZ and the islands.

Last year we had to replace the failed charge controller. We bought the SCR 12 Marine charger regulator (same as what we replaced) as it is designed for the Superwind 350 and takes care of keep load on the wind generator even after the batteries are full. That’s a key job for a wind generator charge controller so that you don’t have to do that manually.

However it uses PWM voltage regulation. Does this matter for a wind generator, or would it be nice if they provided an MPPT voltage regulator? It doesn’t seem that any other wind generator company provides a charge controller with MPPT voltage regulation.

[HankOnthewater]

Never seen a MPTT charger for wind generators, they may exist. In theory, if your wind generator rectifier is not working, one can replace that unit with 6 diodes, similar I guess to the car alternator?
Anyone can confirm that a common set of car-alternator diodes can be used? Or one can use 6 separate diodes like this hmmm, a bit pricey, am sure there are cheaper ones https://au.rs-online.com/web/p/produ...E&gclsrc=aw.ds

I have only experience with KISS that is using a block(6) diodes: x3 leads in for AC, and pos and negative out. I don't think the 0.7 Voltage drop is an issue. If it is, use Schottky diodes, voltage drop is then reduced to 0.3 to 0.4 Volt.

[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.

[singlespeed]

The Aerogen 6 uses a simple bridge rectifier. Very easy to work on and far cheaper than replacing a circuit board. Aerogen recommends throwing a line into the blades when the wind gusts over 40 knots. Works well, without damaging the blades, but getting the line off after the wind dies down can be fun. An in-line electric "brake" worked for short duration, but lengthy periods of excessive wind really required the line.

[kungfoo]

Magnum energy has a MOSFET-based combiner, but I'm not sure about transient response, or switching times.

[RaymondR]

The Rutland 913 uses 1 1/2 of 2 bridge rectifiers mounted in to the generator for the rectification and an external controller.

I ran mine for years without a controller and used a 5/32 SS metal thread screw as a resistor and a heavy switch to manually disconnect it and shunt it to limit the freewheeling.

I could have automated the system by using a relay and the auxiliary terminal on my solar regulator but after prototyping it with the manual switch found that it was not necessary as I hardly ever switched it to shunt anyway.

On a number of occasions I pondered adding another slip ring to the generator and bringing all three phases of AC down off the generator and putting the rectifiers somewhere accessible from the deck as it was a nasty brute to remove from the pole to work on but never got around to it.

The 100 amp, three phase, rectifier you propose to use looks like a rather hefty brute and should do the job nicely.

[Fluenta]

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.

Thanks. I'll look up the Kiss Extractor as a potential replacement when we get to Alaska.

[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

[kungfoo]

Without a regulator, it seems like it'll be subject to E = -dPhi/dt meaning that voltage will increase with wind speed. Some of the voltages can get pretty high and have the potential to damage sensitive electronics connected directly to the bus...or at least be annoying and pop a bunch of fuses...