Watt & Sea Hydrogenerators

[JazzyO]

The engineer of the UK importer in Plymouth told me this and demonstrated it to me. I have no idea if this pertains to older models - it is generator independent, the charging unit is made by another manufacturer., can't remember the name.


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[Reiziger]

Originally Posted by s/v Beth

Jim, did you make a geni out of a trolling motor? I would like to see it and hear how you did it!

Hi newt, this company sells a nice line of low rpm permanent magnet alternators and the regulator.

Link: Wind Blue Power Permanent Magnet Alternators

Cees

[Radio]

W&S advertises 120 W at 5 kn. This is for the "Cruising" version with 24 cm propeller (standard propeller). Please see http://www.wattandsea.com/sites/defa...ruising-GB.pdf
Even more, on page: Cruising hydro generator
at 5 kn they advertise 135 Watts.

My view:
Assuming: generator efficiency = 80 %, AC-DC converter efficiency= 80 %, propeller diameter 24 cm, free flowing water (no any obstacles) 5 kn, hydrodynamic calculated power delivered by 100 % efficient propeller shall not be greater than 145.9 Watts (228 x 0.8 x 0.8 = 145.9) .
As can be see, propeller at 5 kn runs with efficiency = 82% !!!!, Really ?
Based on Betz’s law theoretical max power could not be greater than 59.3 %. !!!!!!!
Practically, propeller efficiency varies between 15% and 30 %, what suggests than power delivered to the source at 5 kn is around 22 to 40 Watts.
If W&S claims are real, than Betz’s law should be rewritten and people from W&S shall get Nobel Price !!!!!!
Any body, any thoughts?
Radio

[Rubikoop]

Originally Posted by Radio

W&S advertises 120 W at 5 kn. This is for the "Cruising" version with 24 cm propeller (standard propeller). Please see http://www.wattandsea.com/sites/defa...ruising-GB.pdf

Even more, on page: Cruising hydro generator

at 5 kn they advertise 135 Watts.



My view:

Assuming: generator efficiency = 80 %, AC-DC converter efficiency= 80 %, propeller diameter 24 cm, free flowing water (no any obstacles) 5 kn, hydrodynamic calculated power delivered by 100 % efficient propeller shall not be greater than 145.9 Watts (228 x 0.8 x 0.8 = 145.9) .

As can be see, propeller at 5 kn runs with efficiency = 82% !!!!, Really ?

Based on Betz’s law theoretical max power could not be greater than 59.3 %. !!!!!!!

Practically, propeller efficiency varies between 15% and 30 %, what suggests than power delivered to the source at 5 kn is around 22 to 40 Watts.

If W&S claims are real, than Betz’s law should be rewritten and people from W&S shall get Nobel Price !!!!!!

Any body, any thoughts?

Radio

My thought is that Betz's law is based on wind, not water. Water being much more dense than air makes me think you should recalculate. :-)


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[OceanPlanet]

Also note that at 5kts you'd be a lot better off with the 280mm prop than the stock 240.

[Stella Polaris]

I'm opening up this thread again, because I'm very interested in hearing what people are now saying about the Watt & Sea Hydrogenerators. They seem like such a great idea, but back in 2014 when this thread was active, it sounded like the owners weren't that that happy.

How do owners of the units feel about them today?

I ask, because I'm very interested in buying a hydrogenerator of some sort.

- Andreas

[OceanPlanet]

We have had many happy users. Occasional glitches however Watt & Sea has been making little improvements here & there and have been good with support and any warranty issues.


If you want one soon you may have to hurry: a few weeks ago there was a fire at the main Watt & Sea office in France that has severely slowed production. There is inventory in the US, however once that runs out could be slow to get more for a while. All should be back to normal eventually; just not sure exactly when.

[OceanPlanet]

Forgot to add...recently our very first W&S client (2010) ordered a new spare 600W lower generator unit (his original was 500W). He has loved the old unit and it's still going strong, however it's out of warranty now and he doesn't want to take any chances.

[Stella Polaris]

Originally Posted by OceanPlanet

We have had many happy users.

Excellent, it's really good to hear that this has been your experience from a sellers point of view. I hope some of the sailors with them on their transoms are on here, because I would love to hear some user experiences.

- Andreas

[Muckle Flugga]

I have used a W+S Hydrogenerator for 25,000 miles. I am generally very happy with it. The only weak point I have seen is prop damage from floating debris. Other than that I think it is an excellent system. Runs my autohelm (RM 6002 hydraulic), radar, instruments and lights continuously if above 7 knots which is usually the case.

[Stella Polaris]

Originally Posted by Muckle Flugga

Runs my autohelm (RM 6002 hydraulic), radar, instruments and lights continuously if above 7 knots which is usually the case.

Thank you. That's interesting to hear. Do you have the 300w or the 600w unit?You say that you generate enough if you sail above 7 knots ... How about if you your speed is somewhere between 5-6 knots?
How many amps do you normally get depending on speed?

- Andreas

[sailabroad]

We have the Watt&Sea 600 Cruiser latest version which includes the locking cleat.

Overall we found some poor engineering for the price, It's not that you can just pain-pay and forget about it, it IS still lots of work!! that is if you take care of it - But it generates a ton of power and looks pretty - From talking to others seems better than the Duogen (where the wind generator is purely cosmetic We would buy another one despite the problems - great for passages, OK for cruising.

(1) Cons

* The generator cannot be left permanently down in the water generating (although most people that I have talked to don't know this!) - Watt&Sea stipulate it must be lifted when the batteries are full = when the generator produces a rumbling noise from the prop free-wheeling or the bearings will be damaged.

The problem with this is ....When charge controller senses 14.4? volts on the batteries - the alternator immediately turns off and does not generate at a float voltage/power for any significant period of time. Sooo (for our 400 ah lead-acid) batteries only get the surface charge back and are not being deeply recharged UNLESS you run solar at the same time.
The manual says it should Float but it doesn't for us perhaps our battery bank is too small?

* As everyone mentions, the mechanism for setting the the wing/alternator down is totally insufficient for the job at any speed more than 4 knots - and due to the problem with Float charging - mentioned above you WILL need to lift and lower the generator on a frequent basis on a long passage something like 5 + times a day. Unfortunately the bracket used to lift and lower is difficult to engineer a sufficient solution around - I tried several different approaches and now have an OK solution - but it's still far from ideal - it would be simple for Watt&Sea to make a slightly longer bracket to incorporate a pulley system in the bottom to pull the wing down. The significant changes that would be needed to make the bracket work void the Warranty.

*?Saragosa? sea weed means that you have to clear the wing occasionally - the prop seems to clear itself more often than the wing..

*Dynamic range of the propellers - This problem is truly idiotic and lazy from Watt&Sea, I suspect they are using the same controller for the cruising version as the racing version?

The range of input voltage for the charge controller is VERY limited at 3 phases of 0-40 VAC - I guess with the original racing version the prop automatically changes pitch to put the voltage within the range of the charge controller - but with the cruising version and a fixed prop as your boat changes speed massively say each time it surfs down a wave or just through ordinary sailing, it puts the voltage outside the range of the controller and then back in again often depending on wind and sea conditions - It should have been a simple and logical decision to increase the input voltage range of the charge controller for the cruising version - and would have meant less prop changes from 240mm to 280m. When the above happens the generator produces the rumbling noise from free-wheeling - which is indistinguishable from the "Batteries are full" noise and the charge controller cycles the output on and off.

*You won't see 33 amps unless your boat can do close to 10 Knots and in wind speeds approaching 15-20 Knots - the dynamic range of the low speed 280mm prop is too limited to run in more than 7 knots boat speed, and the output power increases exponentially with speed..So we mostly get 10-18 Amps in normal cruising speeds - 6-8 Knots, and those last 2 knots of boat speed between say 8-10 knots produce by far the most power 18-33 amps.

*Solar input voltage range is also very limited at 0-50 VDC which means heavy solar cables and panels in parallel, not series - which is OK I guess.

* The charge controller does NOT combine the power generated from the Hydro generator and solar array - and selects the Hydro generator in preference to solar if it's turning: That one was a surprise - So.. we were sailing slowly but there was a lot of sun - and I checked the output from the charge controller - almost nothing - Huh?!! the solar should be cranking out the power - I discovered that I got nothing from the solar unless there was nothing coming out of the hydro generator...So if you want solar power you need to lift the hydro out of the water...Hmm.

* Replacement parts are crazy expensive - 240 Euro for a new propeller!!! - 1K Euro for a poorly engineered charge controller?

* We had several problems with ours( Watt&Sea has good tech support - we talked to them directly) - The oil seals had failed after just 6 weeks of solid use.The charge controller is reporting an "Overheating" or "Missing phase" error but I have extensively tested the unit and neither is true - Watt&Sea have told me just to ignore these errors - it's still under warranty and they will replace if it becomes a hard failure - Hmm not too happy with that.

* The Power plugs (Souriau UTL series) on the Charge controller that you need to use - are completely useless (but look pretty - see a thread here? W&S have a "Design patent" not a "Technical patent" ) It is almost impossible to seat the pins correctly to make sufficient contact - and might require a custom crimping tool(my crimping tool didn't work correctly) - Despite the data sheet specification I would doubt they can pass enough current - perhaps in a Lab .. but in the real world they are dreaming.

*There is a lot of dynamic load + force generated from the wing - The bracket and mounting must be very strong - we needed to get a custom stainless bracket made and also had to reinforce the inside of the boat to guarantee no epics from the bracket being torn off the transom - it took several weeks of work to get this right.

*When not doing longish passages the Hydro-generator doesn't get used much..- so a typical island hopping cruiser might not benefit so much from the high output unless you have Lithium batteries that can charge at 20C


#Pros'

*More power than you can use - we had 2 fridges + Freezer, TV=movies, SW radio, electric winches going all the time on our transatlantic crossing and we still had to find ways to burn power not to have to lift the generator out of the water so often( a real pain -) we didn't have the solar up, Might be a good idea to have a dummy load like a water heater.

*The charge controller includes a Solar charge controller, without that we would not have purchased the Watt&Sea.

*Looks nice

*Strongly constructed wing..and props seem to be able to take abuse before failing - we .

[OceanPlanet]

We never recommend using the solar controller input on the W&S converter over dedicated MPPT controllers. For the investment in solar panels it's pointless to skimp on a few controllers.

The purchase to hold the unit down does requires some attention and often real rigging talent. It takes significant load.

[Muckle Flugga]

Originally Posted by OceanPlanet

We never recommend using the solar controller input on the W&S converter over dedicated MPPT controllers. For the investment in solar panels it's pointless to skimp on a few controllers.

The purchase to hold the unit down does requires some attention and often real rigging talent. It takes significant load.

Agreed I have a dedicated MPPT for my solar panels and the W&S one exclusively for the Hydrogen. I really haven't noted the problems that Sailabroad has. My system is 24v and I have 8 Trojan golfcart type batteries as the main bank. The W&S powers all my systems (apart from watermaker which is 220V generator powered) very nicely, so long as averaging above 7 knots, and has never overloaded or hit the stops. As I said, the props are somewhat vulnerable, and of course the mounting must be VERY strong and yes some rigging skill is necessary… but this is because you don't get all that power without the necessary related friction… and, well, we are sailors, no?

[yelken]

There is also one from SwiTec, the price is around 3.500 Euros. Have seen it at Dusseldorf Boat show 2016. The link to the vendor is below.
Hydro Charger als Spiegelmontage