Oceanvolt Servoprop regen tested by UMA

[Happ]

Originally Posted by malbert73

From Uma’s latest video, they were sailing 7 + knots and generating above 500W. Without commenting on cost/benefit of OV, it seems pretty respectable as an adjunct to solar to maintain house loads.

That translates to about 4.33 amps in a 12v system. Or at about 100amps in 24 hours. Add their solar system they should be close to their Utopia in Norway.

[NaClyDog]

Originally Posted by malbert73

From Uma’s latest video, they were sailing 7 + knots and generating above 500W. Without commenting on cost/benefit of OV, it seems pretty respectable as an adjunct to solar to maintain house loads.

I don't believe this portion was ever in question.


The point of contention is whether or not it's good enough to recharge the bank once you have motored without access to a different source of plentiful power.


I stand by my initial assertions; i) this is not proof of anything and ii) it is NOT enough currently without access to at least on alternative abundant energy source.

[Seaslug Caravan]

Originally Posted by Joli

For those concerned about shark attacks....
https://www.emarineinc.com/brands/WattandSea.html

Don’t forget the Orcas

[Pete7]

Originally Posted by Happ

That translates to about 4.33 amps in a 12v system. Or at about 100amps in 24 hours. Add their solar system they should be close to their Utopia in Norway.

Are you sure? If it generates 500w they should be getting 10A into the batteries at 48v.

Pete

[Seaslug Caravan]

Originally Posted by BigBeakie

From the Sailing Today article on Hydrogenerators - on test:

" Early models towed an impeller on a long line behind the boat, which was attached to an alternator on board. But their trailing impellers were often bitten off by large fish and they frequently tangled up when fouled or if not retrieved correctly."

Apparently others are also under the impression that these can be lost to big fish.

You do understand this is from a sales pitch, right?

Come to think of it ,why would you own a mast?
From all accounts they get struck by lightning.

[zstine]

Originally Posted by Happ

That translates to about 4.33 amps in a 12v system. Or at about 100amps in 24 hours. Add their solar system they should be close to their Utopia in Norway.

hmm. 500w divided by 12v is 41.7Amps... about 1000Amps per day.

[s/v Jedi]

Originally Posted by zstine

hmm. 500w divided by 12v is 41.7Amps... about 1000Amps per day.

Amps per day is nonsense. Y’all probably mean 1000Ah per day or 100Ah, just a factor of 10 off

[Dave_S]

Originally Posted by NaClyDog

How many boats do you know that can sail 20+ knots and for how long?


Also, the kw that are displayed... is that going into the battery or what is being generated?

Sorry, I missed this one. I'm not a huge fan of regeneration for most users, I'm warming to the idea except for the price....

I just posted the video link (duplicated below) because it was interesting. Yeah not many can sustain 20kn+ but quite a few can do mid teens and remember the video is with the old technology props that don't generate as well and I'm interested to see how the other YouTubers, La Vagabonde, go were they will be up in the high teens or better fairly regularly.

They will only have one motor though, still it might work out for them.

I think most people would be pretty happy to make 12kwh in exchange for 10% of their speed when making good progress. There are times when you need to slow the boàt down too, at those times there is no speed cost.

I still have concerns about the weight of a big generator and the fuel to run it if your crossing oceans but for faster boats it's advanced from day/weekend suitability to coastal cruising.

The other issue for Jimmy Cornell's boat was ocean wave action screwed (pun only intended if you think it's funny... otherwise, disregard) with the new self calibrating props, I'd like to see how well they have managed this issue.


The link to regeneration over 20knots with the old design props.... https://youtu.be/ebSotPQd3JY

[Adelie]

Originally Posted by Happ

That translates to about 4.33 amps in a 12v system. Or at about 100amps in 24 hours. Add their solar system they should be close to their Utopia in Norway.

500W is 33.3A, 1,000Ahr/d at 12v; 10.4A at 48v, 250Ahr/d.

That would be a full charge for an EP battery on a boat that size.

[BigBeakie]

500w / 12v = 41.7A , not 33.3, but the rest of your calculation is correct.

At any rate, it is a useful amount of battery charging, and would recharge the amount of house load used overnight at anchor and getting off anchor to be back sailing the next day.

[NaClyDog]

Originally Posted by BigBeakie

500w / 12v = 41.7A , not 33.3, but the rest of your calculation is correct.

At any rate, it is a useful amount of battery charging, and would recharge the amount of house load used overnight at anchor and getting off anchor to be back sailing the next day.

I've asked before but no one has responded. Are those figures being quoted what is being generated or what is going into the battery?

[Adelie]

Originally Posted by BigBeakie

500w / 12v = 41.7A , not 33.3, but the rest of your calculation is correct.

At any rate, it is a useful amount of battery charging, and would recharge the amount of house load used overnight at anchor and getting off anchor to be back sailing the next day.

Oops. Egg on my face. Incorrect math while telling somebody else their math was wrong.

[Adelie]

Originally Posted by NaClyDog

I've asked before but no one has responded. Are those figures being quoted what is being generated or what is going into the battery?

I assume that is what is being generated since it was in the OV app unless the OV app was talking to all the other electrical components which I doubt.

What goes into the battery would be the 500W minus losses in the wiring and controller and minus what the current house demand was.

[catsketcher]

Put me down as a tow generator fan. Even though I have 400 watts of solar I still remember the nice 60-100 watts our tow generator would make all day which was great for our outboard powered boat (read pretty useless alternator). It meant that whenever we moved we would have plenty of power. I never lost the spinner and the old 2hp prop on a stainless shaft is still in the shed.

I would like to make another tow generator someday and don't want to pay lots of money to Watt and sea. I would like to make a longtail style setup which drops down from the bridgedeck of our catamaran. I can't seem to find anything on turbine design. The Watt and Sea models seem to be able to make lots of juice and I would like to up the efficiency of any new build.

Popping on an old prop will work but the blades are cupped the wrong way. On top of that, they are designed to work best at a particular RPM and I just used an old permanent magnet motor that probably had its own efficiency RPM setting. Even though it worked the UMA data shows it was awfully inefficient.

Has anyone come across any articles on designing a turbine for a particular cruising speed and matching this to an alternator or permanent magnet motor? I was thinking an alternator could be better because you could try to adjust the field coils depending on boat speed. All the turbine guff I find is on hydro electric power systems.

I think there is a niche for a system that produces a lot of power to power a big Lithium battery bank. It seems that for us a 300AH lithium setup could allow us to leave a generator behind next cruise and run lots of toys. I still like outboards for motoring, but as solar is the main way we charge the batteries, towing a gen makes lots of sense for rainy times and on long passages. Getting the efficiency up would be a good start.

[Pete7]

For those who don't have $40k to replace their diesel, here is an alternative somewhat cheaper solution and very much along the lines of Uma's early exploits with electric motors.

https://www.youtube.com/watch?v=iEIg...annel=AKTSolar