Triskel power generation system on Distant Shores III

[john61ct]

Originally Posted by Dockhead

you are generating power almost for free when you're using the main for propulsion

As the watts produced increases, that is less true, right? About a HP required per 250-300W IRL output, right?

Now as you wrote, if the system keeps the engine running at a fuel-efficient rpm, and watts output is varied based on the changes in the other loads like propulsion, that would be great.

But up-sizing the engine as required to accommodate high wattage output is far from free.

Edit, saw your edit, seems we agree

> plus you are doing away with the second diesel engine for a huge reduction in cost and complexity.

Now **that** to me is the real benefit of large-alternator setups.

Even if there are already two propulsion engines for overall redundancy.

[john61ct]

Originally Posted by Dockhead

All you have to do is either keep the alternator size down so that its power requirement doesn't eat up the gap between propeller power curve and maximum output plus a margin.

Or, find a way to modulate the alternator output so you can regulate that issue that way.

specifically modulating amps, as with e.g. MC-614 but dynamically

Al Thomason's open source Very Smart Regulator / "Smart Alternator Regulator" project*may be a good basis.

http://www.cruisersforum.com/forums/...d.php?t=195059

http://www.cruisersforum.com/forums/....php?p=2390188

[john61ct]

Originally Posted by stormalong

Granted I did not use electric toasters or air conditioning but all of my needs were met.

Total dependence on engine driven electric power is foolhardy if you are cruising the world.

as long as it's only your household appliances and entertainment systems, not your survival that depends on it, no problem.

And many world cruisers want washing machines and electric stoves.

Different use cases.

[john61ct]

Originally Posted by Q Xopa

The 'control' system they were using looked interesting. If it can wind back the generator requirements as the engine needs more it sounds like a good concept.
…
If the engine load can be maximised in the high SBFC range its a step in the right direction.

yes that would be the newsworthy innovation

> 7kW is heading in the right direction but for a 75Hp engine at anchor its only a fraction of ideal. I would suggest something like 55 HP, which is around 40kW is a more efficient load range.

Real life DC-only generator design IRL usually come out to 250-300W per HP engine capacity. I believe that is more useful than theoretical conversion formulas.

> Also that Serpentine belt set up for a 7kW drive. Lets see but my guess is its ambitious. 7kW has to be way north of 10HP.

Apparently depends on the specific designs, helicopter blades get run off belt systems.

WRT redundancy, propulsion is (should be) more compelling than House loads.

In some design cases, eliminating the dedicated genset may make a second propulsion engine more feasible?

[john61ct]

Originally Posted by MaCro

The Yanmar 4JH80, being ECU controlled, will run at whatever RPM is set by the "throttle" control lever is set to (and potentially by the Integrel controller over J1939 CANbus). The engine load is also reported by the ECU (determined by the amount of fuel required to maintain the RPM), and this is available over J1939 to Integrel. So, they can crank up the alternator to whatever the most efficient load on the engine is, and back it down to avoid overloading the engine

Yes to me that would be a real innovation if made available for sailboats that can't have or don't want a dedicated genset.

Charging very large freezer holding plates, making water at a high GPH rate are the other two uses that could maybe benefit from such an approach,

as battery acceptance amps declines, start ramping up the other secondary loads.

When a higher propulsion load is required - sometimes a safety consideration, any secondary loads get scaled back.

[john61ct]

Originally Posted by MaCro

Eco-tech alternators, but they look very good

Top of my list, Zena is another to check out.

[john61ct]

Originally Posted by LoudMusic

We also have a somewhat crusty generator who's specs currently escape me. Personally I'd like to sell the generator, clean up its locker, and relocate the house batteries to that space.

We are definitely adding an arch with another 1400w to our existing 700w of solar. That coupled to 14,400kwh of lithium batteries I can't see a generator being crucial, and occasional main engine (or two) to bulk load the batteries should be a reasonable request on the system.

Yes. Note a well optimized system along these lines combined with an LFP bank could eliminate the need for **any** solar.

Only add that if it is something you actually want.

LFP's high CAR can mean an hour run-time supplies all your electricity for days.

Bigger AH/day usage just scale the amps output and bank size up, runtime stays the same.

[john61ct]

Originally Posted by LoudMusic

Maybe I'll see how long I can go without firing up the generator and then decide if it needs to get pulled. I wonder what a used generator is worth ...

Aircon means burning dino juice.

Bank storage just gives a little time shifting.

But for a boat always motoring, big enough alternators could do it.

Personally, aircon is only for in the marina.

[john61ct]

Originally Posted by MaCro

Windlasses, winches, and bow/stern thrusters are available in 48V, so that may handle most surge loads.

Since those heavy hitters can be taken care of at 48V

I've seen 48V DC aircon units as well, but maybe they just build in the inverter.

[smac999]

Every boat around here has a large house bank, big alt, inverter, and no gen....

Looks Only diff is his alt is even bigger. But most engines are not going to handle a 10hp lose from an alt. You'd be going 2knots.

[john61ct]

Yes, for high amps production the propulsion engine may need to be selected to take the extra HP required into account.

But at anchor, zero HP used for propulsion, long as the engine's power production is tuned to the best rpm. . .

But yes the goal of eliminating a dedicated genset is IMO where the value of the concept lies.

[Dockhead]

Originally Posted by john61ct

As the watts produced increases, that is less true, right? About a HP required per 250-300W IRL output, right?

Now as you wrote, if the system keeps the engine running at a fuel-efficient rpm, and watts output is varied based on the changes in the other loads like propulsion, that would be great.

But up-sizing the engine as required to accommodate high wattage output is far from free.

Edit, saw your edit, seems we agree

> plus you are doing away with the second diesel engine for a huge reduction in cost and complexity.

Now **that** to me is the real benefit of large-alternator setups.

Even if there are already two propulsion engines for overall redundancy.

Don't forget the OVERHEAD -- that's the main issue, not g/hp/hr of fuel burn. It takes quite a lot of power to turn the engine over even with no load. So if the engine is already being used for propulsion, then you are only paying the MARGINAL cost in power for generation, which is quite a lot less than the average cost. This is the principle efficiency gain.


I posted earlier my generator fuel consumption numbers. Roughly -- divide max fuel consumption in 5. 1/4 of the generating capacity will take 2/5 of the max fuel consumption. 2/4 will take 3/5. And so on. So running lightly loaded is very inefficient.

[john61ct]

Originally Posted by Dockhead

Don't forget the OVERHEAD -- that's the main issue, not g/hp/hr of fuel burn. It takes quite a lot of power to turn the engine over even with no load. So if the engine is already being used for propulsion, then you are only paying the MARGINAL cost in power for generation, which is quite a lot less than the average cost. This is the principle efficiency gain.


I posted earlier my generator fuel consumption numbers. Roughly -- divide max fuel consumption in 5. 1/4 of the generating capacity will take 2/5 of the max fuel consumption. 2/4 will take 3/5. And so on. So running lightly loaded is very inefficient.

Yes after watching the long Nigel video, I can see how "nearly free" is well justified when under way.

Interesting how the completely separate algorithm for charging at anchor was a much greater challenge.

This will likely be out of my budget short term, but look forward to member reviews.

And hopefully open hardware / FOSS projects like Thomas' will get extended into the arena using stock HO large frame alts, even if only at 24V rather than 48.

[Dockhead]

Originally Posted by john61ct

Yes after watching the long Nigel video, I can see how "nearly free" is well justified when under way.

Interesting how the completely separate algorithm for charging at anchor was a much greater challenge.

This will likely be out of my budget short term, but look forward to member reviews.

And hopefully open hardware / FOSS projects like Thomas' will get extended into the arena using stock HO large frame alts, even if only at 24V rather than 48.

Stock cheap high output large frame alternators are beautiful things on a cruising boat, looking from a practical rather than theoretical point of view. I would give up a lot of efficiency (actually) for the sake of the cheap/generic/simple/can be repaired by anyone qualities of these.



But they are not actually even so inefficient. The main thing you care about at anchor, in my opinion, is minimizing engine run time, and putting on a consistent decent load for engine health. I don't think this is hard to achieve so long as you have lithium batteries.




With all due respect to EcoTech and so forth -- I would not rush into making the investment into this sort of alternator, at least not before I'd had one apart on my own bench and had convinced myself that I could fix it myself easily in a remote area, and before I had seen the price list for parts and compared it to the Leece Neville one.

[zboss]

Is there a chance that the controller for that "alternator" hooks into the wire harness of the engine and uses that data as an input for optimizing the load?