Alternator + Inverter vs Generator

[akio.kanemoto]

Originally Posted by s/v Jedi

I think the sewing machine sized Kubota will fit in your cockpit lockers.

For some ideas, look here: Aquamarine, Inc -
28"L x 13.5"W x 15.75"H makes power & water. Check out all the info on that site!!

Also:

http://www.cruisersforum.com/forums/...mbo-14330.html
http://www.cruisersforum.com/forums/...ions-4349.html
HOW TO BUILD YOUR OWN WATERMAKER
NEXT GENERATION POWER ENGINEERING INC.

ciao!
Nick.

Thanks for that - I'll look into these.

[akio.kanemoto]

Originally Posted by Bash

If my outside storage was that limited, the last thing I'd do is store fenders in the cockpit lockers.

Many cruisers tie their fenders to the pushpit rails when they're not in use. This practice leaves room in the lockers and lazarette for more important uses.

Definitely a good point, at the moment, since I'm still building the lockers - visualization is a bit hard - but point taken.

Just out of curiosity - what do you believe is the minimum of "stuff" that should be stored in outside storage? (we're experiencing a bit of thread drift here.. but hey...)

[bobfnbw]

Originally Posted by s/v Jedi

Yes, a combination of induction and propane would be great. I'm not sure about finding room for that though....

cheers,
Nick.

Amazon.com: MAGNEFLUX MODEL 03003 PORTABLE INDUCTION COOKTOP BURNER 1800 WATT: Kitchen & Dining

This is the one we have. Can be unplugged then stored in a locker.
Put it on the countertop, or the stove top while in use.


Doesn't take a lot of room.

[bobfnbw]

Originally Posted by akio.kanemoto

Definitely a good point, at the moment, since I'm still building the lockers - visualization is a bit hard - but point taken.

Just out of curiosity - what do you believe is the minimum of "stuff" that should be stored in outside storage? (we're experiencing a bit of thread drift here.. but hey...)

I believe, everything topsides should/must have a place for offshore voyaging, when heavy weather is expected. Sure you can tie into the pulpits, but then risk loosing it. Also the extra windage if winds should get up above 50 knots may affect performance and safety. Why risk it ?
But then, there are compromises. You can mount almost everything topsides but then shove below when bad weather is coming, but after a while that will be a chore....

[s/v Jedi]

When you spend your time away from docks, make your own water and take enough fuel with you, there's little need for fenders. I would stow them in that spare bunk, put inside an old sailbag or something to keep the bunk clean. I am with Bob that "deck cargo" is a no-no.

Also, reading back my posts, I think it isn't clear that I would have no objection about using DC alternators.... but for a primary charging system, I would mount them on a genset, not the main engine.
When I posted those links yesterday, I was trying to find the thread about this guy who build a tiny set himself, making all the brackets etc. but couldn't find it. It is much like the AquaGen. I have been intrigued with the AquaGen since I first found their website years ago. So many possibilities!

cheers,
Nick.

[Dockhead]

Originally Posted by akio.kanemoto

*grin*

Just as an additional point - it's only 4L/hour because I made a mistake with my rpm and pulley ratios - I calculated based on 2800 rpm, as I was getting too excited and started with by looking at the efficiency curve instead of required power... so I chose the most efficient spot for fuel consumption and went from there - but don't need the full 27HP at that rpm... I only need about 10HP...

So going with 2200 rpm - I could have had this down to 2.3L/hour - but your math still works out better... (but the difference is not as hideous as before.


Believe me, I am really short on space (and waterline).. this is an old racing boat with quite a narrow beam that I've totally ripped out the insides of and redone, but unfortunately the hull is still the same size as when I started... I was feeling romantic at the time so thought against buying a brand new beneteau (we'd have been "out there" for about 4 years by now with that option... *sigh*) .... but this is another story..

On the Honda - yes I have an EU2000i and in fact bought it specifically for this reason originally, thinking of the better fuel economy etc - but there are again various limitations which I've been wracking my brain over and can't resolve.

I have 250L of diesel tankage and 200L of water. Philosophy here was that "I can always make water, but not diesel"...

Batt bank is approx 700AH AGM. Chosen such that running my hideous 240A alternator combination, I can pump the bank full in about an hour. During that hour, I can also use the watermaker (cat 247 pump) on the engine (bought already.. oops) - to produce about 100L of water... about half the tank - meaning no limitations on water usage.

The only thing left here is hot water - still an unresolved issue. I have a raw water cooled engine - so no heat exchanger.. meaning that even if I take the hose off the exhaust manifold and run it though a really efficient/long externally mounted separate heat exchanger unit before plumbing it back into the mixing elbow, I'd probably only take the chill off the water since the engine will only be running at ~40degC anyway.. this part I'm not 100% sure of and will have to see when the engine is commissioned to see how hot I can actually get the water. (I have a very small hope that it will warm the water sufficiently... but not holding my breath..) If this doesn't work - then I need another solution.

Now the theory here was that at 4L/day diesel consumption - I'd get water, power and maybe hot water and assuming efficient usage/timing with moving around etc - it means 62 days without refuelling - away from civilisation. If I redo the pulleys - this will come down to 2.3L/day - meaning 108 days without refuel... much better.

Now on the Honda option - at the moment, I have no petrol tankage at all. Just jerry cans. Assuming say a max of 80L worth of jerry cans stowed around the place - the Honda eu20i will drink about 1L/hour at full load. Meaning 80 hours of runtime max - and if and only if I can complete charging etc in 1 hour per day - that means 80 days between refuels - which is not too bad. (Please note - I value days between refuels much higher than saving $)

Now comes more complexity - with the Honda - I will need a charger... it has been explained to me that the Honda won't power much more than a 75A charger... so this is way less than the alternators, and won't "saturate" the AGM acceptance rate on the bank... so it's probably more like 2-3 hours to charge the batts..

But, with all the power going to the charger - there's also no power left to run a watermaker with an AC motor.

One saving grace here is that with a Honda - I can buy an intant electric waterheater... and shower with that... but again, not all within an hour.

So to make the honda work - I'd have to do it in series - 2-3 hours charging, 1 hour watermaking, then shower. So we're now back to 4 hours or runtime... and 4L/day.... and with less petrol aboard than diesel - we're down to only 20 days between refuels (not counting outboard usage.. but we'll ignore that for now).

So since I really can't fit a diesel genset - (I really mean this - even the Honda would have to be stored in the cockpit in a purpose made box and will barely fit) - I have limited options for making this work - either somehow massively increase petrol tankage for the Honda, or just run everything off the main engine.

I would greatly appreciate wisdom and solution to this dilemma - but no matter how I look at it, the only way I can solve/optimize the problem is using the main engine.

Of course, I remain open to education and BetterSolutions(tm).


(By the way - there will also be a solar panel in the mix as well to help top up the batts as well.. no windgen though)



Unfortunately the Cat 247 pump just arrived.. but the other thing I just remembered is that to run the 247 at max output - you need an approx 2.5HP motor - which the Honda can't start due to the inductive load at start... :\ So if I couple to an AC motor - I'd have to run a smaller motor and run for longer... thus again increasing fuel consumption...



The problem here is that the last remaining bit of space I could possibly manage for a diesel genset is about the footprint of a Honda eu20i. I've just googled what is available here and there's nothing much smaller than something about twice that size... The only other crazy thing I can think of is to buy a really small air-cooled portable diesel genset - remove the frame and try to wedge it in somehow.. :\

But you've answered your own question. Why even think about diesel gensets if it's a priori out of the question? If you are running massive alternators PLUS watermaker off your main engine, then you're using it reasonably efficiently anyway. Just go with that. One small question, however -- you say you can recharge your battery bank in one hour -- I think that's against the laws of physics, no matter how big your alternators are. There is this little thing called charge acceptance. . .

But never mind. Add solar and wind to reduce the need for charging, and charge away and make water when you have to, with the prime mover.

Use the little Honda in a pinch. Your analysis is also, in my opinion, not quite right -- you won't be using the Honda all the time. You'll be charging automatically every time you move; you'll be charging again when you make water. The Honda will be needed only occasionally, which is exactly what it's made for.

As to hot water, just buy the smallest automobile Webato or Eberspaecher hydronic you can find. I think they cost about $1,000. Rig it up to your hot water heater, and if you like and think you'll ever need it, you can put a radiator or a fan coil in the master cabin or saloon or both, as a bonus. It will use about 0.25 liters of diesel an hour giving you almost inexhaustable hot water, and you can warm the cabin as a bonus.

[Dockhead]

Originally Posted by Bash

If my outside storage was that limited, the last thing I'd do is store fenders in the cockpit lockers.

Many cruisers tie their fenders to the pushpit rails when they're not in use. This practice leaves room in the lockers and lazarette for more important uses.

But the windage . . .

[akio.kanemoto]

Originally Posted by s/v Jedi

When you spend your time away from docks, make your own water and take enough fuel with you, there's little need for fenders. I would stow them in that spare bunk, put inside an old sailbag or something to keep the bunk clean. I am with Bob that "deck cargo" is a no-no.

Also, reading back my posts, I think it isn't clear that I would have no objection about using DC alternators.... but for a primary charging system, I would mount them on a genset, not the main engine.
When I posted those links yesterday, I was trying to find the thread about this guy who build a tiny set himself, making all the brackets etc. but couldn't find it. It is much like the AquaGen. I have been intrigued with the AquaGen since I first found their website years ago. So many possibilities!

cheers,
Nick.

Yep, definitely trying to minimize the deck cargo and keeping windage to a minimum.

Since it's an old racing boat - it's already very low windage and I'm trying to keep everything on deck to a minimum unless I can make it naturally a part of the boat's outer envelope - like the lockers underneath the seats for example.

The only real biggie will be the "radar arch" for the solar panel - but there's nothing I can do about this one.

On the home made genset/watermaker - I think you're thinking of "Frankenmaker"

L&A Cruiser's Forum • View topic - Frankenmaker MK II

[akio.kanemoto]

Originally Posted by Dockhead

But you've answered your own question. Why even think about diesel gensets if it's a priori out of the question? If you are running massive alternators PLUS watermaker off your main engine, then you're using it reasonably efficiently anyway. Just go with that. One small question, however -- you say you can recharge your battery bank in one hour -- I think that's against the laws of physics, no matter how big your alternators are. There is this little thing called charge acceptance. . .

On the first point about "why bother" - I'd love to get fuel consumption lower so I can go for longer without refuel - but I feel that the calculations are pretty close to as efficient as one can get without going to a genset etc... so am reasonably happy'ish.

As for charge acceptance - batt bank is AGM, so no problems here pumping silly amps in. This one is a religious topic though and I haven't been able to find any thread where everybody agrees on charge acceptance of AGMs, but going from the most conservative estimate of 0.4C to "unlimited" (I think that was a Concorde Batts statement..) - anywhere in the middle of that is fine with me - at 2200 rpm, alts will put out 200A.. and I really don't expect to be that low on a daily basis, so theoretically one hour should be enough.

But never mind. Add solar and wind to reduce the need for charging, and charge away and make water when you have to, with the prime mover.

Definitely adding solar.. wind looks attractive too, but I'll cross that bridge when I come to it. I'm thinking about 125W on a radar arch doubling as a bimini/cover/shade over the helm - and another 80W on the companionway hatch turtle - which will be shaded a lot at anchor.. but hey, every amp counts.

As for charge regimen, it would have been ideal to bulk charge in the morning with engine.. then let solar do the rest and top up during the day - but depending on the hot water equation - if the engine is needed for this, then it has to be at night, since my wife won't let me anywhere near bed without a shower first.

Use the little Honda in a pinch. Your analysis is also, in my opinion, not quite right -- you won't be using the Honda all the time. You'll be charging automatically every time you move; you'll be charging again when you make water. The Honda will be needed only occasionally, which is exactly what it's made for.

As to hot water, just buy the smallest automobile Webato or Eberspaecher hydronic you can find. I think they cost about $1,000. Rig it up to your hot water heater, and if you like and think you'll ever need it, you can put a radiator or a fan coil in the master cabin or saloon or both, as a bonus. It will use about 0.25 liters of diesel an hour giving you almost inexhaustable hot water, and you can warm the cabin as a bonus.

I'll look into this - thanks for that.

[s/v Jedi]

Yes, the Frankenmaker, that's it. Strange it didn't come up in Goggle for me...

About AGM's... they are just lead acid technology but the construction is different and that affects the charging algorithm. But you still have much less charge current for the last 20% (from 80 to 100% charged) and this takes a long time. With flooded batteries, most cruisers decide just to not go there and only charge to 80%. However, the tricky thing with AGM's is that they really really don't like that and you have to give them a full 100% charge more often. That is where your Honda will come in, plus you need a good monitoring system, like the Victron BMV-600 or similar. You must be able to determine the state of charge using the monitoring system because you have no access to the electrolyte like with a flooded battery.

cheers,
Nick.

[Bash]

Originally Posted by Dockhead

But the windage . . .

Rule #1: all sailboats have too much windage.
Rule #2: few sailboats have enough storage.
Rule #3: on racing sailboats, Rule #2 tends to trump Rule #1.
Rule #4: on cruising sailboats, Rule #1 tends to trump Rule #2.

[tallyhorob]

what about using the solar for hot water? Hell hang a 12 gal camping shower up and have hot water everynight.

[s/v Jedi]

Originally Posted by tallyhorob

what about using the solar for hot water? Hell hang a 12 gal camping shower up and have hot water everynight.

Do you do that at home too?

Sure that works, great when you're out camping or weekend / holiday boat trips but when you live aboard full time, I see no harm in having some of the same luxuries as the folks dwelling on dirt.

On the other hand, some cruisers only get their fix when they punish themselves... in which case doing away with luxuries is the logical course of action. Very often, these types are single handers and they wonder why... ;-)

I'm glad to be the kind who enjoys luxuries.

cheers,
Nick.

[akio.kanemoto]

Originally Posted by s/v Jedi

Yes, the Frankenmaker, that's it. Strange it didn't come up in Goggle for me...

About AGM's... they are just lead acid technology but the construction is different and that affects the charging algorithm. But you still have much less charge current for the last 20% (from 80 to 100% charged) and this takes a long time. With flooded batteries, most cruisers decide just to not go there and only charge to 80%. However, the tricky thing with AGM's is that they really really don't like that and you have to give them a full 100% charge more often. That is where your Honda will come in, plus you need a good monitoring system, like the Victron BMV-600 or similar. You must be able to determine the state of charge using the monitoring system because you have no access to the electrolyte like with a flooded battery.

cheers,
Nick.

I haven't bought the batteries yet and I was originally reading up Estarzinger's battery essay - somewhere on Beth & Evans and was convinced about getting some cheap and skanky T-105 equivalents and abusing them... but then rethought that approach with the big alternators idea to reduce charging time and reduce fuel consumption so I can stay away from the dock longer..

So on that note - what type of batts do you use?

What are your thoughts about AGMs - which say are brought up to 100% once per month, versus Flooded Cells which are cycled between 60 and 80% daily?

[akio.kanemoto]

Originally Posted by Bash

Rule #1: all sailboats have too much windage.
Rule #2: few sailboats have enough storage.
Rule #3: on racing sailboats, Rule #2 tends to trump Rule #1.
Rule #4: on cruising sailboats, Rule #1 tends to trump Rule #2.

Absolutely!