Tiny Powered Alternators & DC Generators

[john61ct]

I have never seen a diesel small enough to carry around, isn't heavy weight even at small HP inherent in the technology?

[john61ct]

Originally Posted by rgleason

11 amps would be fine in Absorption mode for smaller banks.

To me 2-300AH is a small bank.

25+ hours of runtime to recharge?

I would prefer a charge source that only needed to run less than an hour or two a day average, also make my water and freeze the fridge holding plates at the same time.

Going to need a bigger boat 8-)

Actually the propulsion engine should be easily switched to put 100% of its HP to these other uses, rather than having to carry a whole nother engine.

[newhaul]

Originally Posted by john61ct

To me 2-300AH is a small bank.

25+ hours of runtime to recharge?

I would prefer a charge source that only needed to run less than an hour or two a day average, also make my water and freeze the fridge holding plates at the same time.

Going to need a bigger boat 8-)

Actually the propulsion engine should be easily switched to put 100% of its HP to these other uses, rather than having to carry a whole nother engine.

that was kinda my point concerning the dynostarter.

Now I can put up to a 200 amp alternator on my main to charge batteries but kinda severed the purpose of solar on a sailboat.

[rgleason]

25+ hours of runtime to recharge?

How do you figure that John, I said absorption.

[john61ct]

Originally Posted by rgleason

How do you figure that John, I said absorption.

Missed that, but now I don't know what you mean?

My calc was based on fastest possible using LFP, for which there is no Absorption stage afaic.

Replenishing that many AH for lead would take much longer, can't see a low-amp DC genny making any sense there.

The proportion of time Absorbtion takes out of the total varies wildly.

Dino juice sources are usually for the earlier stages precisely because they are high amps and you want to minimize runtime.

[rgleason]

300ah Bank would be nice, we have T-105 225ah FLA Bank
Available .50C=112a

1. Bulk .30C=67a=Constant Current 10-13% of C20, 22-29a rising to 14.82v, 1.5-2.5hrs
2. Absorption .20C=45a=Constant Voltage 14.1-14.7v current falls from 22a to 6.25-2.25a, full charge 1.5 trailing amps, 3-5hrs
3. Float=.005C=1.1a=Constant Current 1-3% of C20, 2.25-6.25a, rising voltage to 14.8-14.9v, with ends when battery is fully charged with 1.5 trailing amps.

Bulk=Engine Alternator
Absorption=Engine Alternator, Tiny Alternator, Solar (3-5 hrs)
Float= Solar
Solar= Quiet, effective, lots of sf, expensive. Not all boats can support 600watts or even 400 watts.

Tiny Alternator= 3-4 hp with 1-10 amp output. (could be diesel, water, wind) Why run the 30hp engine using 3 hp? Not efficient, engine wear, adds maintenance and hours. Use during cloudy days too. Ideal if it were quiet. Would I use it? Sure!

Here is a low rpm alternator that looks interesting.
Helibug 12V 500 Watt Low RPM Axial Flux Alternator/Wind Turbine Alternator/Dynamo/PMA/Battery Charger

[newhaul]

Originally Posted by rgleason

300ah Bank would be nice, we have T-105 225ah FLA Bank
Available .50C=112a

1. Bulk .30C=67a=Constant Current 10-13% of C20, 22-29a rising to 14.82v, 1.5-2.5hrs
2. Absorption .20C=45a=Constant Voltage 14.1-14.7v current falls to 6.25-2.25a, full charge 1.5 trailing amps, 3-5hrs
3. Float=.005C=1.1a=Constant Current 1-3% of C20, 2.25-6.25a, rising voltage to 14.8-14.9v, with ends when battery is fully charged with 1.5 trailing amps.

Bulk=Engine Alternator
Absorption=Engine Alternator, Tiny Alternator, Solar
Float= Solar

Solar= Quiet, effective, lots of sf, expensive. Not all boats can support 600watts or even 400 watts.

Tiny Alternator= 3-4 hp with 1-10 amp output. (could be diesel, water, wind) Why run the 30hp engine using 3 hp? Not efficient, engine wear, adds maintenance and hours. Use during cloudy days too. Ideal if it were quiet. Would I use it? Sure!

400w solar is not out of the question for a 30 ft + sailboat.
I even had 200w on my 24.
Most small sailboats have minimal power needs so 200w would actually do most if not all of the power needs .

[rgleason]

Originally Posted by newhaul

400w solar is not out of the question for a 30 ft + sailboat.

How did you do it on your 30'? Locations, watts, what panel type, manuf, etc

I can fit (2) 60 watt, maybe bigger, flexible panels on the dodger with (2) Genasun boost pb 8a

[newhaul]

Originally Posted by rgleason

How did you do it on your 30'? Locations, watts, what panel type, manuf, etc

I can fit (2) 60 watt, maybe bigger, flexible panels on the dodger with (2) Genasun boost pb 8a

pushpit for 2 renogy 100 watt rigid panels and two 100 watt flex panels ( I was given the flex and was told they are grape)
the flex can be placed where ever on the boat as needed .
In the last picture you can see part of one of the flex panels hanging on the boom at the dock.

[john61ct]

Originally Posted by rgleason

300ah Bank would be nice, we have T-105 225ah FLA Bank
Available .50C=112a

Nit pick.

C rate is usually just for amps, a flow rate proportional to AH capacity.

112.5AH (not amps) is indeed half that bank capacity. But AH is not referred to as a C rate.

.005C=1.1A yes

But not 1-3% of C20, that is .01C - .03C, no need to specify C20, in the U.S. that is how C is defined.

NBD I know, just FYI.
_____

1. Bulk .30C=67a=Constant Current 10-13% of C20, 22-29a rising to 14.82v, 1.5-2.5hrs
2. Absorption .20C=45a=Constant Voltage 14.1-14.7v current falls from 22a to 6.25-2.25a, full charge 1.5 trailing amps, 3-5hrs

Is this your log of actual charge cycles you've recorded with your bank?

Note Absorb should be held until endAmps indicates 100% Full.

Float is a much **lower** voltage, done correctly it does no further charging at all, just carries loads and counteracts a bank's self-discharge when stored over time.

Only Bulk is called CC, the stage before hitting the voltage setpoint,

Float has nothing to do with CC.

If you are thinking of running a tiny DC genny/alt for "the long tail", IMO not cost-effective, we are talking 3-5 more hours. That is what solar's for, after dino juice gets SoC to 75-90% depending on panelage, weather etc.

A Honda eu2200 will be much more generally useful if it turns out you need it.

But hey trying new things is great.

[OceanPlanet]

Hi folks,

FWIW, if anyone in the US NW is interested in a small DC generator, I have one on my late dad's
boat that I'm going to take out. It's a small Kubota (4 or 5hp) with an Ample Power alternator...I think 150A. Runs good and very low diesel consumption however I'll be putting a high output alt on the engine and going with Li batteries.

[rgleason]

Originally Posted by OceanPlanet

Hi folks,

FWIW, if anyone in the US NW is interested in a small DC generator, I have one on my late dad's
boat that I'm going to take out. It's a small Kubota (4 or 5hp) with an Ample Power alternator...I think 150A. Runs good and very low diesel consumption however I'll be putting a high output alt on the engine and going with Li batteries.

Bruce,

That sounds like a great generator for a bigger boat. Out of curiosity how much does the Kubota weigh? I had no idea 4-5 would create 150a.

So what I am thinking of is a tiny one, say 1.5-2 hp that could output 20-30a to eliminate being anchored in reverse at 1100-1600 for 5 hours. Right now it is 1600-1700rpm and very noisey because of 24yr old derated Balmar 90-65 with non OEM stator. Want to get new 120a (approx) Alt with serpentine belt, and not mess around. Would that be big enough for Li/Firefly someday.



Is Li worthwhile for small boats with a bank 225ah --->400ah with some space constraints? If so, what are the advantages and which ones would you suggest and what BMS? Are Fireflys simpler and compatible with most systems? What in particular other than the BMS would you need with Li?

------
Thanks Newhaul.
If you can fit them, I should be able to as well, and the one big advantage is they are quiet.

[newhaul]

Originally Posted by rgleason

Bruce,

That sounds like a great generator for a bigger boat. Out of curiosity how much does the Kubota weigh? I had no idea 4-5 would create 150a.

So what I am thinking of is a tiny one, say 1.5-2 hp that could output 20-30a to eliminate being anchored in reverse at 1100-1600 for 5 hours.

Is Li worthwhile for small boats with a bank 225ah --->400ah with some space constraints? If so, what are the advantages and which ones would you suggest and what BMS? Are Fireflys simpler and compatible with most systems? What in particular other than the BMS would you need with Li?

------
Thanks Newhaul.
If you can fit them, I should be able to as well, and the one big advantage is they are quiet.

not a problem pm me if you need design assist.

As to Lfp yes it is worth it . 200ah of Lfp weighs about 40 to 50 pounds and provides 180ah usable power. To get that with Fla you need at least 360ah of bank at a weight of about 150 or a bit more .

[john61ct]

Originally Posted by rgleason

I had no idea 4-5 would create 150a.

No such claim was made. Very few alt setups can (or should) be configured to output anywhere near the rated max, especially direct into LFP.

In this case 70-90A actual output would be the sweet spot, and if 4HP given the usual power curve, likely best efficiency is at quite a bit lower than the 70A point, may not get even there at a reasonable working rpm.

[rgleason]

1.5-2 hp that could output 10-30a (150watts-450 watts at 14.8v) or maybe water/wind generator but that does not work at anchor and is much less power for water generator (3-6amps I guess) at our low speeds .