Getting rid of alternator?

[DeValency]

Well, what do I know. I’m only a sailor since I was 11, now on my 9th keel boat and EEE post graduate of MIT, circa 1991... So I definitely know nothing about numbers....

But you definitely know so much more, so go ahead and drive a motor cat offshore without alternators. Good luck.


QUOTE=CatNewBee;2966527]Dont mess up the units please, it hurts people with basic electric knowledge.

A (Amps) is the unit of current flowing actually.
A/h Amps per hour is nothing.
Ah is the capacity of a battery of known voltage, better use Wh or kWh for comparison

There is no battery of 600A, if you short a 100Ah start battery you may get even 1000A for a second. What you mean is 600Ah. And it needs maybe 300Ah of charge, 300A is only the current, I doubt your battery would accept a 300A current (0.5C) under normal conditions.

300W from solar at 14V would end up to a charge current of 21A, if you have 300Wp panels, only in perpendicular radiation at noon and cold ambient temperature you may get 300W out. But your rule of thumb is ok, solar peek Watt (Wp) of the panels * 4 is the average Wh harvested per day for flat panels you can expect. 1200Wh or about 90..100Ah per day at 12V would be an average output for a 300Wp solar array.

It really depends on the radiation (clouds, shading from mast, lines, boom), ambient temperature, used voltages and controller (PWM vs. MPPT), type of battery (FLA or LFP) if you can squeeze every electron out of your panels.

And dont forget your running loads while charging, they tend to chew up a lot of the incomming energy before it even reaches the battery.[/QUOTE]

[CatNewBee]

Originally Posted by DeValency

Well, what do I know. I’m only a sailor since I was 11, now on my 9th keel boat and EEE post graduate of MIT, circa 1991... So I definitely know nothing about numbers....

But you definitely know so much more, so go ahead and drive a motor cat offshore without alternators. Good luck.

No offense, just be more presize with the units.

Btw, I am on your side, would never remove alternators, nor would I convert a beautyfull power cat to a kastrated hybrid.

But it's not my money. Whatever makes them happy...

... 7 years ago there was a sailing catamaran Lagoon 420 on the market with hybrid engines, most owners let them convert back by the manufacturer to diesel engines because they were not satisfied with the performance and range. But they kept the 12kW onan generators.

Very few of them still exists as unicorns.

[a64pilot]

If it’s a hybrid in that it keeps one Diesel, then it may not be so bad. He can do the electric thing until or unless it can’t anymore, then he has the Diesel. Surely 135 HP is enough, not as fast as 270 HP, but 135 ought to be enough to keep you out of trouble, and it will either prove or disprove the feasibility of electric propulsion for him.
However I’d keep the engine removed until I was sure, that way you can go back for less money than if you had to buy a new one.

[DeValency]

Thanks.
This beautiful motor cat only need a good carbon mast, a boom, rollers and winches, few sails and sheets and she will be a super yacht.
Personally, I prefer my condo ashore, not in the water.

And by now I don’t think even one suggested the OP to remove the alternators so he should have the forum opinion loud and clear.

Originally Posted by CatNewBee

No offense, just be more presize with the units.

Btw, I am on your side, would never remove alternators, nor would I convert a beautyfull power cat to a kastrated hybrid.

But it's not my money. Whatever makes them happy...

... 7 years ago there was a sailing catamaran Lagoon 420 on the market with hybrid engines, most owners let them convert back by the manufacturer to diesel engines because they were not satisfied with the performance and range. But they kept the 12kW onan generators.

Very few of them still exists as unicorns.

[nebster]

Originally Posted by DeValency

Well, what do I know. I’m only a sailor since I was 11, now on my 9th keel boat and EEE post graduate of MIT, circa 1991... So I definitely know nothing about numbers....

You probably know a lot, but you nevertheless need a refresher on basic units as they relate to energy storage systems.

Everyone benefits when we avoid sloppiness in technical discourse.

[DeValency]

This discussion is closed anyway so no use to waste good time explaining the way the unit calculations were made but rest assure they were 100% correct.

Now just go sailing!

[nebster]

Originally Posted by DeValency

This discussion is closed anyway so no use to waste good time explaining the way the unit calculations were made but rest assure they were 100% correct.

Now just go sailing!

I think it's clear that what you wrote was far from 100% correct. Now that we have set the record straight, I agree with your last sentiment.