Electric sea water pump - D2-55

[SVI]

I plan to upgrade to a large alternator 500A on one of my twin D2-55F.
I do not like that seawater pump and alternator share the same belt.
Is it possible to install a 12v self-priming pump?
Then I would use a shorter belt for flywheel pulley & alternator pulley for better grip.
And carry a spare pump.

Any ideas?

[mcarling]

Switching to an electric pump means that the self-priming challenge is reduced because you have more freedom of where to locate the pump. Obviously, lower is better.

[SVI]

Originally Posted by mcarling

Switching to an electric pump means that the self-priming challenge is reduced because you have more freedom of where to locate the pump. Obviously, lower is better.

It has to be after the strainer, which is at sea level.
The boat is a catamaran, shallow draft.

[mcarling]

It doesn't necessarily have to be at or below the waterline, but you want to mount it as low as possible. Going electric, it should be possible to put it anywhere there is space.

[SVI]

Yes. My question is - which 12v pump.
Actually, I can connect the March A/C pump that supplies my A/C and watermaker. But it is 230v, so the inverter will be also involved... too many to fail.

But I will have the traditional setup on my other D2-55.

[mcarling]

I agree that it would be more reliable to use 12V DC than 230V AC. I would first try to find the lowest suitable location and then measure how much space is available before shopping for a specific pump. I often make a cardboard model of the biggest pump (or whatever item) I can maneuver into the space available and then go shopping with the model in hand.

[sartorst]

Surely you jest

[DougR]

As Sartorst has stated, " Surely you jest".........

Sorry to say it but I think this plan has all the making of a catastrophe.

First off, the sea water pump on the D2-55 is gear driven and is not connected to the belt. The belt driven pump is the coolant circulation pump, and this will be somewhat more difficult to replace with an electric pump.

Secondly, a 500 amp alternator is probably well beyond the power capacity of the serpentine belt on the front of the engine, and probably also beyond the pto capability of the front end of the crankshaft. Think of it this way: 500 amps @ 14 volts is 7000watts. Then, if we're generous and say the alternator is 65% efficient, we have to input almost 11000 watts mechanical into the alternator to get the 7000 electrical output. So you want to pull 11kW or about 14.5 hp off the front of the crankshaft. Without going to my application books for the D2-55 engine, I would say you are asking for a broken crankshaft.

If I had to make a recommendation, I would suggest installing the Volvo extra alternator kits on both engines. This gives you an extra 230 amps capacity (115 amps each) added to the existing 230 amps for a total 460 amps capacity. If you need more than that, add a generator or solar panels.

The advantage of this is that it's already engineered and tested, doesn't void your warranty, doesn't destroy your engine, and doesn't cause your charging alarm buzzer to drive you crazy all the time.

DougR

[Terra Nova]

Really dumb idea.

[oleman]

A fire pump is used to constantly charge the fire mains on a Military War Ship.
If I remember correctly the pumps were powered by 440V 3 phase 60 HZ 120 HP motors and there were were 4 or 6 of them on a USN Cruiser.
I was a computer tech on the ships I was on but, in many years of shipboard life I never recall a failure of one of the motors.
If only the rest of my world was as reliable as a Fire Pump!!!!!

[Cadence]

Originally Posted by sartorst

Surely you jest

[SVI]

Originally Posted by DougR

As Sartorst has stated, " Surely you jest".........

Sorry to say it but I think this plan has all the making of a catastrophe.

First off, the sea water pump on the D2-55 is gear driven and is not connected to the belt. The belt driven pump is the coolant circulation pump, and this will be somewhat more difficult to replace with an electric pump.

Yes, looked in manual and you are right.
It makes it easier - circulation pump does not need high gpm rating and has no head, it is a closed system.
I just don't like the idea that 2 important devices share the same belt.

Secondly, a 500 amp alternator is probably well beyond the power capacity of the serpentine belt on the front of the engine, and probably also beyond the pto capability of the front end of the crankshaft. Think of it this way: 500 amps @ 14 volts is 7000watts. Then, if we're generous and say the alternator is 65% efficient, we have to input almost 11000 watts mechanical into the alternator to get the 7000 electrical output. So you want to pull 11kW or about 14.5 hp off the front of the crankshaft. Without going to my application books for the D2-55 engine, I would say you are asking for a broken crankshaft.

The new alt belt is 12-groove, so crankshaft pulley to be changed to 12-groove. Truck belt.
Load depend on the gearing of the alternator. It produces 570 amp at max rpm. At mid-level it produces 400 amp. At iddle it produces and drags almost nothing. There is a remote switch to activate it (to switch off during docking).

Brake crankshaft? It is not broken when you apply 55hp to your saildrive. It is not broken when you catch a rope on a prop. Why would the alternator brake it?

If I had to make a recommendation, I would suggest installing the Volvo extra alternator kits on both engines. This gives you an extra 230 amps capacity (115 amps each) added to the existing 230 amps for a total 460 amps capacity. If you need more than that, add a generator or solar panels.

Extra mount kit cost $1200 from Volvo for 3-4 simple pieces. No way since the alternator costs $500.

I have two engines, but I only use one on the way. Mainly the right one (water heater).

I have 800ah lithium, so with 500A alt can change it in 1 hour. Also cook on the way, use A/C in hot climate, make water.

I have the 5kw generator and 900W solar. But generator makes noise, and solar is not enough for our all-electric appliance boat.

The advantage of this is that it's already engineered and tested, doesn't void your warranty, doesn't destroy your engine, and doesn't cause your charging alarm buzzer to drive you crazy all the time.

DougR

I am out of Volvo warranty already, and I can do whatever I like - it is my boat, not Volvo's.

How about the other idea?
I replace my stock 110A with Leece 275A (same 6 groove belt and pulley).
I will check the belt slippage and wearing - maybe I can keep the circ pump on the belt?
Then I will add another 275A on extra belt/pulley if I need to.

[SVI]

This one should be a perfect circulation pump, draws 1.2A @12v:

https://www.jabscoshop.com/marine/pu...irculation.htm

[Lepke]

The stock FW circulation pump is low pressure, high volume. To replace the capacity with a 12v pump you will draw many of the new 12v amps. Also, drawing enough hp off the front of the engine, not designed for it, along with the transmission needs can easily lead to a broken crank or other problems. You don't have a heavy duty diesel.
In my own experience with 250VDC diesel electric drives using 500+ amps were all direct drive - no belts. And on this boat going to 250 amp alternators, the belt tension necessary to avoid slipping at full amps quickly wears belts and bearings. Keep several spare bearings.
The first thing I got rid of when buying this boat was the electric stove.

[SVI]

Originally Posted by Lepke

The first thing I got rid of when buying this boat was the electric stove.

Yeah, wooden stove is much better )

Actually, I through away the small propane stove and put LG MW stove with convection (same place) a year ago. Only $300. One year full-time cruising - could not be happier.

Works off my 3kw inverter & lfp batteries. Together with a household fridge it creates a home-like galley.





So think outside the box