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rotorman · 27-10-2011, 15:11

Hi,

I am replacing my 2nd alternator (with the engine). I have a battery bank of 700Ah, wet cell. How would you size the alternator? Which brand would you use?

Regards
Geza

colemj · 27-10-2011, 15:18

What size engine and do you have a serpentine belt?

Electromaxx.

Mark

rotorman · 27-10-2011, 15:40

The engine will be a 55hp Volvo or Yanmar. The alternator will have its own pulley(s) on the engine.

**estarzinger** · 27-10-2011, 15:55

Quote:

Originally Posted by rotorman

Hi,

I am replacing my 2nd alternator (with the engine). I have a battery bank of 700Ah, wet cell. How would you size the alternator? Which brand would you use?

Regards
Geza

The normal rule of thumb for the max acceptance rate for flooded batteries is 25% of the bank size = .25*700 = 175 amps. around 150 amps would be sensible if you can drive it with two belts (need a two belt pulley on the engine). If you can only use one belt then you should not go above about 90 amps.

Here is the SSCA equipment survey ratings of alternators. They are sorted best to worst (lower=1=best, higher=3=worst). The sample size is 832 cruisers rating their alternators.

Hamilton Ferris 1.4
Proline 1.4
Leece Neville 1.5
Lestec 1.6
Ample Power 1.8
Balmar 1.8
Hehr Powerline 1.9
Amtech 2
Mastervolt 2
Silverbullet 2
Bosch 2.1
Yanmar 2.1
Hitachi 2.2
Motorola 2.2
Volvo 2.2
Other 2.2
Delco 2.3
Prestolite 2.3
Powermax 2.4
Cummings 2.7
Lucas 2.7
Ingrams 3
Mando 3
Reece Neville 3

C4 King Cobra · 27-10-2011, 16:05

I put a 120 amp om my Yanmar 55 hp. Single pulley. Electromax about one hour to install, with external regulator works like a champ. John at Elexctromax works with you through the process.

rotorman · 27-10-2011, 18:10

Is this John in NZ?

CAELESTIS · 27-10-2011, 20:07

Balmar paints a rebranded alternator white/blue and puts their name on it. If you look at various pdf files you will see many are identical to the Leece Neville. I don't believe they actually make any alternators.

If you want big amps then you should also consider the AltMount.com - Welcome - Mount a second alternator to your Yanmar marine engine brackets for your Yanmar. They have a 10 rib serpentine belt and powerfully built. It is a far better solution than a V-belt driven alternator.

C4 King Cobra · 28-10-2011, 04:11

Yes, I believe so.

rotorman · 02-11-2011, 20:31

Do you have any contact details for John, please?

C4 King Cobra · 03-11-2011, 08:13

just call electromax he will probably answer

S/V Alchemy · 03-11-2011, 08:53

What is the point of the second alternator, if I may ask?

Do you have one PTO (two alts run on one big belt in a triangular configuration) or dual?

I have a new Beta 60 with dual PTOs precisely because I wanted two 75-90 amp alts to charge my 850-1000 Ah banks. For reasons of heat, cost, wear on the crankshaft, "thieving" of horsepower, and redundancy, it's easier to contemplate a pair of sub-100 amp alternators than one big 'un. Also, I have extensive solar and wind charge sources, so the alts will only be, unusually, the third line of charge sources as I intend to only run the engine for motive power. So the alts will be set up, unless I'm at anchor for five cloudy, windless days, to provide a "finishing off" charge, rather than to recharge a deeply discharged bank.

So it's a case of working backwards from the application to determine a right size, I think. The size of your bank is irrelevant until you tell me your daily draw-down and whether you are going to stay on the hook all the time, etc.

As for make, I favour Leece-Neville because they are popular in Canadian 18 wheeler trucks!

I think Balmar is a little overrated, or rather, I think I can do what they do with external regulation more effectively than their price premium can justify. Just my opinion now; it's subject to further persuasion.