Yanmar 3gm30 replacement alternator

[affinite]

Even though I have a Driftgate 200 alternator controller fitted, the Hittachi alternator on my Yanmar 3GM30 only seems to give a max output of around 25amps. Has anyone fitted a higher power replacement without changing mounting brackets and pulleys etc ?

I dont have the budget for one of the Balmar type units. 50 - 70A would be a big improvment.
Thx
Steve (affinite)

 

[pvb]

What's the Ah capacity of your domestic battery bank?

 

[affinite]

330Ah and 110Ah starter battery. Charge is split between the two using a Driftgate X-Split.

 

[vyv_cox]

With the same engine and alternator, Sterling controller, I get the full 55 Amp output. Maybe something wrong with your alternator, controller or ammeter?

 

[pvb]

330Ah and 110Ah starter battery. Charge is split between the two using a Driftgate X-Split.

The start battery will take virtually no charge, but the 330Ah domestics should accept much more than 25A. Are you sure the alternator booster's sense wire is correctly fitted to the domestic bank?

 

[affinite]

the controller sense wire is connected to the house terminal on the xsplit and not to the actual battery terminal. I suppose a voltage drop on the cable between the splitter and the house battery could be afecting the sense. (Lightbulb moment) !

 

[earlybird]

I would think that the charging current that your alternator produces is very dependant upon the charge level of the battery. Only if it is well down would the full output be produced IMHO.
I have a Driftgate system on my 55amp. Lucas alternator, but with only a 110ah domestic battery.
On boost, it controls at 14.8v, but I rarely see more than 20-25 amps. output, and that level doesn't last very long. However, I tend not to discharge the battery too much to start with. Are you quoting the charge going into a fairly depleted battery?
Perhaps my expectations of the boost controller are low, but my main objective in fitting it was to minimise engine run time for charging purposes.
PS Just a thought, my Driftgate regulator is fixed voltage, but AFAIK, the later products are user adjustable. You have selected the correct battery type I presume?

 

[affinite]

My boat is in Greece and we spend extended periods at anchor. I have some solar panels but in that climate they dont keep pace with the fridge which just eats the amps. So, after just a day or so I do end up with a depleted house bank (cant remember the voltages) but still never see charging current as high as Id expect. I cant remember the names of the battery charging phases but during the heavyweight charging phase I do only see 25A or so.
Before anyone suggests it, I am also trying to resolve my fridge issue but with the boat 1500 miles away maintenance trips are at a premium.

 

[vyv_cox]

After a night at anchor with the fridge running, starting the engine early in the morning usually charges at 55 amps, or nearly that, for a couple of minutes. Later in the day the panels have had a chance to do something so the current is less.

 

[Mistroma]

Sounds sensible, even a small difference in Voltage will make a big difference in Amps supplied (i.e. Regulator sees battery as more fully charged than it is).

I have a similar setup with Yanmar 4JH4AE & Hitachi 80A alernator.

I'm in the process of:

1) Moving 110Ah Engine (leisure type) battery to the existing 3 x 110 Ah domestic bank.
They are all same make, model and age (fairly new). I'll fit a start battery for the engine as it isn't deep cycle.

2) Fitting a new Prestolite 110A alternator (found someone selling them for around £170)
It is only 110 vs. 80 but has a smaller pulley so has higher rpm and output curve looks better to start off.

Based on specs. for both alternators I should get much better output at low engine revs.

1250 rpm 70A vs. 43A
1500 rpm 80A vs. 53A

I try to avoid running just to charge batteries but can't avoid it completely. At least this keeps the time down a little. Not expecting these Amperages of course but should still be much better than with original.

3) Fitting Merlin Smartbank Advanced
I wanted to buy a SmartGauge anyway and buying this saved me uprating the existing diode. Plus this allows me to add a few extras (variable speed battery compartment venting, modified charge voltage etc.).

There are so many different options for charging and everyone has different ideas. But I'm hoping that this will be resonable improvement for the money spent.

You might be interested in the Prestolite alternator. I believe that it can just manage with a standard V-belt and that saves cost of converting to serpentine or dual belt.

Of course I'll not know how this lot actually works until April/May.

 

[pvb]

You might be interested in the Prestolite alternator. I believe that it can just manage with a standard V-belt and that saves cost of converting to serpentine or dual belt.

Prestolite alternators are excellent. I have a 90A Prestolite Leece-Neville which only feeds the domestic bank (630Ah), with Adverc control. It replaced a 130A(ish) large-case alternator, which was just too big/heavy and kept fracturing the bracket. Also, I can only fit a single belt drive and the alternator load was simply too big for a single belt. The 90A alternator overloads the belt too if the batteries are depleted. I would think that your 110A alternator will similarly be a problem on a single belt, especially with a small pulley, although you're not likely to see huge charge currents unless you increase the size of your battery bank.

 

[charles_reed]

Even though I have a Driftgate 200 alternator controller fitted, the Hittachi alternator on my Yanmar 3GM30 only seems to give a max output of around 25amps. Has anyone fitted a higher power replacement without changing mounting brackets and pulleys etc ?

I dont have the budget for one of the Balmar type units. 50 - 70A would be a big improvment.
Thx
Steve (affinite)

Speak with Adverc - they'll find you a 70ah Lucas unit that will bolt on instead of the Hitachi.

I did that with my 2GM though I had to replace the normal belt with an heavy duty (serrated) belt.

However if you're relying on the on board regulator to do the job, you're unlikely to get many more amps out of the Lucas.

I'd suggest retaining the Hitachi and fitting an Adverc smart regulator, which will probably be more effective at upping your charging rate.

The point about the total battery capacity is important - you'll need about 300ah to make full use of the Lucas alternator output.