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Old 27-08-2015, 12:35   #1
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New Alternator/pulley system


I recently upgraded by main power and starter batteries to Lifeline AGM's. I have the following:

2 GPL-4DL 210 Amp Hour batteries
1 GPL-1400T Starter

Currently I have a Balmar 90 series 100 AMP alternator with an older regulator that is not setup to handle the charging needs of AGM's. The Balmar is connected via a 3/8inch belt.

This is all connected to a Westerbeke 38b diesel engine with a single vee pulley system.

The issue I am having on a regular basis is the belt slipping. I have to keep tightening it, but even then it will start slipping when any real load is put on the Alternator, especially if I use the windlass!

The 3/8 belt is under powered for the Alternator running at 100amps which is causing the slippage.

I am looking to upgrade the Alternator/regulator to a newer model to accommodate the new loads my batteries can handle, but in doing so I would have to upgrade the pulleys as well.

I am getting overwhelmed on what to do. Would it be better to get the Altmount system for the pulleys to convert them into serpentine to go with the new alternator or do I get a smaller alternator to fit the size of the belt I currently have and then add another alternator to make it a dual belt systems... That second option seems more expensive and more electrical work.



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Old 27-08-2015, 12:41   #2
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Re: New Alternator/pulley system

ITWMB, I'd get a Balmar MC-614 regulator and then use either or both Small Engine Mode (switch) or belt/amp manager for those times when you're overloading the belt. Once the batteries come up, you can increase the AO.

I am not an expert on those batteries, so if they are the type that continue to take high charge rates, then the LAST thing you want to do is get a smaller alternator. I'd go the dual belt route.

Small Engine Mode - discussion with link to the picture of the toggle switch: Alternator heat, Regulator Controls, Small Engine Mode

Small Engine Mode - the picture of the toggle switch Alternator Output Management with External Regulators [Small Engine Mode]

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Cowichan Bay, BC, (Maple Bay Marina) SR/FK, M25, Rocna 10 (22#) (NZ model)
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Old 27-08-2015, 14:02   #3
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Re: New Alternator/pulley system

Thanks Stu,

I will look into those links.

Here are the charging characteristics of the lifeline batteries:

Bulk Charge Voltages: 14.20 - 14.60
Absorbtion Charge Voltages: 14.20 - 14.60volts
Float Charge Voltages: 13.10 - 13.40
The GPL-4DL is designed for charging amperages up to 525 amps or 250% of the rated Amp Hour Capacity due to low battery internal resistance.
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Old 27-08-2015, 16:51   #4
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Re: New Alternator/pulley system

Go with the serpentine belt kit, and a three stage regulator
There are others than Balmar, but Balmar is fine, you will not need the belt manager with the serpentine belt, I'd recommend a regulator that monitors the alt's temp and will back down on amps based if it gets hot, one advantage of AGM's is the charge acceptance rate, don't give up that advantage by backing down on the alt's output, but it can get hot, especially at lower RPM's

PS, I have 6 of those batteries coming for my bank

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Old 27-08-2015, 17:00   #5
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Re: New Alternator/pulley system

Whatever you do, go with serpentine. You could upgrade your existing one if you'd be happy with the charge rate (say 80A or so for extended running). Once you get rid of the slippage you should be able to see that kind of output. If you want more, get a bigger alternator with a serpentine pulley and add a serpentine pulley to you current one to keep it as a spare. I know some people like the hot-swap of having two alternators running, I think its just simpler to have one on the engine and one that can be put in if needed. YMMV.
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Old 27-08-2015, 19:13   #6
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Re: New Alternator/pulley system

I wouldn't try to force 100 amps out of a 100 amp alternator for extended periods of time. The temp. sensor is really a backup safety device rather than a full time operational device. By dialing the output back to about 80 amps max you will have a long lasting alternator. As others have said if you want more power out of your alternator get one with a higher rating and dial it back about 20% from max.

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