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Old 07-07-2015, 21:58   #1
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Does my generator need an alternator?

So my 5.5KW generator's alternator isn't putting any volts into the generator starting battery. Any reason I can't use the unused 3rd battery charging output of my mastervolt charger and connect to the genset starting battery? The charger is obviously linked to generator.

Upside of this solution is I don't need to fix or replace alternator. Also would have benefit of keeping generator starting battery topped off via shore power when plugged in so it's always charged.

Anyone have any comments or see an issue I could be missing?


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Old 07-07-2015, 22:35   #2
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Re: Does my generator need an alternator?

I would hook the charger up so it'll maintain while pluged in. but I would also fix the alt.


a lot of the mastervolts are only 10a output on the 2nd,3rd outputs. though that's probably enough to keep up with a gen.
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Old 08-07-2015, 08:11   #3
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Re: Does my generator need an alternator?

Why would you fix alternator if its redundant except as backup in rare case charger fails? Charger is always on when generator is running...


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Old 08-07-2015, 08:31   #4
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Re: Does my generator need an alternator?

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Originally Posted by malbert73 View Post
Why would you fix alternator if its redundant except as backup in rare case charger fails? Charger is always on when generator is running...


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In my view, all systems should be maintained and functioning properly at all times. Any device that is unnecessary and/or obsolete should be removed, not merely abandoned-in-place. The generator alternator is clearly not a redundant device. I would determine the fault with the alternator (regulator?) first, before attempting any secondary charging schemes.
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Old 08-07-2015, 09:19   #5
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Re: Does my generator need an alternator?

I repaired the alternator on my 6 kW Panda generator 4 times before giving up and replacing it with an idler pulley. It is not necessary if you have other means of charging the generator starting battery. I don't have a dedicated starter battery, since I am a full time liveaboard and constantly monitor the batteries state of charge, I run all batteries as one big bank, it's better for them that way.
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Old 08-07-2015, 11:22   #6
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Re: Does my generator need an alternator?

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Originally Posted by malbert73 View Post
So my 5.5KW generator's alternator isn't putting any volts into the generator starting battery. Any reason I can't use the unused 3rd battery charging output of my mastervolt charger and connect to the genset starting battery? The charger is obviously linked to generator.

Upside of this solution is I don't need to fix or replace alternator. Also would have benefit of keeping generator starting battery topped off via shore power when plugged in so it's always charged.

Anyone have any comments or see an issue I could be missing?


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Our Panda 10kw generator had both the alternator and water pump replaced with external sources. (i.e., no belt...)

The alternator is just an idler pulley in case a belt driven water pump is of interest in the future.

There is no need on this boat for a generator alternator as when there is AC available [or the main engine is running, it is sunny or windy...] all batteries are being charged.

Why no water pump either?

When the manufacturer had a batch of bad impellers years ago- but didn't admit it until 6 months later- the previous owner bypassed the built-in water pump replacing its function with a spare 110VAC March pump [used for the raw water coolant loops for the air conditioning and refrigeration systems. [10 impeller changes in 2 months would make me re-engineer that system too...]

He also relocated the heat exchanger to outside the generator's acoustic housing so it could be replaced with a larger exchanger [and is more readily serviced... They were in the tropics at the time...]

These changes make everything much more serviceable and provide redundancy if one wanted to put a belt back on to run the built-in water pump [with a functional impeller...]

We don't hesitate to properly [and cautiously] re-engineer [optimize] systems using standard components, methods, and procedures, but only when necessary... [Who needs to make more work on a boat?]

Cheers!
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Old 08-07-2015, 13:52   #7
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Re: Does my generator need an alternator?

Well, since you asked the question, I completely agree with redsky49. I kept my genset alternator in place just in case I ever need it. I have an engine alternator, solar panels, anad a genset. If I ever have a lot of coincident failures but can get the genset to run, then that little alternator will have earned its keep.

Everyone's boat is different, and owner's priorities, as well. If you don't think it's needed, take it off. FWIW, I am keeping mine.

Cheers.

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Old 08-07-2015, 18:36   #8
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Re: Does my generator need an alternator?

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Originally Posted by redsky49 View Post
In my view, all systems should be maintained and functioning properly at all times. Any device that is unnecessary and/or obsolete should be removed, not merely abandoned-in-place. The generator alternator is clearly not a redundant device. I would determine the fault with the alternator (regulator?) first, before attempting any secondary charging schemes.
Why is it not redundant if its battery is connected to the battery charger? I agree on keeping up with systems. My boat is pristine and well maintained. The generator manual lists the alternator as optional. The prior owner didn't connect the battery to charger and hence alternator was only way to keep the starter battery charged. This is inferior IMHO as generator use could be very sporadic for me but I regularly plug boat into shore power after trips- which would maintain battery better.

So given I was considering connecting to battery charger anyway to maintain battery better, the alternator seems completely redundant. Worse yet, would being connected to charger and alternator simultaneously possibly damage the charger or alternator?

Again, different completely than engine, which doesn't power the charger and is needed for emergency. If the battery charger doesn't work I am likely not running the genset anyway.

But great feedback by all. Sounds like it's a philosophical question. I really like the electric pump idea. Then i could actually get rid of the belt assembly. Until I decide completely will leave alternator as a tension pulley. Either can fix, replace, or get a freewheeling pulley to replace it. Can certainly afford a new alternator but can always put the money elsewhere...


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Old 08-07-2015, 22:57   #9
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Re: Does my generator need an alternator?

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Why would you fix alternator if its redundant except as backup in rare case charger fails? Charger is always on when generator is running...


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if you can't afford to maintain your boat then sell it and find a cheaper hobby. everything on the boat should work.
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Old 09-07-2015, 05:12   #10
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Does my generator need an alternator?

Inflammatory replies like this aren't really necessary or appreciated on CF. If you bothered to read above, my boat is in Bristol condition and no expense spared though I do most maintenance and repairs myself to know the boat well.
Like many boat owners I'm blessed to have an income where the cost isn't a factor. However, to spend time and money to replace a piece of equipment that can fail (and hence can't be relied on completely), and which is listed as optional by genset manufacturer is giving me pause. Hence I appreciate some of the intelligent replies that actually show knowledge of systems. You did helpfully suggest output of charger- and my alternator is rated at 10a (yes a baby) so should be okay. Thanks for bringing that up.


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Old 09-07-2015, 05:17   #11
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Re: Does my generator need an alternator?

I will repost another question I buried in there. I had read somewhere that you can damage the alternator regulator on an engine by running it while also running battery charger (ie at dock) and that it's safest to unplug shore power before starting engine when departing. In reality I've done this in past with no issues.

So would this be an issue with both battery charger hooked up to start battery and alternator functional on my generator?



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Old 09-07-2015, 05:41   #12
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Re: Does my generator need an alternator?

If the alternator has a source of power for the field coil then yes it will be damaged by running with no battery. It is not the regulator that will be damaged though. The internal diodes that convert the AC voltage to DC will be zapped. If you are going to abandon the alternator in place make sure there is no possibility for the regulator to get power to the field coil.
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Old 09-07-2015, 15:04   #13
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Re: Does my generator need an alternator?

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If the alternator has a source of power for the field coil then yes it will be damaged by running with no battery. It is not the regulator that will be damaged though. The internal diodes that convert the AC voltage to DC will be zapped. If you are going to abandon the alternator in place make sure there is no possibility for the regulator to get power to the field coil.

Sorry didn't communicate well. Battery will remain connected. Charger and alternator feeding same battery a problem?


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Old 09-07-2015, 18:10   #14
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Re: Does my generator need an alternator?

If you have a Mastervolt like Whisper 6, you can't remove the altetnator. If you do this, your genset will be shut down after 20 seconds and you will have an error message on the remote panel "no alternator". This because the green plug on the alternator is unpluged...
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Old 09-07-2015, 18:34   #15
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If you run your main engine wile the 110 charger is on from either gen or dock side it can damage your reg and or alt
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