Sterling Alternator to Battery Charger

[Seighlor]

Researching battery chargers, I've just become aware of the Sterling charger that is positioned between ones engine alternator and the battery. The manufacturer's literature professes this device will charge up to five times the rate of the alternator alone.

At sea I generally crank up my 5KW generator two or three times a day to maintain the fridge and my house batteries, the batteries being charged by means of a 110v 50 amp 3-bank charger.

The Sterling, it appears, would do a superior job in maintaining my batteries and enable me to get by with a lot less generator time.

Anyone have experience with this product?

Mac

[colemj]

Assuming your battery bank is large enough to accept more than 50A of current, you could achieve less generator time by purchasing a larger AC charger. If they cannot accept more than this, the Sterling isn't going to help much, unless you do not currently have an externally regulated alternator.

That "5X" claim by Sterling makes a lot of assumptions - mostly around having a higher output, but internally regulated alternator set at low charging voltage (really dumb combination to begin with).

Mark

[djmarchand]

First, running your propulsion engine at anchor just to charge batteries is not a good solution. Much better to run your genset. And you are wasting a lot of time with just a 50 amp charger. If you have a decent size battery bank a 100 amp charger will do a faster job and load your genset better.

But back to the Sterling. This device is sort of the opposite of a MPPT controller for solar panels. It "fools' the alternator into thinking its connected to a severely discharged battery bank so that it will output more current. Then it converts that output to a higher voltage to push those amps into the battery bank.

So you are asking a light duty, automotive style alternator to run for hours at high output loadings. It will fail quicker that way.

A much better solution is a high output alternator with heavier windings, better cooling, better diodes and an external 3 step regulator, all of which will let it put out more current and last longer.

David

[Cuttyhunk]

Originally Posted by Seighlor

Anyone have experience with this product?

Mac

I also would be interested in hearing from anyone who has experience with this product...

[goboatingnow]

Originally Posted by bethflkys

I also would be interested in hearing from anyone who has experience with this product...

I've had one ( and their battery chargers ) it does what it says on the tin.

Dave

[goboatingnow]

Originally Posted by djmarchand

First, running your propulsion engine at anchor just to charge batteries is not a good solution. Much better to run your genset. And you are wasting a lot of time with just a 50 amp charger. If you have a decent size battery bank a 100 amp charger will do a faster job and load your genset better.

But back to the Sterling. This device is sort of the opposite of a MPPT controller for solar panels. It "fools' the alternator into thinking its connected to a severely discharged battery bank so that it will output more current. Then it converts that output to a higher voltage to push those amps into the battery bank.

So you are asking a light duty, automotive style alternator to run for hours at high output loadings. It will fail quicker that way.

A much better solution is a high output alternator with heavier windings, better cooling, better diodes and an external 3 step regulator, all of which will let it put out more current and last longer.

David

It's simply not true. The stamdard alternator is quite capable of handling the higher outputs. And you can fit a alternator temp sensor as well.

The new version is a beleive a DC to DC convertor type hence needs no connection other then standard to the alternator

Dave

[Pete7]

Originally Posted by goboatingnow

It's simply not true. The standard alternator is quite capable of handling the higher outputs. And you can fit a alternator temp sensor as well.

The new version is a beleive a DC to DC convertor type hence needs no connection other then standard to the alternator

Dave

Hmm, that is debatable, but I hear what David is saying, small alternator on an engine charging a big bank (its a 44ft yacht). That alternator is going to be working hard.

However, the yacht has a genny on board. What I don't understand is why the genny needs running two or three times a day, something wrong here. Either the batteries are toast, or the bank is way to small or there is no battery monitoring so the charing is guess work.

My suggestion would be to make the genny work properly with a charger sized to the battery bank and a bank that matches the boats requirements rather than try and run the engine for charging.

Pete

[goboatingnow]

Your standard alternator already works hard , but only for a smaller period of the charge cycle mainly because the regulators are set to supply system loads not charge batteries , ie like car systems.

Adding an alternator regulator extends that charge cycle over a longer period.

Yes you get heat build up , but your alternator won't fall apart on Tuesday. It is a good idea to install the alternator temp sensor that all good alternator regulators provide. This will protect the system from abuse.

I was just countering the notion that suddenly the bearings on it will fail. Yes it works the alternator harder but with careful system design , you can increase the ability to charge the battery faster

Dave

[Pete7]

True, still think the genny is the better option, otherwise why have it. Something to be said for small and simple yachts.

Jut wondering if I have any solar panels left after this blast moved all the garden furniture to the other end of the garden

Pete

[colemj]

We have a OEM Volvo 60A alternator that I installed a Sterling external regulator on. I routinely measure temperatures exceeding 250*F on the alternator when the Sterling drives it near capacity for more than 30 minutes or so. And this is with an external fan blowing cooler air through the alternator. Installing the alt temp sensor only means that the alternator rarely operates, since it spends most of its time shut down cooling off. So we leave it on its internal regulator unless we are actually using it for quick bulk charging.

Based on our experience, a standard alternator is NOT able to produce routine higher outputs for hours at a time without entering damaging temperature ranges.

Mark

[Cuttyhunk]

Thank you all for this information. We have a generator, and twin volvos with 80 amp alternators. I am considering the Sterling to intelligently and efficiently distribute the alternators' output. If we are sitting at anchor for any length of time, I would run the generator. So I'm planning on a larger, smart charger (boat came with only a 40 amp charger for a 400 amp house bank) and the Sterling. I'll definitely keep an eye on the alternators' temps.

[Seighlor]

Gentlemen, your input is greatly appreciated. You have convinced me that Sterling's alternator-to-battery charger is not the way to go. So it appears my next move is to shop for a 100 amp charger.

By the way, I do have a 115 amp alternator with an external regulator on my engine. It's just that when sailing, particularly if racing, I would prefer not to use the engine... even to boost the batteries.

Again, thanks to all.

Mac

[goboatingnow]

Based on our experience, a standard alternator is NOT able to produce routine higher outputs for hours at a time without entering damaging temperature ranges.

I think there is some confusion here, the primary reason to install a proper alternator regulator is to ensure a proper charge profile is followed. Not to overload an alternator outside its limits. I think people "slap" these on , suddenly thinking they can pull 70A for a rated 70A alternator, without a care to look at the specs.

Dave

[ullar]

You can use 2 alternators in parallel with Sterling charger.

[colemj]

Originally Posted by goboatingnow

I think there is some confusion here, the primary reason to install a proper alternator regulator is to ensure a proper charge profile is followed. Not to overload an alternator outside its limits. I think people "slap" these on , suddenly thinking they can pull 70A for a rated 70A alternator, without a care to look at the specs.

Dave

So how does one follow a "proper charge profile" with a product designed to use an OEM internally regulated alternator without causing a high temperature due to the continued high current output that product forces on that small OEM alternator?

I'm not arguing that one should not pay attention to their alternator design and limits. I'm arguing that these Sterling products will drive those smaller OEM alternators past their limits (and providing a real example of that).

Sterling markets these products straight into the small OEM alternator market as solutions to get more out of the OEM internally regulated alternators, so this is a real thing to be aware of.

Having said that, these Sterling products do just as they are advertised and work very well. The caveat is one must understand what they do and how they do it and be willing to adapt to the tradeoffs - which is why we own one. Just slapping one on will either burn out your alternator or leave you without charging much of the time while your alternator cools down.

Mark