Alternator to battery charger

[bobbynell]

Hi, been following the forums for a while to help plan things out for our boat, but one thing I haven't really seen much about...

 

Sterling alternator to battery charger

 

As we're planning to be as self sufficient as possible for battery charging, this sounds like a good bet. We've got a 2kw genny and been looking at combi chargers, but as we've got 2 alternators (110A & 70A) I would prefer to keep it simple if it will do the same job.

 

Has anyone used this/know much about it, or have a recommendation for comparisons?

 

Many thanks!

[paulcatchpole]

Popcorn, anyone?

 

PC

[BlueStringPudding]

Popcorn, anyone?

 

PC

 

[steelaway]

Hi, been following the forums for a while to help plan things out for our boat, but one thing I haven't really seen much about...

 

Sterling alternator to battery charger

 

As we're planning to be as self sufficient as possible for battery charging, this sounds like a good bet. We've got a 2kw genny and been looking at combi chargers, but as we've got 2 alternators (110A & 70A) I would prefer to keep it simple if it will do the same job.

 

Has anyone used this/know much about it, or have a recommendation for comparisons?

 

Many thanks!

 

Hi

 

Ignore those two - It's just (only just!!)forum humour

 

I've had one of these for 5 years and it has been spot on, I wouldn't be without it.

I have since learned from the forum that there are (possibly better) alternatives but this is simply to fit and works well.

I also have the same alternators - probably the same engine.

I have both alternators connected together and then to the centre terminal of the controller, then of to the domestics and engine batteries.

I have 4x6V semi traction batterys amounting to 450+A @ 12V and they lasted about 5 years.

I have achieved 70+ amps with this arrangement when the batteries have been particulaly flat.

On a normal day, after a normal night of (pretty heavy) use, my ampmeter usually shows 30/40A, this will charge the batteries pretty thoroughly over a 4 hour cruise.

I would recomend it.

 

Alex

[Gibbo]

Who's gonna lend me some popcorn? Ah, I see Paul has some.........

 

There is nothing wrong with the device you are considering. It does what it says on the tin, in a very devious and clever way, very reliably. But for the same money (in fact less money) there are other systems that will do much more, just as well, but add at least 3 times the value and functions for the same money.

 

But what do I know?

 

Hi

 

Ignore those two - It's just (only just!!)forum humour

 

I've had one of these for 5 years and it has been spot on, I wouldn't be without it.

I have since learned from the forum that there are (possibly better) alternatives but this is simply to fit and works well.

I also have the same alternators - probably the same engine.

I have both alternators connected together and then to the centre terminal of the controller, then of to the domestics and engine batteries.

I have 4x6V semi traction batterys amounting to 450+A @ 12V and they lasted about 5 years.

I have achieved 70+ amps with this arrangement when the batteries have been particulaly flat.

On a normal day, after a normal night of (pretty heavy) use, my ampmeter usually shows 30/40A, this will charge the batteries pretty thoroughly over a 4 hour cruise.

I would recomend it.

 

Alex

 

If you had to do that then either you are talking about a completely different device or you wired it up wrong

 

This thread is about the alternator to battery charger. You do NOT connect both alternators together and to the same terminal with this device.

Edited July 16, 2010 by Gibbo

[bobbynell]

I also have the same alternators - probably the same engine.

I have both alternators connected together and then to the centre terminal of the controller, then of to the domestics and engine batteries.

I have 4x6V semi traction batterys amounting to 450+A @ 12V and they lasted about 5 years.

I have achieved 70+ amps with this arrangement when the batteries have been particulaly flat.

Hi Alex,

Thanks that's very helpful as it sounds like you have a similar system - I have 4x 105Ah 6v batteries currently in 24V series, but I'd like to change them to 12V rather than getting a new alternator as there is not much currently connected to the domestic circuit.

the only thing we'd be taking out would be the 24V Mastervolt charger, but I think it a bit daft using that with the generator when there's 70hp of engine not being used to capacity!

 

In principle this sounds like the ideal solution, & simple to fit & works well sounds better than complicated to set up/marginal improvement, depending on the other possible solutions.

However if theres a comparable product or a 'better' way I think I'd like to plan for it now rather than learn retrospectively.

Cheers, Neil

[steelaway]

If you had to do that then either you are talking about a completely different device or you wired it up wrong

 

This thread is about the alternator to battery charger. You do NOT connect both alternators together and to the same terminal with this device.

 

 

 

Help me Gibbo!!

 

I have been running this controller like this for 4 years on the advice of Charles Stirling and others.

 

Alex

[Gibbo]

Help me Gibbo!!

 

I have been running this controller like this for 4 years on the advice of Charles Stirling and others.

 

Alex

 

There are two alternator inputs on the alternator to battery charger.

 

If yours has only one input then isn't the alternator to battery battery! It's something else.

[Eeyore]

There are two alternator inputs on the alternator to battery charger.

 

If yours has only one input then isn't the alternator to battery battery! It's something else.

Hi Gibbo

Is this Clicky what the discusion is about? The instructions on page 3 seem clear about where to connect both alternator outputs.

Steve

Edited July 16, 2010 by Eeyore

[MikeV]

You do NOT connect both alternators together and to the same terminal with this device.

The recommended configuration by Sterling is to connect both alternators to the input . It has outputs for domestic and starter batteries and is supposed to ensure the starter battery is adequately charged while performing like a multistage charger for the domestic bank.

 

I bought one of these second hand cheap. I wired it in temporarily but did not get a significant charging improvement over my current (no pun intended!) configuration of twin alternators and a voltage sensitive relay. I sold it on eBay for more than twice what I paid for it.

 

I agree if you were installing new, there are less expensive and more effective solutions. Even Sterling say that! It's really design for retro fitting to replace a split charge diode configuration where you don't want to make modifications to the alternator(s).

[steelaway]

The recommended configuration by Sterling is to connect both alternators to the input . It has outputs for domestic and starter batteries and is supposed to ensure the starter battery is adequately charged while performing like a multistage charger for the domestic bank.

 

 

 

 

 

 

Pheww - Gibbo must be confused

 

 

Alex

[Gibbo]

Interesting, it seems they've "primitivised" it. I can't even see a diagram for a twin alternator system anymore (maybe I missed it). If you have to connect both the alternators together then I can see even more systems that beat the pants off it for half the money!

 

I can think of one in particular that will add split charging (like that unit) plus full battery monitoring and a few other goodies for less money. Kinda makes it look rather pointless on a boat.

 

PS. So.... you have to connect both alternators together and connect them to the single input on that device? Well.... considering 99% of modern alternators already charge at the correct voltage you can get the same result with a 30 quid relay. Oh, add in a 2 quid switch and you also get emergency battery parallel starting which that device doesn't have.

Edited July 16, 2010 by Gibbo

[PhilR]

Confucius says (or might have said):

 

Man who lives on canal boat with hand start engine and acceptance of a different lifestyle to living on the land is happy.

Man who wants to take take all mod cons onboard will spend the rest of his life talking about batteries/charging and toilets.

 

Phil

(I hate popcorn - sat back with crisps and scotch)

[Gibbo]

(I hate popcorn - sat back with crisps and scotch)

 

Peanuts and red wine here. And I'm saying no more on the subject.

[Arnot]

Hi, been following the forums for a while to help plan things out for our boat, but one thing I haven't really seen much about...

 

Sterling alternator to battery charger

 

As we're planning to be as self sufficient as possible for battery charging, this sounds like a good bet. We've got a 2kw genny and been looking at combi chargers, but as we've got 2 alternators (110A & 70A) I would prefer to keep it simple if it will do the same job.

 

Has anyone used this/know much about it, or have a recommendation for comparisons?

 

Many thanks!

It comes under the general heading of "male jewellery for narrow boaters". It has purposful looking fins, glitzy gold terminals and a variety of multi coloured flashing lights. A lot of the benefits it claims are either illusory or can be better obtained with simple but good engineering.

 

If you want a pretty and interesting engine hole with masses of copper spaghetti, it's just the job. If you want to support the struggling chandlery business, it's just the job.

 

However if you want to charge your batteries quickly and effectively, there are (as Gibbo points out) a host of better ways.

 

First make sure that your existing alternators (especially the 110A one) are optimally installed. For example if you have one of the popular modern engines then wiring the domestic alternator directly to the domestic batteries with a decent size of cable thus bypassing the original engine harness and connection stud will help a lot.

 

Then, if you really want to soup it up, fit a battery sensed regulator system. As Sterling themselves state on their site "The Digital Advanced Alternator Regulator offers the best low cost technical solution to increase the output performance of your alternator" and for "The Digital Advanced Alternator Regulator" you can read "battery sensed regulator" to all intents and purposes.

 

A generator and combi is probably not a good way to go, as you acknowledge it adds complexity as well as this is increases cost and lowers reliability. Combi's are great as long as you have a shore line and better yet if the boat is left unused for lengthy periods but if you have to power them from a generator is is not always very successful and unless you have a massive battery and combi, not as quick to charge the batteries.

 

Hope this helps,

 

Regards

 

Arnot

[nb Innisfree]

We have an Adverc and a Sterling Pro Digital (long story) and since we have disconnected them both, we have noticed no change with charging times. Alternator is set at 28v. Genny gives occasional equalisation/absorption with Victron.

[Sir Nibble]

OP, I was a professional auto and marine electrician for 35 years, I now teach electrical engineering in further education. Gibbo and Arnot are experts, hear them.

[steelaway]

OP, I was a professional auto and marine electrician for 35 years, I now teach electrical engineering in further education. Gibbo and Arnot are experts, hear them.

 

 

But most of the members on here are not electrical engineers.

The idea of installing relays or adjusting alternators is way beyond most peoples capability's.

Most people want to connect a couple of wires and be done, even if it is more expensive - the Stirling way.

 

Alex

[Sir Nibble]

But most of the members on here are not electrical engineers.

The idea of installing relays or adjusting alternators is way beyond most peoples capability's.

Most people want to connect a couple of wires and be done, even if it is more expensive - the Stirling way.

 

Alex

Indeed. I was intending by establishing my own credentials to demonstrate that what I say is well founded, and what I say is Gibbo and Arnot can be trusted. Many internet forums are haunted by people who confidently and authoritatively spout utter crap. My intention was to identify these two as reliable sources of pukka gen.

Edited July 17, 2010 by Sir Nibble

[ditchcrawler]

Indeed. I was intending by establishing my own credentials to demonstrate that what I say is well founded, and what I say is Gibbo and Arnot can be trusted. Many internet forums are haunted by people who confidently and authoritatively spout utter crap. My intention was to identify these two as reliable sources of pukka gen.

Well said

[Tony Brooks]

Indeed. I was intending by establishing my own credentials to demonstrate that what I say is well founded, and what I say is Gibbo and Arnot can be trusted. Many internet forums are haunted by people who confidently and authoritatively spout utter crap. My intention was to identify these two as reliable sources of pukka gen.

 

 

And I second what you say - also ex auto electrical lecturer.

[Sir Nibble]

Group hug.

[Arnot]

But most of the members on here are not electrical engineers.

The idea of installing relays or adjusting alternators is way beyond most peoples capability's.

Most people want to connect a couple of wires and be done, even if it is more expensive - the Stirling way.

 

Alex

I think there's a bit of an elephant in the room here...

 

I fully accept that a lot of people find the idea of installing relays or adjusting alternators is way beyond their capabilities, that is why professional auto/boat electricians exist.

 

In my experience, the reason for the option of wanting to connect a couple of wires and be done, even if it is more expensive - the Stirling way - is not quite the whole story, it's more about lack of trust and respect. The benefit of this way is that you only pay for the bits that you use, you know pretty much what it will cost and you can see the cooling fins, gold terminals and light display afterwards to justify it all.However, despite the marketing, there really isn't a pre-pack alternative to expertise.

 

If on the other hand you employ a professional, you probably won't see much and possibly won't get much in the way of new flashy equipment, the real deal is usually very understated. What you should get is a solution to the problem based on years of experience allied to a measure of reliability and some good advice. The difficulty is that you will have to place your trust in their competence and you probably won't know quite what the cost is until the job is complete. This is because remedying one problem on a charging system often reveals another and any fault is only cured when it is proven by trial and testing. I often take an educated guess at the cost of a job in advance because I do appreciate that my customers need to budget and decide if the job is likley to be worth the expense, I am no different in this respect. However - I always warn that there is the possibility of additional work being required and if I can what the liklihood of this is.

 

I have seen quite a few of the Stirling alternator to battery chargers over the years and removed almost all of them. In doing so the charging systems have become simpler, more effective, more stable and more reliable. In addition is has become possible to navigate the engine hole without being strangled by the nest of red copper vipers that once festooned it. In every case, the reason they were installed in the first place was along the lines of the above.

 

Having said all this you must understand that I am not bitter, in fact in any given year I probably turn down about as much work as I actually take on and I really don't remember when last I didn't have a list of jobs waiting. I do however get a bit saddened and frustrated by achieving results for people reasonably cheaply after they have wasted a packet on snake oil solutions that just didn't cut it. A lot of installations I look at seem to be the outcome of a trolley dash at a chandlery installed by "my mate who's a sparky".

 

In fairness, there is another reason for this. There are actually very few good auto electricians with experience of narrow boats and with the demise of apprenticeships and engineering training schemes there are fewer each year. I am easing into retirement and suspect others such as Gibbo and Nibble are doing the same. Modern auto electrics relies heavily on computerised diagnostics of digitially controlled systems and the subsequent replacement of any offending item with a new one. There is no real demand for the sort of old fashioned electrical engineering knowledge, craft and experience that is so essential when working on narrow boats. Sad but a reality...

 

Regards

 

Arnot

 

PS

As Red Adair once said "If you think it's expensive to hire a professional to do the job, wait until you hire an amateur."

[WotEver]

I just looked at the price!

 

Snake oil's becoming more expensive every year...

 

Tony

[Gibbo]

Let's have a quick look at how it works, some technical facts (not opinions) and the inevitable results..........

 

An alternator is, to a first approximation, a constant current device. That means, if you take a 70 amp alternator, load it up to full output it will be producing 70 amps. Load it a little bit more and it will continue to produce 70 amps but the output voltage will drop slightly. Continue to increase the load and the output voltage will drop more. But the output current will remain at 70 amps.... to a first approximation

 

So, we have a 70 amp alternator with an internal reg running at 14.6 volts (a common alternator output voltage). Just before acceptance it is producing 70 amps into the batteries at 14.6 volts. Thus 14.6 volts * 70 amps = 1,022 watts is going into the batteries.

 

The alternator to battery charger loads up the alternator so its output drops to about 13.5 volts. The device then, internally, ups it output voltage (not the input voltage obviously) to the batteries (subject to current limits) to 14.8 volts. The output of the alternator will still be 70 amps. Thus 13.5 volts * 70 amps = 945 watts is going into the device.

 

Conservation of energy means we can't get out more than we put in so we instantly know that the output of that device is less than it would have been if it wasn't there!

 

Now, I don't know the efficiency of it but I do know, from the size of the unit, and the cooling fins, that it cannot possibly be any higher than 90%. So, going into the batteries is 945 watts * 90% = 850 watts as an absolute maximum. That's 83% of what we started with. The other 17% is heating the device up. Thus the huge fins and cooling fan.

 

Strapping the alternator directly to the batteries will (not might) result in more charge!

 

The device was designed because many modern vehicle alternator simply will not allow an external reg to be connected. It can throw the engine management system into error mode. So you simply can't put one on. Which means you can't install split charge diodes.

 

In a boat, there is simply no reason to install one. It is pointless. All it will ever do is reduce the available charge.

 

Make sure the alternator charges at a proper voltage (14.4 to 14.6 volts is about right) and put on a split charge relay. 60 quid tops. And the results will be better.

 

The above is a gross over-simplification and there are other different scenarious during the charge cycle where the figures won't come out quite so bad but it deals with facts that cannot be argued against. The reality is that as long as the alternator produces the correct output voltage (usually a simple matter of changing the reg/brush pack) that device will never result in an increase in charge rate.

 

But there again, that's not what it was designed for.