Advice on installing an inverter

[Gibbo]

I have just emailed all the major manufacturers of alternator controllers stating that you claim that their controllers have no real benefit for internal regs from 14.2v and over. I have asked them to to counter your view with facts rather than marketing stuff...........

 

So, Adverc might be in some difficulty replying to you when their own website states:-

 

"A11: No. ADVERC ‘cycles’ between 14.0 and 14.4v at the batteries........"

 

( from http://www.adverc.co.uk/technical/technical-faq.asp )

 

How is that going to increase the charge rate into a battery if the internal reg is already running at 14.4 volts?

 

You'll get to understand this subject eventually. Well..... you might.

 

Gibbo

 

How do you determine the charging voltage - from the manufacturers spec sheets or do you need to measure it directly under some specific conditions? Also, do you need to be aware of the type of batteries you have when choosing a controller (e.g. open vs sealed lead acid batteries)?

 

Thanks

 

Brian

 

Measure it once the batteries are nearly full.

 

For the full gory details see http://www.smartgauge.co.uk/controllers.html

 

Gibbo

[chris w]

So, Adverc might be in some difficulty replying to you when their own website states:-

 

"A11: No. ADVERC ‘cycles’ between 14.0 and 14.4v at the batteries........"

 

( from http://www.adverc.co.uk/technical/technical-faq.asp )

 

How is that going to increase the charge rate into a battery if the internal reg is already running at 14.4 volts?

 

You'll get to understand this subject eventually. Well..... you might.

 

Gibbo

 

Coincidentally, I had my first response from Adverc BTW re alternator controllers. They presumably know you as they were less than charitable about you.

[Gibbo]

Coincidentally, I had my first response from Adverc BTW re alternator controllers. They presumably know you as they were less than charitable about you.

 

Must be true as you've said it twice now. They didn't like having all their business stolen form under their noses. That's the reality.

 

Gibbo

[Guest]

Coincidentally, I had my first response from Adverc BTW re alternator controllers. They presumably know you as they were less than charitable about you.

Did you assume they would say different? Why would they?

Edited May 20, 2009 by Guest

[carlt]

Did you assume they would say different? Why would they?

And if they said anything uncharitable about Chris, he'd just sue them!

[David Schweizer]

Sorry, I copied the detail of the RoadPro website spec where it said the average hourly consumption was 19W (1.6A at 12V) and forgot to put the H afterwards.

 

I'm sorry I asked about the alternator controller - didn't mean to stir up an argument!

Brian

Do not worry yourself about it. Gibbo and ChrisW have been debating this issue for years, yes years, without any significant agreement between them. Both of them are very knowledgeable about electrical matters, and often agree on other issues, but this one is destined to go on.. and on...and on... and on... and on... and.............

 

Oh by the way, those of us who do have an Atlernator Controller fitted (I have a Sterling) have found that they do speed up charging time. I certainly have had no flat battery problems since fitting one.

[Gibbo]

Oh by the way, those of us who do have an Atlernator Controller fitted (I have a Sterling) have found that they do speed up charging time. I certainly have had no flat battery problems since fitting one.

 

Shall I post this once a day for the next year until it sinks in?

 

An external controller will improve charging if your alternator charges at a low voltage.

 

If it charges at the higher voltages that most modern alternators charge at then an external controller will do nothing.

 

Gibbo

[alan_fincher]

I'm not sure that having no battery charging issues with an alternator controller proves a great deal.

 

I don't have an alternator controller, and, AFAIK, have no battery charging problems either.

 

By which I mean

 

1) Batteries don't go flat

2) Batteries show a healthy voltage on an accurate voltmeter after a small discharge to remove any anomalies

3) Batteries are very healthy when tested with a hydrometer.

 

Even my start battery that got neglected for various reasons has recovered, and passes the above tests.

 

On that basis I couldn't justify adding any hardware that does more than the alternator can do for itself.

 

I also avoid the "my alternator controller has gone t*ts up, will Sterling replace it ?", type discussions, that seem so common. In fairness Sterling do seem to most times, but it's hassle I neither need, nor have to put up with.

 

Edited: For finger trouble

Edited May 20, 2009 by alan_fincher

[honey ryder]

just a word of advice, make sure you put the inverter as far away from stray water as possible, ie, not in a doorway or where it might get condensation dripping on to it.

 

3 domestic batteries i think is pretty much the standard/average with a starter battery on the side for the engine.

 

thats what ive got and most people ive spoken to who live aboard. some have 4 or even 5. not many have less than 3.

the charging thing can be helped by using a small generator ( as can be seen as a popular choice if you look around at liveaboards out and about) and a 240 intelligent battery stage charger. we dont depend on our engine alternator charging our batteries, only when cruising. The rest of the time we either use a small gennie or the travel power on our engine.

 

I highly recommend, if you dont already have one, some kind of amp meter readout, or battery state monitor. that way you only charge when you need to and you are never surpised by having dim lights/flat batteries.

keeping the batteries tip top, keeps everything else tickety boo.

[David Schweizer]

Shall I post this once a day for the next year until it sinks in?

 

An external controller will improve charging if your alternator charges at a low voltage.

 

If it charges at the higher voltages that most modern alternators charge at then an external controller will do nothing.

 

Gibbo

You can post whatever you like Chris, All I know is that things seemed to improve when I fitted the Sterling Controller. I have a bog standard Lucas type 55amp A127 alternator. I have no idea what the normal output is. Perhaps you could enlighten me.

 

It looks like this one:-

http://cgi.ebay.co.uk/MINI-NEW-ALTERNATOR-...93%3A1|294%3A50

Edited May 20, 2009 by David Schweizer

[Gibbo]

You can post whatever you like Chris, All I know is that things seemed to improve when I fitted the Sterling Controller. I have a bog standard Lucas type 55amp A127 alternator. I have no idea what the normal output is. Perhaps you could enlighten me.

 

They're available at 13.8, 14.0, 14.2, 14.4, 14.6 and 14.7 that I'm aware of. There may be more available.

 

If yours was previosuly running at 13.8 volts then adding an external controller will make a huge difference.

 

But then again, so would changing the reg/brush pack for a 14.6 volt one (about 20 quid). It would have the same effect.

 

Gibbo

[David Schweizer]

They're available at 13.8, 14.0, 14.2, 14.4, 14.6 and 14.7 that I'm aware of. There may be more available.

 

If yours was previosuly running at 13.8 volts then adding an external controller will make a huge difference.

 

But then again, so would changing the reg/brush pack for a 14.6 volt one (about 20 quid). It would have the same effect.

 

Gibbo

I have no idea which regulator I have in my alternator, and I must admit it is not the same one as was fitted when the Sterling was installed. so the present could be different. The original one was replaced because it failed shortly after the engine started to spew oil all aver the place. That was before the engine re-buld.

 

Is there an easy way of checking the voltage output of the Alternator. I have a moving coil voltmeter fitted which records 14.6 volts when charging through the Sterling, presumably if I disconnect that I will get a reading for the standard output.

Edited May 20, 2009 by David Schweizer

[Gibbo]

I have no idea which regulator I have in my alternator, and I must admit it is not the same one as was fitted when the Sterling was installed. so the present could be different. The original one was replaced because it failed shortly after the engine started to spew oil all aver the place. That was before the engine re-buld.

 

Is there an easy way of checking the voltage output of the Alternator. I have a moving coil voltmeter fitted which records 14.6 volts when charging through the Sterling, presumably if I disconnect that I will get a reading for the standard output.

 

You will indeed. But those analogue panel meters aren't actually renowned for their accuracy.

 

Gibbo

[David Schweizer]

You will indeed. But those analogue panel meters aren't actually renowned for their accuracy.

 

Gibbo

That may well be, although it was an expensive one bought second hand from my local (and unfortunately now defunct) Radio parts shop. However if it records 14.6 with the Sterling connected, any reduction in voltage with it disconnected would surely be noticable.

 

I will try it when I am next on the boat. You will know when that is because I go quiet on here, as I do not have any internet, or even a computer, on the boat.

[chris w]

I have no idea which regulator I have in my alternator, and I must admit it is not the same one as was fitted when the Sterling was installed. so the present could be different. The original one was replaced because it failed shortly after the engine started to spew oil all aver the place. That was before the engine re-buld.

 

Is there an easy way of checking the voltage output of the Alternator. I have a moving coil voltmeter fitted which records 14.6 volts when charging through the Sterling, presumably if I disconnect that I will get a reading for the standard output.

The Sterling has a white wire coming out of it which is the "field" connection. You can safely put a switch (or a fuse) in this line so that you can "break" the white wire temporarily. That will switch off the Sterling. The voltage that you now see at the battery is then the alternator output. Of course, you need to wait about an hour if the batteries are initially low so that the voltage can build up. Expect to see about 14.2v to 14.4v without the Sterling.. You will also see the charge current drop.

 

Reconnect the white wire and you wil see the increase in both charge voltage (around 14.8v) and charge current. You can connect and disconnect the white wire with the engine running at will as there is no danger of damaging your alternator.

 

Chris

Edited May 20, 2009 by chris w

[David Schweizer]

The Sterling has a white wire coming out of it which is the "field" connection. You can safely put a switch (or a fuse) in this line so that you can "break" the white wire temporarily. That will switch off the Sterling. The voltage that you now see at the battery is then the alternator output. Of course, you need to wait about an hour if the batteries are initially low so that the voltage can build up. Expect to see about 14.2v to 14.4v without the Sterling.. You will also see the charge current drop.

 

Reconnect the white wire and you wil see the increase in both charge voltage (around 14.8v) and charge current. You can connect and disconnect the white wire with the engine running at will as there is no danger of damaging your alternator.

 

Chris

Yes thanks for that Chris. The white wire on my instalation has a spade connector to enable the alternator to be changed more easily, I will just pull that apart and re connect it to do the test.

[chris w]

Yes thanks for that Chris. The white wire on my instalation has a spade connector to enable the alternator to be changed more easily, I will just pull that apart and re connect it to do the test.

Do make sure that the battery has had an hour to charge first as otherwise you may read say 13.5v which would still be the (partially charged) battery terminal voltage and not the regulator limiting voltage. If the batteries are already charged then obviously you can do it virtually straight away - give it 15 minutes say.

 

The way to be absolutely sure that you are reading the regulator voltage is to wait till the Sterling is up at about 14.6v and then open the white wire. The new reading will definitely be the internal regulator voltage.

 

 

Chris

Edited May 20, 2009 by chris w

[steelaway]

How do you determine the charging voltage - from the manufacturers spec sheets or do you need to measure it directly under some specific conditions? Also, do you need to be aware of the type of batteries you have when choosing a controller (e.g. open vs sealed lead acid batteries)?

 

Thanks

 

Brian

 

 

Hi Brian

 

Just go out and buy a Sterling alternator controler and some quality WET cell battery's (you set the type of battery's by dip switchs).

Take a wire from the alternator to the centre terminal - a wire fom the connection on the left to your domestics and the one on the right to the start battery - done!. Every thing else is automatic

You will achieve maximum charging from your alternator without having to understand all the science behind it all or get into complicated alternator modifications.

 

Alex

Edited May 20, 2009 by steelaway

[chris w]

sorry - wrong place

 

Hi Brian

 

Just go out and buy a Sterling alternator controler and some quality WET cell battery's (you set the type of battery's by dip switchs).

Take a wire from the alternator to the centre terminal - a wire fom the connection on the left to your domestics and the one on the right to the start battery - done!. Every thing else is automatic

You will achieve maximum charging from your alternator without having to understand all the science behind it all or get into complicated alternator modifications.

 

Alex

I think you are referring to the Sterling ABC (Alternator to Battery Controller) and not the Alternator Controller (DAR or PDAR) to which we have been referring above. Both do the same job in slightly different ways with the ABC being extremely easy to fit but costing a lot more than the DAR or PDAR.

 

Chris

Edited May 20, 2009 by chris w

[Smelly]

But then again, so would changing the reg/brush pack for a 14.6 volt one (about 20 quid). It would have the same effect.

 

Gibbo

 

Gibbo

 

Considering, as you know, I'm in the market for a new reg, can i trust that the modern one I order from ebay will be 14.4, as the unit it's replacing is pushing about 14.3 give or take losses across the cable.

 

Also, chucking spanners in, us working/ liveaboard/non hookup types can't charge our batts all the way very often due to time constraints, so we work within 50-80% or so SOC. Is there any advantage to charging above 14.4... Will it push more charge into the more used range of charge? Having just read your link above I wonder whether, where 100%/ 0 sulphation battery states are unrealistic there may be some value in a higher charge rate in the meantime; especially where the bulk phase is providing the majority of the charge we're putting in to the batts?

 

oh b*gg*r... is the bulk charge algorithm linear, or with twice the amperage going in, will the bulk charge rate be significantly foreshortened so as to render the alt-alt system I'm playing with a waste of money? (hows that for a cr*p time for an epiphany?)

 

I know that the 14.4V is more efficient as to the energy put into the batteries being utilised and can understand that having read your earlier posts, but talking diesel, litre for litre, do we know wheher the extra fuel used for that extra .4V while some of the energy generated is being frittered electolysing tiny amounts of water, is generating valuable extra ahrs?

 

I've mentioned spanners already haven't I?

 

[brich]

I'm sorry I asked about the alternator controller - didn't mean to stir up an argument!

Brian

 

I'm rapidly losing confidence in the whole idea of installing an alternator controller at all, as I might be buying the 'wrong one' or using it with the wrong batteries, or perhaps I'm merely being stupid enough not to understand which is 'best'. If the science of alternator controllers is good science, then surely there is a right and a wrong way to do it?

 

If we have to resort to e-mailing the manufacturers to support our position, then I'm just beginning to wonder if this is all about who produces the best snake oil and I'm going to get fleeced whichever one I choose.

 

I wonder if I fitted gas mantles, a gas fridge, gas water heating and get a soss stick I can chuck all this electrical rubbish out except for the starter battery ... then perhaps Vetus offer starting handles and I could get rid of the engine battery too. Now where did I leave that canal mag that talked about horse-drawn boats....?

[Gibbo]

This is a difficult one, and you'll see why.............

 

Considering, as you know, I'm in the market for a new reg, can i trust that the modern one I order from ebay will be 14.4, as the unit it's replacing is pushing about 14.3 give or take losses across the cable.

 

Not really. As is often the case these days with technical equipment the dealers don't seem to know what they're selling. If you buy from a manufacturer they usually quote the actual regulation voltage. Some of the dealers I've spoken to don't even know what a regulation voltage is!

 

Also, chucking spanners in, us working/ liveaboard/non hookup types can't charge our batts all the way very often due to time constraints, so we work within 50-80% or so SOC. Is there any advantage to charging above 14.4... Will it push more charge into the more used range of charge? Having just read your link above I wonder whether, where 100%/ 0 sulphation battery states are unrealistic there may be some value in a higher charge rate in the meantime; especially where the bulk phase is providing the majority of the charge we're putting in to the batts?

 

oh b*gg*r... is the bulk charge algorithm linear, or with twice the amperage going in, will the bulk charge rate be significantly foreshortened so as to render the alt-alt system I'm playing with a waste of money? (hows that for a cr*p time for an epiphany?)

 

I know that the 14.4V is more efficient as to the energy put into the batteries being utilised and can understand that having read your earlier posts, but talking diesel, litre for litre, do we know wheher the extra fuel used for that extra .4V while some of the energy generated is being frittered electolysing tiny amounts of water, is generating valuable extra ahrs?

 

This is where it gets a bit awkward. It depends upon the alternator size to battery bank size ratio.

 

There is absolutely no doubt whatsoever that charging at the gassing voltage does indeed charge faster than charging below it or above it. Anyone who tells you anything different simply doesn't know enough about battery charging to make such a statement. I will argue with anyone until the cows come home on this matter. Quite simply they are wrong. I don't care how many ways they try to prove it.

 

The difficulty arises in the fact that the gassing voltage isn't fixed. When we say "the gassing voltage is 14.4 volts" or "the gassing voltage is 14.2 volts" or some other figure it isn't strictly true. That's an average figure, usually throughout the range 50% to 100% SoC.

 

The reality is that the gassing voltage changes as a function of the DoD. The flatter the batery, the higher the gassing voltage.

 

With a totally flat wet cell battery the gassing voltage is very, very high. Probably in the region of 15 to 17 volts. Maybe even higher with some types. With a fully charged battery the gassing voltage is not much higher than the recommended float voltage.

 

So ideally we want to charge at a voltage that reduces throughout the charge cycle to match the gassing voltage. I (and many others) have been trying to come up with a workable solution to this dilema for many years. So far no one has succeeded but there are patents (that can never work in practice) for just this process.

 

What this means in practice is that it would initially appear that charging at (say) 15 volts will reduce the charge time. But it depends upon the size of the charger. If the charger is small, then by the time it manages to get the charge voltage up to 15 volts, the batteries will already by quite well charged so it's too late. By that time the gassing voltage is lower and charging at 15 volts is too high and isn't the fastest voltage to charge at.

 

If the charge source is very large (so large that it can get the voltage right up before the batteries start to increase much in charge state) then charging at 15 volts will indeed reduce recharge time. But the problem then is that as the batteries come up to charge (and therefore the gassing voltage drops) it ends up charging at too high a voltage which thus increases the charge time.

 

It's a very valid question you ask and it's all a compromise.

 

If you had a 400Ahr bank and a 200 amp alternator then clearly the alternator can get the battery voltage up to any level it wants, simply because the charger is so big. In that case charging at 15 volts would indeed wack lots of charge current into the batteries during the initial part of the charge cycle. But once the batteries reached about 70% SoC the (genuine) charge rate would reduce dramatically because the charge voltage would be so much higher than the gassing voltage. It would also be using lots of water.

 

With a smaller charger it would take a longer time to reach the regulation voltage so it's difficult to say what the ideal voltage is because it depends upon so many different things.

 

This ideal charging voltage roughly ties in with what became known as "amp hour law" charging (first proposed by amplepower IIRC) which states that the amount of current that can be returned to the battery at any one time is equal to the number of amp hours missing from the battery. So a 100Ahr battery, completely flat can be charged at 100 Amps. After a short time that battery will now be at 1% SoC, so 99Ahrs are missing. It can now be charged at 99amps, and so on and so on. This, by sheer coincidence, ties in almost exactly with charging at the changing gassing voltage.

 

I hope (and expect) you are now more confused than you were before

 

Gibbo

[Smelly]

I hope (and expect) you are now more confused than you were before

 

Gibbo

 

Well, having been watching the ongoing <ahem> debate about adaptive charging that unfortunately is spread across a number of threads then I'm not and there's another question to come but I've got to get wriggling for today's commitments so I'll save it 'til later.

 

However that question is based on the assumption that it's simply ohms law at play, i.e the charging voltage is linear factor of the number of amps being pushed around. If there are other factors then say so and I'll shut up. I know the resistivity will have an effect.

Edited May 21, 2009 by Smelly

[Gibbo]

I'm rapidly losing confidence in the whole idea of installing an alternator controller at all, as I might be buying the 'wrong one' or using it with the wrong batteries, or perhaps I'm merely being stupid enough not to understand which is 'best'. If the science of alternator controllers is good science, then surely there is a right and a wrong way to do it?

 

If we have to resort to e-mailing the manufacturers to support our position, then I'm just beginning to wonder if this is all about who produces the best snake oil and I'm going to get fleeced whichever one I choose.

 

I wonder if I fitted gas mantles, a gas fridge, gas water heating and get a soss stick I can chuck all this electrical rubbish out except for the starter battery ... then perhaps Vetus offer starting handles and I could get rid of the engine battery too. Now where did I leave that canal mag that talked about horse-drawn boats....?

 

You ask a very good question. It's one that I've been trying to answer for many years.

 

The reality is that alternator controllers did indeed make a huge difference when most alternators charged at 13.8 volts. This was a common charge voltage for many, many years.

 

The way they increased the charge rate was quite simply by increasing the charge voltage. They did nothing else. Reading some of the websites regarding alternator controllers they are indeed full of snake oil with talk of "the ideal voltage gradient at the batteries". It's all bollox and marketing speak. All they did was increase the charge voltage. A few bells and whistles were added but basically they made little, if any, difference to the simple process of just increasing the charge voltage.

 

Modern alternators already charge at a higher voltage so external controllers do nothing or next to nothing on these modern alternators.

 

I am, without doubt, unanimously hated amongst alternator controller manufacturers because I have publicly been stating this fact for many years. They do not like it, they threaten me with legal action. But it's all hot air. They can do nothing to stop me because they know in reality that what I say is in fact true.

 

25 to 15 years ago they were brilliant. Now they do nowt. The problem is, one of the biggest suppliers of such devices simply sat on their arses believing they were invincible and that the market would be there for ever. They continued to sell a 25 year old design then all of a sudden the alternator manufacturers made their device redundant. They now use snake oil in order to try to continue selling what is no longer required.

 

I fight a constant battle on this subject. It would be far easier for me to just say "Oh yes, alternator controllers are great, they make a huge difference" and start producing my own. I could make a fortune. But the fact is I'm too honest to extract money from customers for a device that does nothing.

 

To the doubters: Why would I say they don't work if they did? Would it not make more sense for me to simply start making and selling them? I mean, look at my other products, it's not like an alternator controller is rocket science. In comparison they have the technological difficulty of designing a torch.

 

Gibbo

[Gibbo]

However that question is based on the assumption that it's simply ohms law at play, i.e the charging voltage is linear factor of the number of amps being pushed around.

 

To a first approximation that's true. However it's such a rough approximation that unless other factors are also considered the resultant expectations will be miles out.

 

Gibbo