Stirling A to B Charger

[Biggles]

I am thinking about adding one of these to my boat

 

Linky

 

Any comments or experience from users or knowledgeable commentators.

 

Cheers

[nbfiresprite]

I do have the 160 amp version, That I won in a contest, when they first came out.

I would treat Stering's claims with a large pitch of salt. Far too pricey for what it claims to do.

[by'eck]

I am thinking about adding one of these to my boat

 

Linky

 

Any comments or experience from users or knowledgeable commentators.

 

Cheers

 

Worthwhile if your alternator regulates at less than the recommended absorb charge voltage of your batteries. Paralleling alternators allows it to benefit both providing their combined max output current doesn't exceed that of the A to B.

 

If you cruise for long periods, no worries about excessive gassing either.

 

Nearly forgot to mention the dedicated start battery feed as well, so no need for separate split charging system.

Edited February 22, 2013 by by'eck

[Biggles]

Well the thing is my batteries are recommended to be charged at at least 14.8 and anywhere up to 16v. As my current alternators seem to be set to 14.2v I am way under.

 

I'm gonna start another thread with an idea.

[GUMPY]

What make ate the alternators it may just bee a simple regulator change as I did on my Bosch changed voltage from 14.2 to 14.9 cost 10 quid

[n.b.Goldie]

Had one for about three years or so. Does what is says on the box. Batteries always well charged and no apparent deterioration yet.

 

Have used Sterling stuff on previous boat with excellent results.

 

Have no hesitation in recommending Sterling.

 

No connection with them, just a satisfied customer.

 

Regards

Ditchdabbler

[by'eck]

Well the thing is my batteries are recommended to be charged at at least 14.8 and anywhere up to 16v. As my current alternators seem to be set to 14.2v I am way under.

 

I'm gonna start another thread with an idea.

 

So what batteries require to be charged at up to 16 volts assuming they are nominal 12 volt ones?

 

Furthermore what happens to the loads on the batteries whilst charging at this voltage level?

Surely bulbs will pop and devices overheat.

 

I appreciate a de-sulphation cycle if needed would be around 15.5 volts for open lead acid, but needs to be carried out with great care and all loads isolated.

 

The Sterling A to B when configured for open lead acid batteries will give absorb charge at 14.8 volts BTW.

[nicknorman]

 

The Sterling A to B when configured for open lead acid batteries will give absorb charge at 14.8 volts BTW.

 

Is that a straight 14.8v, or nominal 14.8 then compensated for temperature, taking it probably well above 15v with cold batteries?

[by'eck]

Is that a straight 14.8v, or nominal 14.8 then compensated for temperature, taking it probably well above 15v with cold batteries?

 

Both battery and alternator temperature sensors are included with the unit, and give a disengage if the latter hits 100°C.

 

The documentation doesn't show any volts v temperature graphs though, merely stating that quoted voltages are at 20°C ambient and will vary at other temps.

 

Are you considering buying one Nick?

[Biggles]

What make ate the alternators it may just bee a simple regulator change as I did on my Bosch changed voltage from 14.2 to 14.9 cost 10 quid

 

That is an option I have considered but I have heard this can feck the alternator.

 

So what batteries require to be charged at up to 16 volts assuming they are nominal 12 volt ones?

 

Furthermore what happens to the loads on the batteries whilst charging at this voltage level?

Surely bulbs will pop and devices overheat.

 

I appreciate a de-sulphation cycle if needed would be around 15.5 volts for open lead acid, but needs to be carried out with great care and all loads isolated.

 

The Sterling A to B when configured for open lead acid batteries will give absorb charge at 14.8 volts BTW.

 

 

I threw caution to the wind and set my Victron to charge at 16v and nothing died, in fact it all seemed to work better. Anyway my traction battery supplier said these like to be charged at high voltage. I have done it at 16v for 24 hours + on shore power and the have barely become luke warm. NOTHING was isolated! I also have auto watering and gas venting so won't boil them up. I will say they were bubbling nicely though.

 

Is that a straight 14.8v, or nominal 14.8 then compensated for temperature, taking it probably well above 15v with cold batteries?

 

With 350kg of batteries ambiant temperatures change at a very slow rate despite being in the engine room. Of course in winter they can be as low as +5 to 0c if I haven't been to the boat for a while. High voltage charging is the biggest warmer of the batteries. And in winter batteries suffer most from the cold.

[nicknorman]

Both battery and alternator temperature sensors are included with the unit, and give a disengage if the latter hits 100°C.

 

The documentation doesn't show any volts v temperature graphs though, merely stating that quoted voltages are at 20°C ambient and will vary at other temps.

 

Are you considering buying one Nick?

No, just wondering what the perceived wisdom is for max charge voltage of modern open wet cell leisure batts, and the temperature law. I don't need and AtoB because I can charge via the TP and the Mastervolt Combi and set whatever final Absorption voltage I like, up to 16v (viz other thread!). Of course the MV has a battery temperature sensor and does adjust the charge voltage accordingly.

Edited February 23, 2013 by nicknorman

[nb Innisfree]

We have a large framed Leece Neville alternator which replaced one that failed, the old one had an adjustable regulator but the new one had a fixed one, apparently they stopped fitting adjustable ones as some were being set too high resulting in burnt out windings.

[by'eck]

I threw caution to the wind and set my Victron to charge at 16v and nothing died, in fact it all seemed to work better. Anyway my traction battery supplier said these like to be charged at high voltage. I have done it at 16v for 24 hours + on shore power and the have barely become luke warm. NOTHING was isolated! I also have auto watering and gas venting so won't boil them up. I will say they were bubbling nicely though.

 

I think you were lucky not damaging anything. I can guarantee that halogen bulbs will have their life reduced even at 14.5 volts continuous. Some better electronics shut down at 15+ volts.

 

Since the batteries were bubbling and only getting luke warm what charge current were they receiving?

 

I know Charles Sterling published a test between overcharged (high charge voltage) and normally charged identical batteries. He then performed a load test which proved the overcharged one had a greater capacity. What he didn't check was how many times this test could be repeated with similar results!

 

I notice he now publishes a toned down version of the test here.

[OldGoat]

Charles introduced this device because he saw a market for a device that could be fitted by the average spanner wielding boat owner.

AFAIK it works by depressing the battery voltage "seen" by the alternator - fooling it into producing a higher current.

 

I can't understand how that can be done without considerable ? power losses.

Obviously it works - as many folks have said.

 

To my mind it's a case of "If I were going there, I wouldn't start from here".

It's (often) no great stretch of the imagination - or capability to open up an alternator and tap off the field wire. An alternator specialist can do it for a small fee.

I've done it - it's the first one that gets the blood flowing - and it's no big deal.

 

Stop and think - Would it not be better to fit a unit that is designed to charge your batteries with all the magic of float and de-sulphation gizmos buit in,

OR just a device that gets nearly there and wastes power in the process.

[Tony Brooks]

Charles introduced this device because he saw a market for a device that could be fitted by the average spanner wielding boat owner.

AFAIK it works by depressing the battery voltage "seen" by the alternator - fooling it into producing a higher current.

 

I can't understand how that can be done without considerable ? power losses.

Obviously it works - as many folks have said.

 

To my mind it's a case of "If I were going there, I wouldn't start from here".

It's (often) no great stretch of the imagination - or capability to open up an alternator and tap off the field wire. An alternator specialist can do it for a small fee.

I've done it - it's the first one that gets the blood flowing - and it's no big deal.

 

Stop and think - Would it not be better to fit a unit that is designed to charge your batteries with all the magic of float and de-sulphation gizmos buit in,

OR just a device that gets nearly there and wastes power in the process.

 

I think it works like this:

 

it presents a low resistance load to the alternator so the alternator produces its maximum output but at the normal reduced volatge. This load is some form of "inverter circuit" who's output is fed to something like switched mode power supply which boosts the voltage but reduces the current by the same proportion if you see what I mean. AS you say it must lose something because power - amps x volts whatever you try to do with it but it allows a change profile that is similar to a good multistage charger.

 

I think it was produced to allow alternators that are controlled by the engine ECU to charge two battery banks at a higher than programed volatge without the ECU throwing a wobbly and registering a fault.

 

In my view it would be better to spend the money optimising the charging system wiring to avoid voltdrop, sorting the regulator as has been mentioned or doing the diode mod and then spending the rest on beer.

[n.b.Goldie]

Charles introduced this device because he saw a market for a device that could be fitted by the average spanner wielding boat owner.

AFAIK it works by depressing the battery voltage "seen" by the alternator - fooling it into producing a higher current.

 

I can't understand how that can be done without considerable ? power losses.

Obviously it works - as many folks have said.

 

To my mind it's a case of "If I were going there, I wouldn't start from here".

It's (often) no great stretch of the imagination - or capability to open up an alternator and tap off the field wire. An alternator specialist can do it for a small fee.

I've done it - it's the first one that gets the blood flowing - and it's no big deal.

 

Stop and think - Would it not be better to fit a unit that is designed to charge your batteries with all the magic of float and de-sulphation gizmos buit in,

OR just a device that gets nearly there and wastes power in the process.

 

Yep, that's me. Very little electrical or technical knowledge required and it does what it says on the box. Cannot ask for more.

 

Regards

Ditchdabbler

[by'eck]

I'm guessing it employs a switch mode DC to DC converter since voltage amplification is mentioned, to boost the charge process at an early part of the cycle. Its tuned to load the alternator to between 13.5 and 14 volts depending on the alternators own regulator (lower voltage ones can be accommodated). This is then stepped up to eventually give and hold the selected absorb voltage applicable to the batteries, for between 1 and 24 hours, automatically sensed according to battery capacity. After this it drops to float mode, when the boost is removed.

 

The starter battery output is single stage via a priority split diode system. To further enhance its charging, the boost is switched off every 15 minutes for 2.5 minutes. This has the effect of increasing starter battery charge voltage during that shorter time. I'm guessing this provides a form of adaptive charging benefiting the main domestic bank, as well as giving the alternator regular rests since its being asked to work flat-out for longer.

 

Theoretically increasing the output voltage to the batteries would seemingly diminish the current available to less than the max from the alternator. In fact the current drawn by the batteries remains higher for longer with the higher charge voltage available, aided by the switching, so the average current drawn by them is much greater.

 

Its provided with battery and alternator temp sensors with the latter initially removing boost when its temp hits 90°C.

 

Although it may well have been designed with automotive ECU's in mind its real benefit is in requiring no mods to the alternator unlike the fitting of a DAR. This means the fitting is very easy for the non-technically minded and doesn't effect warranty on a new alternator.

 

There are certainly cheaper methods to do the same, but there are many features it contains in a single package, including benefiting both paralleled alternators as long as their combined current doesn't exceed that of the A to B.

[OldGoat]

I'm guessing it employs a switch mode DC to DC converter since voltage amplification is mentioned, to boost the charge process at an early part of the cycle. Its tuned to load the alternator to between 13.5 and 14 volts depending on the alternators own regulator (lower voltage ones can be accommodated). This is then stepped up to eventually give and hold the selected absorb voltage applicable to the batteries, for between 1 and 24 hours, automatically sensed according to battery capacity. After this it drops to float mode, when the boost is removed.

 

The starter battery output is single stage via a priority split diode system. To further enhance its charging, the boost is switched off every 15 minutes for 2.5 minutes. This has the effect of increasing starter battery charge voltage during that shorter time. I'm guessing this provides a form of adaptive charging benefiting the main domestic bank, as well as giving the alternator regular rests since its being asked to work flat-out for longer.

 

Theoretically increasing the output voltage to the batteries would seemingly diminish the current available to less than the max from the alternator. In fact the current drawn by the batteries remains higher for longer with the higher charge voltage available, aided by the switching, so the average current drawn by them is much greater.

 

Its provided with battery and alternator temp sensors with the latter initially removing boost when its temp hits 90°C.

 

Although it may well have been designed with automotive ECU's in mind its real benefit is in requiring no mods to the alternator unlike the fitting of a DAR. This means the fitting is very easy for the non-technically minded and doesn't effect warranty on a new alternator.

 

There are certainly cheaper methods to do the same, but there are many features it contains in a single package, including benefiting both paralleled alternators as long as their combined current doesn't exceed that of the A to B.

 

That makes good sense - I had assumed that loading the input would be mainly resistive (would generate a lot of heat) but a controllable DC converter was the point that I missed. I'm afraid my electronic knowledge is limited to EF50s and EL34s (!).

 

I don't know whether CS had automotive use in mind when he first designed it. I discussed it with him at an Earls Court boat show many years ago before ECUs were commonplace, but that seems reasonable because - IMHO - both he and others in that business sell more out automotive applications than they do for the tiny inland waterways market.

[leeco]

Sorry to hijack, but I'm having high voltage alterantor warning alarm on my Stirling A to B Charger. I think it could be because my batteries are fully charged with the solar pannels.