Replace Sterling Alternator, think it cooked my batteries

[regginald]

About 6 years ago I purchased a Sterling Power 200A alternator from the Sterling website, along with an alternator to battery charger 210A.

 

a few days ago I noticed the charge light for the ignition was on whilst running, but dim, I found that the exciter wire was producing 17V whilst running, I think at some point the alternator may have over volted my batteries because my 3 AGMs now go down to 12.3V in 30 mins of laptop use instead of the 8 hours i was getting the day before. My starter battery is also the same, cranks over a few times then dies. I have to link to AGMs to start the cold engine. I have cycled the AGMs 10 times since but they are not improving. The alternator seems to power the alternator to battery charger normally, at least the voltage on the starter battery is 13.6 and AGMs charge at 14.2, alternator gets hot and appears to be putting current into the batteries.

 

I do not trust my alternator anymore, i have no idea what regulator/rectifier to get to replace them, Sterling no longer sell alternators and I have made custom brackets for the alternator to go on to my 1.8BMC. Many hours of searching I may have found the same size alternator that I hope can be a direct replacement, but I could be wrong.

 

Sterling alternator was about £400 now redundant, https://www.kenixmarine.com/alternatori-di-potenza/56-sterling-power-al12200-alternatore-di-potenza-12v-200a.html

 

The alternators I found that look the same are here but price is £75 - £560 here but only 150A.  https://www.autodoc.co.uk/car-parts/oem/0101542902

 

I was never able to get more than 150A from my 200A sterling and I am sure it was never 200A to begin with.

 

If these alternators are the same physical size, what does anyone think about a £75 new replacement, will it just die killing batteries really quickly?? I have ordered some 280Ah EVE cells and a daly BMS that should arrive in a week and I was hoping to use my alternator to charge them through the alternator to battery charger with an AGM in parallel to protet the charger from sudden open circuit. I have a 9inch car radiator fan blowing on my alternator to cool it, not that it has ever really needed it, I only used it on hot summer days for the first few years. I just kept the rpms up high to cool it.

 

I am pretty skint now and cant spend any money so a £75 shite alternator is about all I can manage, could it work?? Should i try the LAUBER CQ1010010 Alternator Regulator in the second link in my Sterling alternator? they are £10, and hope it will take my exciter wire back to normal voltage and not over volt again, when my lifepo4 arrives any overvolt will be ok due to the BMS.

 

Thanks to anyone who actually reads this and gives me some advice on cheap alternators or anything else.

 

 

 

 

 

 

 

.

[rusty69]

I would want to be more certain the alternator has failed before condemning it and it's not simply an excitation problem. 

 

Take some measurements of voltage and current at the battery and alternator output. Make sure the revs are high enough and the belt tensioned correctly and not slipping. 

 

It may be a simple wiring fault /loose cable/corroded plug. Also check your batteries aren't totally knackered. 

 

Do the same with the alternator to battery charger. Do you actually need the A to B. 

 

Don't install lithium batteries until you have sorted the basics. 

 

Finally, you are never likely to get 200A out of that alternator for very long, particular with an A to B fitted and especially into a lead acid battery. 

 

I would also consider a different BMS to the daly, but that is just personal preference 

Edited November 27, 2023 by rusty69

[regginald]

I thought that the exciter wire putting out 17V was evidence that the diode was shot, that combines with the fact that my batteries are all dead. I do not trust it anymore to not over volt. But you are right, i could try and fix it i guess

 

 

[Jen-in-Wellies]

Fault finding by instinct and sudden dislike of a particular item isn't a cost effective approach. Not one to use when cash is short. Diagnosing and fixing the existing alternator sounds a better idea.

[Tony Brooks]

Is the alternator battery of machine sensing? If the latter, then the sense wire may have developed a resistive connection or has become disconnected. If machine sensed then you are correct, a diode may have failed, especially a field diode and that may well cause the warning lamp to glow and provide excess voltage, but I would find a local specialist and get the thing tested. However, I have no idea how the A to B would react.

 

You must check the ALTERNATOR output voltage a B+ and preferably with the A to B bypassed.

[Tracy D'arth]

Don't know where you are but Lancashire Rotating Electricals will fix your alternator if it is bust.

Was there any bad eggs smell?

What voltage is it on the batteries when running? Sensing wire could simply be disconnected at the batteries.

What pulley arrangement do you have to run a 200A alternator on a BMC 1.8D?

[MtB]

48 minutes ago, Jen-in-Wellies said:

Fault finding by instinct and sudden dislike of a particular item isn't a cost effective approach. Not one to use when cash is short. Diagnosing and fixing the existing alternator sounds a better idea.

 

Seconded.

 

Its a slow and uncertain method of fault finding even when cash is not short! 

 

 

 

 

[ditchcrawler]

If your batteries are being charged by an A to B then I don't see what ever voltage your alternator pumps out it can effect the batteries as the A to B is between them. I am not sure where 17 volts could come from to power up the exciter wire.

[Tony Brooks]

4 minutes ago, ditchcrawler said:

If your batteries are being charged by an A to B then I don't see what ever voltage your alternator pumps out it can effect the batteries as the A to B is between them. I am not sure where 17 volts could come from to power up the exciter wire.

 

If a field diode has failed then the regulator will see a lower voltage than normal and try to boost the voltage to compensate. On a    battery sensed machine a problem with the sense wire will have a similar result. I agree the A to B should mitigate 17 volts, but I don't understand why it did not show its own over input voltage warning - assuming it is so equipped.

[Mike Adams]

How are your AGM's charged? If they are just connected in parallel to the charger I would separate them and check them individually for voltage. If you get a shorted cell they can easily get cooked by the alternator. 6 years use is quite good anyway.

[magnetman]

If it is Sterling equipment maybe there is another failure somewhere. 

I've never had any Sterling gear on any of my boats so no idea but something seems wrong about it.

 

Just a hunch. 

 

 

[regginald]

I have charged the 3 AGMs, left them for a few hours out of the circuit, tested them with a load and measured voltage, they have about 10% capacity of the previous days, they are all identical in their behaviour, I have added 40ml water to each cell and cycled them about 15 times since from 12.1V to fully charged. No change, they are 6 months old and something drastic has happened to them, they are damaged. My starter battery this morning cranked for about 10 seconds then nearly died, I waited 30 seconds, heated the plugs again and cranked it, It started just before the starter battery stopped cranking. it was at 12.5V but no capacity, I can not add water to the starter battery (old sealed superbatt leisure from my previous leisure bank)

 

The A to B has a sense wire to leisure bank but it is not compulsary to use one. It charged my banks for an hour and a half today but the leisure bank voltage just drops off rapidly again. the alternator post was reading 13.5V on initial start up which is 3 minuted not boosted, just regular passive charging. All seems normal except the exciter wire connection on the alternator is producing 17V making the light glow dim.

 

I can not really take my alternator to a specialist, leave it with them for ages and manage without it until they can do something with it and charge me lots of money. It is better for me to take it off, replace regulator myself and put it back together. My issue is that I do not know the manufacturer to order the regulator. I can see the alternators in the link I gave which has a regulator https://www.autodoc.co.uk/lauber/10925567 from a manufacturer of an alternator that looks identical in every way but says 150A. it is £10

 

I have a tripple pully on the crank, double pully on the water pump and 2 v belts. I replaced the v belts 6 months ago as on shredded, they were skinny by then,  they lasted 6 years of daily use for an hour or more, so I have no issues with my belt arrangement.

 

Will this £75 alternator be a piece of shite compared to my sterling one??? how can I order the regulator for my alternator when I have no idea who made it??

 

 

[MtB]

2 hours ago, ditchcrawler said:

If your batteries are being charged by an A to B then I don't see what ever voltage your alternator pumps out it can effect the batteries as the A to B is between them. I am not sure where 17 volts could come from to power up the exciter wire.

 

My guess is it comes from a DVM with a flat battery. 

 

With cheapo DVMs the battery going flat often makes them give nonsense and random results, rather than refusing to work at all.

 

 

[Alan de Enfield]

7 minutes ago, MtB said:

 

My guess is it comes from a DVM with a flat battery. 

 

With cheapo DVMs the battery going flat often makes them give nonsense and random results, rather than refusing to work at all.

 

 

 

Good suggestion - My multimeter always shows ~19v DC (irrespective of the 12v battery being virtually flat or on charge) when the (multimeter) battery needs replacing.

[regginald]

8 minutes ago, MtB said:

 

My guess is it comes from a DVM with a flat battery. 

 

With cheapo DVMs the battery going flat often makes them give nonsense and random results, rather than refusing to work at all.

 

 

No, there is 17V coming out the alternator exciter wire terminal, that is what is causing the light to comeon

[MtB]

5 minutes ago, regginald said:

No, there is 17V coming out the alternator exciter wire terminal, that is what is causing the light to comeon

 

I'm getting the feeling this is going to be like pulling teeth!

 

Ok then, so how do you know this, if you're not measuring it with a battery-powered instrument? 

 

 

[regginald]

8 minutes ago, MtB said:

 

I'm getting the feeling this is going to be like pulling teeth!

 

Ok then, so how do you know this, if you're not measuring it with a battery-powered instrument? 

 

 

extremely unhelpful

[Alan de Enfield]

21 minutes ago, regginald said:

extremely unhelpful

 

How are you measuring the 17 volts ?

[regginald]

with my Fluke 179

[Jen-in-Wellies]

23 minutes ago, regginald said:

with my Fluke 179

Replace the battery in the Fluke. Measure again. Does it still give the same reading?

I've also seen weird readings from DVM's with their internal battery nearly flat. Eliminates this as a potential cause for what you are seeing. Trust nothing, including instruments!

[Alan de Enfield]

20 minutes ago, regginald said:

with my Fluke 179

 

Try testing it somewhere else in the 12v system (maybe directly on the battery posts) and see what it reads.

If you are still getting weird numbers then try changing the Fluke battery.

 

Try to borrow another meter from someone and see what that reads.

 

Fault finding to exclude things from the 'problem'.

[Tony Brooks]

I want to know how you added water to each cell of AGM batteries. As far as I know they are sealed, valve regulated batteries.

 

Charging for an hour and a half seems to me about 8 hours short of what is probably needed to fully charge the batteries, so that calls into question how you decided they were fully charged when you were cycling them.

 

The way you describe the 13.5V as not boosted makes me very suspicious that you may not understand lead acid battery charging, and that calls into question if you have ever been fully charging them. The fact you bought an expensive alternator and an A to B adds to my suspicion. B to Bs are important when trying to charge a second bank from an engine ECU controlled alternator, but probably far less practical use on a boat. The time difference to fully charged between your set-up and an ordinary alternator with a 14.5 V regulator is probably only measured in an hour or so with lead acid batteries.

 

Have you bypassed the A to B yet and measured the B+ charging voltage?

 

At present, we don't know if it is the alternator, the A to B, or both that are causing the problem.

 

That regulator looks like a standard Bosch one to me and many makers seem to use Bosch style regulators, so it will probably fit. Just make sure that it is suitable for whatever sensing system your alternator uses. It won't do any good if a field diode is faulty.

 

Most specialist will at least put an alternator on test while you wait and many do not charge to do it.

 

What makes you think an alternator rebadged by Sterling is anything special. If they fit the mounts, I am sure either will charge you batteries, but there is still a question about the A to B, and an A to B plus shorting batteries could burn an alternator out PDQ.

 

 

[regginald]

16 minutes ago, Tony Brooks said:

I want to know how you added water to each cell of AGM batteries. As far as I know they are sealed, valve regulated batteries.

 

Charging for an hour and a half seems to me about 8 hours short of what is probably needed to fully charge the batteries, so that calls into question how you decided they were fully charged when you were cycling them.

 

The way you describe the 13.5V as not boosted makes me very suspicious that you may not understand lead acid battery charging, and that calls into question if you have ever been fully charging them. The fact you bought an expensive alternator and an A to B adds to my suspicion. B to Bs are important when trying to charge a second bank from an engine ECU controlled alternator, but probably far less practical use on a boat. The time difference to fully charged between your set-up and an ordinary alternator with a 14.5 V regulator is probably only measured in an hour or so with lead acid batteries.

 

Have you bypassed the A to B yet and measured the B+ charging voltage?

 

At present, we don't know if it is the alternator, the A to B, or both that are causing the problem.

 

That regulator looks like a standard Bosch one to me and many makers seem to use Bosch style regulators, so it will probably fit. Just make sure that it is suitable for whatever sensing system your alternator uses. It won't do any good if a field diode is faulty.

 

Most specialist will at least put an alternator on test while you wait and many do not charge to do it.

 

What makes you think an alternator rebadged by Sterling is anything special. If they fit the mounts, I am sure either will charge you batteries, but there is still a question about the A to B, and an A to B plus shorting batteries could burn an alternator out PDQ.

 

 

The AGMs do have removable caps, I cycled them a few times, no change added water, no change.

 

The A to B tells me when they are fully charged, the cycles happen much faster than normal. I have had them on a 6 hour charge, 2 days ago, same results as a 1.5 hr charge. they are ruined. but that is ok. I am not trying to save these ruined batteries, nor learn how to use my fluke volt meter, I am trying to repair my Alternator. I can see the regulators online for 10 - 20 next day delivery but am trying to find one on a shelf retail. with the alternator connected to the starter only it puts out 13.6 volts but i think the starter is ruined so need to test it on a good starter battery. I can get a new alternator for £75 - £600 but want to charge lifepo4 soon so am currently trying to find a regulator for this unit. I have no experience with different alternator prices/quality.It is crazy dirty in there, the brushes and everything else are covered in black gunk, i am now cleaning all the internals.

 

I have called the only alternator tester repairer in kings lynn, they can take it and fix it but it will take time and cost. I pretty sure after reading today that it is the regulator, i am convinced it over volted during a long charge cycle, i do not know what else could have killed all batteries so dramatically. the A to B has a red light that comes on if over volted but does not shut down. no alarm sound so i would not have noticed.

 

 

[magnetman]

1 minute ago, regginald said:

The AGMs do have removable caps, I cycled them a few times, no change added water, no change.

 

 

They don't,

If the batteries have removable caps they are Lead Acid batteries with liquid electrolyte.

 

 

AGM stands for Absorbed Glass Mat.

 

How can you top these ones up?
 

 

[regginald]

1 minute ago, magnetman said:

They don't,

If the batteries have removable caps they are Lead Acid batteries with liquid electrolyte.

 

 

They do