Electrical Issues

[badgerbag]

Can anyone help shed some light on what might be going on with my electrical system? I would appreciate any suggestions.

 

I've one alternator, one starter and 2 domestic batteries. There is also a Sunstore solar panel of unknown output, which on a good day will keep the fridge going. Before we set off the 2, 125A/h DC31 MF domestic batteries died and I replaced them with 2 M110s FLAs, because that’s what the local chandlers had in stock, and we wanted to get going.

 

We were out for 6 weeks, from the 1st of June to the middle of July, the longest, and this year the sunniest of the year. We averaged 4-5 hours cruising most days, and on “rest days” we ran the engine so that the batteries (according to the Smart gauge and the magic eyes on the batteries) were always at 100% at about 4-5 o'clock. The alternator was showing about 13.8v on startup and 14.2v at the end of the day, and as the starter battery was always full I assume the alternator is ok.

 

During the whole trip we used no lights or watched any TV so that the only load on the batteries was the fridge (on lowest setting and new 2 years ago) and the water pump, (replaced this year). 

 

For the first week the Smartguage was indicating at least 80% capacity remaining in the mornings, but this soon fell to, and remained around 65%, and on a couple of occasions fell as low as 56%

 

I know that it was very hot during those weeks, the boat has an engine room and a Lister so things did get pretty warm, and the fridge would have been working hard, I also realise that by fitting the M110s I've reduced the capacity of the battery bank by 30 a/h, but does it sound feasible that just running a fridge overnight would use 40% of the battery capacity? If that is the case we are going to have problems when we go out later in the year and have to use lights in the evenings, and who knows we might even want to watch the telly!

[rusty69]

Are you sure its the alternator voltage you were seeing, not the solar! Have you got an ammeter? 

[alan_fincher]

9 minutes ago, badgerbag said:

The alternator was showing about 13.8v on startup and 14.2v at the end of the day,

I don't really understand this.

In my experience if the batteries are part depleted, and you start the engine, I would expect to see the full voltage that the alternator is capable of, and 13.8V would be low or any modern alternator.

The question I have though is you mention "Lister".

So is this an old fairly slow revving Lister, and if so how fast is the alternator actually being spun?  When you are measuring the 13.8v hat RPM do you estimate the engine is doing, and what is he pulley ratio, (so how fast is the alternator rotating?).  If everything else is correct, I'm tempted to think "not fast enough", but perhaps you can give the detail I have asked for?

[leeco]

11 minutes ago, alan_fincher said:

I don't really understand this.

In my experience if the batteries are part depleted, and you start the engine, I would expect to see the full voltage that the alternator is capable of, and 13.8V would be low or any modern alternator.

The question I have though is you mention "Lister".

So is this an old fairly slow revving Lister, and if so how fast is the alternator actually being spun?  When you are measuring the 13.8v hat RPM do you estimate the engine is doing, and what is he pulley ratio, (so how fast is the alternator rotating?).  If everything else is correct, I'm tempted to think "not fast enough", but perhaps you can give the detail I have asked for?

I have a lister engine and don’t bother with an alternator as it’s too slow 

[bizzard]

9 minutes ago, leeco said:

I have a lister engine and don’t bother with an alternator as it’s too slow 

Which Lister engine? If its an SL, LR, SR, ST the alternator is camshft drive, ie at half crankshaft speed. Large diameter drive pulleys are available to fit the camshaft, 9'' 10'' 12'' to get the alternator up to a good, adequate charging speed.

[alan_fincher]

9 minutes ago, leeco said:

I have a lister engine and don’t bother with an alternator as it’s too slow 

I have two boats, each with Lister HA2 engines - fairly slow revving - max rated 1800 RPM.

I have no other way of charging batteries when on the move, but it is certainly true that unless you get pulley ratios right you may not get particularly high charging rates.  Even if you do get acceptable charge rates at normal cruising RPM, it may well be that you get nothing, (or next to nothing) on tick-over.

 

Raher annoyingly the engine  / alternator combination that can produc most charge is in the boat where very little is needed, (a modern alternator), and he boat with the much greater charging needs has far less capability, (old ACR5 alternator, with pulley ratios less than ideal).

That's why I'm asking more detail of the set up.

 

One more question to OP - when you start up, and are measuring 13.8V at the alternator, does the charge light go out quickly and convincingly, or does it stay on, at least a bit, and maybe flicker?

[leeco]

Just now, bizzard said:

Which Lister engine? If its an SL, LR, SR, ST the alternator is camshft drive, ie at half crankshaft speed. Large diameter drive pulleys are available to fit the camshaft, 9'' 10'' 12'' to get the alternator up to a good, adequate charging speed.

It’s a lister SR2

 

 

[alan_fincher]

10 minutes ago, leeco said:

It’s a lister SR2

 

 

So if it is as Bizzard describes, and driven from the camshaft, you are not looking at the driving pulley going at up to 2000RPM, but only at a maxmum of 1000RPM.  You would need a very large pulley on the camshaft in comparison to the one on he alternator to spin the latter at a good speed.  I would suggest the camshaft one needs to be at least 6 times the diameter of the alternator one, and ideally even more than that.

What has the OP actually got?

EDIT: We don't yet know what engine OP has do we, or whether it's alternator pully is on the camshaftor on the crankshaft.

Some answers needed, I think!

Edited August 4, 2018 by alan_fincher
Because I should have neen asking OP, not Leeco!

[bizzard]

4 minutes ago, leeco said:

It’s a lister SR2

 

 

Has it still got the standard, I think they are 5 or 6'' pulley on the camshaft? if so it'll only start to give a bit of a charge at high engine revs.

[leeco]

1 minute ago, alan_fincher said:

So if it is as Bizzard describes, and driven from the camshaft, you are not looking at the driving pulley going at up to 2000RPM, but only at a maxmum of 1000RPM.  You would need a very large pulley on the camshaft in comparison to the one on he alternator to spin the latter at a good speed.  I would suggest the camshaft one needs to be at least 6 times the diameter of the alternator one, and ideally even more than that.

What have you actually got?

I have a massive pulley on and did have it running at one point with one of them sterling alt to battery chargers but it ended up blowing that unit so I stopped using it all together but I’m not short on power I have 1000w of solar and a generator if needed but I’ve not needed that yet

1 minute ago, bizzard said:

Has it still got the standard, I think they are 5 or 6'' pulley on the camshaft? if so it'll only start to give a bit of a charge at high engine revs.

I think my brother put a 12” pulley on it or something like that 

[bizzard]

10 minutes ago, leeco said:

I have a massive pulley on and did have it running at one point with one of them sterling alt to battery chargers but it ended up blowing that unit so I stopped using it all together but I’m not short on power I have 1000w of solar and a generator if needed but I’ve not needed that yet

I think my brother put a 12” pulley on it or something like that 

Well, if that is so, you have a fault or faults. Alternator faulty, belt slack, wiring connections, warning light not working to excite the alternator perhaps. I take it that you don't actually use or ever move the boat or you'd want the alternator working.

Edited August 4, 2018 by bizzard

[WotEver]

53 minutes ago, badgerbag said:

we ran the engine so that the batteries (according to the Smart gauge and the magic eyes on the batteries) were always at 100% at about 4-5 o'clock.

Magic Eyes are notoriously inaccurate. SmartGauge should not be relied upon when charging (it’s mentioned in the manual) as the sole indicator of ‘full’. So... my first thought is that you’re probably not fully charging the batteries. There are two ways to check. The messy way is to read the acid relative density with a hydrometer. The simplest way is to monitor the charging current at 14.1V+ (your 14.2V is fine) at the end of the charge. The ‘Tail Current’. You’re looking for a current of around 2A. 

[leeco]

11 minutes ago, bizzard said:

Well, if that is so, you have a fault or faults. Alternator faulty, belt slack, wiring connections, warning light not working to excite the alternator perhaps. I take it that you don't actually use or ever move the boat or you'd want the alternator working.

I think the pulley is too big that he fitted. 

 

Yeah i move the boat around but lately mr batteries are fully charged up by 12

[bizzard]

1 minute ago, leeco said:

I think the pulley is too big that he fitted. 

 

Yeah i move the boat around but lately mr batteries are fully charged up by 12

It won't be too big, 12'' is ideal and the maximum you can get for them, I'm pretty certain, and there are still lots of them in use giving no trouble at all.

[MtB]

To people skimming this thread, please note it has morphed into a discussion of leeco's alternator problem, not the OP's.

 

The OP doesn't appear to have returned to the thread to check for responses or answer any questions yet, and his thread has been hijacked. 

[nicknorman]

1 hour ago, alan_fincher said:

I don't really understand this.

In my experience if the batteries are part depleted, and you start the engine, I would expect to see the full voltage that the alternator is capable of, and 13.8V would be low or any modern alternator.

The question I have though is you mention "Lister".

So is this an old fairly slow revving Lister, and if so how fast is the alternator actually being spun?  When you are measuring the 13.8v hat RPM do you estimate the engine is doing, and what is he pulley ratio, (so how fast is the alternator rotating?).  If everything else is correct, I'm tempted to think "not fast enough", but perhaps you can give the detail I have asked for?

No this is wrong. An alternator when first charging depleted batteries won’t make its regulated voltage, it can only supply a specific amount of current and the batteries could take more than that at the regulated voltage - which is a roundabout way of saying that the regulated voltage can’t be achieved until the current demand from the batteries falls to a lowish value.

 

So it is entirely normal to see something like 13.8v at the start of charging, with the voltage gradually increasing as the charging progresses.

48 minutes ago, WotEver said:

Magic Eyes are notoriously inaccurate. SmartGauge should not be relied upon when charging (it’s mentioned in the manual) as the sole indicator of ‘full’. So... my first thought is that you’re probably not fully charging the batteries. There are two ways to check. The messy way is to read the acid relative density with a hydrometer. The simplest way is to monitor the charging current at 14.1V+ (your 14.2V is fine) at the end of the charge. The ‘Tail Current’. You’re looking for a current of around 2A. 

I would say that with modern battery chemistry (calcium in the plates)  14.2v is not enough. 14.6 or more is what is needed to prevent modern batteries from sulphating. Well that said, perhaps 14.2 might be enough EVENTUALLY but it will need a very long charge time.

 

i think the batteries are becoming sulphated due to under charging, but it is going to be difficult to sort out this issue when the charge voltage is only 14.2max.

 

My experience of M110s was that even when charged for long periods at 14.6v every day, they had sulphated enough after 6 month’s leisure use to be down to 1/2 capacity. Personally I don’t really think they are really fit for purpose, but even if you get something better they will still have to be charged properly.

 

i would say the OP’s batteries are at about 1/2 original capacity due to sulphation. Most of that lost capacity can probably be recovered by an equalisation charge but this requires 15.5v or so for a few hours. But then of course the sulphation will start to build up again...

Edited August 4, 2018 by nicknorman

[Tony Brooks]

1 hour ago, alan_fincher said:

I don't really understand this.

In my experience if the batteries are part depleted, and you start the engine, I would expect to see the full voltage that the alternator is capable of, and 13.8V would be low or any modern alternator.

The question I have though is you mention "Lister".

So is this an old fairly slow revving Lister, and if so how fast is the alternator actually being spun?  When you are measuring the 13.8v hat RPM do you estimate the engine is doing, and what is he pulley ratio, (so how fast is the alternator rotating?).  If everything else is correct, I'm tempted to think "not fast enough", but perhaps you can give the detail I have asked for?

And you would be wrong, very wrong - sorry Alan.

 

The higher the charging current an alternator produces the lower the maximum voltage it can produce (A x V = W) and  although we talk about 60 amp alternators they are really rated in Watts so the higher the amps the volts must fall to compensate. I don't have the data to hand but with very discharged batteries you may get less than 13 volts to start with.

 

13.8 volts at first start suggest to me that the batteries were no particularly discharged unless that was the solar voltage and if so all bets are off.

 

To the OP

 

As others have said the magic eye tells you nothing of worth.  As has been said so often before the Smartguage is not so good at telling when the batteries are 100% charged but very good at telling you when to stop discharging & start charging ASAP. Ammeters are better at indication close to 100% charged.

 

Crossed with Nick

Edited August 4, 2018 by Tony Brooks

[leeco]

21 minutes ago, Mike the Boilerman said:

To people skimming this thread, please note it has morphed into a discussion of leeco's alternator problem, not the OP's.

 

The OP doesn't appear to have returned to the thread to check for responses or answer any questions yet, and his thread has been hijacked. 

Sorry I was just saying I don’t use a alternator 

[MtB]

18 minutes ago, leeco said:

Sorry I was just saying I don’t use a alternator 

 

Quite! People were answering you as though you were the OP with the alternator problem. I'm sure the hijack happened accidentally but thought I should point it out as more and more posters seemed to think it was you with the alternator prob.

[badgerbag]

From the OP.

Thanks for all the input. To answer the questions:

The engine is an FR2, with a huge pulley on the front end of the crankshaft. The boat is 20+ years old so I'm sure any issues relating to pulley ratios would have been sorted before now.

The engine does need to be buzzed a bit before the charge light goes out, but once out it stays out, and as the light goes out and one can see the needles on the volt meters flick up to 14v (ish).

The alternator output readings were taken from the Smartgauge, with a coat thrown over the solar panel, and have been the same in the 4 years that we have had the boat.

 

If I need to give these batteries an equalisation charge can I use a car type battery charger connected to a shore line? And if so do I have to disconnect the batteries first, as we used to do when we had to charge car batteries periodically during the winter, or is it sufficient to isolate them at the switch?

 

Can anyone explain the issue with the Smartgauge? I must admit that I bought it under the impression that it was going to tell me when the batteries were charged, to avoid running the engine unnessarily. 

 

Am I right in thinking that if, for example, in the morning before starting the engine  the Smartgauge is showing say, 50% capacity on the batteries but 13V on the voltmeter, the the solar is providing something like 0.9V

 

Many thanks

 

 

[rusty69]

Perhaps check the accuracy of your SmartGuage with a calibrated meter. Also worth reading the manual to know its limitations. 

[MtB]

3 minutes ago, badgerbag said:

Can anyone explain the issue with the Smartgauge? I must admit that I bought it under the impression that it was going to tell me when the batteries were charged,

 

Bloody hell, you must have missed the small print on page 28 of the manual that tells you otherwise. 

 

I made the same mistake and wrecked £400 of new batteries. 

[alan_fincher]

1 hour ago, nicknorman said:

No this is wrong. An alternator when first charging depleted batteries won’t make its regulated voltage, it can only supply a specific amount of current and the batteries could take more than that at the regulated voltage - which is a roundabout way of saying that the regulated voltage can’t be achieved until the current demand from the batteries falls to a lowish value.

 

So it is entirely normal to see something like 13.8v at the start of charging, with the voltage gradually increasing as the charging progresses.

I would say that with modern battery chemistry (calcium in the plates)  14.2v is not enough. 14.6 or more is what is needed to prevent modern batteries from sulphating. Well that said, perhaps 14.2 might be enough EVENTUALLY but it will need a very long charge time.

 

1 hour ago, Tony Brooks said:

And you would be wrong, very wrong - sorry Alan.

 

The higher the charging current an alternator produces the lower the maximum voltage it can produce (A x V = W) and  although we talk about 60 amp alternators they are really rated in Watts so the higher the amps the volts must fall to compensate. I don't have the data to hand but with very discharged batteries you may get less than 13 volts to start with.

 

13.8 volts at first start suggest to me that the batteries were no particularly discharged unless that was the solar voltage and if so all bets are off.

OK, I stand corrected - sorry if I have misled.

It seems I am not depleting my own batteries by anything like as much as I think I am overnight then, because I certainly achieve 14 volts (plus) when I first start up in the morning.

Presumably because the SOC is actually considerably better than the Smartgauge seems to want to tell me?  I must admit I have never really trusted the SG, which seems to show the batteries depleting far faster than I would have expected actual loads I am running.  (Yes, I realise someone will tell me the SG is correct, and my batteries are only at a fraction of their original capacity, but on the whole I find little evidence to support that....)

 

[WotEver]

23 minutes ago, badgerbag said:

Can anyone explain the issue with the Smartgauge?

Yes. It’s impossible to calculate the state of charge of a battery whilst charging it by measuring the voltage because you’re not reading the battery voltage but the charge voltage. SmartGauge therefore makes an intuitive ‘guess’ based on the charge voltage and the length of time it’s been applied etc. But it is still only a guess and could be 5% or even 10% adrift. Hence you need another method of accurately determining 100% SoC. Tail current is the simple way to achieve that. 

 

As as soon as the battery comes off charge and starts to discharge, the SmartGauge will once again ‘know’ the battery and will give an accurate reading, such as your 60% in the morning. 

[nicknorman]

41 minutes ago, alan_fincher said:

 

OK, I stand corrected - sorry if I have misled.

It seems I am not depleting my own batteries by anything like as much as I think I am overnight then, because I certainly achieve 14 volts (plus) when I first start up in the morning.

Presumably because the SOC is actually considerably better than the Smartgauge seems to want to tell me?  I must admit I have never really trusted the SG, which seems to show the batteries depleting far faster than I would have expected actual loads I am running.  (Yes, I realise someone will tell me the SG is correct, and my batteries are only at a fraction of their original capacity, but on the whole I find little evidence to support that....)

 

It depends on the size of the alternator compared to the battery bank size, where you are measuring the voltage and the SoC of the batteries. So a large alternator feeding a smallish battery bank that is reasonably well charged may result in 14v or more, especially if there is a bit of resistance in the wiring and you are measuring the voltage further upstream than at the batteries themselves. But the main point which we took exception to, was your statement that the voltage decreased as the charge progressed. The opposite is true.