Alternator Problems

[DasDsm]

Morning all,

I've read a lot of alternator and battery charging posts on here as seem to have a problem charging the domestic set and wanted your views to see if my assumptions from what I've read is correct.

My boat has a Beta 43 with a standard Iskra 175amp domestic alternator which is fed into a Mastervolt Distribution 500 which is then connected into a Mastervolt Mastershunt with a main 2 x 200ah gel domestic batteries connected to that.  There is also 660w of solar going into the Distribution 500 via a Mastervolt MPPT.

The boat up until recently has been in a marina so on shore power but we are now continuous cruisers and having problems charging the batteries back up to 100% soc after we have used about 120 ah capacity even after crusing for 8 hours plus.

When we have moored days and we use about 150ah we have run the engine for 8-10 hours and still don't get back to 100% only really 75%(ish). The engine is running at about 1000rpm while trying to recharge the batteries.

The main thing I have noticed which seems to point to a alternator problem is that the voltage I am getting both at alternator terminals and when bulk charging the batteries is about 13.4v and even if I increase revs to 1500-2000rpm in netural I'm only getting up to 13.6v. When charging the highest voltage I've seen the batteries at is about 13.78v which I believe is far too low.

So would this be pointing to a failed alternator or could it also be something else?  I've checked all the Mastershunt settings and all correct for battery type and ah capacity.

Not sure of the age of the alternator but it might be original to the boat in 2010.

Thanks in advance.

[Boater Sam]

How old and in what state are the batteries? Is there a seperate alternator controller? How were you charging when on the land line?

[Alan de Enfield]

Alternators are fitted with voltage regulators - it may be that yours is fitted with a 'low voltage' regulator when it needs to be fitted with a 14.6v regulator. The regulators are only a 'matter of pennies' (well a couple of pounds) depending on type.

Simply 'pull out' and push in the new one.

This may be of some help :

https://www.howacarworks.com/electrical-systems/fitting-a-new-voltage-regulator

Look at the back of your alternator and you should see it - it may look something like this (mine is a 'Cargo 14.6v) :

 

 

Edited April 21, 2018 by Alan de Enfield

[DasDsm]

4 minutes ago, Boater Sam said:

How old and in what state are the batteries? Is there a seperate alternator controller? How were you charging when on the land line?

The batteries are about 18months old and believe to be pretty good state and been mostly on shore charge via a Mastervolt Combi 12/2500 charger.

I'm not aware of a separate alternator controller.

Thanks

[Alan de Enfield]

3 minutes ago, DasDsm said:

I'm not aware of a separate alternator controller.

Its not 'separate' - its either 'plugged in the rear (like mine) or underneath the cover. (as per the link I posted)

[DasDsm]

6 minutes ago, Alan de Enfield said:

Alternators are fitted with voltage regulators - it may be that yours is fitted with a 'low voltage' regulator when it needs to be fitted with a 14.6v regulator. The regulators are only a 'matter of pennies' (well a couple of pounds) depending on type.

Simply 'pull out' and push in the new one.

 

Look at the back of your alternator and you should see it - it may look something like this (mine is a 'Cargo 14.6v) :

 

 

Thanks Alan,

Just what I've read is that this type of alternator which comes as standard with Beta 43 is usually around 14v+, so you are saying it might have been downgraded? 

I'll have a look at the back of the unit. 

[WotEver]

18 minutes ago, DasDsm said:

the voltage I am getting both at alternator terminals and when bulk charging the batteries is about 13.4v and even if I increase revs to 1500-2000rpm in netural I'm only getting up to 13.6v.

At what current?

Just now, DasDsm said:

Thanks Alan,

Just what I've read is that this type of alternator which comes as standard with Beta 43 is usually around 14v+, so you are saying it might have been downgraded? 

I'll have a look at the back of the unit. 

I doubt it’s that. No alternator manufactured in the last 30 years has a regulator set to 13.6V

[DasDsm]

1 minute ago, WotEver said:

At what current?

I doubt it’s that. No alternator manufactured in the last 30 years has a regulator set to 13.6V

The current starts off at about 45amps and then starts decreasing as the charge takes. Never seen anything higher than about 60amps for a few seconds before it starts decreasing. 

[Alan de Enfield]

1 minute ago, WotEver said:

At what current?

Good (and very relevant) question.

But - after 8-10 hours of running you (I) would expect the battery to have gone 'more than' from 60% SoC to 75% SoC

1 minute ago, DasDsm said:

The current starts off at about 45amps and then starts decreasing as the charge takes. Never seen anything higher than about 60amps for a few seconds before it starts decreasing. 

Makes you wonder why it needs a 175A alternator.

Maybe just a selling tactic "charges you battery 3 times faster than a 60a alternator"

[DasDsm]

4 minutes ago, Alan de Enfield said:

Good (and very relevant) question.

But - after 8-10 hours of running you (I) would expect the battery to have gone 'more than' from 60% SoC to 75% SoC

Makes you wonder why it needs a 175A alternator.

Maybe just a selling tactic "charges you battery 3 times faster than a 60a alternator"

Also don't know if this is normal or as a result of the same problem...

When running the engine to charge the batteries if the 240v fridge kicks in and as the compressor starts the engine has a 1-2 second 'dip' where you hear the revs go down as load increases but then goes back to normal.

[WotEver]

From those figures I’d suspect the alternator. Hopefully @Tony Brooks will be along shortly and advise you how to check it. 

Tony

1 minute ago, DasDsm said:

Also don't know if this is normal or as a result of the same problem...

When running the engine to charge the batteries if the 240v fridge kicks in and as the compressor starts the engine has a 1-2 second 'dip' where you hear the revs go down as load increases but then goes back to normal.

That’s perfectly normal and expected. 

Two additional questions. 

1. What are you measuring the voltage with? Do you know its accuracy?

2. How are you determining the state of charge?

[Alan de Enfield]

Presuming you also have a starter battery alternator - what is the output of that ?

What happens if you put a jump-lead across from the starter battery to your domestics ? (will it charge to 100% - how are you measuring 60% - 75% - 100% ?)

[DasDsm]

5 minutes ago, WotEver said:

From those figures I’d suspect the alternator. Hopefully @Tony Brooks will be along shortly and advise you how to check it. 

Tony

That’s perfectly normal and expected. 

Two additional questions. 

1. What are you measuring the voltage with? Do you know its accuracy?

2. How are you determining the state of charge?

Measuring voltage with a multimeter, although not recently calibrated it seems pretty correct and also verified by the voltage reading on the Mastershunt of what is going into the batteries. 

The soc is via the Mastershunt calculations. I know where can be pretty inaccurate at best so also looking at battery voltage once the surface charge has worn off. 

Thanks!

[Alan de Enfield]

Thinking about it a bit more - It may be a battery problem.

You have 660w of Solar and for the last few days we have had 'record sunshine' you should have been potentially getting 50a  for 10+ hours per day.

If the batteries are still showing only 75% SoC after that lot AND 8 hours engine running I'm beginning to think it may not be an alternator problem.

[DasDsm]

Just now, Alan de Enfield said:

Presuming you also have a starter battery alternator - what is the output of that ?

What happens if you put a jump-lead across from the starter battery to your domestics ? (will it charge to 100% - how are you measuring 60% - 75% - 100% ?)

That's one I've still got to measure to see what I'm getting out of the starter battery alternator. On the instrument panels the starter and bow are looking like 14+ volts while the domestic is always 13ish volts when charging via the alternators.

I've not investigated everything in massive detail but I believe there is a split charge relay next to the starter battery but I'm not sure if this is for the domestics and starter or the starter and bow thruster or a combination of all of these! If it is that the starter alternator only charges the starter battery and bow thruster this is the reason why the voltage is much higher on these as opposed to the domestic batteries which are only charged by the 175amp alternator. 

As for soc I've mentioned this in my last post which is a mixture of the Mastershunt calculations and also battery voltage. 

[Alan de Enfield]

1 minute ago, DasDsm said:

I've not investigated everything in massive detail but I believe there is a split charge relay next to the starter battery

It is possible to 'lose'  up to 1 volt depending on the type of split-charge regulator.

Can you identify type / model and what it is split to & from ?

[DasDsm]

1 minute ago, Alan de Enfield said:

Thinking about it a bit more - It may be a battery problem.

You have 660w of Solar and for the last few days we have had 'record sunshine' you should have been potentially getting 50a  for 10+ hours per day.

If the batteries are still showing only 75% SoC after that lot AND 8 hours engine running I'm beginning to think it may not be an alternator problem.

Nah I'm in a shaded location at the moment so only been getting a max of 14amps out of the solar and then usual load is about 8amps so only a input of 6amps to the batteries and I'm probably only getting 14 amps for a few hours as the sun passes over. Most of the time I'm getting 3-4 amps going into the battery. 

(Must move to a less shaded position) 

Just now, Alan de Enfield said:

It is possible to 'lose'  up to 1 volt depending on the type of split-charge regulator.

Can you identify type / model and what it is split to & from ?

I'll put that on my to-do list as well.

[WotEver]

11 minutes ago, Alan de Enfield said:

Thinking about it a bit more - It may be a battery problem.

I can’t see this.

A 175A alternator isn’t being stressed at circa 40A output so should be regulating at 14.4V+. If the batteries are pulling the voltage down they can only do so by demanding a high current - simple Ohms law - and they aren’t. 

[Detling]

I wonder if you have a duff battery. Have you the checked the level of the battery acid in the cells, could need topping up. What is the voltage when not being charged? If you can use a DC clamp meter to check the current to each battery, Measure the current in the positive link between the batteries and the alternator feed current which should be about double the battery link if both batteries are the same. You could also disconnect one battery and measure its voltage after a few hours to what the soc is.  

[Dr Bob]

You have one alternator and 3 separate battery banks. Important then to measure the volts and amps going into each one once you start the engine in the morning. That would help diagnose the problem. I had an issue with my 90A alternator on a Beta 43 that refuses to put out more than 13.9V (but 2004 vintage) and similar to the alternator on my old lumpy water boat (Volvo, 2005 vintage). I bought a £30 DC current clamp meter that is excellent for identifying what is going on.

If you move to a sunny spot, you will soon suss out if it is alternator or battery. My money is on the alternator regulating too low.

[WotEver]

36 minutes ago, Detling said:

I wonder if you have a duff battery.

I refer you to the post before yours. 

[DasDsm]

Thanks all,

It does seem that the starter alternator does the starter battery and the bow thruster battery and they are separated by a split charge relay.  The domestic 175amp alternator just does the domestic batteries via a Mastervolt Shunt and Distribution 500 unit.

The voltage gauges on the interment panel quickly jump to 14.5v on the starter and bow thruster when I turn on the engine but the domestic only goes up to about 13.5v.

For example - The battery voltage this morning was 12.27 and I've now run the engine for 6 hours and only reached a voltage of 13.6(ish) and currently putting in about 18amps and slowly decreasing.

As the batteries are gel and sealed there is nothing I can do with those to maintain them so at the moment I'm concluding its the alternator so probably going to look at a replacement one from Beta.

unless anyone else has any bright ideas

Thanks all.

[Dr Bob]

3 minutes ago, DasDsm said:

Thanks all,

It does seem that the starter alternator does the starter battery and the bow thruster battery and they are separated by a split charge relay.  The domestic 175amp alternator just does the domestic batteries via a Mastervolt Shunt and Distribution 500 unit.

The voltage gauges on the interment panel quickly jump to 14.5v on the starter and bow thruster when I turn on the engine but the domestic only goes up to about 13.5v.

For example - The battery voltage this morning was 12.27 and I've now run the engine for 6 hours and only reached a voltage of 13.6(ish) and currently putting in about 18amps and slowly decreasing.

As the batteries are gel and sealed there is nothing I can do with those to maintain them so at the moment I'm concluding its the alternator so probably going to look at a replacement one from Beta.

unless anyone else has any bright ideas

Thanks all.

Ah, you have 2 alternators.

Same as my Beta 43. See previous post. My solution was to buy a Sterling AtoB which now allows me to tailor the charge regime to the domestic bank and get 14.8v. Previously I only ever got 13.9V. They are expensive £350 but then the replacement alternator from Beta was £200 ish. Most people on here havent got a good word to say about Sterling and I am disappointed my unit will not allow the two alternators to be wired together (as per their literature) as it demands power from the smaller alternator before drawing power from the bigger one, DUH! Written to Sterling (twice) and no response. Piss poor that! ...but I have control over charging my domestic bank and have some flexibility if one alternator fails.

Interested to hear if you can change the regulator in yours.

[WotEver]

8 minutes ago, Dr Bob said:

Interested to hear if you can change the regulator in yours.

As I keep repeating, I very much doubt that the alternator has a 13.6V regulator in it. It’s far more likely that the alternator is faulty. 

There are several folks who repair alternators. Our very own Snibs is one. Cox electrical in Atherstone is another. Repair will be considerably cheaper than replacement. 

[DasDsm]

7 minutes ago, WotEver said:

As I keep repeating, I very much doubt that the alternator has a 13.6V regulator in it. It’s far more likely that the alternator is faulty. 

There are several folks who repair alternators. Our very own Snibs is one. Cox electrical in Atherstone is another. Repair will be considerably cheaper than replacement. 

Thanks and have been searching for repair around Watford but not finding anyone so might buy new as can't do without it for too long and get old one repaired to sell on.