Is my leisure battery alternator working

[SandyD]

Having gone for a long trip (6 hours) I would have expected my house battery bank to be pretty much full. On plugging back into the shoreline and puting my inverter to charge (its a Victron inverter /charger) it seemed to be working hard to charge the house batteries (it's cooling fan was on for at least 3-4 hours).

Is there any (easy!) way of telling wether my leisure battery alternator battery is working? I assume the alternator warning light on the engine display is for the engine battery and alternator is for that system only. the only other indicator I have is a voltage indicator on the electric switchboard?

[Jen-in-Wellies]

Without being able to measure some voltages, it is near impossible to tell. Do you have a multimeter? What is the voltage indicator on the electric switchboard? Can you post a photo?

 

4 minutes ago, SandyD said:

I assume the alternator warning light on the engine display is for the engine battery and alternator is for that system only.

Don't assume anything with boat electrics! 😀 My Beta Marine engine panel has a warning light for the engine alternator and another for the house alternator. For a traditional alternator, it will need either a bulb, or a high power resistor connected between the D connection on the alternator and the +12V to get the alternator to start up.

[Alan de Enfield]

Quite simple - do you have a voltmeter and ammeter ? (not a built into the instrument panel, but a hand held multimeter)

 

 

[BWM]

If you can access the body of the alternator, it should be red hot when, or just after running. 

[Alan de Enfield]

With the engine running you can test the output voltage, and then clamp over the wire and it will show the charging current.

[Tony Brooks]

6 minutes ago, SandyD said:

Having gone for a long trip (6 hours) I would have expected my house battery bank to be pretty much full. On plugging back into the shoreline and puting my inverter to charge (its a Victron inverter /charger) it seemed to be working hard to charge the house batteries (it's cooling fan was on for at least 3-4 hours).

Is there any (easy!) way of telling wether my leisure battery alternator battery is working? I assume the alternator warning light on the engine display is for the engine battery and alternator is for that system only. the only other indicator I have is a voltage indicator on the electric switchboard?

 

Do you have TWO charge warning lamps, often red? If so what do they do when you turn the ignition on and the start and rev the engine? If only one then you need a high current ammeter and voltmeter.

 

Are there ant strange smells or sounds from the batteries when under charge?

 

Do any batteries have any local hot spots when under charge for an hour or so?

[SandyD]

Yes two charging lamps on engine board! So according to that everything working fine.

 

Only indication that somthing might be wrong is the inverter/charger warming up enough to run it's cooling fan. (No smells or hot spots)

 

Yes I do have a multi meter where how do I use it?

[Tony Brooks]

8 minutes ago, SandyD said:

Yes two charging lamps on engine board! So according to that everything working fine.

 

Only indication that somthing might be wrong is the inverter/charger warming up enough to run it's cooling fan. (No smells or hot spots)

 

Yes I do have a multi meter where how do I use it?

 

If you really do want help, then please fully answer the diagnostic questions - all of them, not just the ones you feel like answering.

 

I want to decide if this is a battery or an alternator fault, and without answers to my questions, I can't. Even when you have answered, then I am sure more will follow.

 

the questions:

Do you have TWO charge warning lamps, often red? If so what do they do when you turn the ignition on and the start and rev the engine? If only one then you need a high current ammeter and voltmeter.

 

Are there ant strange smells or sounds from the batteries when under charge?

 

Do any batteries have any local hot spots when under charge for an hour or so?

 

You have only confirmed two warning lamps, not what they do.

 

To properly diagnose the alternator you need a voltmeter and a high current (say 200 amp) ammeter, only recently have clamp type multimeters become available to measure such high DIRECT currents so your meter may only be usable for volts.

 

There is a procedure and a series of tests that need carrying out, but basically put the voltmeter across your domestic batteries and note the voltage, start and rev the engine to about 1200 to 1500 rpm and note the voltage, then tell us what it said.

 

 

 

[SandyD]

16 minutes ago, Tony Brooks said:

Do you have TWO charge warning lamps, often red? If so what do they do when you turn the ignition on and the start and rev the engine? If only one then you need a high current ammeter and voltmeter.

 

Are there ant strange smells or sounds from the batteries when under charge?

 

Do any batteries have any local hot spots when under charge for an hour or so?

 

You have only confirmed two warning lamps, not what they do.

 

To properly diagnose the alternator you need a voltmeter and a high current (say 200 amp) ammeter, only recently have clamp type multimeters become available to measure such high DIRECT currents so your meter may only be usable for volts.

 

There is a procedure and a series of tests that need carrying out, but basically put the voltmeter across your domestic batteries and note the voltage, start and rev the engine to about 1200 to 1500 rpm and note the voltage, then tell us what it said.

 

 

Yes two warning lamps both go out when I start the engine.

 

No strange smells from batteries - they are sealed units.

 

I will check for hot spots when I next run the engine for a reasonable time. (BTW with engine running voltmeter on board says appr 14v - not that I think it is very accurate)

 

Sorry if I appear a bit paranoid - I have lots of practical experience of older classic petrol cars but little of diesel and leisure systems - and have never had to be fully reliant on them for periods of time!

[BoatinglifeupNorth]

 Often when I’ve been out for hours and batteries have shown full on my display, when I plug in shore line my Victron has gone into bulk then started it’s staged charging. Also if I switch it off for a minute or so it will go into Bulk and once again go through its sequence. My batteries are fine and my alternator is working as it should and Victron seams fine.

[Tony Brooks]

17 minutes ago, SandyD said:

Yes two warning lamps both go out when I start the engine.

 

No strange smells from batteries - they are sealed units.

 

I will check for hot spots when I next run the engine for a reasonable time. (BTW with engine running voltmeter on board says appr 14v - not that I think it is very accurate)

 

Sorry if I appear a bit paranoid - I have lots of practical experience of older classic petrol cars but little of diesel and leisure systems - and have never had to be fully reliant on them for periods of time!

 

Although not definitive, that 14V suggest that the alternator probably is working well enough. When charging fully charged batteries from the alternator nowadays, I would expect a reading of between 14.2 and 14.6 volts, depending on the alternator.

 

Putting the voltmeter on the as described above should give a reading to one or two decimal places, so a bit more accurate, and can be used after following  a procedure, for assessing the batteries rough state of charge.

 

FWIW, diesel engines tend to be more reliable and longer lasting than petrol units and the alternators systems are just the same, except it chargers more batteries for a boat's domestic system.

[MtB]

56 minutes ago, SandyD said:

I will check for hot spots when I next run the engine for a reasonable time. (BTW with engine running voltmeter on board says appr 14v - not that I think it is very accurate)

 

You may not have sussed it yet but the decimal points of voltages are critically important when working out if alternators are working, batteries are charging correctly etc, which is why people are asking you to use a hand-held digital multi meter.

 

 

Edited September 17, 2023 by MtB
sp

[SandyD]

Thanks all, my mind is now more at rest! I will look into investing in a decent multi meter!

 

[MtB]

Just now, SandyD said:

Thanks all, my mind is now more at rest! I will look into investing in a decent multi meter!

 

 

A cheap one is usually perfectly good. About a fiver on ebay. Cheap enough to consider them a disposable tool. I have perhaps a dozen of them kicking around in the boats, the van and the hovel. 

 

 

[Tony Brooks]

Actually, after thinking about it, that 14V could be from the engine battery rather than the domestic.

[MtB]

E.G. this:

 

https://www.ebay.co.uk/itm/305012448100?

 

Ok its seven quid now, but they were a fiver last year! 

 

[Tony Brooks]

3 minutes ago, MtB said:

 

A cheap one is usually perfectly good. About a fiver on ebay. Cheap enough to consider them a disposable tool. I have perhaps a dozen of them kicking around in the boats, the van and the hovel. 

 

 

 

But one with a DC current clamp is likely to be closer to £30. To properly diagnose an alternator, you need both voltage and current readings. A £5 one is unlikely to measure more than 10 amps and doing so by the inexperienced may well end in a blown fuse, a damaged meter, or a cable fire.

 

The one Mike linked to will only measure up to 10 amps, and to do so requires cables are disconnected and reconnected through the meter. More than adequate for DC volts though.

Edited September 17, 2023 by Tony Brooks

[MtB]

Just now, Tony Brooks said:

 

But one with a DC current clamp is likely to be closer to £30. To properly diagnose an alternator, you need both voltage and current readings. A £5 one is unlikely to measure more than 10 amps and doing so by the inexperienced may well end in a blown fuse, a damaged meter, or a cable fire.

 

 

True, but as a professional technician I find the clamp meter is best treated as a separate tool from the multi meter. I suggest the OP buys a separate clamp meter.

 

But are they really that cheap now? The last DC clamp meter I bought was about £60 IIRC. 

 

 

[Tony Brooks]

This one looks OK

 

https://www.google.com/aclk?sa=L&ai=DChcSEwi-oK6tuLGBAxVYjFAGHRGLBysYABAJGgJkZw&gclid=EAIaIQobChMIvqCurbixgQMVWIxQBh0RiwcrEAQYCCABEgIIW_D_BwE&sig=AOD64_1bj8QkLWoBOXWRBcjG-hWcD29IKA&ctype=5&q=&ved=2ahUKEwilmqWtuLGBAxX5UUEAHXQRApkQ9aACKAB6BAgEEHg&adurl=

 

But £44

[MtB]

But looking on ebay, this one appears to claim to measure 1,000A DC!!!

 

Not sure I believe that...

 

https://www.ebay.co.uk/itm/352905954704?

[Tony Brooks]

Just now, MtB said:

But looking on ebay, this one appears to claim to measure 1,000A DC!!!

 

Not sure I believe that...

 

https://www.ebay.co.uk/itm/352905954704?

 

I also would not give much for its amps accuracy, but good enough for a boater. Unless one is intent on measuring a short circuit, I doubt 1000 amps would be measured on any boat, even the initial starter current.

[Ex Brummie]

If you keep your eyes open for the Amazon Prime Days, or other similar offers, a bargain can be found. Like MtB, I have  a selection of multimeters around the boat and home, but last year I picked up a bargain from Amazon with a Clamp Meter that was AC/DC , plus multimeter meter and non contact voltage detection for just ubder £20. It is also useful for checking Solar circuits.

[Alan de Enfield]

1 hour ago, MtB said:

 

A cheap one is usually perfectly good. About a fiver on ebay. Cheap enough to consider them a disposable tool. I have perhaps a dozen of them kicking around in the boats, the van and the hovel. 

 

 

 

Can you point me in the direction of one of those, I could do with a spare one for measuring the DC current.

[MtB]

Just now, Alan de Enfield said:

 

Can you point me in the direction of one of those, I could do with a spare one for measuring the DC current.

 

You really should read the thread before posting.

 

 

[Alan de Enfield]

Just now, MtB said:

 

You really should read the thread before posting.

 

 

 

 

I read as far as your post, not realising that there were more posts on another page, where the discussion of 'current measurement' had taken place.

 

I did say in post ~3 that she needed one that measured both volts and amps.

 

 

3 hours ago, Alan de Enfield said:

Quite simple - do you have a voltmeter and ammeter ? (not a built into the instrument panel, but a hand held multimeter)