Buzzing relay Beta 43

[sbainbridge]

The 12 volt 40 amp relay behind the control panel is buzzing.

 

It only occurs with the engine running

It does not occur with the engine switched on but not running

It does not occur with the engine switched off

The engine is a Beta 43, 2006 vintage

The control panel is the Beta "C" with tachometer, oil pressure gauge, volt meter, water temperature, green power on light, red warning lights for oil pressure, engine alternator, domestic alternator. And warning buzzer.

The control panel shows all lights before engine startup and all red warning lights go out after engine start up.

The engine needs to be started at higher revs than tickover but as soon as the engine starts the alternator warning lights go out and remain out when returned to tickover.

The engine battery appears to charge ok (the engine alternator feeds a diode splitter which then feeds the engine battery and the bow thruster battery) charging is a little slow but I think this could be explained by the lower voltage that would be obtained by using a diode splitter.

The domestic batteries appear to charge ok (4x Trojan t105 type batteries wired series/parallel for 12v.

Solar recently installed

I thought it could possibly be the solar causing it, but it still happens with the solar controller output isolated.

 

Can anyone

A) tell me what this relay does

any suggestions as to what the problem is and how to fix it

Ps

I did not insert the emoji, the furum software did. It was supposed to be "B bracket"

 

[Sea Dog]

Beta Panel Immediate Action Drill

 

Locate the big multiplug on the loom just behind the panel itself, separate it and reconnect it. Cures 75% of odd occurences: keep it clean and tight.

 

It won't necessarily cure your problem, but it's a fine place to start and a good thing to rule out before you go somewhere more complex and expensive. 

 

 

[sbainbridge]

Thanks, will try this tomorrow as it is getting dark now. Will report back if it is successful.

[Boater Sam]

27 minutes ago, Sea Dog said:

Beta Panel Immediate Action Drill

 

Locate the big multiplug on the loom just behind the panel itself, separate it and reconnect it. Cures 75% of odd occurences: keep it clean and tight.

 

It won't necessarily cure your problem, but it's a fine place to start and a good thing to rule out before you go somewhere more complex and expensive. 

 

 

And do the same with the one down near the engine too.

[sbainbridge]

Curiosity got the better of me and I disconnected/reconnected the multiplug behind the panel about half a dozen times. No change and still buzzing. The relay that is; not me. Don't fancy going down the engine "ole" at the moment so will try the engine ole multiplug tomorrow, thanks for the suggestion.

[Sea Dog]

8 minutes ago, sbainbridge said:

Curiosity got the better of me and I disconnected/reconnected the multiplug behind the panel about half a dozen times. No change and still buzzing. The relay that is; not me. Don't fancy going down the engine "ole" at the moment so will try the engine ole multiplug tomorrow, thanks for the suggestion.

Ah, sorry to hear it didn't work for you. If t'other plug doesn't do it either, the folks who've had more bother than Sam and I have had will be along shortly! At least they don't have to start with "There's a plug..."!

 

[Iain_S]

The relay behind the panel is energised by the ignition switch and connects domestic positive (taken from B+ on the domestic alternator, via warning light) to D+ on the same alternator.

 

Despite the buzzing, your's seems to be working, or the domestic battery light wouldn't be!

[Tony Brooks]

9 hours ago, Iain_S said:

The relay behind the panel is energised by the ignition switch and connects domestic positive (taken from B+ on the domestic alternator, via warning light) to D+ on the same alternator.

 

Despite the buzzing, your's seems to be working, or the domestic battery light wouldn't be!

 

I think it might be a good idea to check the charging current first thing in the day and charging voltage last thing before shutdown for the night. It might just be a ripple caused by a failed alternator diode.

[Boater Sam]

If a DC relay buzzes it must be getting an AC voltage from somewhere to its coil.

The only place on a boat with low voltage AC is the alternator which generates 3 phase AC and has rectifier diodes inside to produce a DC output. Sounds like its alternator overhaul time.

It won't be charging your batteries properly.

[sbainbridge]

1 hour ago, Boater Sam said:

If a DC relay buzzes it must be getting an AC voltage from somewhere to its coil.

The only place on a boat with low voltage AC is the alternator which generates 3 phase AC and has rectifier diodes inside to produce a DC output. Sounds like its alternator overhaul time.

It won't be charging your batteries properly.

Are there any simple multimeter voltage/resistance checks that could verify this. I have a basic multimeter.

Would the frequency of buzzing vary with engine revs?

Am I likely to be damaging the batteries by continuing to run in this potential condition?

Another possibility that has been proposed to me is that the feed from the ignition switch is intermittent/not sufficient to hold power to the coil and collapses / remakes the connection I.e. dodgy ignition switch contact.

 

[sbainbridge]

2 hours ago, Tony Brooks said:

 

I think it might be a good idea to check the charging current first thing in the day and charging voltage last thing before shutdown for the night. It might just be a ripple caused by a failed alternator diode.

Unfortunately I do not have any method of checking the charging current or output other than observing that when the missus is using high current mains appliances with the engine running (hair dryer, microwave, iron) the engine responds to the extra loading and the measured battery voltage is above the full battery rest voltage running between 13.0 to 13.5 volts. Indicating perhaps that the alternator is providing a significant part of the power demand.

 

[Boater Sam]

No it is not. At 13.5v it is not fully charging your batteries. You need to see 14.4v to 14.8v when running to keep your batteries in good order.

 

Very unlikely a duff switch or connection, it would have given up completely by now.

 

You need to get the alternator checked.

[sbainbridge]

2 minutes ago, Boater Sam said:

No it is not. At 13.5v it is not fully charging your batteries. You need to see 14.4v to 14.8v when running to keep your batteries in good order.

 

Very unlikely a duff switch or connection, it would have given up completely by now.

 

You need to get the alternator checked.

When not under heavy external load it charges at around 14.6 volts, however it still looks like I need to get the alternator checked.

I was hoping that there was a relatively simple check I could do with a multimeter to isolate if there was a problem.

The switch connection possibility came from Beta Marine technical services, however I can see flaws in the hypothesis.

 

[Tony Brooks]

2 hours ago, sbainbridge said:

When not under heavy external load it charges at around 14.6 volts, however it still looks like I need to get the alternator checked.

I was hoping that there was a relatively simple check I could do with a multimeter to isolate if there was a problem.

The switch connection possibility came from Beta Marine technical services, however I can see flaws in the hypothesis.

 

Ar you sure that voltage is from the relevant battery (from Ian_s's post the domestic battery). I would suggest as a general rule 14.6 volts when charging a close to full battery with little other load is perfectly acceptable. I would be concerned if I found 14.8V although I know Beta did supply some 14.8 volt alternators and consequentially wrecked some batteries.

 

I think it is time to buy a clamp type ammeter that will measure charging and starting currents. That way you can always monitor the alternator output current. When the batteries are fairly well discharged or you have a heavy external load on the system the output current should be around the alternator's rated output BUT the charging voltage will be low until the batteries are well charged or the load is removed.

 

If you can still get to 14.6V on a well charged battery without any help from solar etc. I suspect thee is not much wrong with the alternator but can't be sure without a current reading with discharged batteries or a heavy external load.

 

An oscilloscope would measure and show the ripple on the output terminal but who has access to an oscilloscope!

[WotEver]

2 hours ago, Tony Brooks said:

An oscilloscope would measure and show the ripple on the output terminal but who has access to an oscilloscope!

:::waves:::

[cuthound]

20 minutes ago, WotEver said:

:::waves:::

 

Sine waves?

 

Oh you mean the 'scope that MtB is STILL in the post ?

Edited October 2, 2018 by cuthound
MtB, not MOB as autowrong changed it to

[WotEver]

5 minutes ago, cuthound said:

 

Sine waves?

 

Oh you mean the 'scope that MtB is STILL in the post ?

No, it arrived TODAY!!

[Tony Brooks]

2 hours ago, WotEver said:

:::waves:::

It would show ripple  superimposed on the DC charging voltage even with the machine in perfect order. Individual ripples get larger and more pronounced when a diode fails. That might be called a wave but as with one diode down it is likely to still be half wave rectified it may appear as just a larger ripple on every third peak.

[WotEver]

No... I was waving... ‘cos I now have a little pocket ‘scope. 

[Detling]

The control panel and probably the relay are powered by the starter battery not the domestic and this is charged by the smaller alternator which could be emitting AC. The domestic battery and inverter etc are powered by the bigger alternator and apart from the 0volt connection will be totally separate.

Edited October 2, 2018 by Detling
Spall chucker

[Boater Sam]

Damn good point .   I forgot that most have 2 alternators, impoverished by single alternator. Greenie sent.

[nbfiresprite]

8 hours ago, Tony Brooks said:

An oscilloscope would measure and show the ripple on the output terminal but who has access to an oscilloscope!

I do own one, had it for nearly 30 years.

[system 4-50]

How much would an "adequate" oscilloscope cost these days?

[WotEver]

1 hour ago, system 4-50 said:

How much would an "adequate" oscilloscope cost these days?

For the kind of stuff you’d need to check on a boat (alternator, mains waveforms) less than £100 for a pocket scope. Maybe as low as £60 from Wish or similar, or perhaps used from Ebay. Note that for mains work you’d need an attenuator (just a couple of resistors) as the max input voltage of these little scopes is only about 80V p-p. 

 

£56 here: https://m.banggood.com/MINI-DSO211-DS211-ARM-Nano-Pocket-Portable-Digital-Oscilloscope-p-977755.html

[cuthound]

2 hours ago, system 4-50 said:

How much would an "adequate" oscilloscope cost these days?

 

They are digital now. A decent cheap one such as this by Uni T can be had for £300-£400.

 

https://www.tester.co.uk/unit-utd1025dl-handheld-digital-oscilloscope?gclid=Cj0KCQjw0dHdBRDEARIsAHjZYYCvKAbEiJ5NIY2m0tfzYmiegriyd3OuLQfbMWqtCPL0z4BcfTPgIvYaAn6xEALw_wcB