Vetus m4.17 split charging problem

[Farey]

I've got an 11 year old boat, owned from new, fitted with a Vetus m4.17 engine which charges a domestic bank of 4 batteries, the starter battery and a bow thruster battery.

 

A while ago my wife accidentally ran down the domestic batteries while we were moored up, but when I came to start the boat the starter battery was also flat. This made me suspicious that they may in fact be connected together, so I checked the wiring, and found that they did do indeed appear to be connected. With the engine stopped I disconnected the terminal from the starter battery, and found the disconnected terminal had the same charge as the domestic batteries rather than zero. By disconnecting various things I was able to isolate the connection to the split charging system.

 

I searched the internet for more information, and found http://www.12voltplanet.co.uk/split-charging.html where the wiring setup appears to match the third example shown, a voltage sensitive/sensing relay (VSR).

 

Is this likely to be caused by a failed relay, or is there possibly another fault? If so, what can I do to diagnose the problem? And is a VSR the best solution for my set-up?

 

Any help or advice would be appreciated.

[Tony Brooks]

If and its a big if without photos you are correct then yes, it could just be a relay with its contacts welded closed. However this is more likely to occur if the alternator output is fed to the engine bank rather than the domestic bank.

[nicknorman]

What Tony is saying that yes, most probably the relay is faulty but when you get that replaced, in order to reduce the likelihood of a recurrence, you should move the main alternator charging lead from the engine battery + to the domestic battery +ve. But there is a caveat to that, on some engines the alternator and starter +ves are connected together on the engine and so cannot be seperated easily (ie if you move the lead, you will cause the starter motor to be powered from the domestic bank rather than the engine battery). If that is the case I would recommend disconnecting and removing the existing +ve lead between alternator and starter, (be careful, it will be live) and adding a new lead from alternator direct to the domestic battery + (or via the domestic isolator if you want to fully comply with the BSS).

 

The point of all this is that it is the domestic battery that takes most of the current. It is therefore better if the source of the current goes direct to that battery, and just the very small amount required to recharge the starter battery, goes via the VSR.

[Farey]

If and its a big if without photos you are correct then yes, it could just be a relay with its contacts welded closed. However this is more likely to occur if the alternator output is fed to the engine bank rather than the domestic bank.

 

Thanks for the responses. Here's a photo of the relay:

 

I'm not on the boat now, but I'm pretty sure the alternator output went direct to the starter battery, not the domestic batteries.

Edited April 12, 2016 by Farey

[Guest]

 

Thanks for the responses. Here's a photo of the relay:

 

I'm not on the boat now, but I'm pretty sure the alternator output went direct to the starter battery, not the domestic batteries.

I have seen similar relays weld before, and would think this is your problem. I have a much more substantial relay on my Vetus.

I am puzzled as to why the relay is on the engine though.

[Farey]

I have seen similar relays weld before, and would think this is your problem. I have a much more substantial relay on my Vetus.

I am puzzled as to why the relay is on the engine though.

 

Is there a relay you'd recommend?

[Guest]

 

Is there a relay you'd recommend?

I got a voltage controlled relay off these people about 12 years ago now: http://www.intellitecmv.com/

 

At the time many of the doom mongers on here told me what a load of crap I had bought ( ) but still going strong after 12 years of use and abuse.

Vetus alternators can be fussy about what is connected to them it seems, so a VCR was the obvious way to go and has worked really well for us.

Edited April 13, 2016 by Guest

[Tony Brooks]

 

Thanks for the responses. Here's a photo of the relay:

 

I'm not on the boat now, but I'm pretty sure the alternator output went direct to the starter battery, not the domestic batteries.

 

 

That looks more like a an ordinary split charge relay to me because it has two thin wires on it. Before condemning the relay check that one of the wires is connected to battery negative (Earth - probably the black one) and make sure the other one has 12V+ voltage on it whine the alternator is charging. If both these tests are OK then it is probably a relay failure.

 

You may find the positive (purple?) wire is connected to the ignition switch in which case the relay would be connecting all the time the ignition is turned on. In this case is there any possibility you left the ignition turned on? Old switches and keys can allow the key to EB removed with the switch turned on.

 

We can talk more about the wiring if this is the case.

[Guest]

 

 

That looks more like a an ordinary split charge relay to me because it has two thin wires on it. Before condemning the relay check that one of the wires is connected to battery negative (Earth - probably the black one) and make sure the other one has 12V+ voltage on it whine the alternator is charging. If both these tests are OK then it is probably a relay failure.

 

You may find the positive (purple?) wire is connected to the ignition switch in which case the relay would be connecting all the time the ignition is turned on. In this case is there any possibility you left the ignition turned on? Old switches and keys can allow the key to EB removed with the switch turned on.

 

We can talk more about the wiring if this is the case.

You have just reminded me of something: If the key on the Vetus panel is left in the "stop" position (fully anticlockwise) it flattens the start battery. I know of two people who have done just this. The key needs returning to the mid position after stopping the engine. easily done without realising.

Edited April 13, 2016 by Guest

[mayalld]

I have seen similar relays weld before, and would think this is your problem. I have a much more substantial relay on my Vetus.

I am puzzled as to why the relay is on the engine though.

 

Engine fitters seem to like fitting it to the engine.

 

Mine is just above the starter motor.

 

As you say, these Durite split charge relays aren't the best on the market, but they are easily available, and cheap enough.

 

I replaced ours last year, and one on the kids boat at around the same time.

[Guest]

 

Engine fitters seem to like fitting it to the engine.

 

Mine is just above the starter motor.

 

As you say, these Durite split charge relays aren't the best on the market, but they are easily available, and cheap enough.

 

I replaced ours last year, and one on the kids boat at around the same time.

A little off topic, but somebody once said that if the spring washers are not used on the main terminals and are replaced with plain washers, that the relays tend to last a lot longer. I have never tested this theory. Then agin of engine mounted, it would definitley need spring washers.

 

Hadn't seen them mounted on the actual engine before. Must be more common than I realised.

Edited April 13, 2016 by Guest

[Tony Brooks]

Vetus also fit a control relay and circuit breakers/fuses on the engine all, it seems to me, to be designed for a short vibrating life.

 

Much better mounting such things to the boat's structure but then that would mean more work for the fitter and not being able to supply a "drop it in and fit a couple of battery cables" type package.

 

Not only Vetus Catweasel. Any boat that uses a key position that is not spring loaded to stop the engine is likely to suffer the same way. My Bukh has just suffered this. the worn key & switch allowed the yard to pull the key out in the stop position AND they left the master switches on. Hopefully not too much battery life was lost because I got to it within a week.

[Sir Nibble]

That's an ordinary Lucas 60A relay.

[Farey]

 

 

You may find the positive (purple?) wire is connected to the ignition switch in which case the relay would be connecting all the time the ignition is turned on. In this case is there any possibility you left the ignition turned on? Old switches and keys can allow the key to EB removed with the switch turned on.

 

 

 

The ignition switch was definitely turned off. If the relay closes when the ignition switch is turned on, wouldn't that mean that the starter was drawing power from the domestic batteries?

[Tony Brooks]

 

The ignition switch was definitely turned off. If the relay closes when the ignition switch is turned on, wouldn't that mean that the starter was drawing power from the domestic batteries?

 

That depends upon the relative voltage difference between the two banks. If the partially discharged domestic ban has a lower terminal voltage than the fully charged starter bank when cranking then no, if the cranking starter battery voltage is lower then yes. However the voltage difference is likely to be small so the currents involved for most of the time will also be small unless the starter battery is well discharged.

 

At present we do not know how your relay is wired - basically where does the purple wire come from - so we can not have any idea about what is going on. I think Vetus fit battery sensed alternators and if someone has mistaken the sense terminal on the alternator for the warning lamp terminal then the relay would be energised all the time.

 

Personally I would now fit a VSR with the main alternator lead feeding the domestic bank. I will do so when my ordinary split charge relay packs up.

 

[Guest]

 

Vetus also fit a control relay and circuit breakers/fuses on the engine all, it seems to me, to be designed for a short vibrating life.

 

Much better mounting such things to the boat's structure but then that would mean more work for the fitter and not being able to supply a "drop it in and fit a couple of battery cables" type package.

 

Not only Vetus Catweasel. Any boat that uses a key position that is not spring loaded to stop the engine is likely to suffer the same way. My Bukh has just suffered this. the worn key & switch allowed the yard to pull the key out in the stop position AND they left the master switches on. Hopefully not too much battery life was lost because I got to it within a week.

.

Yes mine is like that. One relay for glow plugs, one for starter. Never been keen on the engine mounted idea.

 

Didn't know that, we live and learn

[Farey]

 

At present we do not know how your relay is wired - basically where does the purple wire come from - so we can not have any idea about what is going on. I think Vetus fit battery sensed alternators and if someone has mistaken the sense terminal on the alternator for the warning lamp terminal then the relay would be energised all the time.

 

Personally I would now fit a VSR with the main alternator lead feeding the domestic bank. I will do so when my ordinary split charge relay packs up.

 

 

Unfortunately I'm not on the boat, and its a 2 hour drive away, but I got someone at the marina to take a look. I appears that the purple wire goes to the engine control panel, so I presume that means its controlled by the ignition switch. It does look like a Lucas relay, as suggested by Sir Nibble, so that would make sense.

 

If I was to change to a VSR, is there a manufacturer/model you'd recommend?

Edited April 14, 2016 by Farey

[smileypete]

For split charge, looks like Durite just do the one:

 

http://www.ebay.co.uk/sch/i.html?_nkw=durite+split+charge&_sacat=0

 

As said though, could be worth checking the existing relay isn't getting a permanent feed due to a wiring or ignition switch fault.

 

For that it just needs checking across the the two smaller 'coil' terminals on the relay. They should read zero volts on a multimeter set to DC volts range, or fail to illuminate a 12V test lamp.

Edited April 14, 2016 by smileypete

[Tony Brooks]

For split charge, looks like Durite just do the one:

 

http://www.ebay.co.uk/sch/i.html?_nkw=durite+split+charge&_sacat=0

 

As said though, could be worth checking the existing relay isn't getting a permanent feed due to a wiring or ignition switch fault.

 

For that it just needs checking across the the two smaller 'coil' terminals on the relay. They should read zero volts on a multimeter set to DC volts range, or fail to illuminate a 12V test lamp.

 

To add - with the ignition off and the engine stationary. Just to be clear.

[Farey]

For split charge, looks like Durite just do the one:

 

http://www.ebay.co.uk/sch/i.html?_nkw=durite+split+charge&_sacat=0

 

As said though, could be worth checking the existing relay isn't getting a permanent feed due to a wiring or ignition switch fault.

 

For that it just needs checking across the the two smaller 'coil' terminals on the relay. They should read zero volts on a multimeter set to DC volts range, or fail to illuminate a 12V test lamp.

 

I found this one for £44: http://www.12voltplanet.co.uk/voltage-sensitive-relay-12v-140a.html or this more expensive one with flashing lights: http://sterling-power.com/products/pro-con-vsr-voltage-sensitive-relay-12-24-auto-select-plus-fine-adjust-1?variant=884583603

 

But I'll check the feed to the existing one first. Thanks for all your help.

[Tony Brooks]

Provided the main charging lead goes to the domestic bank I think the first one will do the job.

 

Be aware that for a short time after turning the engine off the LED on it may show the relay is still engaged. It will drop out very soon afterwards when a load has pulled both bank's voltage down to 12.8 (fully charged).

[smileypete]

 

I found this one for £44: http://www.12voltplanet.co.uk/voltage-sensitive-relay-12v-140a.html or this more expensive one with flashing lights: http://sterling-power.com/products/pro-con-vsr-voltage-sensitive-relay-12-24-auto-select-plus-fine-adjust-1?variant=884583603

 

But I'll check the feed to the existing one first. Thanks for all your help.

 

Bit cheaper on Ebay btw....

 

http://www.ebay.co.uk/itm/Durite-voltage-sensitive-relay-140A-/262381694249

[Farey]

So, I went to the boat yesterday. The purple wire was not live, so I fitted a Voltage Sensing Relay, with the main alternator fed going to the domestic batteries and the relay feeding the starter battery (as it was with the previous relay). I started the engine, and was surprised to get a voltage reading of over 15 volts from the voltmeter connected to the domestic bank, but a more sensible reading of around 14 volts across the starter battery, which makes no sense to me, unless there was a significant drop across the VSR. So now I'm even more puzzled?

 

I also checked electrics come more, and found that before I connected the new relay, I still had 12.4 volts on the (disconnected) starter battery terminal. I traced it back, and found it was coming from the Victron Multiplus charger/inverter, which has a trickle charge connection for charging the starter battery. It appears that this is live even when the charger is disconnected from shore power, so that the domestic batteries are potentially charging the starter battery. I contacted Victron, and was told this was correct, and that a dud starter battery could potentially flatten the domestic batteries (but not vice versa). I think I'll add a switch, so that I can turn off the trickle charge when the boat is not on shore power.