Power Failure

Motor, Motor Maintenance, Winches, Cooker, Heater, Fridge, Battery, Battery Charging, Shore Connection, Instruments, Autopilot, Anchor etc
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Gonzo
Posts: 19
Joined: Thu 02 Nov 06, 10:58
Your Country: UK, Devon

Power Failure

Post by Gonzo »

We experienced occasional power failures during the RBI in the Summer which we put down to low battery levels, but its been getting worse over the last week or so and goes off for seconds, minutes or an hour sometimes if a light or equipment is turned on. It happened again this morning , battery voltage is currently 12.7 v.
I assume that the main power switch on the Fuse Panel connects to a relay somewhere in the bow as I can hear a loud clunk when it happens. Has anyone any experience of this or any suggestions other than to get an electrician in.

cheers

Gonzo
Crew. Cold Fusion Reloaded - DF35 #28
Double Horizon
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Joined: Wed 09 May 07, 0:18
Your Country: USA

Re: Power Failure

Post by Double Horizon »

Gonzo wrote:We experienced occasional power failures during the RBI in the Summer which we put down to low battery levels, but its been getting worse over the last week or so and goes off for seconds, minutes or an hour sometimes if a light or equipment is turned on. It happened again this morning , battery voltage is currently 12.7 v.
I assume that the main power switch on the Fuse Panel connects to a relay somewhere in the bow as I can hear a loud clunk when it happens. Has anyone any experience of this or any suggestions other than to get an electrician in.

cheers

Gonzo
Crew. Cold Fusion Reloaded - DF35 #28
I don't know the details of a DF-35 but check your battery and main switch connections first. Look behind the main battery switch panel. The relay you hear in the bow might be a solenoid for the thruster or windlass.
Larry - Former Owner DF-1200
Steve B.
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Post by Steve B. »

We need more information.
Are you plugged into shore power when this happens or are you strictly on battery?

Steve B.
Gonzo
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Post by Gonzo »

Shore Power isn't connected. There are 2 Solar Panels but given its Britain in the winter not much is happening there.
Mario
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Post by Mario »

So it can be one of the batteries. Check them separately, one of them can be kaput even the total voltage is 12,7. Larry is right; solenoid for thruster gives a click at the bow.
Gonzo, have you managed autopilot fuse?
Gonzo
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Post by Gonzo »

The autopilot is not fixed yet, but there is a fuse on the outside of the box and the fuse is ok.
Einar Gloersen
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Post by Einar Gloersen »

The system is made so that 12V is connected to radio, solar cell, heater glow, bilge pump and the main switch in the electric panel all the time. When you operate the main switch in the electric panel a solenoid connects/disconnects the main power to all other equipment in the boat. The clunk you hear from the bow comes from this solenoid. You can see this on sheet No. 4 and 5 of the electric drawings.
So, if you hear the clunk when you get power failure the problem is located to the first 12V circuit. If no clunk it's located to the main power circuit.
I don't think there is a battery problem because you got 2 or 3 batteries in parallell and if one of these was damaged you wouldn't have 12.7V.
More likely the solenoid in the bow is damaged or you have a bad connection somewhere.
To find out what's the problem, start with removing the cover above the batteries. Then you will see the batteries, the solenoid and a main switch. (Everybody with a DF35 should know about this switch, because you have to disconnect here if the system shall be completely unpowered, and don't forget to disconnect the engine and bowthruster batteries also).
The first 12V circuit has thinner wires(16mm2) than the main power(25mm2).

I haven't looked into the battery compartment for some time, so may be my memory fails me, but I think it's like this:

If you hear a clunk when you get power failure check the thin wires connected to the solenoid in both ends. The other end of the thin red one should be connected to terminal 1.1 behind the electric panel. Check here also. There should also be a "thin" red cable from the batteries to the electric panel. The drawings don't tell me where this one is connected in the electric panel. Also there is a black cable from the electric panel to a copper connector with a lot of black cables behind the shelf in the aft compartment.
Make sure all these connections are good.

If you don't hear a clunk, check all the thick cables connected to the batteries and the solenoid, and all cables connected to the copper terminal behind the shelf in the aft compartment.

If you have some more information about what happens when you get the power failure let me know. Like, is something working at all? What do you do to get the power on again? The more information the better.

Just in case, if you get power failure and it's critical to get the power back on, you can connect the two thick red cables on the solenoid together with a suitable bolt. Please, remember to turn off the main switch in the battery compartment before doing this, and isolate the connection.

One more thing, never turn off the main switch in the battery compartment unless the diesel heater is completely stopped or you can damage it.

Please reply if you need more information and I will try to help you further.
Einar
DF35 No.16 Gwaihir
penryj
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Post by penryj »

Apologies if this is a really basic question but electrics are definitely not my strongpoint. Can anyone tell me, when my engine is running, should the amp display on my instrument panel be showing a high positive charge at all times?
Einar Gloersen
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Post by Einar Gloersen »

I would say no, so something must cause this, but you don’t say how high the charging amperage is. I’m an electronic engineer but not a specialist on batteries but here are some details from my boat. I do have a solar panel on deck and this is normally enough to charge the batteries during summertime. So when I start up the engine Friday evening, the batteries are charged for only a few minutes.

On my boat I have observed that if voltage is below 12.5V the charger normally runs for 10-15 minutes with an amperage of 35-45A. After that it goes down to 8A for some time, may be 10-20 minutes, then down to almost zero. The charging voltage is 13.2V. I have never run the batteries lower than 12.3V, and then only for a very short period, for example when the diesel heater starts up. When using less than 2A the lowest voltage I have noticed has been 12.5V.

The batteries in the DF35 have a total capacity of 300Ah, but you can’t use more than 40-50% of this. So if the batteries are “empty” you need to charge them with 150Ah. This equals to 3 hours of 50A of charging in theory. In practice you need more since the efficiency is not 100%.

I don’t know what could cause this. Is it possible that something is draining the batteries when the boat is not used? You could check the voltage when you leave the boat and when you comes back. No charger should be connected. Check the correct voltage, it's not the start battery that is the problem, but the other batteries.

The charging voltage could be wrong. In the equipment we make at work we normally charge the batteries with 14V, absolute maximum should be 14.4V. On the DF35 it’s 13.2V as mentioned above. If you have run the engine for 2-3 hours and then stops the engine, I think you should still have at least 12.8V after a few minutes if using 1-2A.

It could be something wrong with the instrument also. I do have an electronic controlled anchor winch in the aft. When turning on this one only, the instrument shows 4A. If I’m already using 5A when turning this on, it increases only to 6A. I think the instrument is “fooled” by some means by the electronics in this equipment. It should use only 0.4A.

Charging batteries are the same as moving energy into the batteries. This is not possible when the batteries are fully charged. In that case it should generate heat somewhere or the current has to go into the sea. I don’t know if it’s possible to have a kind of failure in the dynamo that could let current move through the engine to the sea when the engine is running. In that case you should see this as a lot of wear on the zinc anode or the saildrive itself.

I don’t know if you have noticed this, but if you start the engine and let it run in idle, the sound is changing a little after 10 seconds. I think this is caused by the dynamo on the engine starting to charge. If the batteries are fully charged this does not happen, because there is no additional load on the engine. May be you could check what happens on your boat when the batteries should be fully charged. For instance after running the engine for several hours or been on shore power for a sufficient time. Then you stop and start the engine again.

If you’re not sure what causes this, contact your local dealer or an electrician, preferably one with knowledge of marine electrics.
Einar
DF35 No.16 Gwaihir
penryj
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Post by penryj »

Hi Einar,
Thanks so much for the comprehensive reply. My post was probably a bit misleading - what I meant is that the meter doesn't show any charge over and above the solar panel input (I have 3) when running the engine. I have a feeling that the engine is not charging the batteries at all.
One thing I have noticed is that originally when the boat was new, I would notice that the switch that put the batteries in parallel would switch in and out automatically, with a clicking sound coming from the aft cabin. This doesn't happen anymore and the switch doesn't light up when I hold the switch over.
My suspicion is therefore that the engine batteries and the house batteries are permanently bridged - perhaps this is a broken switch.
I assume that if I checked the voltage of all the batteries, they would be identical if they were bridged, so I will heed your advice and check them out in this way.
The added complication is that I've just brought the boat to the US and I haven't found a solution yet that will let me use the shore power here to charge the batteries.

Regards
Penry

DF35-25
Gwas Y Neidr
Einar Gloersen
Posts: 30
Joined: Thu 11 Oct 07, 15:46
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Post by Einar Gloersen »

That's ok, I'll try with some more information based on what I know about the electrics for the DF35.

The battery parallel switch should connect the start battery in parallel with the other batteries if voltage is 12.6V or more, and the light should be on. If voltage is below 12.6V the start battery is disconnected and the light goes off.

You are correct, if all batteries are connected all the time the voltage should be the same on all batteries. You can check this by reading the voltage of battery 1 and 2 on the panel when it’s dark, and the engine is not running (no charging is necessary for this test, see below).

The electric drawings are in my boat, so I can’t check the details at the moment, but there is another possibility. Since the light is off and you don’t mention any starting problems I think the batteries are permanently disconnected. The engine is charging the start battery and the solar panels are charging the rest of the batteries.
You can check this by reading the voltage of battery 1 and 2 on the panel when it’s dark and the engine is running. The battery 2 should have the highest value. The opposite should be the case with the engine off in daylight and the solar panels are charging.

In both cases it could be a damaged relay or a damaged voltage sensor, I don’t remember if this is one unit or two different ones, but if I remember correctly I've seen an electric unit behind the instrument panel that is the voltage sensor. The relay is behind the shelf in the aft cabin.

May be the charger in the boat can be changed to US electric standard with a switch on the back side.
Einar
DF35 No.16 Gwaihir
penryj
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Post by penryj »

Thanks Einar,

I'll check your observations at the weekend.

Regards
Penry

DF35-25
Gwas Y Neidr
penryj
Posts: 51
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Post by penryj »

Hi Einar,
Got the following observations over the weekend. Unfortunately two very rough and cloudy days so almost zero reading from the foredeck solar panel (the other two are covered when folded).
Dark/no engine Battery #1 12.8V, Battery #2 12.5V
Dark/engine on Battery #1 14.4V, Battery #2 12.5V
Light/no engine Battery #1 12.8V, Battery #2 12.5V (zero draw and zero charge from solar panel)

So from this, I would say that the batteries are not bridged as the readings are different and battery #1 is the engine battery as is reads 14.4V when the engine runs.
Now, the Fox solar regulator only seems to give a reading called Battery #1 and was showing 12.5V, so I assume the number simply refers to the fact that it is only monitoring one bank of batteries i.e. the house batteries.

So from all this I would tend to think that this is a damaged relay. Behind the panel in the aft cabin there are two fuses labelled 50A "direct", 125A "switch" and a small box labelled voltage sensor. Then a circular box with some thick orange wires (and some thin ones) connected to it and a metal bar with some thick black wires connected to it. Is one of these the relay?

Regards
Penry

DF35-25
Gwas Y Neidr
Einar Gloersen
Posts: 30
Joined: Thu 11 Oct 07, 15:46
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Post by Einar Gloersen »

Hi Penry,
Your conclusions are correct, the batteries are not bridged and the solar regulator only shows the voltage of the housing batteries (same on my boat). The problem could be related to the relay, the voltage sensor or a bad connection.

The items behind the panel are:
50A fuse “Direct” is for equipment that has power when the main switch is off. You can see which, if you press the test fuse button with the main switch off. The automatic bilge pump is one for example.

125A fuse is for most of the rest of the electric system.

The metal bar is a main 0V connection point (“ground”)

The voltage sensor could be the sensor for the bridging, but it could also be the sensor for the display in the electric panel. I think it’s the first alternative, but you could find out this by following the wires. See below.

The circular box is the relay. The thin wires are the one that controls the relay. If there are one red and one black, the black is 0V and the red one is the active one, operated by the sensor. My guess is that a black one goes to the metal bar and a red one to the voltage sensor. Both could be black, but the procedure below should work in any case.

To find out if it’s the sensor or the relay you could do as follow:
If you have an instrument, measure the voltage on both of the orange wires. One is connected to the start battery the other to the housing batteries. So, you should get same voltages as shown in the display. Also measure the voltage between the two thin wires. I think it should be 12V when the batteries are bridged. At least it should change between 0V and 12V when the engine is running or not, and the voltage on the housing batteries is less than 12.6V. This because the bridging should go on and off in this case.

If you don’t have an instrument you could do this: Find out which of the thin wires that goes to the 0V. Disconnect the other thin wire from the voltage sensor and hold it so that it’s just in contact with the “Direct” fuse. (The thin wires are most likely lengthened with crimp on connectors, so cut the wire at this point if it’s not possibility to disconnect it.) If you hear a clicking sound when connecting and disconnecting to 12V (the fuse), the relay is ok and the sensor is defect. If no clicks, the relay is defect.

A relay like this should handle something like 1.000.000 cycles, so may be more likely it’s the sensor, or a wire that’s not connected properly. The wires you should check are the ones connected between the voltage sensor and the relay, and the wires between the voltage sensor and the batteries. Check in both ends, and look also for damages along the wires where this is possible.
Einar
DF35 No.16 Gwaihir
penryj
Posts: 51
Joined: Thu 12 Jun 08, 7:19
Your Country: New York, NY

Post by penryj »

Thanks again Einar,

I have my tasks for the coming weekend.
One rather basic question: if the whole system was working properly, I'm assuming I should see the engine charge the house batteries, once the engine battery is charged?
Regards
Penry

DF35-25
Gwas Y Neidr
Einar Gloersen
Posts: 30
Joined: Thu 11 Oct 07, 15:46
Your Country: Norway, Oslo

Post by Einar Gloersen »

Correct, I tested on my boat yesterday. When starting the engine the start battery is charged imidately. When the voltage is above a given value (I'm not sure of the value, could not observe all the time but something like 13.0 - 13.5V) the relay connects the battery systems together. You can hear it on the engine if running in idle.
I was wong earlier, my system is charged with 14.1V.
Einar
DF35 No.16 Gwaihir
penryj
Posts: 51
Joined: Thu 12 Jun 08, 7:19
Your Country: New York, NY

Post by penryj »

Belated thanks for all the info, Einar.

I finally replaced the relay last week and everything is fine again, switch automatically between engine and house. The ACR manufacturer (US based incidentally) was really helpful and even though that particular model is discontinued, they had some surplus stock for replacements. They sent this through free of charge. So easy to replace as I could use the same mountings and just replace each wire at a time.
Regards, Penry
Penry

DF35-25
Gwas Y Neidr
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