All DC Breakers tripping

[Jaston10078]

1 minute ago, Alan de Enfield said:

Re-connect then and see if the problem goes away.

That's a start... I'll try it. 

 

Another thought... Could it be that circuit that distributes power to the led indicators on the breakers is malfunctioning... This circuit drawing a momentary surge of current to trip all of the breakers? The led indicators are on the load side. 

[Tony Brooks]

2 minutes ago, Jaston10078 said:

That's a start... I'll try it. 

 

Another thought... Could it be that circuit that distributes power to the led indicators on the breakers is malfunctioning... This circuit drawing a momentary surge of current to trip all of the breakers? The led indicators are on the load side. 

LED on when active are normally fed via the breaker contacts from the main feed. Any LED wire is typically a negative.

 

LED on when open is normally bridged across the contact so no third wire.

[Jaston10078]

18 minutes ago, DandV said:

A neutral should be at earth potential, the same as a negative earthed DC system, but if a single neutral was connected to a DC12V  +ve then this neutral would be at earth plus 12v DC. Would this disrupt the AC feed? 

And what would 230V AC on  the 12V +ve  DC bus do to the 12V DC breakers?

I am just worried that any AC system on board has lost its earthing integrity and is earthing via the DC system.

Hi DandV, 

 

Would the RCD trip in this case? 

[Tony Brooks]

2 minutes ago, Jaston10078 said:

Hi DandV, 

 

Would the RCD trip in this case? 

Should do if you have one and if not possible an AC breaker.

[Jaston10078]

We do have an RCD and It has never tripped. I have just tested it... Seems to function correctly 

I did email mastervolt with the symptoms last night though I'm not holding out much hope for a reply 

[Tony Brooks]

If you are running a mains battery charger please measure the voltage cross the batteries and note it. then turn it off for a hour or so and remeasure the voltage across the batteries and post the results here. Connect the meter to the terminal clamps, not the lead of the battery. If you are not running  a charger ignore this.

[DandV]

16 minutes ago, Jaston10078 said:

Hi DandV, 

 

Would the RCD trip in this case? 

I am not sure it would necessarily. An RCD trips if there are two parallel paths to earth, the neutral plus a rogue other path.

[Tony Brooks]

4 minutes ago, DandV said:

I am not sure it would necessarily. An RCD trips if there are two parallel paths to earth, the neutral plus a rogue other path.

That is true but if all the DC appliances are turned off how will the AC get to DC negative and the earth bond. Even if it did then there is a parallel path via the hull and water.

[Jaston10078]

Hi Tony, I can probably tell you this now with some degree of accuracy... Our battery monitor reads voltage at the terminals. We tend to charge when the batteries are at about 12.1.

 

During bulk charging (multi stage charging) the voltage is around 13.2 at around 57 amps it stays like this for about 40mins then the absorbtion phase rises to about 14.2 and current slowly reduces until float stage... Further reducing current. 

 

Battery voltage soon after charging has stopped is around 12.5v... Our bank (of 4 x 160 amp hour) is supposedly nearly 10 years old. It's capacity I estimate to be half of its original. 

 

Any clues here? 

 

 

 

 

 

 

[Jaston10078]

4 minutes ago, Tony Brooks said:

That is true but if all the DC appliances are turned off how will the AC get to DC negative and the earth bond. Even if it did then there is a parallel path via the hull and water.

I'm certain that there is an appliance always on after each breaker... The led indicators. The led for each breaker takes a feed from the load side positive... Unless I misunderstand the way this panel works. 

 

 

[system 4-50]

Any solar in the system?

[Jaston10078]

Just now, system 4-50 said:

Any solar in the system?

No solar

[Tony Brooks]

6 minutes ago, Jaston10078 said:

Hi Tony, I can probably tell you this now with some degree of accuracy... Our battery monitor reads voltage at the terminals. We tend to charge when the batteries are at about 12.1.

 

During bulk charging (multi stage charging) the voltage is around 13.2 at around 57 amps it stays like this for about 40mins then the absorbtion phase rises to about 14.2 and current slowly reduces until float stage... Further reducing current. 

 

Battery voltage soon after charging has stopped is around 12.5v... Our bank (of 4 x 160 amp hour) is supposedly nearly 10 years old. It's capacity I estimate to be half of its original. 

 

Any clues here?

 

No apart from the fact that "soon after" charging has stopped the voltage should be around 12.7 to 12.8 with no load or even higher. That makes me suspect the batteries either have virtually zero capacity or are shorting internally. Are you sure all the breakers are tripping, that is flicking themselves off, and its not simply flat batteries.

 

If you do have badly discharged batteries the water pump may well try to draw so much current it trips its own breaker but not the others.

 

 

 

2 minutes ago, Jaston10078 said:

I'm certain that there is an appliance always on after each breaker... The led indicators. The led for each breaker takes a feed from the load side positive... Unless I misunderstand the way this panel works. 

 

 

 

But if the LED in some way carried sufficient current to trip a breaker it would probably exploder or very quickly burn out. There is probably a resistor in series with each LED to limit the current or just maybe an electronic circuit within the LED package to do the same.

[DandV]

16 minutes ago, Tony Brooks said:

That is true but if all the DC appliances are turned off how will the AC get to DC negative and the earth bond. Even if it did then there is a parallel path via the hull and water.

Yeah I can't see a path past any DC open circuit. That is one switched off.

Just I am super sensitive to maintaining earth continuities. 

[Jaston10078]

11 minutes ago, Tony Brooks said:

 

No apart from the fact that "soon after" charging has stopped the voltage should be around 12.7 to 12.8 with no load or even higher. That makes me suspect the batteries either have virtually zero capacity or are shorting internally. Are you sure all the breakers are tripping, that is flicking themselves off, and its not simply flat batteries.

 

If you do have badly discharged batteries the water pump may well try to draw so much current it trips its own breaker but not the others.

 

 

 

The batteries are far from their prime but I'm pretty sure they ain't dead yet... Last night I tried running all DC appliances at once drawing around 20 amps with no problem at all. Come to think of it we can run a 1000W belt sander from the Inverter without any issues on the DC side

 

A short could be possible. How could I check that? 

 

Are you implying that when the DC supply voltage is so low the current will raise to satisfy the demands of the connected appliance beyond the rating of the breaker? Could a brief interruption of the positive supply also cause this? 

 

[Tony Brooks]

12 minutes ago, DandV said:

Yeah I can't see a path past any DC open circuit. That is one switched off.

Just I am super sensitive to maintaining earth continuities. 

Very wise in my view

[Jaston10078]

26 minutes ago, Tony Brooks said:

Are you sure all the breakers are tripping, that is flicking themselves off, and its not simply flat batteries.

Yeah, all breakers physically flicked themselves off 

[Tony Brooks]

4 minutes ago, Jaston10078 said:

The batteries are far from their prime but I'm pretty sure they ain't dead yet... Last night I tried running all DC appliances at once drawing around 20 amps with no problem at all. Come to think of it we can run a 1000W belt sander from the Inverter without any issues on the DC side

 

A short could be possible. How could I check that? 

 

Are you implying that when the DC supply voltage is so low the current will raise to satisfy the demands of the connected appliance beyond the rating of the breaker? Could a brief interruption of the positive supply also cause this? 

 

I simply do not see how a short can develop across ALL the DC circuits between the individual breakers and their loads can happen on an intermittent basis. That is the problem. Once the electricity reaches the breakers they are all individual circuits. I can see that something metallic cutting into a cable harness could trip a number of circuits but the chances of it tripping all of then seems so unlikely one could discount it. You can't test for it unless you do it when the breakers all trip. Then I would disconnect each end of the cable run and put a meter set to 200 ohms between each cable and DC negative. Hope for a 1 on the wrong end of the meter window. If it shows any other number you have either not disconnected both ends of the cable or the cable has  a short.

 

On the other matter the slower a motor spins the more current it draws so at low voltage it will turn slowly and the current rises.

[Jaston10078]

I've just deliberately shorted the water pump cables to test the breaker. Just the water pump breaker tripped and no others. 

[Tony Brooks]

That is exactly what one would expect and its why the whole bank tripping at once makes no sense.

[Jaston10078]

Just now, Tony Brooks said:

That is exactly what one would expect and its why the whole bank tripping at once makes no sense.

Indeed 

[Bod]

What was the last thing added to the boat(Electric wise)before this all started?

Disconnect that, and does the problem go away?

Failing that, disconnect 1 item at a time, till the fault stops.  Starting with the fridge, as you say this is randomly happening.

 

Bod.

 

[Jaston10078]

6 minutes ago, Bod said:

What was the last thing added to the boat(Electric wise)before this all started?

Disconnect that, and does the problem go away?

Failing that, disconnect 1 item at a time, till the fault stops.  Starting with the fridge, as you say this is randomly happening.

 

Bod.

 

Good suggestion... The last thing I installed electric wise was the horns. Before that, the fridge, before that the battery monitor. If my memory serves me correctly I seem to remember this starting after installing the fridge (coolbox) 

 

 

 

 

[Tony Brooks]

29 minutes ago, Bod said:

What was the last thing added to the boat(Electric wise)before this all started?

Disconnect that, and does the problem go away?

Failing that, disconnect 1 item at a time, till the fault stops.  Starting with the fridge, as you say this is randomly happening.

 

Bod.

 

I agree that is one way forward but although it may well indicate a  circuit fault on one circuit I don't see how the one circuit can cause all the other breakers to trip.

 

Long, long shot. Is there any possibility this coincides with sharp movements or heavy vibration?

[system 4-50]

What have you got that is wired directly to the batteries?

Is there anything that could result in a battery being in series rather than in parallel?