Battery charger problem,any experts on here?

RobWales

RobWales

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Joined
21 Sep 2006
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Location
Gran Canaria
www.3ksengineering.com
An after market charger has been fitted to my SS portofino (by previous owner) its a 3 output Shark msc 4012 made by Zetagi in Italy.

When I switch it on it causes not only the rcd on board to trip but also my pontoon supply rcd also!?

I have opened her up to take a look and I have found that the black output cable (earth?) is fused and its a 40A unit, the three red outputs are not fused.

I pulled the fuse only to find its burnt and blown!!!!

So would this cause my tripping problem?

And what might have caused this blown fuse in the first place?
Any help appreciated.

Thanks
Rob

PS Been on the manufacturer website but no techie info orther than sales info!
 
It either has a serious fault or it has been wired incorrectly. You really need to obtain the installation/operating instructions.

I guess they fuse the negative output lead rather than individually fusing all three positives

I'd certainly want to check the mains input wiring.

Possible that there is no connection between the blown fuse and the RCD tripping. After all once the fuse is blown that sould be that! If that's the case you may be looking for two faults.
 
Thanks Vic,
Strange thing is that it has worked fine in the past?

It was last weekend while I was onboard that it tripped at first, so I reset rcd's after making sure all mains appliances were off, then tried various thing i.e fan heater=worked,dehumidifier=worked,small electric kettle+worked, it was only when I switched the charger on on the main switch panel that everything tripped again??
I cannot fathom it out!
Rob
 
It's possible that there is a path via the positive DC, to the mains earth ( bonding system ), and this is tripping the RCD. I have also come across a high voltage zener fail short circuit on a switchmode charger. This took out the control circuit, and put in a path from mains live to neutral. So could be a number of things.

If it is switchmode, keep your finger out, there are some high voltages in there.

Brian
 
[ QUOTE ]
I guess they fuse the negative output lead rather than individually fusing all three positives.

[/ QUOTE ]

I'm advised (and I think it's in my supplier's catalogue, that the negative side fusing is "required by regulation" and come to think of it on my first BSS inspection I was required to be able to isolate the negative line rather than the two positives (I have a 12V tap).

Seemed daft to me.....

On the RCD issue - the charger has a lot of electronics in it and these are known to blow at the supply side (especially as something has happened at the low voltage end).

That said - once electronics blow, they're gone - so why do the RCD's carry on tripping.

Be aware that a good RCD will trip at "the slightest excuse". I have (at home) outside devices which get damp and trips my 30mA RCD (that's what it's for..).
A day to dry it out and everything's hunky dory again.

Sooo, is there any moisture around?
 
Danpness could well cause the RCD to trip but it does not explain the blown fuse.
 
[ QUOTE ]

I pulled the fuse only to find its burnt and blown!!!!

So would this cause my tripping problem?

And what might have caused this blown fuse in the first place?
Any help appreciated.

[/ QUOTE ]

Looks like the unit has had a major electronic failure. There must be a leakage to earth within the mains side of the unit causing the trip to operate. The blown output fuse may have been caused by the internal electronic failure (maybe the output regulator that controls the charge voltage isn't functioning, hence too much current and blown fuse!).

Sounds like a pro repair job needed I'm afraid (or a new one). Just because the output fuse has blown doesn't mean that the mains input side doesn't still have a fault which is taking the trip out. The problems are almost certainly related.
 
I asked about

- the moisture because I had an IBM mini system, stored in the garage bit covered up. Brought it in, left to stabilise for a day. Powered it up.

Big bang
RCD tripped
Power supply blown
Main logic board blown.
Cause - damp in the P/s.

They don't like it on 'em
 
If only the -ve is fused it means the entire +ve circuit remains +ve through the unit up to the blown fuse - just waiting for a path to earth!

If moisture then enters the system it could short the +ve down to earth (-ve assuming the unit is well earthed)! I am surprised they have not fused the +ve!

I would temporarily fit fuses to +ve outputs and replace the -ve fuse. Then turn on to see which blows first, which may help you to isolate the fault.

Or perhaps first drying the entire unit thoroughly, look for any obvious earth faults and if this does not solve the problem I would suggest the unit needs to be replaced! /forums/images/graemlins/frown.gif
 
I had a similar problem which turned out to be an electronic failure, the supplier replaced the unit under warranty.

My question is...

IF RobWales's unit failure and indeed my own unit failure is due to damp. Why? These are marine chargers which will be used in a damp environment so should surely not fail due to damp?

Fingers crossed my replacement unit lasts?! /forums/images/graemlins/confused.gif
 
I totally agree, if damp is the probable cause, you could argue the charger is not fit for purpose! However, the manufacturers contra-argument might inevitably be that the engine room should not get excessively damp! (I dont think so!)

I am probably going off-track here, but could it be condensation forming on say a metal back plate within the unit? Particularly if it is fixed close to a cold side of the boat? Insulation and/or a vapour barrier? Just a thought!

Probably a duff unit - will be interesting to hear the final outcome!
 
Put a tester on it in situ yesterday and from my relative inexperience of leccy stuff I've discovered the following....

Tried the tester on the back of 240v domestic sockets with the breaker on main panel set to off and the blue neutral is live with earth and brown having no reading (now I take it this is all correct?) switch the breaker on and blue and brown are live so all ok.

On to the charger and with the breaker off I am reading 240 on the input at both blue and brown and no reading on the earth!

Hence I think I have a dead short in the charger which is tracking power from the blue neutral to the brown live and knocking the rcd's off when the charger is switched on by its circuit breaker on the panel!

Next move is to remove the unit and get a local electronic co to take a look for me.

Post more when I know more.

Rob
 
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