Flat Battery

[Pulsynetic]

Hi Folks,

I’m hoping that some of you electrical whiz kids out there can help. We have a Rapido Club 32 TDE and I noticed when I fitted the terminals on the battery there was some sparking, although nothing was switched on.
Never thought anymore about it till today about a week after fitting the battery there was no power, lights wouldn’t work. On checking the battery it was completely flat, so something is drawing currant and draining the battery and the sparking you can hear when the lead is run across the battery terminal.
Sadly this draining of the battery has about killed it, being about 3+ years old, but I’m hoping it might recover.
The caravan is fitted with a PowerPark MAC 5/12 PSU, is it possible that this unit has a fault as is instead of charging the battery pulling currant from it, as there is nothing switched on in the van to drain the battery.
Any help/advice would be very welcome as to the possible cause, by the way there are no blown fuses.
Many thanks.
Ian.

 

[Sproket]

If everything is off then I would remove the battery terminal & ..........
Pull all of the fuses & then couple the battery back up & see if it still sparks......
If you don't have a spark, then start to put the fuses back in & watch to see if one of them sparks, that way you will be able to easily isolate & find out what runs from that fuse.....

If you buy one of these it will tell you if any & how much power is being drawn from that fuse.......

 

[Pulsynetic]

Hi Sproket,

Many thanks for your reply and suggestions. There are 3 fuses that I have found, so did as you recommended and pulled them all out putting them in one by one, but pulling the one before out, so only 1 fuse was in at any one time.
Having tried all 3 I still had the same effect on each fuse, everyone of them there was sparking as I put the terminal back on the battery, so I couldn’t even isolate this sparking to one of the circuits as they all behaved exactly the same.
So back to square one sadly. I can not think of anything inside the caravan apart from the fridge and although the previous owner was a bit of a DIYer, and his DIY skills were none to clever, that he would wire the fridge into the fuse(s), the fridge does not run when the battery in connected any way.
But something is drawing currant a few amps judging by the sparking and thanks for the link to the tester, I think I might just invest in one as I would know how much currant is being drawn.
Odd that its doing it on all 3 circuits unless they have all been linked together, which would defeat the point in having 3 fuses. Unfortunately I don’t have a wiring diagram how the van is wired, which would be a help.
Thanks for your help, hopefully I can get it sorted, its a bit of a mystery, unless it is a fault in this PSU, which seems to be working and charging the battery when I switched it on as the lights went a tad brighter and everything in the van works, lights, water pump etc.

 

[colin-yorkshire1]

hi Pulsynetic,
bit of a odd one this, not knowing exactly how the van is wired is allways going to make diagnostics difficult but judging by your question and subsquent anwer to Sproket it would appear that something is direct wired to the battey assuming you had a current drain (spark) when all the fuses were pulled, this is the point I would start from,
after the battery is fully charged pull all the fuses and check if there is a current drain on the system using a circuit tester I would then check to se if any componant was getting power do them all everything that uses 12v, I Will bet something has been bodge wired into the wrong circuit somewhere, with regards to the psu not sure how this is wired in your van but mine sparks (but only a little bit) when the battery is connected but it is only a small drain and caused by " the battery gauge" good luck with the investigation let us know what you find.
colin

 

[Pulsynetic]

Hi Colin,

Thanks for your reply. I did as you said and pulled all 3 fuses, I had you have found on your caravan some sparking, which went after the first initial touch of the lead on the battery terminal.
Put any of the fuses back in and bingo we have sparking again, so something what ever that is and I have yet to determine what, is taking currant from the battery at a steady pace till it exhausts the battery.
The wiring certainly leaves a lot to be desired to me and I’m no great sparks but have rewired previous vans we have had with no problem at all. Standard heavy 3 core mains cable has been used, with the earth wire used for power!!.
No doubt I will get to the bottom of it, but a few amps is being drawn for something but have yet to find out what. Will keep you posted.
Thanks for your help.
Regards,
Ian.

 

[colin-yorkshire1]

hi Ian,
just a thought from your last post , if as you say he has wired the van with 3core wire and used the green earth wire as a positive feed is is possible that somewhere the wire is connected to the return circuit eathing it out and causing a dead short as you will be fully aware the 12v system does not acctually have a earth unlike the 240v, the earth is a return to the battery via the chasis once it has gone through a componant allwoing power to the return circuit will have the effect of joining all the circuits together like reverse polarity and would give the symptoms you describe with all the fuses drawing power no matter which one is fitted. with the other 2 disconnected.
this may not be the case but it is a damn good place to start.
colin

 

[Pulsynetic]

Hi Colin,

A very valid point and I have no idea if this was done professionally or by this DIYer, as the van was fitted with water heater etc after it left the factory I think and extra UK type power points fitted to replace the continental type.
Its certainly a rats nest of wires around the battery box where the fuse box, PSU etc is fitted. I’ve gone round the van with a fine tooth comb trying to find a possible drain source but couldn’t find a single thing, so what you suggest sounds very plausible.
With all the fuses otu the sparking is just as you motioned with your van and if memory serves me right the one and only new van we bought, (big mistake that was but that’s another story) that also did the same thing. So perhaps the PSU is OK and its this feedback you mention.
I’ve looked on the net for a wiring diagram or any info on this Powerpart MAC 5/12 but so far drawn a blank as it would be helped knowing what goes where and so trace the wiring. So if nay one has any info on these units I’d be very grateful to hear from them.
Thanks Colin for your continued input, really appreciated.
Regards,
Ian.

 

[Pulsynetic]

Hi folks,

Just to let you know I have now traced the problem and many thanks to Sproket and Colin for their assistance and help.
I eventually traced it to the lighting circuit and after a lot of messing around found it was the bathroom light causing it. Once that was taken out of the circuit, no sparking at all, apart from the initial sparking that Colin mentioned.
So something about this 12” fluorescent light was keeping some power on even with it switch off, but not enough power to light the tube which it did when the switch was pushed, odd.
So now to get a new light, not worth messing about try to find out what is wrong with it the little PCB inside is out of my league.

Regards,
Ian.

 

[Gafferbill]

Pulsynetic

…… I do not know how your bathroom florescent light was wired but the on/off switch should electrically disconnect/connect the whole light fitting.

Thus if the light switch was turned off it should be impossible that it was using any 12 volt current unless the switch was faulty.

The PCB you refer to is in fact a small inverter that boosts the voltage to near mains levels in order to light the tubes.
These units have to be treated with respect as they can give you a nasty electrical shock.
There is a warning printed on them to disconnect from the 12 volt supply before handling for this reason.

 

[Pulsynetic]

Hi Gafferbill,

Yes I agree with all you say, its a mystery for sure, but it was certainly this light fitting that was causing the drain on the battery. As you rightly say the only explanation I can think of as well was the switch was faulty in some way and letting some currant pass. All the wiring when I took it off behind the light was OK, didn’t see any places there was a short so the switch was being bypassed.
I did notice after I took the light off but with 1 wire still connected, when I touched the second wire on the choc block, the light for a split second started to illuminate and this with the switch off.
Have fitted a new light now and all seems to be working fine, so long may it stay that way, only time will tell.
Thanks also for the explanation on the PCB, I remember now.

Regards,
Ian.

 

[colin-yorkshire1]

hi Ian,
glad you got it sorted mate and pleased to have been of some assistance, now everythings working ok all you have to do now is clean up the birds nest

when you have time.
colin