dwaviation Posted February 16, 2008 Share Posted February 16, 2008 Having watched my leisure battery discharge every 10 days or so since I parked the MH up for the winter I decided to fully investigate what the culprit was. It would seem that my motorhome has a constant discharge of 0.5 amp and there was nothing I could do to get rid of it - On delving deeper into the myriad of wiring I discovered that there are a number of relays, one of which only 'closed' when the battery was connected, there seemed to be no other purpose for it and the only thing keeping it closed was the battery ie; battery connected 'click' relay closed, battery disconnected 'click', relay open. This errant relay seems to have no other purpose in life than 'close' when the battery is connected and in doing so drains the battery... After some 10 days the battery would fully discharge and the relay would 'probably' open (I never let the battery go that low) The other two relays all do as advertised ie; switch the van electrics off when the ignition is on, isolate everything when the relevent 'isolator' switch is made and 'open' when the vehicle battery is selected - None of the previous actions made the slightest difference to my third and suspect relay... I have temporarily bypassed this relay and as a result get zero drain - Iwill let you know how I get on but what could be the purpose of such a pointless design? Link to comment Share on other sites More sharing options...
cronkle Posted February 16, 2008 Share Posted February 16, 2008 What make of vehicle is it? Link to comment Share on other sites More sharing options...
sshortcircuit Posted February 16, 2008 Share Posted February 16, 2008 The relay itself will only take a few mA when you have measured a load of 500 mA, which suggests it is feeding something else. If you have isolated that relay what does not work now? Link to comment Share on other sites More sharing options...
dwaviation Posted February 16, 2008 Author Share Posted February 16, 2008 I suspect that the law of unintended consequences is likely to kick in as a result of my bypassing this relay but at the moment all is well! So far I have measured the alarm at 0.03amp and the voltmeter display at 0.05amp which is my only drain. With the relay 'ON' the drain increases to 0.5amps. I agree about the excessive drain from just a relay - There must be something else taking this power? After all, what is the point of taking two feeds off of the battery only for one feed to power a relay that allows the other feed to power the van electrics? The van is a new Explorer Compass 115 All suggestions welcome? PS - Sorry I have just thought about what I have stated above... The line that went through the relay is still connected and live, it just doesn't get switched by the relay anymore, so any drain that was on the line with the relay 'on' would still be there with the relay bypassed... It isn't therefore I have assumed it's the relay coil drawing the power??? Link to comment Share on other sites More sharing options...
Derek Uzzell Posted February 17, 2008 Share Posted February 17, 2008 On a UK-built motorhome I'd anticipate the presence of 3 relays - a charge relay, a fridge relay and an isolation relay. A 0.5A drain is what you'd get if a 6W light bulb were in constant operation and, if the relay's coil alone were drawing that amount of current, the relay would be glowing red hot. Only thing I can think of (assuming there's no actual fault) is that you haven't turned your fridge's control-switch to the OFF position. Recent model Dometic fridges will draw 12V power continuously unless switched fully off, but the amount shouldn't be 0.5A. (Perhaps the light inside the fridge is on too!) Suggest you contact Explorer Group for advice and see if they can't supply you with a wiring diagram. Link to comment Share on other sites More sharing options...
maggyd Posted February 17, 2008 Share Posted February 17, 2008 Well I wish you luck with that !! my OH wrote to Swift for a wireing diag and recieved back a copy of the same diag that is in his book which was impossible to read which only shows part of the system. We bought a new battery last Summer which was carbon fibre costing £85! we are having same trouble again we keep charging the battery up every 4 or 5 days I have also changed all the bulbs to Led type everything is switched off in MH including the fridge ! what I would like to know Where are the relays? are they in the EC 200 PSU 007 I would like to know how to contact the people that make this unit to see if I can obtain a plan of the layout of the relays. Link to comment Share on other sites More sharing options...
bob b Posted February 17, 2008 Share Posted February 17, 2008 Have you checked things like, the wardrobe light is off when the door is shut ? Glovebox light ? etc, etc. Link to comment Share on other sites More sharing options...
dwaviation Posted February 17, 2008 Author Share Posted February 17, 2008 I have just enlarged to A3 the postage stamp sized wiring diagram that appears in the back of my handbook and I believe I have tracked it down. I think the relay in question is switched by the pump on/off switch near the voltmeter. I don't have my van in work with me at the moment so I can't check it out but I am pretty sure I have cracked it. I will confirm it later on but for those of you who experience flat leisure batteries on Explorer Group Vans it might be worth checking that the pump on/off switch is in fact 'off' when you park the van up for an extended period as leaving it on leaves a relay in the powered 'on' position which will do your battery in after a week or so. Link to comment Share on other sites More sharing options...
maggyd Posted February 17, 2008 Share Posted February 17, 2008 Sorry for hyjacking your thread!! Our pump is on a seperate control panel above the door with its individual warning light that lights when its live I suspect that this control panel which charges the Van battery and the liesure battery and operates the low voltage supply to the fridge etc; and regards blowing up the diagram in the book it just gets more vague the larger you make it!! all its good for is telling you where the wires go to with no details. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted February 18, 2008 Share Posted February 18, 2008 maggyd: I believe that your Swift's "EC 200 PSU 007" unit is manufactured by Sargent Electrical Services in East Yorkshire. See the following links: http://www.sargentltd.co.uk http://www.sargentltd.co.uk/PSU_2007_User_Instructions__GENERIC__Issue_01.pdf There was also an article on this firm by Clive Mott-Gotobed in MMM, January 2008 (pages 213/214) that gave a Sargent customer support phone number of 01482 678981. dwaviation: It makes good sense for a component with a high-ish 12V current 'draw' (eg. a pressure-sensitive water pump) to be powered remotely via a relay rather than have the full load going through a leisure-vehicle's control panel (my Hobby uses this sort of arrangement). However, I still don't see why causing a relay to be in the ON state should produce a 0.5A current drain unless something electrical is actually being operated via that relay. I can envisage a situation where, say, a very quiet submerged water pump might accidentally be left running, as that could draw around 6W, but I'm sure that doesn't apply in your case. I did wonder about the wardrobe-light Bob B mentions as it happened to me due to Hobby's pathetic design for the door-switch mounting, but I assumed that no 'caravan' lights would operate if the switches on your motorhome's control panel had been turned OFF. I had also assumed that, if you weren't using your 'van for a long time, you would have ensured that all the control panel switches would have been religiously placed in their OFF positions. (Doesn't your Avantgarde's control panel have a master switch that turns off all 12V power to the living area, including power to the water pump?) Seems that the Explorer Group is well named, with baffled buyers of their motorhomes doing the exploring! Link to comment Share on other sites More sharing options...
dwaviation Posted February 18, 2008 Author Share Posted February 18, 2008 Well the mystery deepens... Even though I estimated my survival time to be less than three minutes due to the weather, I ventured into the van today and tried the pump, which worked, so I tried switching the pump off at the pump on/off switch and, unsurprisingly, it didn't work (although I thought it might because of the bypassed relay, Keep up at the back) and irrespective of the position of the pump on/off switch - the van master switch isolates everything anyway, including the pump. So my original question stands - What on earth is this (bypassed) relay for? PS - Despite the cold snap the leisure battery is holding a healthy 12.6v Link to comment Share on other sites More sharing options...
maggyd Posted February 18, 2008 Share Posted February 18, 2008 Thanks for the info Derek that will come in very usfull :-D M&J. Link to comment Share on other sites More sharing options...
michele Posted February 18, 2008 Share Posted February 18, 2008 Why can people please not fill in the details as suggested re make and model of M/home ? It would save alot of questions easy to change on the profile. Link to comment Share on other sites More sharing options...
Brambles Posted February 18, 2008 Share Posted February 18, 2008 Just a shot in the dark, but the relay maybe used to isolate the battery should the voltage drop below a set level to help protect it. It is possible the coil in the relay is faulty and is drawing 0.5Amps instead of its designed few milliamps. Maybe worth checking the coil resistance if your meter gives resistance measurements. In my Motorhome, if the battery volage drops below about 8 volts then it gets isolated from the system. The only way I can charge it again is to use a seperate charger on te battery to bring the voltage back up to 10 volts or so and then the on board charge is connected again via the relay and all is fine again. It also means if I was to start the engine and the split charge relay was to close, I would not blow a fuse with the very heavy amps to charge a TOTALLY flat battery. The down side is this relay wil flatten my liesure battery in about a month of storage so important to diconnect the battery when laid up. Jon. Link to comment Share on other sites More sharing options...
dwaviation Posted February 19, 2008 Author Share Posted February 19, 2008 I think you've got it Brambles and that is the theory I am working to. What are you talking about Michele? Link to comment Share on other sites More sharing options...
Derek Uzzell Posted February 19, 2008 Share Posted February 19, 2008 dwaviation: Michele's talking about this: http://www.outandaboutlive.co.uk/forums/forums/thread-view.asp?tid=10256&start=1 I intend to visit the NEC Show sometime this week and I'll try to remember to interrogate the Compass chaps about this. (Doubt if I'll get much joy though - a couple of years back, when I asked the Auto-Sleepers 'technicians' about battery-charging on their motorhomes I got blank looks and information that was clearly cock-eyed.) Could you say, please, where the relay you are concentrating on is located in your Avantgarde 115? Link to comment Share on other sites More sharing options...
dwaviation Posted February 19, 2008 Author Share Posted February 19, 2008 Thanks Derek http://www.explorer-group.co.uk/downloads/2008/motorhome_handbook.pdf Page 69 is the wiring diagram In the middle of the diagram there are two banks of fuses, the first bank has BATT at the top, the second bank has PUMP at the top. To the left of those fuse banks are three relays, the top two are vertical in orientation and the bottom one is horizontal - It is this horizontal relay that is always energised. Physically located behind the fuses in the fusebox. I am convinced it is in the pump circuitry but everything works well without it and my battery is holding 12.6v Much easier to see when enlarged - Comments on the destination of the mysterious Brown wire particularly welcome! Link to comment Share on other sites More sharing options...
Clive Posted February 20, 2008 Share Posted February 20, 2008 The Sargent EC 235 consumes 0.007 Amp in standby mode, the EC200 a little more but nothing like half an amp. (But you did call it a VOLTMETER?) The normal arrangement for a water pump is for the pump slave relay to be energised by the pressure switch when the water pressure is low so it can run the motor. When the pressure come back up (because the taps are closed and the pipes preasurise) then the pressure switch will open and the slave relay will open. Half an amp is about right for the light in the cocktail cabinet!!!! C. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted February 21, 2008 Share Posted February 21, 2008 dwaviation: I asked Clive if he would take a look at your battery-drain problem as he is the forum's Mr Sparky, but I also had a word with a Compass technician at the NEC Show yesterday. (This was a 'proper' technician, by the way, not a salesman!) The technician told me that, as far as he was aware, there had been no reports of leisure batteries on current-model Compass 'vans flattening themselves rapidly for no apparent reason. He thought it most unlikely that a 0.5A drain could be caused by a faulty relay. His final advice was that either something must be ON (like a light) to cause the drain, or there was a fault with the electrical system that should be checked out by someone with the necessary expertise (in your case a Compass dealer as your vehicle is under warranty). Link to comment Share on other sites More sharing options...
Brambles Posted February 21, 2008 Share Posted February 21, 2008 dwaviation, Agree with what is being said above, although relay coil faults are unlikely it is not impossible. Do you know where the BROWN wire from the relay goes. This looks like it should go to ground somewhere possibly via the control panel or some other pump control switch. If I understand you correctly when you remove the relay and short out the switch contacts to complete the circuit the curent drain is normal.That just leaves the relay activation/coil circuit at fault. Check the resistance of the relay coil. Using I= 12/Resistance you can work out the current it will draw, but ideally you also need to check it with the relay energised. What you could also do is check, with your ohm meter there is an open circuit between the relay coil connections and the switching contacts. It is also possible the fault lies in where the Brown wire goes if it has a controlling function on some other item. For the life of me I cannot see where it connects to in the circuit diagram which sadly is not well drawn. I would be shot for producing a cct Diag like that one for the automotive companies I work for....vague, lines too close to follow when reduced in size, errors in labelling, etc. I shall have another look later. Jon. Link to comment Share on other sites More sharing options...
dwaviation Posted February 21, 2008 Author Share Posted February 21, 2008 Thanks for all the help and advice so far - Great stuff. My van is suffering no apparent ill effect from this bypassed relay (so far) and the battery is still holding 12.6v. More investigation required this weekend I think. Keep you posted Link to comment Share on other sites More sharing options...
Uncle Bulgaria Posted February 21, 2008 Share Posted February 21, 2008 David, Does your van have a battery master switch for the liesure battery? I turn mine off whenever the van is laid up. I guess each convertor arranges things their own way, but I know the dump valve on my Truma C6002 water heating system draws current to hold it closed even when the main switch on the control panel is off. Using the master switch I know that everthing is turned off. Vehicle alarm system etc is off the vehicle battery. Richard. Link to comment Share on other sites More sharing options...
maggyd Posted February 28, 2008 Share Posted February 28, 2008 maggyd - 2008-02-17 7:09 PM Well I wish you luck with that !! my OH wrote to Swift for a wireing diag and recieved back a copy of the same diag that is in his book which was impossible to read which only shows part of the system. We bought a new battery last Summer which was carbon fibre costing £85! we are having same trouble again we keep charging the battery up every 4 or 5 days I have also changed all the bulbs to Led type everything is switched off in MH including the fridge ! what I would like to know Where are the relays? are they in the EC 200 PSU 007 I would like to know how to contact the people that make this unit to see if I can obtain a plan of the layout of the relays. ------------------------------------------------------- The latest is we found the fault was with the battery which was new last year but luckly we had a 5 year Gaurantee! we took it back to Catterick Caravans and they put it on test for 2 days and found it was faulty and replaced it with a new one ( I thought an Elecsol battery was foolproof) were glad that the control panel and onboard charger wasnt at fault . Link to comment Share on other sites More sharing options...
dwaviation Posted February 28, 2008 Author Share Posted February 28, 2008 My engine let go last night on the A14 - Wrecked. :-S Will let you know how I get on :-( Link to comment Share on other sites More sharing options...
maggyd Posted February 28, 2008 Share Posted February 28, 2008 Gosh!! sorry to hear that :-( Link to comment Share on other sites More sharing options...
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