Guest Syd Posted September 10, 2007 Share Posted September 10, 2007 I have just about completed a safety overhaul of our caravan wireing. Over three years I have been adding circuits (12 volt) but not putting them through the consumer unit or fuses really, thought it time to get safe. I have added a reverse polarity switch and also a relay system that will cut off the supply from the inverter when I plug into the site supply to prevent reverse supply to the inverter if I had forgotten to switch the inverter off first. I have added relays to allow me to charge the caravan mover battery and the new alarm backup battery and leisure batterys from the car I have also installed a Domitec Air conditioning unit to the roof and wired that up. This is no doubt a simple task for most of you but it has been a pretty big undertaking for me as I know only what I have picked up over the years messing about in the house, slowly slowly get's you there, so they say To cut out the inverter I decided to use two single pole single throw relays, not because I think they are the best way to go but because I have two of them anyway, one for pos and one for neutral, this job took me over a day to work out as I couldn't find anyone who knew what I was talking about regarding wireing them up together, anyway I have achieved it (I think) What I would like is for some input into wether I have got it right BEFORE I switch it all on, Im quiet confident myself with everything but would like confirmation or otherwise from here. Now a second problem, you cannot advise me unless you can see what I have done and although I have made a sketch of the wireing for the inverter switching relays I cannot seem to get the hang of uploading it onto this forum, how do I do that, so enabling me to give you all a laugh. Thanks in anticipation, work calls, I will be back tonight if I am not electrocuted before then Link to comment Share on other sites More sharing options...
michele Posted September 10, 2007 Share Posted September 10, 2007 Syd Press reply and down next to the reply button you will find on your left a add after posting press and upload. Link to comment Share on other sites More sharing options...
Clive Posted September 10, 2007 Share Posted September 10, 2007 I feel obliged to suggest that if you are not confident yourself that all has been done correctly and safely then you should get someone who is qaulified to check out your work by both inspection and measurement before you turn it on. Link to comment Share on other sites More sharing options...
michele Posted September 10, 2007 Share Posted September 10, 2007 :D :D :D Clive that hats way to small for you to fit all your brains in. :D Link to comment Share on other sites More sharing options...
Dave Newell Posted September 10, 2007 Share Posted September 10, 2007 I'm inclined to agree with Clive. I recently fitted a simple solution to not having the inverter and mains connected to the sockets circuit simultaneously and althouugh its not automatic it is simple. Take one double pole double throw switch rated to 16 Amps at 240 Volts. This switch will have six terminals in two banks of three. Centre terminal of each bank or pole is common to that pole and one or other of the other two terminals depending on the position of the switch. So the centre pair of terminals goes to the sockets circuit, the two terminals at one end of the switch go the inverter output and the other two go to the mains output from the consumer unit. When you want to use the inverter you simply switch it on and select the inverter position on this switch, vise versa for mains but the mains cannot ever be connected to the inverter. D. Link to comment Share on other sites More sharing options...
Guest Syd Posted September 10, 2007 Share Posted September 10, 2007 Thanks so far people, Im most grateful. I continue with part two I HAD every confidence in my work and just wanted to be sure, anyway I couldnt stop myself from gingerly switching it on and low and behold...............................................................................................................................................................................................................................,,,, Everything works correctly and my inverter automatically switches off when I Plug into external power and all for £14, I feel really good I have checked and checked every posible source of current when switched on and switched off and all is ok I will still post my sketches in due course but I have noticed one small problem and that is that all the conections to the alarm system are hidden (of course) and one source of power for it comes from the 240 volt systems 12 volt supply, when I'm plugged into the mains with everything working correctly the small m/c battery that I use for the alarm backup is getting rather warm, in fact HOT. Obviously it is getting a very heavy charge pumped into it, or I think it is, and I cannot measure what Amps it is getting as I do not have the gear. The question is My consumer box is a Domitec MK140. 230v/50hz 12v dc 140w. Is this consumer box charging this small battery up and if so I suspect it wont stop when the battery is full but will a relay in the direct feed stop it when the battery is charged, if so what relay do I need and then can I do the same for my leisure batteries. Not too much of a problem for you is it, one small step for man etc etc Thanks Link to comment Share on other sites More sharing options...
michele Posted September 10, 2007 Share Posted September 10, 2007 Syd, Really sorry I am rotflmao now I didn't read the post one of the kids were at it fighting so I only read the botom part on how to upload 8-) Now it makes sense... :D :D :D Link to comment Share on other sites More sharing options...
sshortcircuit Posted September 10, 2007 Share Posted September 10, 2007 Syd Had a look at a site of a motorbike battery supplier "Warning. Motorbike batteries should not be charged with car battery chargers." It sounds like you have cooked your battery. Is it 6volt and not 12 volts? Have had a scan at your posting am realy concerned at some of your modifications particularly with your quote "This is no doubt a simple task for most of you but it has been a pretty big undertaking for me as I know only what I have picked up over the years messing about in the house, slowly slowly get's you there, so they say " When you part with your MH suggest you give a warning that it should be checked by a competent person. Please take this as a positive posting. Link to comment Share on other sites More sharing options...
Guest Syd Posted September 10, 2007 Share Posted September 10, 2007 sshortcircuit - 2007-09-10 9:34 PM Syd Had a look at a site of a motorbike battery supplier "Warning. Motorbike batteries should not be charged with car battery chargers." It sounds like you have cooked your battery. Is it 6volt and not 12 volts? Have had a scan at your posting am realy concerned at some of your modifications particularly with your quote "This is no doubt a simple task for most of you but it has been a pretty big undertaking for me as I know only what I have picked up over the years messing about in the house, slowly slowly get's you there, so they say " When you part with your MH suggest you give a warning that it should be checked by a competent person. Please take this as a positive posting. Hi sshortcircuit Thanks for your post, no offence taken as your post is obviously well meant. Clive, Thanks, I would automatically be getting my work checked anyway. Yes, I know the difference between car and motorcycle batteries and the battery concerned is 12v, it is not cooked just began getting rather warm and so I disconected it from the 12v supply and everything is normal again. I will have to leave that little conection problem until tomorrow when I can give it some more attention but I belive I know the answer already. I have checked everything again and all is as it should be, I have had everything running from 240v for about an hour, air con, microwave, TV, hoover and central heating and still everything is ok, no heating up anywhere in components or wireing, I have also run everything through the inverter, and everything works just fine, had everything running on 12v for some considerable time and still everything is ok, even from the car too. Even the reverse polarity switch works correctly I may not be an electrician but I do understand my limitations and so I work things out slowly and carefully. Im confident that I have achieved in two days work just what I set out to do, I am also aware that it would have taken anyone else less than a day to do it, but Im happy, Ive got there I just thought it would be a good idea to run through what I had done on this forum as an additional check. Link to comment Share on other sites More sharing options...
Guest Syd Posted September 10, 2007 Share Posted September 10, 2007 Dave Newell - 2007-09-10 5:43 PM I'm inclined to agree with Clive. I recently fitted a simple solution to not having the inverter and mains connected to the sockets circuit simultaneously and althouugh its not automatic it is simple. Take one double pole double throw switch rated to 16 Amps at 240 Volts. This switch will have six terminals in two banks of three. Centre terminal of each bank or pole is common to that pole and one or other of the other two terminals depending on the position of the switch. So the centre pair of terminals goes to the sockets circuit, the two terminals at one end of the switch go the inverter output and the other two go to the mains output from the consumer unit. When you want to use the inverter you simply switch it on and select the inverter position on this switch, vise versa for mains but the mains cannot ever be connected to the inverter. D. Hi Dave I had a similar set up to what you have discribed myself but I thought "One of these days either my wife or myself could foul up here" and so I decided to make the change over automatic. For a manufactured auto switch I have been quoted from £213 up to £300 and once even more than that but even when ordered at these prices delivery was never forthcoming As I said I have done it with two single pole, single throw relays, one for Pos and the other for Neg, what took my time up was actually figuring out just how to wire them up to work together as there are five terminals on each relay, that took me a full day, but now that it is all working correctly it was worth it and as I have said elsewhere on here the cost was about £14 from RS Components Ltd. Link to comment Share on other sites More sharing options...
Clive Posted September 10, 2007 Share Posted September 10, 2007 Then again there is always ... http://www.motts.dsl.pipex.com/INVERTER.htm Link to comment Share on other sites More sharing options...
Guest Syd Posted September 11, 2007 Share Posted September 11, 2007 Clive - 2007-09-10 11:58 PM Then again there is always ... http://www.motts.dsl.pipex.com/INVERTER.htm Hi Clive Yes heard about them and made enquiries, there is another type too I believe, was quoted around £800 or so but when I ordered one they never materialised either. There is something to be said for british businesses when they promise high value equipment then dilly dally about until eventually you get peed off and tell then where to install it. I expect that I will get one sometime in the not too distant future though Link to comment Share on other sites More sharing options...
Guest Syd Posted September 11, 2007 Share Posted September 11, 2007 Sorry Clive Got a bit mixed up there, what I thought you were talking about was an inverter that had a charging system built into them. I think they are a marine application. Jumped in before engaging the brain but then again I have had a hard day Link to comment Share on other sites More sharing options...
Guest Syd Posted September 11, 2007 Share Posted September 11, 2007 Clive And again I have two relays each with five terminals which I numbered myself as and when I worked out what they were for, my numbers are not the numbers on the relays I have wired them up as follows Pos relay 1) neutral from outside supply 2) live from inverter 3) live from outdoor supply 4) live feed to supply unit 5) live from outdoor supply Neg relay 1)neutral from outdoor supply 2) neutral from inverter 3) neutral from outdoor supply 4) neutral supply to consumer unit 5) live from outdoor supply I realise that you will understand more easilly when I manage to put up a picture of the relays and the wireing diagram that I worked out. Hope to do that tomorrow now Link to comment Share on other sites More sharing options...
davenewellhome Posted September 11, 2007 Share Posted September 11, 2007 Syd - 2007-09-10 11:48 PM Dave Newell - 2007-09-10 5:43 PM I'm inclined to agree with Clive. I recently fitted a simple solution to not having the inverter and mains connected to the sockets circuit simultaneously and althouugh its not automatic it is simple. Take one double pole double throw switch rated to 16 Amps at 240 Volts. This switch will have six terminals in two banks of three. Centre terminal of each bank or pole is common to that pole and one or other of the other two terminals depending on the position of the switch. So the centre pair of terminals goes to the sockets circuit, the two terminals at one end of the switch go the inverter output and the other two go to the mains output from the consumer unit. When you want to use the inverter you simply switch it on and select the inverter position on this switch, vise versa for mains but the mains cannot ever be connected to the inverter. D. Hi Dave I had a similar set up to what you have discribed myself but I thought "One of these days either my wife or myself could foul up here" and so I decided to make the change over automatic. For a manufactured auto switch I have been quoted from £213 up to £300 and once even more than that but even when ordered at these prices delivery was never forthcoming As I said I have done it with two single pole, single throw relays, one for Pos and the other for Neg, what took my time up was actually figuring out just how to wire them up to work together as there are five terminals on each relay, that took me a full day, but now that it is all working correctly it was worth it and as I have said elsewhere on here the cost was about £14 from RS Components Ltd. Exactly my point Syd, there is no way to "foul up". The switch is either in the inverter position and the sockets are connected directly to the output of the inverter with the mains totally disconnected or its in the mains position where the sockets are connected to the mains and the inverter is totally disconnected. What is there to "foul up"? D. Link to comment Share on other sites More sharing options...
Guest Syd Posted September 11, 2007 Share Posted September 11, 2007 Hi Dave Yes, I noted that your setup was foolproof, pretty neat too. mine wasn't so I have gone the whole hog and made it automatic If I had seen yours or Clives setups before starting out I may have gone to the same setup but really I wanted to go automatic. I am satisfied with what I have got now (so far) but have printed out both of your posts and placed them in my " Things Electrical" file. I will post tonight if I come across anything wrong, thanks for the guidance, I really do appreciate it Link to comment Share on other sites More sharing options...
mikey72 Posted September 11, 2007 Share Posted September 11, 2007 Hi, a word of warning. reading through the postings, it appears that relays or switches are being used to switch between inverter outputs and mains hook-up, both manually and automatically. There are two types of switch and relay. MBB (make before break) and BBM (break before make) Exactly as it says, a make before break will connect the output to a new source before disconnecting from the old source, a break before make will disconnect from the old source before connecting to a new source. Both have their place, but ensure you use a break before make if you are switching the inverter to hook-up, or you risk connecting the inverter output to the mains input. Even better, use a contactor to the same spec as Clive has, it's MBB by inherent design. Me. I just use two separate 13A sockets, but I also rarely use the inverter. Mike Link to comment Share on other sites More sharing options...
Dave Newell Posted September 11, 2007 Share Posted September 11, 2007 Good point Mike, mine was for a customer and yes I did use a BBM switch for exactly the reason you mention. Although I have an inverter in the 'van it almost never gets dug out of its hidey hole. D. Link to comment Share on other sites More sharing options...
sshortcircuit Posted September 11, 2007 Share Posted September 11, 2007 Mike I really, really like your method. Simple and fool proof. I was going down the avenue of a change over switch (break before make) but the two sockets are just so simple Link to comment Share on other sites More sharing options...
Guest Syd Posted September 11, 2007 Share Posted September 11, 2007 Todays update I have had everything running all day today (10am until 7.30pm) and absolutely no problems surfaced. Kept switching from 240v to 12 v to inverter and useing different equipment all of the time, sweet as a nut. Battery heating up problem solved with a minor adjustment, everything now tidied away. Im a happy man and ready for the off. Thanks for the advice about the two different types of relay because that point is very important, I had taken it into consideration before starting the work but it is a point well made. I have noticed that my consumer box is putting out around 16/17volts on the 12 volt supply side, I think this is wrong, far too high, and will probably fit a new consumer box tomorrow unless anyone on here can advise me otherwise. Thanks everyone who offered me advice, please dont think that I have ignored it because I have not and have used the advice as my safety checker Link to comment Share on other sites More sharing options...
davenewellhome Posted September 12, 2007 Share Posted September 12, 2007 When you say your "consumer box" do you mean your battery charger? If its putting out 15-16 Volts then it will probably be a simple single stage charger (15 volts open circuit is not unusual) I'd replace it with a decent 3 stage unit, in my own 'van I fitted a Ctek 7000 which is a three stage unit that can also be used as a 7 Amp supply. D. Link to comment Share on other sites More sharing options...
Guest Syd Posted September 12, 2007 Share Posted September 12, 2007 davenewell@home - 2007-09-12 7:24 AM When you say your "consumer box" do you mean your battery charger? If its putting out 15-16 Volts then it will probably be a simple single stage charger (15 volts open circuit is not unusual) I'd replace it with a decent 3 stage unit, in my own 'van I fitted a Ctek 7000 which is a three stage unit that can also be used as a 7 Amp supply. D. Hi Dave Thanks No it isnt a charger, on the caravan I have only got a small Domitec consumer unit/distribution unit/fuse box. Only one 12 volt fuse 15amp and a trip button for the 240 volts, as in the house only smaller and with 12 volts too. My consumer box is a Domitec MK140. 230v/50hz 12v dc 140w. It supplies the 240v power to three lights, micrwave, refrigerator, aircon, water heater, central heating and eight 240v three pin sockets, on the 12 volt side it supplies the power to 10 lights, the refridgerator, water heater, flush toilet and central heating. NOT all at the same time I hasten to add It receives the electricity supply from whatever source and distributes it around the caravan, it also has a transformer inside that gives a 12 volt supply to the caravan. The 240 volt supply is correct but the 12 volt supply is, as I said, 16/17 volts and I realise that this is too high. I could fit a voltage stabiliser thingy to the 12 volt output supply thereby making the 12 volt supply to the van the safe voltage that it should be but I think that if nothing can be done to reduce the voltage at the box then the box is faulty and all I will be doing is masking a problem that will eventually manifest it's self later at some most inconvienent time. If nothing can be done then I think that I had better replace it now. Bought a better ammeter, or whatever you call them, yesterday so I can now measure amps, once I have worked out how to get the packaging off the thing I am going to Brownhills today anyway so I will see what they have got in stock Link to comment Share on other sites More sharing options...
Guest Syd Posted September 12, 2007 Share Posted September 12, 2007 Picture of finnished work, don't laugh Link to comment Share on other sites More sharing options...
sshortcircuit Posted September 12, 2007 Share Posted September 12, 2007 Frightening. I must reiterate "When you part with your MH suggest you give a warning that it should be checked by a competent person." Hope you carry a fire extinquisher Link to comment Share on other sites More sharing options...
mikey72 Posted September 12, 2007 Share Posted September 12, 2007 Hi, I hate to be the pessimist, but without seeing the installation in full, a word of warning about the battery installation. They appear to be in a compartment with the relays and other switchgear. As I say, I don't know the full details, but if the batteries are charging and gas off, (an explosive gas), it is possible the relays may ignite the vapour as they switch, as the contacts can create a spark when they change over. The batteries should be in a battery box, ideally sealed from the living compartment, with ventilation outside, but definitely away from any source of ignition or spark. Mike Link to comment Share on other sites More sharing options...
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