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Post by phoenix on Nov 17, 2016 8:48:44 GMT
have posted this on cwdf but as all the electrical experts are here hope no one objects to posting here too. I want to wire a switch to switch between shore line and the output from the Victron multiplus inverter/battery charger. The victron can of course do this for itself having an internal switch but what I wanted to achieve is to be able to turn off the Victron entirely so that it is not trying to charge the battery at the same time. I have drawn the attached diagram, will this work?, I switched live and neutral lines as a belt and braces job but that would appear to be pointless as the neg lines remain attached to earth (or should i switch the earth too!) Any advice appreciated  Attachments:
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Post by Telemachus on Nov 17, 2016 9:12:56 GMT
Yes I think that would work. You'd have to remember to switch off the inverter too. As you say, since the whole thing is NE bonded there may be no need to switch the N but I'm not too sure about how the Victron's NE bond works in the unpowered state. If it was NE bonded when unpowered you'd introduce a "fault" that would trip the RCD. Therefore probably best to do it as you've shown. Make sure you use a break before make switch.
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Post by tonyqj on Nov 17, 2016 9:13:37 GMT
Yes, you should switch Neutral as well as Line. N-E linking should be at source, so can be ignored. Take a look at the 6th and 7th diagrams here to show the best way to do it: smartgauge.co.uk/nb_ac_sys.htmlCheers, Tony |
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Post by tonyqj on Nov 17, 2016 9:15:16 GMT
The 10th & 11th diagrams on that page also show how to automate it if required.  |
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Post by phoenix on Nov 17, 2016 9:30:30 GMT
You'd have to remember to switch off the inverter too Thanks to both of you Tboat 2 cwdf 0 Yes the inverter would have to be off too to avoid draining battery but I take it nothing terrible would happen if it was left on by mistake? |
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Post by tonyqj on Nov 17, 2016 9:31:38 GMT
You'd have to remember to switch off the inverter too Thanks to both of you Tboat 2 cwdf 0 Yes the inverter would have to be off too to avoid draining battery but I take it nothing terrible would happen if it was left on by mistake? That's correct |
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Post by Telemachus on Nov 17, 2016 9:38:21 GMT
You'd have to remember to switch off the inverter too Thanks to both of you Tboat 2 cwdf 0 Yes the inverter would have to be off too to avoid draining battery but I take it nothing terrible would happen if it was left on by mistake? Yes it would just defeat the object of the switchery since it would be slowly draining the battery. |
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Post by phoenix on Nov 17, 2016 13:13:15 GMT
thanks to both of you
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Post by smileypete on Nov 17, 2016 13:58:43 GMT
The victron can of course do this for itself having an internal switch but what I wanted to achieve is to be able to turn off the Victron entirely so that it is not trying to charge the battery at the same time. What's the reason behind this if you don't mind me asking? |
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Post by phoenix on Nov 17, 2016 18:21:12 GMT
What's the reason behind this if you don't mind me asking?
We are in Belgium and I am going to leave the boat unattended for several weeks.
I want to leave the shore electric on to run a heater off an accurate frostat but am reluctant to leave the battery charger connected on an unattended boat with all 12 volt appliances off (I know I can turn the settings down but that is not a job I want to do every time I come and go) Also we did some calculations and found that the victron was using about 1kw hour a day even with fully charged batteries, no idea what it was doing but it was. The price of electric here is .30 euros/kilowatt hour so that saving is not to be sneezed at!
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Post by smileypete on Nov 17, 2016 19:30:43 GMT
Fair do's, though I'd have thought a 3 pole changeover make before break 'cam' switch would do it. Two poles switch the sockets between the combi output/RCBO and the IT output/RCBO. Then the third pole switches the live feed from the IT RCBO to the combi live input connection. Earthing needs particular care on an isolated supply as losing the earth can mean the RCDs/RCBOs don't work, and it's not adequately clear to me from the diagram. Partly on that basis, personally I would recommend getting a registered spark with some relevant boats experience to do the work or at least check it. If you do it all yourself then the liability is all yours too I'm afraid.  Should be an easy hours work if you can mount the switch ready. |
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Post by Robbo on Nov 17, 2016 19:41:58 GMT
What's the reason behind this if you don't mind me asking? We are in Belgium and I am going to leave the boat unattended for several weeks. I want to leave the shore electric on to run a heater off an accurate frostat but am reluctant to leave the battery charger connected on an unattended boat with all 12 volt appliances off (I know I can turn the settings down but that is not a job I want to do every time I come and go) Also we did some calculations and found that the victron was using about 1kw hour a day even with fully charged batteries, no idea what it was doing but it was. The price of electric here is .30 euros/kilowatt hour so that saving is not to be sneezed at! When you did your calculations did you make sure that every single 12v item was switched off as well? |
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Post by smileypete on Nov 17, 2016 19:44:03 GMT
If the combi standby power is acceptable, one alternative may be wire a low value DC circuit breaker across the DC isolator, at least it should trip if the batts start to 'boil' and pull mucho current.
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Post by phoenix on Nov 17, 2016 22:09:48 GMT
Fair do's, though I'd have thought a 3 pole changeover make before break 'cam' switch would do it. Two poles switch the sockets between the combi output/RCBO and the IT output/RCBO. Then the third pole switches the live feed from the IT RCBO to the combi live input connection. Earthing needs particular care on an isolated supply as losing the earth can mean the RCDs/RCBOs don't work, and it's not adequately clear to me from the diagram. Partly on that basis, personally I would recommend getting a registered spark with some relevant boats experience to do the work or at least check it. If you do it all yourself then the liability is all yours too I'm afraid. Should be an easy hours work if you can mount the switch ready. Thanks, that sounds simpler, I will redraw the diagram and post tomorrow for comment. As for the earths I think I will leave everything permanently connected to earth/hull bond (though there does not seem much point in switching the negative as well as live I suppose this is safer?) As for getting a sparks in it is a bit difficult here their English is good but if i did find a sparks I am not sure I could explain the whole thing! |
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Post by phoenix on Nov 17, 2016 22:11:48 GMT
When you did your calculations did you make sure that every single 12v item was switched off as well? I think so, but I am going to check this again, (even so why would I want to run small 12 volt appliances off the mains if the solar panels are covering it) |
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Should be an easy hours work if you can mount the switch ready.
