spirou Posted October 3, 2019 Share Posted October 3, 2019 As it seems likely the solar regulator in our new van will be in a slightly more difficult to reach location, it means disconnecting the solar panels (probably 2x 160W in series) for maintenance would be better done with a switch, rather than pulling the fuse on the regulator. The question is what kind of switch to use? A battery disconnect switch is sort of what I'd like but they only handle 24V so only useful on the output from the regulator, not input. https://si.farnell.com/carling-technologies/bd1-1a1/battery-disconnect-sw-spst-250a/dp/2915229 What can I do with a 100V/30A system? Is there a more "elegant" way than an inline fuse holder in a convenient location? Something that's not terribly expensive, huge and made for industrial machinery would be nice. Link to comment Share on other sites More sharing options...
Charles Posted October 3, 2019 Share Posted October 3, 2019 I hear you, and it took me a while to find something convenient, good quality and correct rating. It's a breaker but would never trip as it's rated at 60amps, so it's a heavy duty switch... https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F372748544393 Link to comment Share on other sites More sharing options...
Charles Posted October 3, 2019 Share Posted October 3, 2019 PS I wouldn't bother too much about it's voltage rating, the only time it has voltage across it is when it's tripped and 50v isn't going to jump anywhere B-) Link to comment Share on other sites More sharing options...
Alanb Posted October 3, 2019 Share Posted October 3, 2019 I think that you may be in a corner given your requirements. At 100V you have the possibility of arcing when breaking the circuit, and for 30A maximum current you will want to keep contact resistance low. Unfortunately a small industrial type fuseholder, with even just a solid link seems to be the simplest solution. Can you hide it in a cupboard? Also consider a voltage warning label, perhaps also labels near battery giving location. Alan Link to comment Share on other sites More sharing options...
spirou Posted October 3, 2019 Author Share Posted October 3, 2019 It can be hidden yes, just don't have loads of room to play with. Currently I'm thinking of just going with the fuse holder and not complicate my life too much for the few times it will be needed. There is already one next to leisure batteries, presumably for leisure/starter disconnect. Link to comment Share on other sites More sharing options...
Charles Posted October 3, 2019 Share Posted October 3, 2019 100v at 30amps is 3kw but your panels are rated at 320w total, so something doesn't add up. Link to comment Share on other sites More sharing options...
BruceM Posted October 3, 2019 Share Posted October 3, 2019 Given how few times you're likely to be disconnecting your solar panels from your solar regulator (my assumption) I’d suggest that you stick with your current method, assuming, that is, that pulling the regulator's on board fuse does actually disconnect it from the panels (double check) or alternatively,as I’ve done, keep it simple and install an inline fuse. In three years of ownership I’ve had to pull the fuse maybe three times – it’s in a relatively difficult to access place place low down next to the regulator and batteries which for a once in a blue moon event is just fine. Link to comment Share on other sites More sharing options...
Charles Posted October 3, 2019 Share Posted October 3, 2019 My controller fuse just disconnects the battery circuit. Link to comment Share on other sites More sharing options...
spirou Posted October 3, 2019 Author Share Posted October 3, 2019 Charles - 2019-10-03 1:23 PM 100v at 30amps is 3kw but your panels are rated at 320w total, so something doesn't add up. Victron specs on 100/30 model list max Wp as 440W @ 12V, 880W @ 24V Their mppt calculator, using actual panel data, suggests the smaller 100/20 regulator could limit current at low temperatures (max 29A @-10°C) so I'm going for the 100/30, which also gives me the option of adding another small panel if required. A 75/30 version would be more than enough on the voltage side but they don't make it. Link to comment Share on other sites More sharing options...
niktam Posted October 3, 2019 Share Posted October 3, 2019 Have I missed somethng but to reduce the current put cardboard over the panels first? Link to comment Share on other sites More sharing options...
dipsticks Posted October 3, 2019 Share Posted October 3, 2019 I have used a solid state relay, mine is controlled by a 7day 12v programmeable timer to avoid overcharging the batteries when laid up but could easily be operated by a simple small switch. https://tinyurl.com/y45nfudb Current draw is neglible Link to comment Share on other sites More sharing options...
ChrisCM Posted October 4, 2019 Share Posted October 4, 2019 I put some MC4 connectors in the cables from the panels to controller in an accessible location to break the cables for maintenance. Not very elegant but it works! Link to comment Share on other sites More sharing options...
mikefitz Posted October 4, 2019 Share Posted October 4, 2019 There are some interesting numbers being sugested in this thread. A typical 160 watt panel will have a specification at maximum power of 18 volts and 9 amps. Two in series will give 36 volts and 9 amps into the controller. If a switch is needed, and I cannot see any need for one, any automotive switch or relay rated at 10 amps or more would work. The controller will work it's magic on the solar power and converts to a suitable battery voltage at a maximum of about 24 amps in theory. The Victron controller once connected to the battery for the first time auto selects 12v charging, this setting is retained even is the battery is disconnected at some stage. Adding an extra panel to the existing 160 watt panels, requires it to be similar if added in series. If a smaller panel is added the current would be limited to the current of the smaller. If all the panels, with similar voltage, are connected in parallel the currents just add, so a mix is possible. Mike Link to comment Share on other sites More sharing options...
spirou Posted October 4, 2019 Author Share Posted October 4, 2019 mikefitz - 2019-10-04 11:12 AM There are some interesting numbers being sugested in this thread. A typical 160 watt panel will have a specification at maximum power of 18 volts and 9 amps. Two in series will give 36 volts and 9 amps into the controller. If a switch is needed, and I cannot see any need for one, any automotive switch or relay rated at 10 amps or more would work. Mike Quite, my mind is all over the place so logic took a break. Victron marks the models as max input voltage (e.g. 100), max output current (e.g. 30). I forgot I need to think about input current/voltage. Link to comment Share on other sites More sharing options...
plwsm2000 Posted October 4, 2019 Share Posted October 4, 2019 dipsticks - 2019-10-03 10:45 PM I have used a solid state relay, mine is controlled by a 7day 12v programmeable timer to avoid overcharging the batteries when laid up but could easily be operated by a simple small switch. https://tinyurl.com/y45nfudb Current draw is neglible This particular type of SSR will waste power as it uses a bipolar transistor on its output (according to the ebay info). This type of transistor has a saturation voltage of at least 1V at 10A so losing over 10W of your solar energy. A SSR with a MOSFET output should be a lot less (2W or so). On the subject of voltage rating on switches etc. it is also worth mentioning that most automotive fuses (ATO, maxi, mega) are only rated at 32VDC. I think this is mainly for safety reasons (rather than voltage withstand limits) since it is easy to touch the spade contacts when changing fuses. Link to comment Share on other sites More sharing options...
Paul- Posted October 4, 2019 Share Posted October 4, 2019 The instruction on my controller are to connect battery first so the controller knows what voltage the battery is (12 or 24v) and then to connect the solar, it must not be connected to the battery while the solar is connected. A switch would save covering the panels or unscrewing a terminal at the controller. Link to comment Share on other sites More sharing options...
John Allen Posted October 4, 2019 Share Posted October 4, 2019 I knew we would miss Allan of aandncaravanservices.co.uk. I just didn't realise how quickly or how much. He must be dispairing as looks down and reads this thread. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.