Guest 1footinthegrave Posted February 1, 2012 Share Posted February 1, 2012 Having scoured the internet for hours, I do not seem able to find an answer to the following questions with regard to fitting a solar panel. Can anyone help fill in the blanks. I'm up to speed with the need for a charging regulator before wiring in to the batteries, but this is what I'm stuck on. As most vans have a split charging relay from the alternator output, and also a mains charger when on hook up, and of course on a sunny day the output from the panel, do these systems have to be isolated in some way from one another. I simply can't get my head around how either an alternator or a mains charger can be left connected so bringing about the possibility of two charging systems attempting to charge the same batteries, or is the answer to fit an isolation switch to the solar panel output when either on the move, or on mains hookup, so that this does not occur, any help gratefully received. ;-) Link to comment Share on other sites More sharing options...
spospe Posted February 1, 2012 Share Posted February 1, 2012 Just add the solar panel output to the leisure battery. The full answer would take some time to type out (and for you to read), would inevitably contain some aspect which was not 100% clear and would thus generate a fair amount of 'correspondence' between the various experts on here; but the bottom line is as stated above ;-) Link to comment Share on other sites More sharing options...
neillking Posted February 1, 2012 Share Posted February 1, 2012 Dead straightforward as said. If you contact me direct I'll gladly email a wiring diagram, it is for the systems we sell but the general scheme of things is very similar for all add-on installations. There can be some differences if adding-in to a system with a solar point pre-installed but unless in a very new 'van many of us choose to ignore those anyway. Link to comment Share on other sites More sharing options...
Guest Tracker Posted February 1, 2012 Share Posted February 1, 2012 I wired my solar panel directly to the battery via the regulator and then via an isolating switch on the positive side to avoid live leads dangling if I needed to remove either or both batteries. You may need extra cables - I did - from regulator to battery, so make sure you use good quality high amperage cables to avoid voltage drop. I went mad and used 30 amp (from local motor factor) which was similar in thickness to the original panel cable but the extra cost was minimal. For the cable run from the roof locker down to the floor locker I used self adhesive 15mm trunking (from Screwfix) discreetly fixed not to be obtrusive. Might mean an extra bit of cable but that should not be a problem if the cable is adequate for the job. Link to comment Share on other sites More sharing options...
BGD Posted February 1, 2012 Share Posted February 1, 2012 In very simple terms I thought it went:- solar panel on roof. Two wires leading from it to a charge regulator, two wires coming out of charge regulator to leisure battery. We've actually got our single, roof mounted, 75 watt solar panel wired to TWO charge regulators, one then feeding the leisure batteries and the other feeding the vehicle battery. I assume they just share the power coming from the solar panel on a 50/50 basis. (As an aside - I'm not sure whether adding a second solar panel would need a second charge regulator. Maybe someone could tell me: if I bought a second, say 80 amp solar panel and put it on the roof, with its wires coming down into the existing charge regulator that then feeds the leisure batteries, would that be OK?) Link to comment Share on other sites More sharing options...
spospe Posted February 1, 2012 Share Posted February 1, 2012 BGD Provided that the total output of your solar panels does not exceed the rating of the regulator, then just connect them in parallel and all will be well. Link to comment Share on other sites More sharing options...
neillking Posted February 1, 2012 Share Posted February 1, 2012 Might be easier to change the reg to one that takes two panels and also offers starter battery charge 'oversplill'? Link to comment Share on other sites More sharing options...
Guest Tracker Posted February 1, 2012 Share Posted February 1, 2012 BGD - 2012-02-01 2:11 PM (As an aside - I'm not sure whether adding a second solar panel would need a second charge regulator. Maybe someone could tell me: if I bought a second, say 80 amp solar panel and put it on the roof, with its wires coming down into the existing charge regulator that then feeds the leisure batteries, would that be OK?) With all that luverly sunshine that you get Bruce I am surprised that you need another solar panel, and I have to wonder whether an extra leisure battery would be a cheaper and easier solution to more battery power or duration? I haven't a clue how one panel would split it's output between two regulators but I suspect that in theory at least ,as electricity is like water and takes the path of least resistance, I suspect that the lowest charged battery will take the highest, or maybe the total output? A solar panel can mask an iffy battery because it is constantly recharging every day and if you have built in battery voltage monitoring or a multimeter as you could check each battery voltage to see how well they are holding their charges. You would need to disconnect them from charging for a day or so to get a true picture I think. No doubt Brambles will be along later to put me right again! Link to comment Share on other sites More sharing options...
Brambles Posted February 1, 2012 Share Posted February 1, 2012 1foot, Basically they do not fight each other but just have a little disagreement who wil supply the power and soon settled amongst themselves. If you have the Sargent system which controls battery charging differently an basically takes advantage of when it is not being used to pump in a higher voltage and charge quickly then you need to contect the solar panel to the sergent system on its deditcated input for solar panels. So ignoring this specialised system. They work by just connecting everything to the battery directly. If the solar panel is only thing suplying power then it will and control the charging. If you then switch on mains power and the 12 volt onboard supply, all that happens is the solar panel controller sees the battrey volts rising so cuts down how much it supplies to the battery and may indeed even stop supplying power. The same goes if you now start your engine and the alternator kicks in via the slave relays and supplies 14.4 volts. Both the onboard charger and solar comtroller will not be required to supply any power and so will basically just stop supplying it or not so much. It all works quite nicely together. Who ever tries to supply the max volts will win the argument, sometimes each supplying a little and sharing who supplies. Link to comment Share on other sites More sharing options...
Brambles Posted February 1, 2012 Share Posted February 1, 2012 Either I am not reading the posts correct, got out of sync or just plain rushing this as busy doing too much at once. Re Solar panels in parallel. You could have two separate controllers, but because they operate the same way they actually could start having a fight, probably be fine and all work nicely, but no need to have two controllers. As long as your controller can cope with the max wattage from the two panels you just parallel up the panels together and then feed into controller. The panels have diodes fitted, so if one saw dark and one sunshine, it would not feed the other panel . If your panels did not have diodes, most do so battery power does not feed back into them, then you would have to fit diodes. So do check panels have diodes and are not relying on diodes built into the controller or cables. Edit - corected typos - as many typos as there are words...oops! Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted February 1, 2012 Share Posted February 1, 2012 Many thanks guys for all the help, Final question, is this likely to be a load of crap considering the price, as they all look the same to me, be they £500 or a £100. http://www.ebay.co.uk/itm/ws/eBayISAPI.dll?ViewItem&item=120838714240&ssPageName=ADME:X:AAQ:GB:1123 : Link to comment Share on other sites More sharing options...
BGD Posted February 1, 2012 Share Posted February 1, 2012 Thanks - and apologies to 1Foot for my earlier post which started as an attempt to help him, but then sort of wandered into me asking my own question and thus rather high-jacked his original query. Link to comment Share on other sites More sharing options...
Dr Dave Posted February 1, 2012 Share Posted February 1, 2012 After reading your post A simplistic explanation is as follows. The battery is a device that has a terminal voltage that will vary between 12+volts when it is discharged up to about 13.8 volts when it is fully charged. All the charging devices that are connected to your battery are one way devices that will provide current to the battery but will not allow it to flow back into the charger. They are all trying to push current into the battery by providing a voltage that is higher than the battery terminal voltage this continues until the battery terminal voltage rises to the magical 13.8volt (ish) fully charged figure and the charging devices monitor this voltage to achieve full charge. So if the battery is fully discharged and the Mains charger is providing say 10 amps into the battery but the voltage is still below 13.8v say for example its 13.2 volts the solar panel controller will try to provide additional current as it has monitored that the voltage is under 13.8 Volt so both will be providing current into the battery same with the alternator. Then when enough charge current has been provided by the combined charging sources the battery terminal voltage will rise up to 13.8v this would be the monitored maximum at which the charging sources will supply the battery and the charging sources voltages will reach equilibrium and no more current will flow until the battery becomes discharged and the terminal voltage falls again. Remember 12 Volt circuits require thick cable due to voltage drop and always install correct value fuses near to power sources. Some control units prefer to manage the solar charge themselves so check with the supplier if in doubt Link to comment Share on other sites More sharing options...
rolandrat Posted February 1, 2012 Share Posted February 1, 2012 1Foot if you ring Leisure Tech at Clitheroe they stock SunworksSB1 Solar Panel Charger Controllers, I think they cost £129 plus postage and are in stock. Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted February 1, 2012 Share Posted February 1, 2012 Thanks, however I'm looking at an 80 watt panel and controller for around £140, hence my earlier question, is it likely to be any good. (?) http://www.ebay.co.uk/itm/ws/eBayISAPI.dll?ViewItem&item=120838714240&ssPageName=ADME:X:AAQ:GB:1123 Link to comment Share on other sites More sharing options...
rolandrat Posted February 1, 2012 Share Posted February 1, 2012 Try it off your motorhome first. If it works then you can make it permanent. Link to comment Share on other sites More sharing options...
Brambles Posted February 1, 2012 Share Posted February 1, 2012 Put it this way, I would not pay £500 or a panel or £140 for a controller. Far too expensive. I might have paid £500 for a panel a few years ago but certaily not now. Like all things when supply chain prices plumet there will be a lot of stockists left beind with high prices . The US have accused the chinese of dumping panels below cost into the US markets. Maybe they are doing the same in Europe and poor fred with stock on the shelves bought a while ago is going to lose money. Link to comment Share on other sites More sharing options...
Melvin Posted February 1, 2012 Share Posted February 1, 2012 1footinthegrave - 2012-02-01 4:59 PM Thanks, however I'm looking at an 80 watt panel and controller for around £140, hence my earlier question, is it likely to be any good. (?) http://www.ebay.co.uk/itm/ws/eBayISAPI.dll?ViewItem&item=120838714240&ssPageName=ADME:X:AAQ:GB:1123 Hi, I started of with a 80 watt panel, most are resonable quality and value, by the time you add solar panel brackets, a gland and wiring you will nearer the £200 mark, and was more than happy for a while, however, I ended up going mad fitting a 20 AH MPPT controller alond with 2 x80 watt panels in series costing approximately £450.00 Link to comment Share on other sites More sharing options...
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