Wiring for 2 solar panels?

[yamsack]

Hey all,<br>I have 2 flexible solar panels that I will be mounting onto the roof of my van.&nbsp; How will I be able to connect the wiring from these 2 panels to my charge controller?&nbsp; Do I strip the wires from the 2 positive ends and simply twist them together to crimp onto the positive terminal of the charge controller (likewise with the neg ends)?<br><br>Secondly, since I have 2 pos ends (from the 2 panels), should there be a separate fuse for each of the pos wires, or will 1 fuse be sufficient?&nbsp; Thanks everyone.<br><br>

 

[yamsack]

Hi <b>sparky1</b>,<br>Since you've been so good at responding to my questions, and you seem to know what you're doing, could you bare with me as I'll be asking a few more questions in the next few posts regarding how to wire the solar electrical components together.&nbsp; I've got almost everything else set up for my campervan except the knowledge of how to wire the electrics.<br><br>First off, others in this forum have attempted to help me with the wiring, but I am a complete newbie to this and get confused/overwhelmed very easily.<br><br>My first question again is how to take the 2 positive and 2 negative wires (from my 2 solar panels) :<br><br>http://www.amazon.com/Uni-Solar-PVL...=sr_1_3?ie=UTF8&amp;qid=1327492661&amp;sr=8-3<br><br>and wire them to this:<br><br>http://www.morningstarcorp.com/en/sunsavermppt<br><br>Do I expose about 1/2" inch on each of the 4 ends, twist together the 2 positive and 2 negative ends, then connect them to the positive and negative terminals of the controller?<br><br>By the way, please keep the terminology as simple as possible.&nbsp; Thanks a million for your responses.<br><br>

 

[yamsack]

Hi sparky1,<br>First off, please be patient with me as I want to go 1 baby step at a time.&nbsp; It's critically important that I get this right, or else either I go up in flames from an electrical fire or damage expensive stuff.&nbsp; For now, I'm only going to ask questions regarding your first paragraph:<br><br><b>"... be careful NOT to ground or short circuit them to each other.put the Positive together twist them tightly,Tape them together,or if there is enough wire---them straight to the Morningstar controller-Inputs. Not sure how your coming (inside) the vehicle but Be careful NOT to pinch-them,(Damage) ..."<br></b><br>__&nbsp; Do you mean that touching the positive wire to the negative wire would short circuit or ground them?<br><br>__&nbsp; By "pinching" the wires, do you mean bending them sharply?<br><br>__&nbsp; When connecting the solar panel wires to the Morningstar, should there be an order of which wires get connected first (positive or negative)?<br><br>__&nbsp; At this stage only (between solar panels and controller), should there be any fuses attached and if so, how many, what kind and where specifically?<br><br>Once the positive and negative wires are each twisted together (and taped together), I was going to then tape the 2 combined sets of cables together in a row and run them through the back door into the van (at the rubber lining around the door hinge).&nbsp; The controller, batteries and inverter will be situated near the back door, so wire runs will be no more than 2-3 feet.<br><br>

 

[blars]

Most of what Sparky said, plus:<div><br></div><div>12&nbsp;gauge&nbsp;wire is plenty for those panels (even if connected in series (together).

<br><br>Correction: parrallel not series.&nbsp; You could do series if you have a mppt controller, but people have reported problems when one of the panels is in partial shade when doing so.<br><br></div>

 

[yamsack]

<b>@ sparky1</b>,<br><br>OK, now we get to the wiring from the Morningstar to the 2 AGM batteries.<br><br>__&nbsp; Since there are 2 batteries, do I need to run 2 positive wires and 2 negative wires from the Morningstar to each positive and negative posts of the 2 batteries, or does 1 pos and 1 neg need to go to only one of the batteries?<br><br>__&nbsp; Do I still need to fuse the positive wires before they connect to the batteries?&nbsp; If so, would 10 amps be sufficient as before?<br><br>__&nbsp; What gauge wire would you recommend running from the Morningstar to the batteries?<br><br>Since the 2 panels are rated at 138 Watts total, I was planning on getting the 2 batteries to be roughly around 140-150 amp hours total (70-80 amp hours each).&nbsp; From what I've read, batteries with anything higher amp hours and the panels, even at max efficiency, would not be able to keep up with fully charging the batteries daily.&nbsp; I understand that there are many variables, such as usage, amount of daylight, etc.<br><br><br><b>@ 4x4tour</b>,<br><br>I know I've bugged you several times before with questions about this stuff.&nbsp; That's why I want to get another person's opinion about this.&nbsp; This is my project and I want to be as thorough as I feel is necessary, even if it means asking stupid questions or sounding repetitive.&nbsp; I understand that if I still don't get it, I may need to shell out a lot of money to have someone else do it for me.&nbsp; But, I know I can do this.&nbsp; While I appreciate all of your advice, please allow me to do this my way.&nbsp; Thank you.<br><br><br>

 

[akrvbob]

The Unisolar panels come with its own quick connector. I forget what it is but it is probably either an MC3 or MC4or it may be propietary. Unless your controller accepts one of those you are going to have to cut something to get to the wire. Cutting the connector coming from the panel will void the warranty so I would buy an extension and cut the end off it which will get you into the + and - wires. Then crimp on an end and connect them to the same post on the controller. <br><br>If you're two batteries are 12 volt then you just hook them up in parallel (+ to+, - to -). I would want at least 200 amps of battery bank.&nbsp; I would use 8 gauge wire. from the controller to the batteries since it is carrying twice the amps of a single panel. Bob<br><br><br><br>

 

[akrvbob]

I've got to ask why are you getting the flexible panels. Unless you are getting an incredible deal for them you would be much better off buying a normal panel. You know they are 9 feet long right? You can get a 185 watt Kyocera panel for $300 which will take up much less room on your roof.&nbsp; Or you can buy blemished 205 watt panels for $270. Sometimes the only thing that will work is the flexible panels, but unless you have a specific problem to solve, I'd buy regular panels. Bob<br>

 

[yamsack]

<b>@ akrvbob</b>,<br><br>Thanks for the info.&nbsp; The reason I'm getting a couple of flexible solar panels is that I have a high top conversion van, which is somewhat curved, as well as for the low profile of the panels, which are very thin.&nbsp; I'm trying to hide the panels once they've been mounted onto the roof.&nbsp; Unless someone is higher up looking down on the van, I'm thinking that most folks won't notice the panels at all, except the cables running through the back doors.<br><br>I hope you don't mind picking up where sparky1 left off, but I really need someone knowledgeable to baby walk me through this, especially since you're the one who wrote that very informative article on this website.&nbsp; So far, I think I've got the wiring figured out from the panels to the controller.&nbsp; Next is wiring from the controller to the batteries.<br><br>__&nbsp; Since I've got 2 batteries, do I need to run 2 positive and 2 negative wires to both batteries (from the controller) or only 1 set of pos/neg to only the first battery?<br>__&nbsp; Do I need to fuse the positive wire(s) before they connect to the battery(ies)?&nbsp; If so, how many amps do you recommend?<br><br>Thanks very much for any help you can give.<br><br><br><br>

 

[blars]

<b></b><br>__&nbsp; Since I've got 2 batteries, do I need to run 2 positive and 2 negative wires to both batteries (from the controller) or only 1 set of pos/neg to only the first battery?<br>__&nbsp; Do I need to fuse the positive wire(s) before they connect to the battery(ies)?&nbsp; If so, how many amps do you recommend?<br>

<br>If you have two twelve volt batteries, you run the positive wire to the postitive terminal of one battery and the negitive wire to the negitive of the other.&nbsp; That equalizes the wire lengths to the batteries.&nbsp; With two 6-volt batteries, you wire them in series and treat it at a single twelve volt.<br><br>For 140 watts at 12 volts, that's just under 12 amps.&nbsp; (140/12)&nbsp; The fuse should be 20-50% larger, so use a 15 or 20 amp fuse.&nbsp; In practice, you'll almost never get the 12 amps, so the 15 amp fuse should work.<br><br>

 

[yamsack]

Thanks so much blars.<br>

 

[akrvbob]

Blars gave you good advice about wiring your batteries together. Once you wire batteries together in parrallel (+ to +, - to -)&nbsp; they stop being two 12 volt batteries and become one single, giant 12 volt battery. Or if you have 6 volt batteries wired in series (+ of one battery terminal to the - of the other battery post) they stop being two 6 volt batteries and become one 12 volt battery. Your eye sees two batteries, but electronically they are only one. Because you only have one battery, you would only run one set of wires from the controller. <br><br>Yeah, some of the class B roofs are impossible to mount panels on and the flexible panels work great. Sometimes it is a pain to mount normal panels on fiberglass roofs also, then the Uniroyal are much easier. Bob<br><br><br>