Parallel Panel Connections / System overview

tr0y Solar Expert Posts: 99 ✭✭✭
So my solar powered horse trailer project begins, 4 12V ( 17.6Voc 7.2a) 135 watt panels, a Xantrex c35 CC ( wanted the rogue mppt but budget did not allow it), Xantrex trace 1512 inverter charger, 4 or 6 400 AH AGMs and a Honda 2000i Generator.

My question is all the + on the panels tie together and all the - tie together to stay at 12V, join them in a junction box ? The PWM CC can not down convert current Correct ?

Feed this in to a breaker box with 15A breaker, then to C35 through another fuse to the battery bank and out to batteries. If these are not the right size breakers / fuses what would you recommended ?

Is the C35 a waste of time and money ? it was $75.00 vs the Rogue at $315.00 I know the MPPT is better but is it worth the extra cost ?

From the battery bank to the 1512 inverter and then to my 120V power center.

Sound about right ? Experts your thoughts ? Any Changes I should make ?


  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Parallel Panel Connections / System overview

    Correct, the C35 is a PWM controller, and you should use 18-20V panels with it, and program to manual equalization cycles.
    If you can keep the solar DC wires fat and short, you will lower the losses, locate the charge controller where you can read it easily, and purchase the battery temperature sensor for it, for best battery life.

    You could have up to 30A of DC, so you need in your combiner box, a 10A breaker or fuse, on each panel feedline. There are marine 12VDC circuit breakers, and then there is a big step up to higher grade DC breakers. Midnight makes some combiner boxes, our host carrys them, and breakers, and the other goodies you need.

    Don't forget a fuse on your battery, I love the simple and compact MRBF terminal fuse by blue sea (MRBF - Marine Rated Battery Fuse) I wish Wind Sun would carry these goodies.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    gen: ,

  • arkieoscar
    arkieoscar Solar Expert Posts: 101 ✭✭
    Re: Parallel Panel Connections / System overview

    If the C35 is the same line as the C40 and C60, it's a good charge controller for the money. For what you paid, I bet you didn't get the face plate with the LCD display and only have a single light on the front, which blinks code for battery condition. Dip switches set voltage and equalization settings and two pots are for adjustments. Pretty bullet proof and probably a good choice for your application. The blue sea fuses are great in that they don't need enclosures or take up much space. You can also use them on a small bus bar for the panels.