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Mello_Mike's avatar
Mello_Mike
Explorer
Dec 22, 2015

Solar Advice Needed - Renogy Solar Suitcase Install

I'm a long-time solar power user and have had solar power in my last three RVs. I currently have a 240 watt solar power system in my truck camper. I'll soon be upgrading my system from a Zamp PWM to a Morningstar MPPT controller. I just ordered a Renogy 100 watt solar suitcase which will allow me to aim an additional two 50 watt panels toward the sun. A huge bonus, giving me a total of 340 watts.

Here's my question: should I tap my new 100 watt suitcase into my current solar power system or keep the suitcase wiring to the batteries separate? The Renogy suitcase has a built-in 10 amp PWM controller, so I don't have to tap into my current solar power system if I don't want to. Just not sure which direction I should take. I don't want to make this installation more complicated than it really is.

I purchased a two-pole 12 volt plug and socket to connect and disconnect the suitcase from the camper. Does anybody else have a hybrid fixed and portable solar panel mount for their RV?
  • tonymull's avatar
    tonymull
    Explorer
    Dec 22, 2015
    Keep in mind that you might want to use the suitcase for something like charging a trolling motor battery. I'd keep them separate.
  • SkiSmuggs's avatar
    SkiSmuggs
    Explorer
    Dec 22, 2015
    I have a similar set up, but for now, my are separate. I have thought of bypassing the 10w controller in the suitcase and connecting to the 30w PWM controller for the efficiency of having the controller close to the battery bank. I suppose with a little ingenuity you could have it both ways by having a 2-pole plug at each controller. Just plug into the controller of choice. Leave the original wires but make a separate long 30-50' cable with connectors at each end for the run to your MPPT controller. That gives you more flexibility for locating the suitcase panels in the sun while you are camped in the shade.
  • BFL13's avatar
    BFL13
    Explorer II
    Dec 22, 2015
    Need more info.
    -Is the 240 now two 120s in parallel nailed flat to the roof? or can they be tilted?
    -will the two 120s be in series with the new MPPT (which affects options for how the 100 can be integrated)
    -how many amps (size) is the PWM controller? (can you just add the 100 to that--very simple then)
    -what do you expect to gain from changing the 240 to MPPT?
    -how far away from the rig will you be deploying the suitcase set?
    -100w will do about 6.2amps aimed at high sun. Why is that considered "huge?" What do you get now with the 240 as is?

    There are too many ways to connect it all to try suggest any one way without knowing more of the situation.
  • Almot's avatar
    Almot
    Explorer III
    Dec 22, 2015
    Are you adding parallel 2*50W/12V to parallel 2*120W/12V?

    If it's 2*120W/12V, it will work, all 4 panels, on your MPPT, but it won't be efficient because panels are so different. It's better to add a single 120W and wire 3 panels either in parallel or in series. With series wiring watch out for voltage limit of controller.

    Don't know whether using an old PWM with 2 panels and MPPT with 2 other panels will be more efficient than all 4 on one MPPT - there will be quirks with this scenario either.
  • BFL13's avatar
    BFL13
    Explorer II
    Dec 22, 2015
    When you park the TC, do you unplug the truck to camper 7 (or 6) pin?
    I do to keep the truck's battery from running down (Chev truck, no isolation)

    That leaves the TC 7-pin socket empty, So you could add a 7-pin type plug to the battery wires on the suitcase (pin 4 and ground only) and just plug the suitcase (which has the built-in controller) into that, which will then charge the TC battery in parallel with the other solar set.

    Not ideal for distance from controller to battery, but you still get something from it.
  • Mello_Mike's avatar
    Mello_Mike
    Explorer
    Dec 22, 2015
    In response to BFL13:

    -Is the 240 now two 120s in parallel nailed flat to the roof? or can they be tilted? Two fixed 120 watt panels in parallel
    -will the two 120s be in series with the new MPPT (which affects options for how the 100 can be integrated) In parallel
    -how many amps (size) is the PWM controller? (can you just add the 100 to that--very simple then) - 30 amps
    -what do you expect to gain from changing the 240 to MPPT? Need every watt I can get out of my system for my new Danfoss compressor refrigerator
    -how far away from the rig will you be deploying the suitcase set? Not far at all, about 10-15 feet
    -100w will do about 6.2amps aimed at high sun. Why is that considered "huge?" What do you get now with the 240 as is? It's huge for me because my existing 120 watt roof panels are fixed. Not only does this suitcase give me another 6 amps, but it's aimed directly at the sun unlike the roof panels.
  • Mello_Mike's avatar
    Mello_Mike
    Explorer
    Dec 22, 2015
    BFL13 wrote:
    When you park the TC, do you unplug the truck to camper 7 (or 6) pin?
    I do to keep the truck's battery from running down (Chev truck, no isolation)

    That leaves the TC 7-pin socket empty, So you could add a 7-pin type plug to the battery wires on the suitcase (pin 4 and ground only) and just plug the suitcase (which has the built-in controller) into that, which will then charge the TC battery in parallel with the other solar set.

    Not ideal for distance from controller to battery, but you still get something from it.


    No, it's always plugged in. I have a battery isolater in my truck camper. Your idea has merit except I always leave my camper plugged in. It might work for someone else, though.
  • NinerBikes's avatar
    NinerBikes
    Explorer
    Dec 22, 2015
    Mixing different watts and different input voltages from different panels will confuse the MPPT. If you use a PWM charge controller and run all parallel inputs into a 20 amp PWM controller, you will get better results.

    You will be lucky to get 5.5 amps out of a 100 watt suitcase solar panel. Don't ask me how I know this. I was lucky to get 6.2 to 6.3 amps out of my 120W solar panel in early October, aiming at the sun. Less in winter.
  • Almot's avatar
    Almot
    Explorer III
    Dec 22, 2015
    If you have space left on the roof, you can add one more panel - as big as you can. 140W flat will work the same as 100W tilted. BFL will probably argue with graphs and numbers, that is is not quite "the same" during fall and spring seasons when sun is low, - but it won't be much different either. Last time I checked, AZ was pretty far South.
  • BFL13's avatar
    BFL13
    Explorer II
    Dec 22, 2015
    The 30a PWM can handle the 340w ok, so you could just add the extra 100 to that controller. That would be the easiest right off, then see how it goes for daily AH. If you still need more AH once you have tried it a little, then you might want to consider a more drastic solar upgrade anyway.

    If you go MPPT on the 240, you must add the 100 separately to the battery via its own controller. The Vmp tracker works best with all same panels.

    You could put the two 120s in series with the MPPT as 24-12 instead of 12-12 and get a bit more output in low-light or shoulder hours--no diff in high sun though.

    You could yank one 120 off the roof and make that your portable and put the 100 on the roof instead (staying all PWM for mixed panels) That puts more of the total "aimed"

    You could keep the money for the new MPPT, stay with the existing PWM, and spend that on a second suitcase 100. That would give you 440w.

    Lots of choices!

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