Adding portable panel power to existing system

bluewickedburner
bluewickedburner Solar Expert Posts: 78 ✭✭✭✭
in Solar Beginners Corner #1
At times it will advantageous to put out some ground based panels to augment roof mounted panels (motorhome). My question is what is common practice in connecting the portable panels to the remainder of the system as a plug and play arrangement.

All of the panels are 12 volt and so is the battery bank.

I'm thinking I would put a combiner box near the charge controller which is in the basement storage since this is an additional array. My goal is to have a plug in type arrangement with the objective of being able to plug the portable array in (2 or 3 100 watt panels) and then open the circuit to allow energy to flow.

Storage space considerations limit the size of the portable panels I can take along since they will be stored edgewise in a suspended carrier instead of flat.

Ideas are appreciated.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Adding portable panel power to existing system

    It can be done.

    Concerns, other than transportation of the panels themselves, include safety of the panels on the ground. Big hunks of expensive glass + people activity = potential big hunks of broken glass. Securing them against theft or just plain being blown away is another issue.

    Can your existing charge controller take the additional panels? Or will you be adding a second controller? Remember to consider wire sizes in this, including the run from the "ground mount" panels which may be fairly long and subject to some noticeable Voltage drop.

    There's been discussion about this before on the forum. One of the safety concerns was for the connector itself, and the notion that you could potentially have exposed current source either at one end or the other. I think the Anderson connectors came out on top as best choice to minimize the hazard. Could be wrong.

    Of course you need to figure on circuit protection as needed, and at least a switch to close (*ahem*) the circuit for use if not a breaker to handle both jobs.

    Lots of possibilities.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,654 admin
    #3
    Re: Adding portable panel power to existing system

    Also, if you are remote mounting panels:
    1. Make sure they are staked to ground--Don't blow or walk away
    2. Recommend a non-locking connector (Andersons are fine) if somebody trips over the extension cable or if somebody drives away and forgets the panels--you don't yank them up and drag them behind you
    3. Use the panels in series with a MPPT type charge controller. This allows you to use reasonable gauge extension cable for 50-100' and still have an efficient charging system. If you use Vmp=17.5 volts and a PWM controller--the extension cable has to stay short or the copper gauge goes way up to keep voltage drop low.
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • bluewickedburner
    bluewickedburner Solar Expert Posts: 78 ✭✭✭✭
    #4
    Re: Adding portable panel power to existing system

    The storage of the panels is taken care of, they aren't going to break since they can't bump into anything including each other and are basically suspended.

    Thanks for that connector link, makes it simple for me.

    Panels only go out when there is little wind and we go places where others do not. Just in case the tripod stand in staked to the ground and secured with lock and cable. Insurance takes care of theft.

    So I'm down to a connection method. My thoughts are to use #8-3 wire (10') with a female terminator and plug that into a a junction box with circuit breaker that I can use for on-off. That box is keyed and so is the storage bay for the charge controller.

    That box then feeds to a combiner for the source from the roof and also the portables. The panels on the roof go to a combiner box already so just that feed down to below.

    That does mean if the breaker is set to on there is an exposed live feed (12 volt) but then opening my battery bay reveals the same thing, battery terminals are exposed, the idea being not to touch them.

    In the end, take cord, open storage bay and junction box. Check breaker for off, plug in portable array, turn breaker on, lock up. Lock bay door. Done. I can't think of another way to do it.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,654 admin
    #5
    Re: Adding portable panel power to existing system

    Anderson connector (power pole) are somewhat protected against shorting--So you should not have a big issue with them.

    Exactly what panels are you looking at (Vmp/Imp/Watts) and what charge controller are you thinking of using (PWM or MPPT)?

    That will help us to size the wire and the connectors.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • PhilS
    PhilS Solar Expert Posts: 370 ✭✭✭
    #6
    Re: Adding portable panel power to existing system

    I have one portable panel with our RV in addition to the one mounted on the roof.

    I discussed how I wired it in this thread http://forum.solar-electric.com/showthread.php?t=11258

    Phil
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  • bluewickedburner
    bluewickedburner Solar Expert Posts: 78 ✭✭✭✭
    #7
    Re: Adding portable panel power to existing system
    PhilS wrote: »
    I have one portable panel with our RV in addition to the one mounted on the roof.

    I discussed how I wired it in this thread http://forum.solar-electric.com/showthread.php?t=11258

    Phil

    Thanks for that, gives a good idea.
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