Combining panals of different manufacturers?

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Gregmik
Gregmik Registered Users Posts: 19 ✭
in Solar Beginners Corner #1
I just joined as I had a specific question and will be reading and I am sure learning more from here.

I have a 18 watt Amorphous panel from Northern Tool, and I have bought 2-50w Poly crystalline panels from Epcom. My question is would it be ok to hook the 18 watt in Parallel with the two 50w?

Thanks in advance,

Greg
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #2
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    Re: Combining panals of different manufacturers?

    what is the vmp and imps of the pvs and assuming you have one, what is the ampere capacity of your controller?
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  • Gregmik
    Gregmik Registered Users Posts: 19 ✭
    #3
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    Re: Combining panals of different manufacturers?
    niel wrote: »
    what is the vmp and imps of the pvs and assuming you have one, what is the ampere capacity of your controller?

    I am very new to this, so I do not know what VMP or IMPs stand for. The rated voltage of the 50w panels is 17.8v with an amp rating of 2.78a. The 18w panel does not give me ratings but in the sun it puts out 21v at .9a. I have a 7 amp controller.

    I have a source for free used gelcells from electric wheel chairs. I currently have 8 of those, but only am only charging 3 at a time.

    Next purchase is a 40amp HPPT controller as I know I am at my limit with the 7amp NPower(Sunforce) I currently have.

    Thanks,

    Greg
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #4
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    Re: Combining panals of different manufacturers?

    ok, i think you could parallel them if the controller you have can really take that much current. the 21v for the one is most likely open circuit voltage and would fall more inline with the other pvs being in the 17v range. if it's not open circuit voltage (voc) and is 21v vmp then there will be an imbalance and some wasted power too, but it should still operate.

    i guess i better add that if there is a large voltage difference that one pv could backfeed some of its power into the smaller voltage pvs if there aren't any blocking diodes in place to the lower voltage pvs. only you can verify if the voltages are near each other as some will say within 10% and i often recommend 5%, but 10% will function without a bad backfeed in power.
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  • Gregmik
    Gregmik Registered Users Posts: 19 ✭
    #5
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    Re: Combining panals of different manufacturers?

    Another newby question. I just checked and the amps of my panels are at 7.5amps. the controller is getting warm. I am thinking of taking the controller out and maybe hooking a couple more bats up just so I don't over charge them. Good idea? Or just take the small panel off until I get the bigger controller?

    Thanks for all the help,

    Greg
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #6
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    Re: Combining panals of different manufacturers?

    it seems you are overloading your controller. you will need to take out a pv to continue using that cc or risk burning it up depending on the controller. i think you'll like an mppt controller, but remember it is the current that is outputted that they are rated for and this can exceed the input current due to the nature of mppt. be sure you get an mppt controller large enough to handle any of you needs now and in the future as it is a pain in the rump to continually buy a new cc every time you upgrade.
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  • Frxddy
    Frxddy Solar Expert Posts: 113 ✭✭✭✭
    #7
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    Re: Combining panals of different manufacturers?

    I'm probably not helping, but wanted to bring up.... I use gel batteries from wheel chairs to power an electric motorcycle. They can not be charged with a "normal" battery charger, they need a "smart charger". I'm not sure how this enters into your equation, but I do know that if you notice your batteries bulging during charging, stop charging! I'm told if they are charged on a "normal" charger they will bulge, then self destruct. With the worst of luck one could burst.
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  • Gregmik
    Gregmik Registered Users Posts: 19 ✭
    #8
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    Re: Combining panals of different manufacturers?
    niel wrote: »
    it seems you are overloading your controller. you will need to take out a pv to continue using that cc or risk burning it up depending on the controller. i think you'll like an mppt controller, but remember it is the current that is outputted that they are rated for and this can exceed the input current due to the nature of mppt. be sure you get an mppt controller large enough to handle any of you needs now and in the future as it is a pain in the rump to continually buy a new cc every time you upgrade.

    I am thinking of an instaspark 40 amp mppt controller. They seem to relatively inexpensive and this should give me plenty of space to grow. Any other suggestions at what I should be looking for?

    Thanks

    Greg
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  • Gregmik
    Gregmik Registered Users Posts: 19 ✭
    #9
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    Re: Combining panals of different manufacturers?
    Frxddy wrote: »
    I'm probably not helping, but wanted to bring up.... I use gel batteries from wheel chairs to power an electric motorcycle. They can not be charged with a "normal" battery charger, they need a "smart charger". I'm not sure how this enters into your equation, but I do know that if you notice your batteries bulging during charging, stop charging! I'm told if they are charged on a "normal" charger they will bulge, then self destruct. With the worst of luck one could burst.

    Yes I do know this. You need to charge at a lower amperage than a normal starting battery. If you put too many amps thru it the battery will start to form hydrogen. These hydrogen bubbles will push the gel electrolyte away from the plates and the result will be like running a flooded battery to low on water. Same result if you over charge them. With a flooded type the hydrogen will form and just start the electrolyte bubbling, which will not harm anything until the electrolyte level gets low enough to expose the plate. You get those bubbles tho in a gelcell.

    Thanks

    Greg
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #10
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    Re: Combining panals of different manufacturers?
    Gregmik wrote: »
    I am thinking of an instaspark 40 amp mppt controller. They seem to relatively inexpensive and this should give me plenty of space to grow. Any other suggestions at what I should be looking for?

    Thanks

    Greg

    never heard of it. it may or may not be good, but i don't know for sure either way so you could be taking a chance with that. now you could go with the rogue 30a mppt as it is uncertified or go with a tristar 45a mppt. don't confuse their pwm tristar with the mppt one.
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  • Gregmik
    Gregmik Registered Users Posts: 19 ✭
    #11
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    Re: Combining panals of different manufacturers?
    niel wrote: »
    never heard of it. it may or may not be good, but i don't know for sure either way so you could be taking a chance with that. now you could go with the rogue 30a mppt as it is uncertified or go with a tristar 45a mppt. don't confuse their pwm tristar with the mppt one.

    Wow, I am on a budget. ;)

    Those are a little out of my price range right now. The instaspark is about $150. I know it will not be as good. But for right now I hope it will suffice.

    Thanks for all your help,

    Greg
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  • Gregmik
    Gregmik Registered Users Posts: 19 ✭
    #12
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    Re: Combining panals of different manufacturers?

    OK after reading a bit about the instaspark. It does not do a DC to DC conversion. It just applies a "Load" to drop the voltage. I don't see how that works for anything but rob power away from your cells. So maybe right now I just get a pwm in the 30a range and save up for the true MPPT controller.

    Thanks again for the help...saved me a bit of money today.

    Greg
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  • bmet
    bmet Solar Expert Posts: 630 ✭✭
    #13
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    Re: Combining panals of different manufacturers?

    I have difficulty with some of these Chinese products based on the word association.

    Instant Spark - not what I want in a CC
    We'll See - How long that solar device lasts....

    ...and I'm sure you know a few more.
    Gregmik wrote: »
    Wow, I am on a budget. ;)

    Those are a little out of my price range right now. The instaspark is about $150. I know it will not be as good. But for right now I hope it will suffice.

    Thanks for all your help,

    Greg
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