E panels, combiners and such.

Seven
Seven Solar Expert Posts: 292 ✭✭
in Solar Beginners Corner #1
I have questions on the Epanels and other electrical boxes. My system will have 9 of the Kyocers 210w panels(3 here, 6 yet to be ordered) and a Classic 150 CC.
I plan to run the panels in a series of three. That gives me a 99.6Voc. As I add the rest of the panels I plan on doing two more strings of three, and then parallel the strings together as they are added. This will keep me below 100v and add 7.9a per string.

What kind of electrical panels will I need for this? This is going to be an off-grid setup for now.

P.S. I know the answer could be a long one, but I really need the help.
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #2
    Re: E panels, combiners and such.

    Hi Leper,

    The exact DC/AC panel that you will need will prob depend on exactly what you are running for Inverter and battery bank etc. Probably you will be using Midnite boxes, as e-Panel is one of their lines, and they have many solutions at a reasonable price (to my way of thinking):

    http://www.midnitesolar.com/productCat.php

    As an aside, I hope that you plan to snag yhour Kyo 210s fairly soon, as the supply of panels seems to come and go over time, mostly they seem to go. Perhaps the 210/215 will be produced for some time to come, but this panel has 54 cells, and much of the production seems to have moved on to 60 cells per panel, and that might be a suboptimal solution should the 210s become difficult to find in the future.

    You might want to check with your supplier regarding the possible future availability of the 210/215s. Often one can find some older panels to match existing ones installed, but sometimes, the price is higher than one wants to pay, and so on.

    YMMV, Good Luck with your installation. Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,622 admin
    #3
    Re: E panels, combiners and such.

    Just use a Combiner Box of some sort (breakers or fuses) that take 4 or more parallel strings, adds a breaker per string, and one common bus out.

    Combiner Boxes

    There are several types, ones rated to ~150 VDC and another rated to ~600/1,000 VDC... The high voltage box is typically used for Grid Tied inverters with high Vmp-array voltages.

    Otherwise, the maximum number of strings/panels is limited by how much the single controller can pump into your battery bank (need to know controller maximum amperage rating and battery bank voltage).

    With an MPPT Charge Controller, you can put more panels on it than it can output (power wise)--It will simply limit its maximum output current to it max. rating. No danger/overheating.

    Was this the answer to your questions? Or did I miss something.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Seven
    Seven Solar Expert Posts: 292 ✭✭
    #4
    Re: E panels, combiners and such.

    Bill,
    Both posts help with my needed answer. Thank you.

    The reason for asking is that I keep looking at the different panels: combiner, disconnect, Epanel, and they seem to do basically the same thing, but have just enough difference to make me think I will need both. As you well know, I am still new at this.

    As far as I can tell the combiner box it what takes all the panels and makes them into a single output. They have breakers so that the strings can be disconnected from the rest of the system if they need to, or they is a problem that trips the breaker.

    E-panels seem to be down the line from the combiner box. This would be where the charge controller would be mounted close to and/or have the inverter mounted on them. They also have breakers. It seems like they always have AC breakers due to the inverter. Do they have DC breakers or is there supposed to be a combiner box before them. Is it ok for a single box to have AC and DC running through it? It seems like a sub panel and some wiring is all they provide. Is an E-panel just a cleaner way to wire everything? That is what it seems like to me.

    The disconnect box I get. A way to shut the power down.

    A transfer switch is a device that lets you go from grid to backup by disconnecting the main fuse box from commercial power and then applying power from the battery bank. I have seen manual ones and automatic ones. I don't need one of these right now as I am still building my setup as offgrid. I will need one when the time comes to go grid-tie-hybrid.

    Ok, answers and more questions. Seems to have become a habit of mine.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,622 admin
    #5
    Re: E panels, combiners and such.
    Leper wrote: »
    The reason for asking is that I keep looking at the different panels: combiner, disconnect, Epanel, and they seem to do basically the same thing, but have just enough difference to make me think I will need both. As you well know, I am still new at this.
    In someways, yes, there is an overlap.

    If you use the DC Ground Fault Protection--You can end up with several breakers in series from the PV Array main line to the charge controller.
    As far as I can tell the combiner box it what takes all the panels and makes them into a single output. They have breakers so that the strings can be disconnected from the rest of the system if they need to, or they is a problem that trips the breaker.

    The combiner box would typically be mounted at the solar array and a pair of DC lines from the array/combiner to the in-battery-shed E-panel / charge controller.

    You could also run individual wires from the Array to the battery shed and install combiner in the battery shed--really your choice.

    And, lastly, the combiner box breaker/fuses are intended to protect one string being shorted and being fed energy from the other parallel strings. The series breaker protects the shorted string from catching fire (hopefully).

    You can use the combiner box as a PV cut-off too--However, you have make the decision to purchase breakers instead of touch safe fuses.

    If you pop a touch safe fuse holder while it is under load--there is a very good chance that you will have a sustained arc that will destroy the holder/box. Fuses cannot be removed under load to shut off power.
    E-panels seem to be down the line from the combiner box. This would be where the charge controller would be mounted close to and/or have the inverter mounted on them. They also have breakers. It seems like they always have AC breakers due to the inverter. Do they have DC breakers or is there supposed to be a combiner box before them. Is it ok for a single box to have AC and DC running through it? It seems like a sub panel and some wiring is all they provide. Is an E-panel just a cleaner way to wire everything? That is what it seems like to me.

    Epanels save you from having to purchase components and wiring them up... Very nice.
    A transfer switch is a device that lets you go from grid to backup by disconnecting the main fuse box from commercial power and then applying power from the battery bank. I have seen manual ones and automatic ones. I don't need one of these right now as I am still building my setup as offgrid. I will need one when the time comes to go grid-tie-hybrid.

    Transfer switches are a safe way to switch between grid, generator, and inverter power AC output power... You can get inverters that contain their own transfer switch or switches.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #6
    Re: E panels, combiners and such.

    think of the epanel as a master hub for everything. it will have 1 dc input from pvs, 1 input/output for batteries, 1 ac utility input, and 1 ac output. the inverter and controller will mount on the epanel and for multiple pv strings this would need a separate combiner and more than 2 inputs to the combiner are required to be fused or circuit breakered. the output for the ac is the same way as more than 1 output should have its own distribution box with appropriate circuit breakers. i also elected to put a large circuit breaker on my battery box to protect the wiring beyond the battery box. there will be a breaker for the input of the inverter, but that leaves no protection from battery wiring shorts before it and is why i went with the one at the battery box.
    does this help?
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  • Seven
    Seven Solar Expert Posts: 292 ✭✭
    #7
    Re: E panels, combiners and such.
    niel wrote: »
    does this help?

    lol You guys are great!
    I try to not ask too many stupid questions, but when I hit a roadblock I always come here for clarification. You guys always provide it.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,622 admin
    #8
    Re: E panels, combiners and such.

    Be a very quiet forum if nobody asked questions and we never answered the few that were asked. ;)

    -Bill :D
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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