Author Topic: different panels on Midnite Classic 150  (Read 75 times)


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different panels on Midnite Classic 150
« on: March 12, 2018, 02:21:09 PM »
New to this forum and this is my first post. I probably already messed up by mixing the panels I bought. Here is what I have.

panel size   watts   number of cells   rated voltage   rated current   over voltage   short circuit current   number of panels       
60x40   255           60                   30.8                   8.29                   38                   8.89                           4
72x40   285           72                   35.54           8.12                   45.39           8.32                           2
72x40   280           72                   36.3                   7.72                   44.3                   8.36                           2

The plan was to connect the first array as one of the 285w panels in series with one 280, then parallel them to the second two panels in the same configuration. Then parallel those to the second array of four 255w panels configured is series parallel using only the Midnite Solar Classic 150 with a battery voltage of 24. Sounds like this won't work right? Could it cause damage or just not be very efficient?

The other option was to use two arrays, the first being the one listed first above using the Midnite Solar classic. The second array would be handled by my EPEver 40A controller in the array listed second. Then both arrays would be connected to the same battery bank with all battery voltage settings set the same on both controllers. Will this work? Any precautions I should take to keep the two controllers from damaging one another? By the way, the battery bank is 12 6V 220AH lead acid batteries configured for 12v. I would have to reconfigure them to 24V. I hope this seems clear to everyone, if not let me know where any confusion is.
I should have done more research on combining panels I guess.


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Re: different panels on Midnite Classic 150
« Reply #1 on: March 12, 2018, 09:49:28 PM »
Hi Dan,  Welcome to the Forum,

It is not exactly clear what is the purpose of this system.

But,   you would probably be much better off running a 24 volt system,  than trying to have SIX parallel strings of batteries at 12 volts.   You may well be better off,  yet with a 48 volt system.

Parallel battery strings,   generally,   are difficult to keep balanced.  Ideally,  one would have a single string of batteries,   that are of sufficient size to deliver the Ah Capacity needed.

As you probably know,   Charge Controllers (CCs) are rated at output current.  If the system voltage is doubled,  the CC can make use of two times the power,  at the same output current.

Am not familiar with the EP-Ever CC.   It does claim to be an MPPT CC.   Multiple CC can generally charge the same battery bank,  without issues.

What is the purpose of this system?   Is going to 24 V simple (ie do you have an inverter now?)?

At 24 V,  you could probably get away running one 60-Cell PV,  in series with one of the 72 Cell PVs in each of four strings.   The 280 W PVs have an Imp difference of about 7%,   which is OK,   but not ideal. [Generally,  the Rule-Of-Thumb is that ideally Imp ratings should match within 5% for differing PVs wired in series,  10% maximum difference]   The Vmp difference is too large between the 60 and 72-Cell PVs for parallel wiring.

More later,   Vic
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!


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Re: different panels on Midnite Classic 150
« Reply #2 on: March 13, 2018, 11:15:21 PM »
So I don't see any inverter .
ME , this is what I would  do .

48 Vdc system is my choice , 72 panel panels in 2 series and two in parallel
4 60 cell panels in 2x2 in S/P on to the second EPEver 40A controller .

For 12 Vdc use a Pyle 48Vdc to 12Vdc converter for a small amount of 12Vdc power (1000 watts @12Vdc)
the rest use 48Vdc . You harvest more at a higher voltage . If you need 24Vdc as I do in my equipment barn to charge my Genie 24Vdc lift and all my 12Vdc Six  tractors .

So your options are open , What have you bought so far ?

Canadian Solar 350W 37.6 VOC  30.6 VMP 8.22 ISC 7.87 IMP ,-15 c +30c max  4 strings in 2 in Series for 24v Classic 150 -1020 Ah  Freezers & fridges ~~~ Second Array same panels of 3sx3 parallel for 24 V Classic 150 -440 Ah Outback Barns & out blds.
48Vdc almost done.


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Re: different panels on Midnite Classic 150
« Reply #3 on: March 19, 2018, 06:18:51 PM »
Thanks for the replies. I already have a running 12v system with a 3000w PSW 12v inverter. I planned to go forward with a 5000w PSW inverter at 24v. That will require me to rework the charge controller on the 600w axial flux wind turbine. I started small and am upgrading. I could have saved a lot by doing it right the first time. I have 16 circuits I can switch between grid and green power but no 220v. The upgrade will allow me to run the well pump. I'm trying to maintain some kind of normal in case of a longish term grid failure.
All work is on hold until my newly broken arm heals though.