Large Power charge controllers

SledderSledder Registered Users Posts: 2
I have searched with no luck.   What are people using for a charge controller when they have 24   - 300 watt panels connected together ? 

Thanks for the help 


  • mike95490mike95490 Solar Expert Posts: 8,875 ✭✭✭✭✭
    Morningstar and Schneider both make 600VDC charge controllers     You may have to split the panels to 2 strings to stay within power limits.

    48V @ 60A = 2880 watts    3 required
    48V @ 80A = 3840 watts    2 required

    24 x 300w = 7200 watts of panels.  No way only 1 controller will manage that. 
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    gen: ,

  • BB.BB. Super Moderators, Administrators Posts: 30,740 admin
    What is it that you want connect too?

    A 1,000 AH @ 48 vdc battery bank or what?

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • PhotowhitPhotowhit Solar Expert Posts: 5,249 ✭✭✭✭✭
    edited May 2019 #4
    You say "connected together", No controller I'm aware of can handle a single string.

    With 7200 watts of array, you will have a Normal Operating Cell Temperature value of around 75% of 7200watts or 5400 watts, with bulk charging a 48 volt system at 50% the charging voltage would be around 52-54 volts or around 100 amps. If you connected them within Magnum's 100 amp charge controllers specs, I think a max VOC of around 240volts, 6 strings of 4(?) You should be cost effective with it. Perhaps slightly over paneled but not by much.

    Magnum Energy PT-100 MPPT Solar Charge Controller
    Magnum Energy PT-100 MPPT Solar Charge Controller
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do
  • SledderSledder Registered Users Posts: 2
    I have a cottage with a 12 volt system   and currently im maxed out on panel that a midnite classic will handled 
    I plan on staying there more when im retired in a year  and the loads will be more   
    I currently have 4 305 watt panels in two strings which about 90% of the midnite classic 150 capacity based on the midnite sizing tool 
    I have a magnum 2200 watt inverter charger and have been trying to make that last   
    Maybe its time to bite the bullet and upgrade to a 24 or 48 volt system  with a new invertor   
    Would you suggest an invertor charger   or just the invertor    i know i love how the magnum is very flexible on set up   
    Was trying to avoid that 
    Currently  i have 4 -  6v  605 surretre batteries connected in 2 strings of 12 volts 

  • petertearaipetertearai Solar Expert Posts: 443 ✭✭✭✭
    I would certainly consider waiting and going 24 or 48 volts . If your batterys are not too old then 24 volts . But if nearing end of life then. Bit the bullet and go 48 volts 
    . Inverter charger in my opinion is a good idea , gives you that piece of mind if you need to charge 
    2225 wattts pv . Outback 2kw  fxr pure sine inverter . fm80 charge controller . Mate 3. victron battery monitor . 24 volts  in 2 volt Shoto lead carbon extreme batterys. off grid  holiday home 
  • PhotowhitPhotowhit Solar Expert Posts: 5,249 ✭✭✭✭✭
    We did assume you would be running a 48 volt system. I should be, but already had the forklift battery from my cabin system, that was 1 year old.

    You could see what it would cost each way... I almost always like to use what I have until some failure that requires replacement. So for me, I'd likely stick with the 12 volt system and inverter. Perhaps add 1 more string of panels, understanding that it doesn't help other than running daytime loads, but only if the system will benefit from it later. Then bite the bullet in a year, when I can do most or all of the work and switch out the inverter for a 48 volt inverter and try to find a new home for the batteries.

    That's a huge output though. I've been 6 years waiting for my battery to die, I was still using my small 1800 watt inverter from the cabin system. I ran across a 24 volt - 4000 watt Magnum inverter, one that I had originally thought of for $700 with the controller thingy that is 8 year sold. If it's still working when the battery finally dies in another 4-5 years, it will be a hard choice to switch to a 48 volt system. 

    In your case if the batteries aren't too old, you might consider a 24 volt system, if you do I'd see if my energy needs really requires a 7200 watt array, I think about 6000 watts could cost effectively be handled by 2 Midnite charge controllers in a 24 volt system. with 470 amp hour battery bank at 24 volts, you could use roughly a 470 x .13= 61 incoming amps. So 61/.75=81 (NOCT value of panels) 81 amps x 29 volts = 2350 watt array at a system voltage of 24 volts. Use that until the old batteries die, then replace with about double the battery bank. Generally you don't want to add new batteries to old...

    So a lot of thinking out loud, Hopefully you can follow as I sort of looked at the options. 
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do
  • EstragonEstragon Registered Users Posts: 4,478 ✭✭✭✭✭
    Before buying anything, I'd highly recommend giving some though to what your loads and needs/expectations might look like after retirement.  For example, is the cottage mostly summer use now, and likely to be used more in fall/winter later?
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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