Add Xantrex C60 controller (set to 12 volt) to 24 volt system

Hello Folks,
I've got another system question.
Does anyone see an issue with adding a C60 controller(set to 12 vdc) to my 24 volt system?
I have recently upgraded to a Outback MX60, and have the old C60 units sitting here.

Any reason I can't add the c60 to my system to keep a seperate set of 12 volt batteries charged?
With a max open circuit voltage of aprox. 42 vdc, it's still under the C60 55 volt max input.

I have unused charge capacity many days and it would be great to use it the charge the 12 volt system.
(12 volt system is strictly a backup system for my 12 volt prosine2.0 inverter)

I guess the real question is can I input the 24 volt nominal PV voltage to the C60 set at 12 volt without complications?'thanks

Comments

  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    As long as you are within the voltage limits no problem. In fact a while back we set up a remote cell phone and weather site with 3 different controllers - 12, 24, and 48 volt all running off the same panels.
  • James
    James Solar Expert Posts: 250 ✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    Thanks for the fast reply!
    Seeing the NAWS logo on the reply makes me very comfortable with adding the C60 unit.
    No real reason to grid charge my standby 12 volt system at this point.
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    ?? I'm not sure I understand your question

    You have a controller set to 12V, what is the "source" that is providing power to it ? If it's a "shared" PV panel on a 30V panel, every "pulse" (PWM) will drag the array power to 12V possibly starving the 24V battery of charge. ??
    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

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • James
    James Solar Expert Posts: 250 ✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    Here is what I have:
    24 volt panel arrays/24 volt battery/ MX60 controller set to 24 volt operation.

    I want to add a Xantrex C60 controller set at 12 volt operation to charge a separate 12 volt battery bank.

    Are you stating that the C60 will try to pull down the batteries, causing problems?
    i can see how that would happen.
    please explain
  • James
    James Solar Expert Posts: 250 ✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    WINDSUN, Just curious, what was the PV array open voltage max. for your described system?
  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    It was around 90 volts, but we used the Morningstar MPPT x 3 so that was not an issue.
  • James
    James Solar Expert Posts: 250 ✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    Well, I tried to add the C60 PWM controller to my system. I tied it to the PV output.
    There does seem to be a conflict...about every 4 seconds, there is a short duration buzzing sound from both the MX60 and the c60. The c60 seemed to be charging, but i did not like the sound it was making so rather that wait and take a chance of seeing smoke, I disconnected. I was watching the PV voltage reading on the MX60 during the cycling of the buzzing sound and it definitely was droping in voltage down toward the battery reading of the C60.....So I'm guessing these two don't want to play nicely together. Maybe because the C60 is PWM?
    I don't know...any thoughts here?
    thanks
  • Thomas
    Thomas Solar Expert Posts: 291
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    Maybee while your c60 is engaged your line voltage is 12v, or whatever the need thru the c60 is, nominalise this need and that differential noise may go away. It could be initial or acclimating time that your mx60 may or may not be designed to handle, if the two systems are charged and nomonal...I remember having problems with chargers untill I realized some do not work with dead batteries, so I bought new batteries and my problem went away. Unqualified, uneducated ,non-creditable, un professional, observations.(disclaimer)
    Always troubleshoot with adequate sunlight.  Hi Ho Hi Ho
    2.3kW [10] Enecsys SMI-240-60 micro inverters

  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system
    James wrote: »
    ........ I was watching the PV voltage reading on the MX60 during the cycling of the buzzing sound and it definitely was droping in voltage down toward the battery reading of the C60.....So I'm guessing these two don't want to play nicely together. Maybe because the C60 is PWM?
    I don't know...any thoughts here?
    thanks

    Exactly as I said in post #4
    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

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • Thomas
    Thomas Solar Expert Posts: 291
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    RE: post # 2 the batteries were probobly new and similarly charged,?
    Always troubleshoot with adequate sunlight.  Hi Ho Hi Ho
    2.3kW [10] Enecsys SMI-240-60 micro inverters

  • James
    James Solar Expert Posts: 250 ✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    yes Mike, you were right.
    So, do you think that using a MPPT controller would work in this situation rather than a PWM controller?
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system
    James wrote: »
    ...So, do you think that using a MPPT controller would work in this situation rather than a PWM controller?

    I think a MPPT would work much better, and if they came from the same Mfg, it woudl likely be better still. And think about using the 24V battery as the source for the 12V MPPT charger, that would completly eliminate any chance of interaction between the 2, perturbing the PV array. You might loose a few points of efficency, but the gain in reliability would likely be worth it in my book.
    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

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • James
    James Solar Expert Posts: 250 ✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system
    mike90045 wrote: »
    I think a MPPT would work much better, and if they came from the same Mfg, it woudl likely be better still. And think about using the 24V battery as the source for the 12V MPPT charger, that would completly eliminate any chance of interaction between the 2, perturbing the PV array. You might loose a few points of efficency, but the gain in reliability would likely be worth it in my book.

    I had tried direct connection to the battery bank, no go, but of course, it was with the PWM controller.
    I can't afford another Outback MPPT, such as the FM60 at this point in time....do you you a smaller (30-40 amp) MPPT controller from another MFG. would work or am I just taking a chance?
    Thanks
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    if your 12V loads are light, the Morningstar Sunsaver MPPT (15A ) should be able to keep up. Or, the Rogue 30A MPPT. If I was to buy again, only for 12 or 24V - I'd get the Rogue, it has the meters built in
    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

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    i'm thinking somehow the outback might be pulsing the pv input voltage and thus modulating it and confusing the c60 which in turn confuses the outback. i would not give up too fast if you have some electrolytic caps in the tens to hundreds of thousands of uf value on the pv input. even a toroid core or a ceramic disc cap with .01uf or there abouts might change things if you place them on the cc input.

    note, if you don't have these things on hand then i don't expect you to try it as it is a see what works thing rather than dump possibly more $ on stuff that may not work.
  • James
    James Solar Expert Posts: 250 ✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system
    niel wrote: »
    i'm thinking somehow the outback might be pulsing the pv input voltage and thus modulating it and confusing the c60 which in turn confuses the outback. i would not give up too fast if you have some electrolytic caps in the tens to hundreds of thousands of uf value on the pv input. even a toroid core or a ceramic disc cap with .01uf or there abouts might change things if you place them on the cc input.

    note, if you don't have these things on hand then i don't expect you to try it as it is a see what works thing rather than dump possibly more $ on stuff that may not work.

    i've got plenty of capacitors around my bench. just for fun, i'll try a few.
  • James
    James Solar Expert Posts: 250 ✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    No good results to report.
    I think the simplist way to address this untill I can afford a new MPPT outback, is to separate one string(2 pv's) of PV's out from the 24 volt system and wire them to the 12 volt PWM C60. The wiring is in place so I just need to rewire and add the breakers.
    they won't take much away as the wattage is mostly unused in the 24 volt system due to the MX60 limitations. (yes, I have the MX60 adjusted for 68 amps)
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    too bad it wasn't going to be easy for you and just simply work. dedicating pvs will always work.
  • Robin Gudgel
    Robin Gudgel Registered Users, Solar Expert Posts: 58 ✭✭✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    DO NOT DO THIS!!! You are essentially connecting the 12V battery to the PV input of the MX60. ALL PWM controllers try to become a piece of wire when charging. They only PWM when the battery gets up to the set points. I'm surprised the MX60 didn't immediately blow up. You MUST use a separate PV array into each controller.
    I was the mechanical engineer on both of those controllers. My brother boB was the electrical engineer on the MX60. Doug, who also works for Midnite did the repackaging of the C-40 into a C-60.
    The input voltage isn't an issue as long as it stays below the max allowable voltage. You cannot connect two sources of power to the input of any MPPT controller.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    i thought he meant to the 24v pv system and not the battery. as i understand it he would have one pv array that goes to the mx60 and to his 24v battery bank. he also wanted to charge his 12v battery and so connect the c60 to the pvs and go to the 12v battery. this would waste power of course, but it is how i understand what he meant. i could be wrong though.

    james, could you confirm how you meant it to be?
  • James
    James Solar Expert Posts: 250 ✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    Since the original idea of using one array to supply power to both the mx60 and the c60 didn't work, i am now separating 2 pv panels off from the 24 volt array, wiring those for 12 volt, and feeding that to the c60 controller. totally isolated systems. i can't imagine that creating any conflicts.
  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    James,

    I'm not sure if I follow correctly.

    Are these the configurations you are talking about?
    Attachment not found.
  • James
    James Solar Expert Posts: 250 ✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    yes, SolaRevolution,
    Your very nice layout is correct as to what i wanted to do, and what i will end up doing, except the array for the prosine system would be two panels in parrallel for 12 volt array
    thanks
  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system
    Windsun wrote: »
    As long as you are within the voltage limits no problem. In fact a while back we set up a remote cell phone and weather site with 3 different controllers - 12, 24, and 48 volt all running off the same panels.

    So, what gives?

    I understand what Robin was saying about the PWM basically going closed circuit between the PV and the battery.

    So if this is not a problem for paralleling MPPTs, why are you not supposed to parallel MPPTs?

    Is it just a MPP sweeping war?

    -Alex Aragon
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    this is not a case of 2 mppt controllers as a c60 is a pwm controller and it does apparently not mesh very well with an mppt as i thought it should from the same pvs. he is able to dedicate some pvs to this in a 12v configuration so he will run efficiently from a dedicated system, or at least as efficiently as a pwm controller will allow. he just won't have the benefit of a larger array available to either controller should a higher draw be warranted from either controller as was his plan. now even a pwm controller is a regulator circuit so it will hold back on the on connection time to keep the voltage lower from a 24v source to a 12v battery. maybe robin was worried about the amount of current available when it's pwm is on as it could exceed the c60's abilities if the current from the array is large enough. a 24v battery would certainly be large enough for dumping large amounts of current. now a pv array is limited by the isc of the pvs and a large current spike will be very limited by this providing your array is not going to exceed the c60 controller's abilities from an imp standpoint. in other words, it's not normally possible for an array outputting say 45a to overload a c60 controller even when the output is shorted, at least in theory as i don't recommend shorting the output or guaranteeing no damages for other reasons. now a battery can dump huge amounts of current even from a small battery under the same circumstances if connected to the c60 and i believe that's what robin was cautioning on.
  • jsim
    jsim Registered Users Posts: 4
    Re: Add Xantrex C60 controller (set to 12 volt) to 24 volt system

    Why waste two valuable panels when you can use a cheap trickle charger (120vac input). Connect the charger to a cheap wall wart timer and set it to 10am to 2pm so as to eliminate night time draw.
    Just a thought.