2nd INVERTER ?

clamclam Registered Users Posts: 6
I have two Suntech 175 watt Panels the same ,parallel connection,(I plan to add two more 175's,all in parallel),two 130 watt Suntech panels the same,series connection.

All are contected to a Outback Flexmax 80 and two 6 volt ,GC2 220 amp hour ,batteries,1 year old.(I think I need two more batteries).

To max out the energy return,should I contect the two 130 watt panels to a PSW Rogue 30 amp controller?

I need about 700 watts to run a Pure Sine Wave, Sunforce 1000 watt inverter,Dell XPS ALL IN ONE 24 desktop,Panasonic HDTV TC-L32dt30 ??

(I still have a Sunforce 30 amp Modified Sine Wave inverter,used to run the two 130 watt PV's.)

Thankyou.

Comments

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: 2nd INVERTER ?

    Welcome to the forum.

    You seem to have a few things confused. First of all, the panels don't run inverter; the batteries do. The panels are there to recharge the batteries.

    This brings up issue #1, will your 220 Amp hours of battery supply enough for the two inverters?
    Batteries do not care how many loads are attached to them, so long as the combined load doesn't not exceed their ability to supply power. I don't know what a "Sunforce 30 Amp" inverter is, because inverters are rated in Watts output, not Amps. The Sunforce 1000 Watt PSW inverter makes sense.

    That said, the real issue is how much power each has to supply. Just because an inverter is 1000 Watts doesn't mean it is supplying that all the time (with corresponding draw on the batteries). The actual draw depends on the actual load (plus the power consumed by the inverter itself). So there is a range of current demand based on load and battery State Of Charge.

    Example:
    1000 Watts (full power) on 12 Volts @ minimum battery Voltage (usually 10.5) = 95 Amps from the batteries.
    250 Watts (1/4 power) on 12 Volts @ battery charging Voltage (usually 14.4) = 17 Amps from the batteries.

    The other issue is your mixture of panels. You have two different types. If the specifications are too far off you will be losing potential power from some. For panels in parallel the Vmp needs to be close between all (example: all panels have Vmp of 17.5 to 18). For series connections the Imp needs to be close (example: all panels have Imp of 5.0 to 5.5).

    It is likely that your 175's have a Vmp of 35 and an Imp of 5. The 130's are probably Vmp 17.5 and Imp of 7. That would make sense with your series & parallel connections. If not, placing the two 130's on a separate MPPT (not PSW - that applies to inverters only) controller like the Rogue would be a good idea.
  • BB.BB. Super Moderators, Administrators Posts: 32,018 admin
    Re: 2nd INVERTER ?

    What are the Vmp/Imp (voltage/current maximum power) ratings of the panels you want to use?

    They should match to withing ~10% for optimum power collection (parallel panels should match Vmp to ~10%; series connected panels should match to ~10% of Imp).

    If the panels are >10% difference in Imp/Vmp, then usually you have to use a second charge controller to match panels up optimally for charging the same battery bank.

    Also, if you have more than two parallel strings, you should have a series protection fuse (or breaker) on each parallel connected string for protection against electrical shorts.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: 2nd INVERTER ?

    Forgot to mention that for recharging 220 Amp hours of 12 Volt battery you only need around 400 Watts of panel. Here's a little short-cut calculation for it:

    22 Amps (10% rate) * 14.4 Volts (charging) = 316 / 0.77 (typical efficiency) = 411 Watt array.

    Right now you have 610 Watts ((2 * 175) = 350 + (2 * 130) = 260 = 610) which is more than enough for those batteries.
  • clamclam Registered Users Posts: 6
    Re: 2nd INVERTER ?

    130 watt Vmp 18.00,Imp 7.22.
    175 watt Vmp 35.80,Imp 4.90.

    Sunforce 1000 watt inverter...255 watts draw
    Dell desktop 200 watts draw
    Panasonic HDTV 110 watts draw
    Led lights 3 watts draw

    Sunforce 30 Controller, not inverter (oops!)

    Is the gain greater from installing the Rogue to service the 130 watt panels vis a vis the loss of power from mixing the 130's and 175's on the Flexmax 80?

    In my case, would having 2 controllers give greater power than one controller?

    Also adding new batteries to old ,(I have just read from your site), is not a good idea.
    Therefore adding new batteries would have a bias,to 2 controllers,as separate entities?

    I have just run out of power,due to 2 days of overcast skies.It has taken me about 3 days to charge the batts.Had to go to an old laptop )

    I feel I need to add two 175's (4 total) to the Flemax and add two new GC2 220 amp hr batteries connected to a new Rogue controller (saw it on your site),as a separate system.
    Once the Flexmax 80 and the 175's run out then switch to the Rogue 30 and 130 watt panels ???

    Thankyou very much for your professional response and expert advice.
  • BB.BB. Super Moderators, Administrators Posts: 32,018 admin
    Re: 2nd INVERTER ?
    clam wrote: »
    130 watt Vmp 18.00,Imp 7.22.
    175 watt Vmp 35.80,Imp 4.90.
    You can certainly place the two 130 watt panels in series, then in parallel with single 175 watt panels (18+18=36 volts vs 35.8 volts--virtually the same Vmp for the array).
    Sunforce 1000 watt inverter...255 watts draw
    Dell desktop 200 watts draw
    Panasonic HDTV 110 watts draw
    Led lights 3 watts draw

    Sunforce 30 Controller, not inverter (oops!)

    In general, I highly recommend that you look at conservation first. The 200 watt desktop + 110 watt monitor may be replaced by a 30-50 watt laptop. A huge win.

    You can always compare the cost of a new laptop vs the cost of building out a solar PV system that has to be 5-10x larger to meet your needs.
    Is the gain greater from installing the Rogue to service the 130 watt panels vis a vis the loss of power from mixing the 130's and 175's on the Flexmax 80?
    Don't bother with a new controller--You can run your pair of 130 watt panels in series for the same Vmp as a single 175 watt panel.

    For charging a 24 volt battery system, the 80 amp Outback controller is good for:
    • 80 amps * 29 volts battery charging * 1/0.77 panel+controller derating = 3,013 watts maximum (cost effective) solar array
    Also, you could put 2x 175 watt panels in series (and 4x 130 watt panels in series) and connect the entire ~72 Volt Vmp to your Outback (maximum Vmp~100 VDC input for many climates).

    Having a high voltage Vmp array can save you lots of cost on copper wiring from the array to the controller/battery shed.
    In my case, would having 2 controllers give greater power than one controller?
    Not really... Stay with the one large controller unless you are looking for backup power or just want to do some lab time with another brand/model. (Rogue is a very nice/cost effective controller with great support from the designer).
    Also adding new batteries to old ,(I have just read from your site), is not a good idea.
    Therefore adding new batteries would have a bias,to 2 controllers,as separate entities?
    Adding batteries is always a personal choice... In theory, worst case, the new batteries may age out about the same time as the older batteries.

    Or, you will end up piece part replacing batteries one or two at a time as they wear out over the period of several years. A pain in itself (sort of always running with a 1/2 crippled bank).

    Otherwise, if your present bank is too small to support your needs--you need to do something. Adding batteries may not be the worst thing in the world.
    I have just run out of power,due to 2 days of overcast skies.It has taken me about 3 days to charge the batts.Had to go to an old laptop )
    Ideally, we recommend 1-3 days of "no sun" backup power and running the bank down to 50% state of charge.

    You have to measure your "observed capacity" vs name plate capacity... If the batteries are at 2/3 or 1/2 of rated capacity--they probably are going to need replacement anyway.

    And you always have the choice of "cheap" golf cart batteries or expensive/nice deep cycle. From what little I have read, it works out that the 2x more expensive batteries will last about 2x as long as the "cheap" batteries. So, no win there (other than fewer change outs over the years).

    If you are still playing and learning about your system and golf cart batteries last 3-5 years on your system--May be worth sticking with the older batteries so you can "upgrade" as needed 3-5 years down the road as you get more experience with the system and your needs.
    I feel I need to add two 175's (4 total) to the Flemax and add two new GC2 220 amp hr batteries connected to a new Rogue controller (saw it on your site),as a separate system.
    Just to be clear, the moderators are not connected with NAWS (Northern Arizona Wind and Sun, our host), or any other solar related Mfg/Sales organization.

    The two Admins (Windsun and Rick) are from NAWS. And a few other posters here are designers/support staff from a few other vendors/mfg, and speak for themselves.

    Rogue is not sold by NAWS, but direct from his own site (www.roguepowertech.com).

    The Rogue unit is in its second version now--with some nice additions (I really like the remote voltage sense leads). It has been a solid performer and a good cost point (and the digital display is not an $$$ option).
    Once the Flexmax 80 and the 175's run out then switch to the Rogue 30 and 130 watt panels ???
    I like to keep solar PV systems "unified" into one larger system instead of breaking them up into several smaller system powering one site/home/cabin.

    It makes you get into balancing power usage across several systems--More work that it is worth (in my humble opinion).
    Thank you very much for your professional response and expert advice.
    Who 'dat? :roll:

    Have fun! :D
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • clamclam Registered Users Posts: 6
    Re: 2nd INVERTER ?

    Thankyou, Both , BB and Cariboocoot.
  • clamclam Registered Users Posts: 6
    Re: 2nd INVERTER ?

    I have right now, two x 130 watt panels and two x 175 watt panels connected to the Flexmax 80.

    This rig is not powerful enough to drive the Sunforce inverter (new), Dell desktop (cannot change this,3 yrs old Never been used,cant chuck it) !!! ,Panasonic new state of the art $800 ,and finish with a fully charged 2GC, 220 amp hr ,battery bank at the end of the day.

    I am constrained by limited space.I can only add two 175 watt panels or two 130 watt panels.Which must be of matching specifications to 175 watt or 130 watt,as you have stated.

    Copper wire is not consideration.Cost is not a consideration in this instance...

    Which is better to MAX what I have in hand?

    1.Add two x 175 watt panels to the rig?
    2.Add two x 130 watt panels to the rig?
    3.Add two x 175 panels ,but take away the 130 watt panels and connect to a Rogue controller?
    Thereby maxing the full 260 watts, not giving up two 130 watt panel 's (260 watts) to one 175 watt panel, a loss of (-85watts) !

    Thanks again Guys,
  • BB.BB. Super Moderators, Administrators Posts: 32,018 admin
    Re: 2nd INVERTER ?
    clam wrote: »
    Which is better to MAX what I have in hand?
    • 1.Add two x 175 watt panels to the rig? [most power]
    • 2.Add two x 130 watt panels to the rig? [bit less added power, your choice]
    • 3.Add two x 175 panels ,but take away the 130 watt panels and connect to a Rogue controller?[should not make any difference in total power output--no reason to do second controller unless you run the 175 watt panels at Vmp=72 volts and the two 130 watt panels at Vmp=36 volts]
    Thereby maxing the full 260 watts, not giving up two 130 watt panel 's (260 watts) to one 175 watt panel, a loss of (-85watts) !
    The only reason to add a Rogue controller is because you have a mix of Vmp (or Imp) which you cannot mix/match into one array--In your case, if you stick with a Vmp~36 volt array with your 175/130 watt mix of panels--then a second charge controller will not do anything for you.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • clamclam Registered Users Posts: 6
    Re: 2nd INVERTER ?

    "should not make any difference in total power output--no reason to do second controller unless you run the 175 watt panels at Vmp=72 volts and the two 130 watt panels at Vmp=36 volts]"

    Bill,

    As you can see ,I am not yet up to speed,please bear with the pain...

    I cant see how to run "175 watt panels at Vmp=72 volts,and the 130 watt"panels at Vmp=36 volts?

    By running two controller's ,I think I am maxing the two 130 watt panels minus the watt cost of firing up the second controller???

    I cant give up any watts.I am trapped for space,(on a boat)...

    plus I gain the added life span of the two separate battery banks?
  • mike95490mike95490 Solar Expert Posts: 9,362 ✭✭✭✭✭
    Re: 2nd INVERTER ?
    clam wrote: »

    130 watt Vmp 18.00,Imp 7.22.
    175 watt Vmp 35.80,Imp 4.90.

    ......

    I cant see how to run "175 watt panels at Vmp=72 volts,and the 130 watt"panels at Vmp=36 volts?....

    Put the 2, 130W in series. (36V)
    and then 3 parallel :
    36v
    35.8
    35.8
    gives you 7.22 + 4.9 + 4.9 amps
    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 ,

  • BB.BB. Super Moderators, Administrators Posts: 32,018 admin
    Re: 2nd INVERTER ?

    The question of two vs one battery banks... For a home, I would say one.

    For a boat--you tell me. Do you want two separate banks for emergency backup (ocean going sailboat), or would one good sized bank with solar+backup genset of some sort be good enough for the house battery (plus a second battery enough to start the motor/run the navigation lights for a house boat)?

    The only reason to split the solar array is because you NEED two separate battery banks. Otherwise, you can always run one main house bank and even get a small battery charger to recharge the motor/start battery bank (several types available).

    Again, being limited in solar power space, changing over to energy conservation type laptop (and second monitor, if needed) is a much better way to go unless you have backup shore power for much of your normal usage (and/or the computer is not used 8-12 hours a day but only a couple hours a day instead).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • clamclam Registered Users Posts: 6
    Re: 2nd INVERTER ?

    ok.Thankyou Bill.
    Appreciate the help.
    I will stick to the one controller.
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