Midnite classic 250 VS 250ks

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Nila
Nila Solar Expert Posts: 173 ✭✭
in Solar Beginners Corner #1
Hi All

I have figured out my office loads and have come into conclusion that I might need this setup

400AH at 96V battery
5kw solar array ( may scale upto 8k later on , or alteast to keep that as an option)
6KW inverter.. possibly xantrex 6048

Now comes the hard part- Charge controller..

Classic 250 has higher amperage but does not support 96V battery bank..
Classic 250KS has higher nominal bank size but has like cap on the max output current which is 35.


I think I would waste atleast 500Watts of solar power If i go with the KS model.. is that correct? or would i waste more/less ?

Now question is..

Should i go with the 250KS.. I know I cannot scale with this setup easily.. but I am happy as i can live with 1 CC and save another 700$

or go with any other MPPT like tristar,etc and Should i use 2x Charge controllers charging 2 battery banks at 48v and use them in series for the inverter ..
so this way I can add more arrays later on easily?



And is there any other options for me apart from asking my Chinese manufacturer to create a 96V charge controller for this setup specifically?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
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    Re: Midnite classic 250 VS 250ks

    Here's another problem for you: an XW 6048 doesn't run on a 96 Volt battery bank either.

    Where did you come up with that battery Voltage from?
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  • Nila
    Nila Solar Expert Posts: 173 ✭✭
    #3
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    Re: Midnite classic 250 VS 250ks

    Ok , 96V came from the 5Kva cheap Inverter available here locally

    I was assuming Xantrex was 96 too, My mistake.

    Anyways, we have 5kva inverters here available for under 1K$ close to 800$ lol. comparing xantrex its like about 3200$..1/4th of the cost.
    I do not want to go with no-name stuff when it comes to use at office .


    If 6048 is 48v.. I can just use 600AH at 48V with my 12v batteries ( 3 strings ) , I believe using 4 is not advised?

    I can conserve lot more at the office so I have some headroom to work with.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #4
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    Re: Midnite classic 250 VS 250ks
    paimpozhil wrote: »
    400AH at 96V battery

    6KW inverter.. possibly xantrex 6048
    Not quite sure what you are thinking of, but as far as I know the Xantrex XW 6048 is only a 48 volt inverter.
    Finding inverters which will accept 96 volt nominal DC will limit your choices considerably.

    Do not plan on charging two separate 48 volt battery banks to be used in series. You would have to use different panel arrays as well as different CCs and the chances are very good that you will end up with an imbalance between the two 48 volt sets anyway.
    SMA SB 3000, old BP panels.
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  • Nila
    Nila Solar Expert Posts: 173 ✭✭
    #5
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    Re: Midnite classic 250 VS 250ks

    Please accept my apologies.. i pulled that number out of the air it seems .. Please check my reply to Coot :)
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #6
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    Re: Midnite classic 250 VS 250ks

    That's what the model number "6048" means: 6000 Watts, 48 Volts. Clever, eh? :D

    That 5kVA inverter is probably a beauty for $800. Square wave, no doubt. As much as I don't like 'Brand X' it has to be better than that one!

    Do you actually need 6kW worth? Can it work with 4? Magnum makes nice 4kW 48 Volt inverters for about $2,000. http://www.solar-electric.com/maenms4444wa.html

    Another possible would be SMA's Sunny Island. They are expensive in the NA version, but for some reason less so in the European spec.

    400 Amp hours @ 96 Volt is equivalent to 800 Amp hours @ 48.
    You can run four parallel battery strings, it's just that each additional parallel connection increases the potential for current sharing problems. You could also get larger capacity batteries in 6 Volt or go hog wild for 2 Volt cells (tend to be very expensive) or if there's room for forklift batteries that might be an option.
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  • Nila
    Nila Solar Expert Posts: 173 ✭✭
    #7
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    Re: Midnite classic 250 VS 250ks

    http://www.su-kam.com/Power-Solutions/Business-Solutions/Corporate-Solutions/High-Capacity-Inverters/Colossal-Series/99/74
    http://www.su-kam.com/Upload/UploadedCatalogue/3a9a7_COLOSSAL-Series.pdf

    Take this: True Sine Wave

    Now would you go with it ;) they have 2 year warrenty..


    I believe this kind of circuit may harm the battery bank in long term, which is why I am trying to go with a Xantrex or a bigger brand.
    Cariboocoot wrote: »
    That's what the model number "6048" means: 6000 Watts, 48 Volts. Clever, eh? :D

    That 5kVA inverter is probably a beauty for $800. Square wave, no doubt. As much as I don't like 'Brand X' it has to be better than that one!

    Do you actually need 6kW worth? Can it work with 4? Magnum makes nice 4kW 48 Volt inverters for about $2,000. http://www.solar-electric.com/maenms4444wa.html

    Another possible would be SMA's Sunny Island. They are expensive in the NA version, but for some reason less so in the European spec.

    400 Amp hours @ 96 Volt is equivalent to 800 Amp hours @ 48.
    You can run four parallel battery strings, it's just that each additional parallel connection increases the potential for current sharing problems. You could also get larger capacity batteries in 6 Volt or go hog wild for 2 Volt cells (tend to be very expensive) or if there's room for forklift batteries that might be an option.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #8
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    Re: Midnite classic 250 VS 250ks

    Well 3% THD would be true sine. If you can trust them.

    Also you need 230 VAC 50 Hz. Not sure Xantrex is available in that or not. Outback is and so is the SMA but OB would need two inverters to meet the Wattage so there's the price of the SMA Sunny Island right there. Definitely check them out and search for Victron as well, which many of our overseas members recommend.
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  • Nila
    Nila Solar Expert Posts: 173 ✭✭
    #9
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    Re: Midnite classic 250 VS 250ks

    Xantrex is sure available at 230V, 50hz.. I spoke to someone here at the Xantrex and they are selling it allover India.

    Cariboocoot wrote: »
    Well 3% THD would be true sine. If you can trust them.

    Also you need 230 VAC 50 Hz. Not sure Xantrex is available in that or not. Outback is and so is the SMA but OB would need two inverters to meet the Wattage so there's the price of the SMA Sunny Island right there. Definitely check them out and search for Victron as well, which many of our overseas members recommend.
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  • Nila
    Nila Solar Expert Posts: 173 ✭✭
    #10
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    Re: Midnite classic 250 VS 250ks

    They are local to me, but I dont know if i can trust them for an 5KW inverter, I use theirs for my home 3.5kW -no issues so far.

    Regarding 2 inverters it is not really possible.. I would like to keep one CC/ one inverter and one bank if possible :)

    I want to meet my power needs without spending tons of money as we are just small business.
    Cariboocoot wrote: »
    Well 3% THD would be true sine. If you can trust them.

    Also you need 230 VAC 50 Hz. Not sure Xantrex is available in that or not. Outback is and so is the SMA but OB would need two inverters to meet the Wattage so there's the price of the SMA Sunny Island right there. Definitely check them out and search for Victron as well, which many of our overseas members recommend.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #11
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    Re: Midnite classic 250 VS 250ks
    paimpozhil wrote: »
    They are local to me, but I dont know if i can trust them for an 5KW inverter, I use theirs for my home 3.5kW -no issues so far.

    That's a good sign. :D
    Regarding 2 inverters it is not really possible.. I would like to keep one CC/ one inverter and one bank if possible :)

    You only have to divide up the AC side if they aren't stackable; no problem running two inverters off one bank.
    I want to meet my power needs without spending tons of money as we are just small business.

    I hear you. That is the #1 requirement of us all; how can we meet the needs without spending like we're Bill Gates? Equipment is much cheaper than it was, but it still isn't cheap.
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  • Nila
    Nila Solar Expert Posts: 173 ✭✭
    #12
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    Re: Midnite classic 250 VS 250ks

    Hi Coot

    Thanks for the reply.

    Now if i go with them I am going to deal with the 96V as they confirmed their inverter wil work only with that bank size.

    Now back to my original question lol.. Please answer which CC to go with?

    I dont want to retype my first post again but its just the same question again.

    How big the array can go without going over the 35A limit of the 250KS.
    35*114 = 3990? i assume 4k, may be add something for losses and keep it upto 4500? or does these values change based on the VMP/IMP's?

    Cariboocoot wrote: »
    That's a good sign. :D



    You only have to divide up the AC side if they aren't stackable; no problem running two inverters off one bank.



    I hear you. That is the #1 requirement of us all; how can we meet the needs without spending like we're Bill Gates? Equipment is much cheaper than it was, but it still isn't cheap.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #13
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    Re: Midnite classic 250 VS 250ks

    The MidNite Classic 250KS is the only single controller I know of that will charge a 96 Volt battery bank. At that its derated current limit is 33 Amps. This is approximately a 4kW array.

    Basically all your numbers will be 2X a 48 Volt system, as in expecting an array Vmp of 140 Volts or more (I believe MidNite lists 180 and 200 for their power curves) and Absorb Voltage around 115 +/- depending on the actual batteries used.

    You should be able to support 330 +/- Amp hours @ 96 Volts, or up to about 15kW hours stored power.

    For the most accurate info on setting up the 250KS contact MidNite directly: you can't beat going straight to the source and their customer support is top notch!
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  • Nila
    Nila Solar Expert Posts: 173 ✭✭
    #14
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    Re: Midnite classic 250 VS 250ks

    Thanks coot or Neil? I forgot :)

    I m picking up a 250KS !, factory refurbished with full warranty straight from their site / forums.

    Battery sizes here are usually 150AH /12v or 180AH /12v.. So i guess I have to do it at either 300AH / 96 or 360AH.

    Is 360AH okay or would it require extra charging from my grid?





    Cariboocoot wrote: »
    The MidNite Classic 250KS is the only single controller I know of that will charge a 96 Volt battery bank. At that its derated current limit is 33 Amps. This is approximately a 4kW array.

    Basically all your numbers will be 2X a 48 Volt system, as in expecting an array Vmp of 140 Volts or more (I believe MidNite lists 180 and 200 for their power curves) and Absorb Voltage around 115 +/- depending on the actual batteries used.

    You should be able to support 330 +/- Amp hours @ 96 Volts, or up to about 15kW hours stored power.

    For the most accurate info on setting up the 250KS contact MidNite directly: you can't beat going straight to the source and their customer support is top notch!
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #15
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    Re: Midnite classic 250 VS 250ks

    33 Amps peak into 360 Amp hours of battery is close enough to work just fine. :D
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #16
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    Re: Midnite classic 250 VS 250ks

    to throw more into this potpourri, exeltech has inverters that can go from 66v or 108v battery banks and they have models available at 230v 50hz. may be low on the wattage, but splitting up the loads to dedicated inverters is possible from a single large bank. they do not have a built in charger though.
    http://lib.store.yahoo.net/lib/wind-sun/xpspecs.pdf
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  • MarkC
    MarkC Solar Expert Posts: 212 ✭✭✭
    #17
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    Re: Midnite classic 250 VS 250ks
    Nila wrote: »
    Thanks coot or Neil? I forgot :)

    I m picking up a 250KS !, factory refurbished with full warranty straight from their site / forums.

    Battery sizes here are usually 150AH /12v or 180AH /12v.. So i guess I have to do it at either 300AH / 96 or 360AH.

    Is 360AH okay or would it require extra charging from my grid?

    Have you installed and tested the 250KS yet? Did you find the full or "lite" version? If the "lite" version, is it easy to "program" with a PC (I have an old one dedicated to my system). Where did you find a reburbished unit?
    3850 watts - 14 - 275SW SolarWorld Panels, 4000 TL-US SMA Sunny Boy Grid tied inverter.  2760 Watts - 8 - 345XL Solar World Panels, 3000 TL-US SMA Sunny Boy GT inverter.   3000 watts SMA/SPS power.  PV "switchable" to MidNite Classic 250ks based charging of Golf cart + spare battery array of 8 - 155 AH 12V Trojans with an  APC SMT3000 - 48 volt DC=>120 Volt AC inverter for emergency off-grid.   Also, "PriUPS" backup generator with APC SURT6000/SURT003  => 192 volt DC/240 volt split phase AC inverter.  
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