A Forum run by Enthusiasts of MidNite Solar

Charge Controllers and Clippers => The "Classic" charge controller => Topic started by: Mechanicalbird on July 15, 2015, 02:15:47 PM

Title: Classic 250 maximum input?
Post by: Mechanicalbird on July 15, 2015, 02:15:47 PM
Right now my Classic 250 has 1800w PV @ 215v coming in. I am just wondering how much more PV wattage I can add on a single classic. What is the maximum input to the classic 250?

I'm asking because id eventually like to add another 1800w if possible so I can run heavy loads while still getting a full charge.
Title: Re: Classic 250 maximum input?
Post by: Vic on July 15, 2015, 02:36:05 PM
Hi M b,

Have you tried this Classic  String Sizing Tool?:
http://www.midnitesolar.com/sizingTool/displaySizing.php

Also,  look at this Classic Power Chart,  from that,  it looks like doubling the 1800 W array would be quite a bit too much for the Classic 250:
http://www.midnitesolar.com/images/classicFrontPage/graphs.php

Was not certain just what was the "215 V coming in" might be.    Is that the String STC Vmp,  or,  just what?

FWIW,  Vic
Title: Re: Classic 250 maximum input?
Post by: Mechanicalbird on July 15, 2015, 02:57:44 PM
Thanks Vic.

Sorry. The 215v is string voltage into the Classic.
Title: Re: Classic 250 maximum input?
Post by: Mechanicalbird on July 15, 2015, 03:07:47 PM
Thanks for the link to the calculator. Looks like I'm right at the limit now with 1 controller.

What's involved with adding a second controller? Can you have 2 controllers to the same battery bank?
Title: Re: Classic 250 maximum input?
Post by: Westbranch on July 15, 2015, 03:25:35 PM
Anther Classic can be put into FOLLOW ME mode and they will be happy to work together... :D
Title: Re: Classic 250 maximum input?
Post by: Vic on July 15, 2015, 03:30:13 PM
Hi M b,

YES,  you can use two or more CCs on a single battery bank,  each with its own separate PV array.

And since they would be MN Classics,  you can use 'Follow Me' so that each can coordinate charge stages.   'Tis very cool.

No problem on the 215 V,  just was not certain if that was the STC String Vmp, observed Vin,   etc.

Good Luck,   Vic