A Forum run by Enthusiasts of MidNite Solar

Charge Controllers and Clippers => The "Classic" charge controller => Topic started by: plongson on September 08, 2011, 11:32:47 AM

Title: "Set Current Limit"
Post by: plongson on September 08, 2011, 11:32:47 AM
How do I determine the "Set Current Limit" in the wizard setup on my 250? I will have 10(ea) 235w panels in 2 strings. 37.6 voc/8.56 Isc

This has me confused.

ALSO... is the Float, Bulk and other setting options calculated at this point in the wizard? Do they NOT need to be changed at this point and accepted?

THANKS!! Paul
Title: Re: "Set Current Limit"
Post by: Halfcrazy on September 08, 2011, 12:58:28 PM
Typically the current limit is set to its maximum setting on PV systems. The EQ, Absorb and Float set points DO need to be set by you to the battery manufacturers recommended settings. The default we use is on the low side to avoid damage to a sealed battery.
Title: Re: "Set Current Limit"
Post by: plongson on September 08, 2011, 02:28:32 PM
Thanks HC, I'm just using the simulator and getting ready for when I will soon use it for real. It looks like the current limit stops at 54 amps with the 250. So are you saying I should use that number? As for the batteries, I'm using 16(EA) Rolls Surrette S460's and I downloaded their care and feeding manual for the batteries, but it looks like I really need to now how much voltage this system is producing. Generally, is this all set once  we are producing power or can it be set initially by the defaults in the controller?
Title: Re: "Set Current Limit"
Post by: Vic on September 09, 2011, 01:27:18 PM
plongson,

YOU will need to set the Classic charger yourself.  Since the S-460 are Flooded cells,  you will be able to use a Hydrometer to help you zero in on the exact settings required for your batteries,  useage,  and charging source.

Personally,  I would recommend a glass-float type hydrometer.

You could begin by using the mid values provided by Surrette as a starting point,  and carefully monitor the SGs during the first week,  and, then less frequently as you gain confidence that you are moving the charger values in the correct direction.
Title: Re: "Set Current Limit"
Post by: PKsolar on March 27, 2012, 10:21:07 PM
I was suprised to see "Current Limit" (or something like that) in the display while equalizing for the first time. Not to cold out 50F (way too warm for March here in WI) and my current configuration only allows 40A at most (two parrallel 20A breakers in the MS combiner). I was hoping for higher amperage for a boost to the 48V (400AH) battery bank.

Am I reading the display incorrectly?
Title: Re: "Set Current Limit"
Post by: boB on March 28, 2012, 01:12:49 AM
Quote from: PKsolar on March 27, 2012, 10:21:07 PM
I was suprised to see "Current Limit" (or something like that) in the display while equalizing for the first time. Not to cold out 50F (way too warm for March here in WI) and my current configuration only allows 40A at most (two parrallel 20A breakers in the MS combiner). I was hoping for higher amperage for a boost to the 48V (400AH) battery bank.

Am I reading the display incorrectly?

OK, what Classic is that ?   150 ?  200 ?  250 ?  and what was the current (approximately) when you saw it limiting ??

boB
Title: Re: "Set Current Limit"
Post by: Halfcrazy on March 28, 2012, 06:41:30 AM
Quote from: PKsolar on March 27, 2012, 10:21:07 PM
I was suprised to see "Current Limit" (or something like that) in the display while equalizing for the first time. Not to cold out 50F (way too warm for March here in WI) and my current configuration only allows 40A at most (two parrallel 20A breakers in the MS combiner). I was hoping for higher amperage for a boost to the 48V (400AH) battery bank.

Am I reading the display incorrectly?

There are 3 reasons to see "Amp limit" on the display:
Output current limit set lower than necessary or more panels than the Classic can handle. This can be set close to the Battery side breaker on the Classic.

Input Current limit set to low. This should be set to 99 for solar by default. This was mostly intended for Hydro and Fuel Cell guys.

The Classic is regulating do to being to hot.

My guess is the output current limit is set to low.

Ryan
Title: Re: "Set Current Limit"
Post by: PKsolar on April 05, 2012, 07:50:58 PM
My classic 250 only asked for module info, # of modules in array, Total battery bank AH and voltage when I did the wizard set up. Looks like I have to enter the PV array total amps manually per your thoughts. Evergreen 215s are 12.9A so my series of two arrays (5 modules each) should yeild 26A. Each array is protected with your 20A breakers. I'll give that a try. Or, should I just be entering the 12.9A which I just did?

PK
Title: Re: "Set Current Limit"
Post by: PKsolar on April 05, 2012, 07:59:35 PM
I also forgot to ask... Is there any written info on set up for the classic? Most of what I see while scrolling along isn't covered in the manual. It would be nice to see step by step instructions considering the Wizard obviously didn't set important info like Amp Limit.

I thank you for your time,
PK
Title: Re: "Set Current Limit"
Post by: boB on April 05, 2012, 08:24:37 PM
Quote from: PKsolar on April 05, 2012, 07:59:35 PM
I also forgot to ask... Is there any written info on set up for the classic? Most of what I see while scrolling along isn't covered in the manual. It would be nice to see step by step instructions considering the Wizard obviously didn't set important info like Amp Limit.

I thank you for your time,
PK

The amp limit should be set the same as your battery side circuit breaker size in amps or lower.
Or, it may not matter if your PV array (or source) won't let the Classic put out any more
current than the Classic is already set for.  That setting will be in the CHARGE menu
under LIMITS.

boB


Title: Re: "Set Current Limit"
Post by: PKsolar on April 06, 2012, 09:38:48 PM
Thank you!

That did it. It Equalized just fine as well now. Just got the first check from the utility this year - two months earlier than normal. Love your equipment! Now the house is completely fossit fuel free and WE Energies is going to pay for the little they give back to the environment.

Cheers to Midnight Solar,
PK