Midnite classic 250 amp issues

[Sandrat]

I am having an issue where my output amps are peaking out at 64 with my amber light coming on and it occasionally saying "amp limit" I have 4 of the panels in the specs picture. My math says i should only be pulling in like 36a 4x9a on each panel... Can I turn down the output amps to stop this? Also the amps on the right side fluctuate from 64 down to 20 and then back up again... Im lost do im hoping someone can tell me what im doing wrong ...pictures below

 

[snoobler]

Product - MidNite Solar

MidNite Solar Product Page.

www.midnitesolar.com

FEATURES:

• 250 operating voltage
• Max current out: 63 amps
• ETL listed to UL1741 and CSA
• Type 1 environmental rating
• Terminals are rated for 75 C
• Exclusive HyperVOC extends VOC limits
• 12-72V battery
• Built in DC-GFP and Arc Fault
• Detector
• Solar, wind and hydro MPPT modes

You have reached the OUTPUT amp limit. Your charge controller is over-paneled - more array power than the charge controller can handle.

You have 1400W of panels. 1400W/14V = 100A - a lot more than the charge controller can handle.

More realistically, you can collect 63A * 14V = 882W

 

[Sandrat]

So. Could I just pull one panel and be good? I have them all 4 together with a 4 branch y connector...

 

[OffGridInTheCity]

I have Classic 150. Occasionally I hit the 86a max and it threw the 80a circuit breakers I had at the battery control box.
You can set this 'down' to whatever you need to avoid issues.on the Advanced section - mid-scroll:

 

[Sandrat]

I have Classic 150. Occasionally I hit the 86a max and it threw the 80a circuit breakers I had at the battery control box.
You can set this 'down' to whatever you need to avoid issues.on the Advanced section - mid-scroll:
View attachment 53836

Ok. So I can just go in and lower my output amps and it will stay under that so I dont blow my scc up... When I do this. I set it down to like 54. The amber LED stays on... I removed one panel just now to see how it does... Wouod it be more practical to series 2 sets of panels then parallel them together?

 

[OffGridInTheCity]

Ok. So I can just go in and lower my output amps and it will stay under that so I dont blow my scc up... When I do this. I set it down to like 54. The amber LED stays on... I removed one panel just now to see how it does... Wouod it be more practical to parallel 2 sets of panels then series them together?

Series vs parallel changes voltage vs amps BUT - its the same amount of power. So if you parallel panels and the voltage range still works for the 250 - you'll still have the same amount of amps

Maybe you have "Rick Mode" on and its just telling you you have an over current situation? Lowering Output amps won't affect input.

Did you change the input amps setting as well? I don't know if lowering the input setting will change the detection of an 'over current' situation... but (to me) I'd make a plan to adjust your PV array to avoid over current as a regular condition.

 

[Sandrat]

Series vs parallel changes voltage vs amps BUT - its the same amount of power. So if you parallel panels and the voltage range still works for the 250 - you'll still have the same amount of amps

Maybe you have "Rick Mode" on - so its just telling you what you already know - e.g. over current on the input.
View attachment 53838

I just removed one panel. Thats what I get now. I dunno... Im screwed on this one.

 

[OffGridInTheCity]

Let's backup to your panels / input situation....

You talk about 4 panels of 350w each?... and in the first post I see 30.1v @ 63.1a and 13.2v (e.g. 12v nominal) battery. So you have 4 panels in parallel? 4 x 350w = 1400watts / 12v = 116.7amps. *116a is an over current situation

The Midnite 250 specs are a max of 60a @ 12v - e.g. your first screen. That's all this unit can do and you only need 2 panels (700w / 12v = 58a) to get there. No wonder you're getting over-current with 4 panels


You need to go down to 2 panels or up to 24v or 48v battery. A 24v battery @ 62a = max of 1488w of PV input *This is your situation. A 48v battery @55a = a max of 2640w PV input.

FYI....
>I just removed one panel. Thats what I get now. I dunno... Im screwed on this one.
Maybe you just have a bad connection or some such - the Classic is pretty hardy for short durations! Just go down to 2 panels, hooked in parallel, and see if it works for you at 12v battery

 

[Sandrat]

Let's backup to your panels / input situation....

You talk about 4 panels of 350w each?... and in the first post I see 30.1v @ 63.1a and 13.2v (e.g. 12v nominal) battery. So you have 4 panels in parallel? 4 x 350w = 1400watts / 12v = 116.7amps. *116a is an over current situation

The Midnite 250 specs are a max of 60a @ 12v - e.g. your first screen. That's all this unit can do and you only need 2 panels (700w / 12v = 58a) to get there. No wonder you're getting over-current with 4 panels
View attachment 53843

You need to go down to 2 panels or up to 24v or 48v battery. A 24v battery @ 62a = max of 1488w of PV input *This is your situation. A 48v battery @55a = a max of 2640w PV input.

FYI....
>I just removed one panel. Thats what I get now. I dunno... Im screwed on this one.
Maybe you just have a bad connection or some such - the Classic is pretty hardy for short durations! Just go down to 2 panels, hooked in parallel, and see if it works for you at 12v battery

Thanks so much! This was easy to understand and i appreciate the time for that reply.

 

[snoobler]

Thanks so much! This was easy to understand and i appreciate the time for that reply.

I'm curious. In my initial response, I drew the same conclusions and conveyed everything @OffGridInTheCity divulged by indicating that you're over-paneled, the total array charge current was too high for the controller, and you could only harness about 883W max.

What about the way I explained it made it less than easy to understand? I'm being sincere and looking to improve my communication.

 

[OffGridInTheCity]

I'm curious. In my initial response, I drew the same conclusions and conveyed everything @OffGridInTheCity divulged by indicating that you're over-paneled, the total array charge current was too high for the controller, and you could only harness about 883W max.

What about the way I explained it made it less than easy to understand? I'm being sincere and looking to improve my communication.

I agree - my initial answer was sloppy! and yours was absolutely correct. Maybe it was just the idea that 2 panels is the max for 12v didn't click and further (round-about) discussion eventually got there.

 

[snoobler]

I agree - my initial answer was sloppy! and yours was absolutely correct. Maybe it was just the idea that 2 panels is the max for 12v didn't click and further (sloppy) discussion eventually go there.

This isn't about any sloppiness whatsoever. Once I saw his charge current was pegged to the unit's max, I knew what was going on. It's one of the things I don't like about the Classics - they trade voltage for current, and they're expensive.

I'm just looking at ways to better convey that info to make the less experienced understand it more easily.

FWIW, the Classic solar calculator has 3X of those panels at a "1.2 classics needed" level. They recommend another controller at more than 1.2, so they implicitly allow a 20% over-panel. I personally don't see any harm in extracting the full rated current from a SCC, so I would be inclined to go 3X of those panels in series and get more total daily energy even if it might be maxed out for a couple hours a day.

 

[OffGridInTheCity]

This isn't about any sloppiness whatsoever. Once I saw his charge current was pegged to the unit's max, I knew what was going on. It's one of the things I don't like about the Classics - they trade voltage for current, and they're expensive.

I'm just looking at ways to better convey that info to make the less experienced understand it more easily.

As a retired software development engineer - I understand + agree. My wife was a technical writer and would write things that did not include technical detail very well BUT get the idea across with just minimal words. She repeatedly schooled me to cut my emails in 1/2 and then in 1/2 again... Its an interesting topic for sure.

FWIW, the Classic solar calculator has 3X of those panels at a "1.2 classics needed" level. They recommend another controller at more than 1.2, so they implicitly allow a 20% over-panel. I personally don't see any harm in extracting the full rated current from a SCC, so I would be inclined to go 3X of those panels in series and get more total daily energy even if it might be maxed out for a couple hours a day.

I have 3 x Midnite Classic 150s... and I get what you're saying but I wasn't able to determine how 'harmful' it actually is so I'm sized to only reach 1.0 max.

I've often wondered what Classics do with the extra power from the panels. Is it shunted to a big resistor and heat burns off? In this case there might have been up to 60a of extra current. Do you know how it works?

 

[snoobler]

As a retired software development engineer - I understand + agree. My wife was a technical writer and would write things that did not include technical detail very well BUT get the idea across with just minimal words. She repeatedly schooled me to cut my emails in 1/2 and then in 1/2 again... Its an interesting topic for sure.

Continual process for me. I've gotten pretty good with it at work, but I know that audience.

I have 3 x Midnite Classic 150s... and I get what you're saying but I wasn't able to determine how 'harmful' it actually is so I'm sized to only reach 1.0 max.

I've often wondered what Classics do with the extra power from the panels. Is it shunted to a big resistor and heat burns off? In this case there might have been up to 60a of extra current. Do you know how it works?

The PV array, like a battery, is a source. When you put a 12V light bulb on the battery, it doesn't explode because it only pulls what it needs to function. It provides a resistance that limits the battery's output.

It helps to think of the charge controller as a load or resistance on the PV array. The MPPT will pull as much load from the array as it can up to its peak output and the array just doesn't supply any more power than that.

 

[time2roll]

Dang, if those panels are in parallel you needed to get the Midnite 150.
Can you trade it in?

 

[Hedges]

If you can connect the panels 2s2p (or 4p) not 4s, then you can orient the two strings (or 4 panels) differently. That will reduce peak so not over-paneled, but give you more hours, more Wh produced.

 

[snoobler]

If you can connect the panels 2s2p (or 4p) not 4s, then you can orient the two strings (or 4 panels) differently. That will reduce peak so not over-paneled, but give you more hours, more Wh produced.

This is a good idea, and one of these days, I'm going to remember to think this way!

 

[Sandrat]

Sorry guys. I meant no disrespect. My brain works in an off the wall way... I honestly can't tell you that you did poorly. I think it just my brain interpreted it all screwy. Plus I was trying to fix all this craps running around in the desert heat.. You both did well explaining. I think I just was in a calmer frame of mind lol

 

[snoobler]

Sorry guys. I meant no disrespect. My brain works in an off the wall way... I honestly can't tell you that you did poorly. I think it just my brain interpreted it all screwy. Plus I was trying to fix all this craps running around in the desert heat.. You both did well explaining. I think I just was in a calmer frame of mind lol

None taken at all.