i am currently adding a few more solar panels on my classic 150,which is functioning at 12v nominal,however the the set of panels hooked up would be too much than what the classic can handle in total wattage. (6 phono 250w,vmp 30.0,voc 37.8,imp 8.3 in two strings of 3 total of 1500w).i want to know if using the amps in and amps out setting on the classic can be used to limit the input and out amperage of the panels when functioning at peak levels,without harming the classic.i do not plan on keeping it this way forever just until my 48v inverter arrives.please advise.
yes, this should be fine, Mahendra.
At least it's not something like 15kW of solar on one classic !
That I might worry about a little bit.
boB
thanks bob
Yes, I am also using the current limiting function of the Classic and it works fine. Settable under Charger->Limits->MaxAmps In and Out, as I remember. What the Classic does, is raise the PV array voltage when it is current limiting, so IV curve of the panels limits the amps output.
thanks lazlo
laszlo*
Also rely on Limits on the output current of Classics here, as we really must use EA, and EA currently (so to speak) only works with a single Classic. So, have two arrays wired in parallel (now) going to a single Classic, limited to about 75 A output, while we *wait* for the MN Bat Current Monitor.
Works fine here. FWIW Vic
Quote from: Vic on August 29, 2013, 12:59:36 PM
while we *wait* for the MN Bat Current Monitor.
and *wait* and *wait* - ;) I guess this isn't high on the software priority list. Unless they are finding issues with the single wire hardware design. Hopefully there are a few out there in Alpha Test land by now.
Quote from: Resthome on August 29, 2013, 06:32:40 PM
Quote from: Vic on August 29, 2013, 12:59:36 PM
while we *wait* for the MN Bat Current Monitor.
and *wait* and *wait* - ;) I guess this isn't high on the software priority list. Unless they are finding issues with the single wire hardware design. Hopefully there are a few out there in Alpha Test land by now.
YaY !! It's REAL close now !
I mean...
REAL Close.
boB
boB!!
That's great news!
Can just barely wait for it. Thanks! Vic
nice !
Lazlo, how far over the midnites theoretical capacity are you operating? I'm planing on doing the same very shortly with some arrays facing different directions to try ad give me a flatter output throughout the day. I don't need more than the peak output of one classic at any one time but would like some extra panels for winter cloud.
Quote from: boB on August 30, 2013, 12:13:51 AM
Quote from: Resthome on August 29, 2013, 06:32:40 PM
Quote from: Vic on August 29, 2013, 12:59:36 PM
while we *wait* for the MN Bat Current Monitor.
and *wait* and *wait* - ;) I guess this isn't high on the software priority list. Unless they are finding issues with the single wire hardware design. Hopefully there are a few out there in Alpha Test land by now.
YaY !! It's REAL close now !
I mean... REAL Close.
boB
:-* :-* :-* ;D ;D
Good to hear boB
Hi, there was a question regarding my current limiting on Classic. How much over capacity on the Classic. I realize you could do that, but in my case actually, it's within capacity. The array is 4.4 KW and 48V nominal system, so the Classic 200 that I have can support that no problems. The limiting factor I have is the DC breakers in and out of the Classic being 63amp, and also that I wish to limit max DC going into the batteries. Under normal peak full-sun operating condition I have around 55-62 amps DC so this current limiting only steps in when let's say it's cloudy for a few minutes then the cloud moves away and so it's a cold array you and you get "cloud-edge" effect as well. With that, it could easily pump 80 amps from array -- and that would be too much. So this is what I use the current limiting feature -- basically to shave off transitory peak amps.
bOB may have more info on current limiting over capacity -- we had a chat a while back about this. As I understand, as long as the Classic is operational it will raise array voltage and limit current. But if it goes belly up, then it will short the array.
So I would not recommend to do this in a production system, or if you do make sure that theoretical maximum current is handled by your OPD and wire sizing.
ok i fully understand i was trying to clarify that earlier because i don't want to fry my classic .since i am in the tropical regions i rarely see over or full output of my arrays only in situations like you mentioned laszlo(cloud edge effect pv amps and volts can really jump up in those brief conditions) .just a reminder the array will be 1500w at 12v on a classic 150, so i would be about 120w above the recommended wattage by mindite solar.However Bob mentioned earlier it would be ok.
Quote from: laszlo on September 06, 2013, 04:33:10 PM
The limiting factor I have is the DC breakers in and out of the Classic being 63amp, and also that I wish to limit max DC going into the batteries. ... you get "cloud-edge" effect ...With that, it could easily pump 80 amps from array -- and that would be too much. So this is what I use the current limiting feature -- basically to shave off transitory peak amps.
Id tend to be a litle careful with this if your classic breaker in the din rail kind. They are of necessity in kinda backwards, positive to the battery, if you trip it with a controller overload it will reverse trip which wont be pretty. However those breakers are duty rated ie theyll carry their trip amps indefinately. But how long a 60 amp breaker would take to trip at 80amps you need to look at the tech specs or ask bob.
Another thing, MPPT controllers use by definition a sweep type of regulation that isnt absolute. You cant guarantee that sudden sun changes wont cause off regulation type output surges. Batterys are tough and dont mind that sort of thing, but issues have from time to time shown up in systems with very large panel to battery ratios, where over charging occurs as a result of this issue.
Hence what im getting at is im not sure how the current limit feature works, whether its a hard limit of more of an average kind of thing. Again bob will know.
The Classic current limit works on average current so if your current shoots up because of
edge of cloud, it may take a second or two to back down. But edge of cloud is not
instantaneous anyway so it should catch that pretty well.
If you abruptly connect a large PV array to it, then it may give you higher current
for a bit longer but that doesn't happen all that often.
There is also hardware over-current protection so connecting Hoover dam to the
Classic should also be pretty much taken care of but still... be semi careful with
fusion and fission energy.
Also, the 250 and 250KS has additional peak responding current limit in software so
it may respond somewhat faster in some instances than the 150 or 200 Classics.
boB
Quote from: boB on September 09, 2013, 03:12:48 AM
be semi careful with fusion and fission energy.
Hey waaaiiit a second...... What about that fusion energy coming from 92,960,000 miles away....... :P
BTW - I've found my Classic's amps out limit to work very well. Even with rapid cloud edge effects/transient spikes.
Quote from: mtdoc on September 09, 2013, 02:52:52 PM
BTW - I've found my Classic's amps out limit to work very well. Even with rapid cloud edge effects/transient spikes.
Interesting. To see this, have you been able to monitor the transients somehow ?
Quote from: mtdoc on September 09, 2013, 02:52:52 PM
Quote from: boB on September 09, 2013, 03:12:48 AM
be semi careful with fusion and fission energy.
Hey waaaiiit a second...... What about that fusion energy coming from 92,960,000 miles away....... :P
BTW - I've found my Classic's amps out limit to work very well. Even with rapid cloud edge effects/transient spikes.
Yes, the Wireless Transmitted Fusion from the generator 92 M Miles away is what I was talking about.
If you have a large WTF receiving antenna pointed at the transmitter source and suddenly connected it up
to the receiver (Classic) you will get an input surge. Just make sure that antenna isn't capable of
supplying like, 100 megawatts to the Classic or you will see the light !!
boB
Quote from: zoneblue on September 09, 2013, 03:43:10 PM
Quote from: mtdoc on September 09, 2013, 02:52:52 PM
BTW - I've found my Classic's amps out limit to work very well. Even with rapid cloud edge effects/transient spikes.
Interesting. To see this, have you been able to monitor the transients somehow ?
On bright - mostly sunny days with large cumulus clouds moving across the sky- I've watched on the local app as the amp limit kicks in with a cloud edge induced spike in PV output.
When I added my second arrray it put my total nominal PV wattage at 4.5K. Since I sell back to the grid and my inverters rated continuous output is 3.6K, I was worried about overloading it and nervous that the Classices amp output limit would not be dependable enough to count on. After watching it on several such days - my fears were put to rest.
mtdoc -- right on. I have been using the current limiting feature for several years, in the method I described above. It's sea-worthy.
Regarding breaker polarity - the Midnite 63amp DIN breakers from South Africa do observe polarity. You need to wire them to have the greater potential electrical source come in from bottom terminal. Read the Classic manual and the Midnite website on this.