Strange Problem

[Deleted member 1888]

I woke up this morning to find my Controller giving a over voltage warning. I don't see how Im over on this, here are the spcs, I had to drop it down to
7 panels to get rid of the warning. This is a 12v system and battery bank.
Updated
All Panels in series
4x 100w 18v Polycrystalline 12v
4x 100w 18.5v Polycrystalline 12v
EPEVER 60amp MPPT Charge Controller 12V Negative Ground Max 150V
Battle Born LiFePO4 Deep Cycle Battery - 100Ah 12v
4 Iornworks LiFePO4 Deep Cycle Battery - 40Ah 12v each

 

[Steve_S]

Are these 12V panels and how do you have them wired ?
Is yoru battery pack 12 / 24 V ?
8 x 12V panels = 96V but the input voltage max is relative to the battery bank voltage and should be in your manual.

From the
eTracer Series(45-60A) MPPT Charge Controller Models：ET4415BND, ET6415BND, ET6420BND, ET4415AD, ET6415AD Manual

 

[Deleted member 1888]

As far as the battleborn I cant find a voltage limit on it just amps. As for the Ironworks they are used and I cant find any info on them.

 

[Deleted member 1888]

Could it have something to do with open current voltage? I don't know that that is.

 

[Bob142]

The short version of my suggestion is: switch your PV array to 2 parallel strings with 4 panels each in series.

More details:
Furthering what @Steve_S responded with, it looks like your Epever manual recommends a maximum of 4 panels in series for a 12V system (see below).

Assuming the 18V and 18.5V you list above are the Vmp (voltage at max power) rating from the panel sticker, it doesn't seem strange for you to achieve an over voltage situation for your 150V max SCC. 8*18V = 144V (right under your 150V max)

Vmp is the measurement under Standard Test Condition (certain panel temp, irradiance, etc.) which is not what your system typically experiences in the real world.

Typically I've seen the Voc (open circuit voltage) used to determine max panels in series for an SCC (your manual uses Voc). In that case, since your 100W panel Voc ratings are probably north of 20V, it puts you at a minimum voltage of 8*20V = 160V. Too high!

I made an assumption that you have the Tracer 6415 AN model. Snippets from the manual are below. I got this from pages 5-6.

 

[Deleted member 1888]

Thank you for that I was wondering what was wrong, so the VOC is what I need to work with. If that is the case they system is
18.5 vmp/22.6 voc
18 vmp/21.9 voc

If that is the case I can safely due 12 panels in 2 strings of 6(6 of each 22.6 and 21.9)
Is that correct? or do I need to stay with 3 strings of 4?

 

[Bob142]

What we didn't get into yet is that once you put the strings from different manufacturers in parallel you will be (roughly) doubling your amps. So you need to make sure your wire going from PV array to SCC is a large enough gauge to carry it safely. Use the various charts/sites on this forum for what gauge wire to use for the combined short-circuit current (Isc) of the strings and round trip length of the wire run from PV array to SCC. (Based on my 100W panels, I suspect you'd be at roughly 12-13A.)

If you're going to go to 12 panels, I suggest you consider converting the system to 24V and staying with 2 strings (6 panels each). Your manual looks like that's the recommended max in series for a 24V system and it would keep your amps to double what you have now. If you do three parallel strings you'll have triple the amps which means calculating wire gauge for the even higher current etc.

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