Charge controller rating confusion

[Withered+Flame]

I have a 48v 16s battery with this charge controller:

https://www.amazon.com/gp/product/B07HHP9N8P/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

It says its rated for 60 amps, however it says the wattage max is only 2800w with a 160v input max.
My panels are 6.5 open circuit amps with 21.6v, so...
7 in series per pair = 151.2 volts
9 parallel pairs = 6.5 * 8 = 58.5 amps

Or 6,300 watts with 63 100watt panels.

Its still under ONE of the rated specs (amps) but not the wattage in the description. This descrepency is also in the instruction manual.
Should I ignore the wattage recommendation? This has "dumbed down for the normal people" written all over it.

I vaguely remember something about voltage drop over large distances, does that come into effect here? Like when the voltage drops does it automatically increase the amps flowing?

Edit: providing the link to the panels

https://www.amazon.com/gp/product/B095WRXB55/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[shavermcspud]

The 60Amps is the battery charge current, not the panel input current! if you provide PV input max of 2800Watts / 48Volts = 58.33Amps

 

[Tomthumb62]

t says its rated for 60 amps, however it says the wattage max is only 2800w with a 160v input max.
My panels are 6.5 open circuit amps with 21.6v, so...
7 in series per pair = 151.2 volts
9 parallel pairs = 6.5 * 8 = 58.5 amps

This won’t work. 151v is way too close to the max input of 160v. In cooler and cold weather, the panel voltage will actually be higher than 151v and almost certainly will go over 160v. That will fry your charge controller.

You can usually over panel a charge controller for amps but not volts. If you go over 60A, the controller will simply clip any extra amps. The upside of this is you’ll get a controller putting out max amps for more hours of the day, assuming ideal sun conditions and panel angle/orientation. The downside is the charge controller will have a reduced lifespan due to running hotter.

 

[Withered+Flame]

This won’t work. 151v is way too close to the max input of 160v. In cooler and cold weather, the panel voltage will actually be higher than 151v and almost certainly will go over 160v. That will fry your charge controller.

You can usually over panel a charge controller for amps but not volts. If you go over 60A, the controller will simply clip any extra amps. The upside of this is you’ll get a controller putting out max amps for more hours of the day, assuming ideal sun conditions and panel angle/orientation. The downside is the charge controller will have a reduced lifespan due to running hotter.

even when accounting for that 151.2 number being the short circuit voltage of the panels?

 

[mikefitz]

151.2 volts is the panel string volts at 25 deg C with no loading on the panels. When searching for maximum power its likely the controller will experience this voltage.
60 amps output rating for the controller seems over optimistic for the maximum of 2800 watts of panels. At a 95% estimated efficiency the unit has to get rid of 140 watts of heat, its going to get hot.
If you are going to invest in a large solar array and expensive 48 volt battery, using a low cost questionable controller would seem a poor decision .
With 63 100 watt panels, (are you serious about this?), 6300 watts at 48 volts is 131 amps output from the controller.

Mike

 

[12VoltInstalls]

95% estimated efficiency the unit has to get rid of 140 watts of heat, its going to get hot.
If you are going to invest in a large solar array and expensive 48 volt battery, using a low cost questionable controller would seem a poor decision .
With 63 100 watt panels, (are you serious about this?)

This is good thought.

I have a similar quandary myself. Not really a quandary for me, just a part of the thought process.

First,

My panels are 6.5 open circuit amps with 21.6v

I understand what spec you are referring to but there are zero amps in an open circuit.

Now onto the stuff.
When trying to achieve ’quality’ performance with any budget or cheap components you have to in your own thinking and design factor for dependability.
In my system I have a number of SCCs including two like OP of the PowrMR brand; I consider them 40W SCCs from a design perspective. They will and I have done 60A in my ‘tests’ but they get more than sufficiently hot at 38-43A output to run the fan; I’m comfortable with 40A max for these and by using multiples that aren’t overpaneled you have redundancy for the likely failures, and by assuring you aren’t running them max you probably have extended the time to failure a great deal. Many have run these for several years without failures. But don’t ‘push’ them imho

I would calculate for ~40A output given a VOC 77*F 160V when configuring panels. So roughly 136V max VOC. But they do run more stably at ~80V as indicated in the literature. Just buy one each of these controllers for every calculated series+parallel string of 600-800W to output 40A at 12V, obviously more wattage if 24- or 48V.
That’s what I’m doing. I have 5000W+ of panels and I’m going to only “switch on” additional charge controllers in the short-day, dark winter months when needed rather than pounding the SCCs with overpanelled setups 2/3 of the year.

To use all your panels at max you could use a more robust, more expensive SCC or AIO. Cost wise that won’t be hugely different than multiples of these bottom-shelf controllers. But you lose redundancies and the ability to cut out charging when not required, plus some other benefits I can think of.

At 48VDC system voltage I’d guess you need 4 or 5 of these units - $450- to ‘safely’ operate in practical terms imho.

Maybe you got a deal but 63 100W panels is not something I’d want to play with otherwise. I got 40 60W thinfilm panels for free, 96VOC, 1.2A and even 12 of those parallel in three different arrays seems a little crazy; but those will be my cloudy-months panels and I have enough 40-60A charge controllers on hand to not worry about it.

 

[Tomthumb62]

even when accounting for that 151.2 number being the short circuit voltage of the panels?

Yes, because that is how the calculations are done, with the short circuit voltage. In cold weather, you could easily go over your 160V limit. This is a HARD limit and will let out the 'magic smoke' in your charge controller. Now if it never gets cold where you are and since you're not likely to be reaching the short circuit voltage, you might be okay. But it's your risk of frying a charge controller. Decide if the cost of replacing it (and if you have a spare on hand so you don't lose power for long) is worth it to you.