Can I revive these seemingly dead panels?

[HalfBaked]

No, you'll only measure current if the SCC draws it. If the battery voltage is 48, the PV voltage will have to be greater than that by probably at least 10V for it to draw any current from the PV, unless your's has a boost converter in it, and that is unlikely.

Thanks for all this. All becoming clear now. Going to wire them 3s1p now and remove one before the next freeze.

 

[400bird]

Thanks for all this. All becoming clear now. Going to wire them 3s1p now and remove one before the next freeze.

Where abouts are you located? What are your winter temps? From the looks of it, that charge controller hasn't died by pure luck if the morning and afternoon 3s arrays are made of the same panels.

 

[HalfBaked]

Do you have multiple charge controllers? Or multiple MPPTs in that one charge controller?

You've got a combiner box, so I'm guessing not. How did the mid day array ever work? It's in parallel with the 3s arrays. Not a great set up.

Currently one ts-mppt-60, will be getting another.

I live in a hole in the forest. Each array is only active at a time as they face different directions.

 

[HalfBaked]

Where abouts are you located? What are your winter temps? From the looks of it, that charge controller hasn't died by pure luck if the morning and afternoon 3s arrays are made of the same panels.

Midsouth. Winter can go between 32⁰ and 0⁰ for lows. The morning array is made of 260w panels, but it's high angle makes it taper off while the midday array is tapering on. This has been working since March, but may cause problems at low temps.

 

[HalfBaked]

You guys (and this entire community) rock!
Thank you all for the continued education!

 

[ghostwriter66]

Midsouth. Winter can go between 32⁰ and 0⁰ for lows. The morning array is made of 260w panels, but it's high angle makes it taper off while the midday array is tapering on. This has been working since March, but may cause problems at low temps.

Check the max voltage for your MPPT also -- some will allow you to go over a bit and still be fine ... some will explode and kill everyone in a 100 mile radius 1 volt over - and some will start acting really funny anything over 80% of maximum ...

I may have missed it -- but what MPPT SCC are you using ??

 

[400bird]

I live in a hole in the forest. Each array is only active at a time as they face different directions.

Now the parallel arrays make sense. If more than one was producing at the same time, it would never have worked.
If all 3 arrays were the same, the two shaded ones would have the chance to add a few watts while the 3rd worked.

Midsouth. Winter can go between 32⁰ and 0⁰ for lows.

The panel spec sheet earlier in this thread doesn't have the temperature coefficient, so I used the default in the Midnight calculator. Says you'll go over 150 volts at 60f. Should probably look at getting another charge controller real soon!

The morning array is made of 260w panels, but it's high angle makes it taper off while the midday array is tapering on. This has been working since March, but may cause problems at low temps.

There's plenty of other string sizing tools. This is the one I use.

MidNite Solar - Classic Sizing Tool.

MidNite Solar is the industry leader and manufacture of quality Renewable Energy System electrical components and E-Panels.

www.midnitesolar.com

If you haven't been through a winter yet, nows a good time to make sure you aren't 3 months from blowing up that charge controller ?

Check the max voltage for your MPPT also -- some will allow you to go over a bit and still be fine ... some will explode and kill everyone in a 100 mile radius 1 volt over - and some will start acting really funny anything over 80% of maximum ...

Don't over react! They only kill everyone on the internet that read about it, but we all get to point and say "I told you so" as our last dying breath.

 

[HalfBaked]

Check the max voltage for your MPPT also -- some will allow you to go over a bit and still be fine ... some will explode and kill everyone in a 100 mile radius 1 volt over - and some will start acting really funny anything over 80% of maximum ...

I may have missed it -- but what MPPT SCC are you using ??

It's a TriStar mppt 150v/60a

 

[HalfBaked]

Now the parallel arrays make sense. If more than one was producing at the same time, it would never have worked.
If all 3 arrays were the same, the two shaded ones would have the chance to add a few watts while the 3rd worked.

The panel spec sheet earlier in this thread doesn't have the temperature coefficient, so I used the default in the Midnight calculator. Says you'll go over 150 volts at 60f. Should probably look at getting another charge controller real soon!

There's plenty of other string sizing tools. This is the one I use.

MidNite Solar - Classic Sizing Tool.

MidNite Solar is the industry leader and manufacture of quality Renewable Energy System electrical components and E-Panels.

www.midnitesolar.com

If you haven't been through a winter yet, nows a good time to make sure you aren't 3 months from blowing up that charge controller ?


Don't over react! They only kill everyone on the internet that read about it, but we all get to point and say "I told you so" as our last dying breath.

You're right, 60f is coming in a few months. I will do my homework. Also, my 2nd SCC will have higher specs

 

[Hedges]

Lack of string fuses won't damage panels. Only if there is also a short, so excess current backfeeds. Then fuse can protect.

Strings of panels in the sun and equal length in darkness doesn't result in excessive backfeed. With 2s || 1s, I was only able to get about 1/2 Isc.

Partial shade on a string that otherwise has full sun can short diodes. That would show up as reduced Voc. Might even melt/crack something.

A bad panel can have full Voc and full Isc, yet low Vmp/Imp. I connected to a resistive load (couple of electric radiators in parallel) to test 165W panels, found some bad ones.

So while I had my back turned, upgrading my system from 12 to 48v, my midday array quit on me. I'm sure it's my fault, as I had these 3 panels in parallel without fusing between panels. (Now I know better). But these 3 have been working in this configuration for a couple years without issue.

What is your string design in terms of Voc and Vmp?
With 48V system, what voltage is required into your particular MPPT to charge?

Hot weather and full battery would reduce or stop current.
But 48Voc, you must have more than one panel in series for 48V battery, I would think.
3p bad. 3s bad. 2s good.

 

[HalfBaked]

What is your string design in terms of Voc and Vmp?

Now in 3s1p, 144.63voc, 120.15vmp

With 48V system, what voltage is required into your particular MPPT to charge?

I only know the SCC requires 8v to operate.

But 48Voc, you must have more than one panel in series for 48V battery, I would think.
3p bad. 3s bad. 2s good.

Thanks for this, I believe this is what the other guys were trying to get across to me. It's tiresome being ignorant.

 

[Hedges]

Now in 3s1p, 144.63voc, 120.15vmp

Thank your lucky stars the weather is hot not cold.

I only know the SCC requires 8v to operate.

Try 2s.

Thanks for this, I believe this is what the other guys were trying to get across to me. It's tiresome being ignorant.

Understanding takes time. Also sorting the wheat from the chaff.
What's in manufacturer literature doesn't always tell the whole story, so our being familiar with internal circuitry helps.
Some of us have been at this for half a century or more.
We're still learning.