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Post Info TOPIC: Cleaning Solar Panels
oldtrack123


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Cleaning Solar Panels
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I give up
Another rambling post !!
I will let real electricians decide what is directly applicable to the situation in question..

Perhaps you could explain in a few simple words what changing the cable to a bigger size size actually did!!

The smaller cable could only have two effects

 It could have overheated IF the current exceeded it's continuous rating 

ThAt was not the case!!

The voltage drop in the cable  limited the panel output,due no doubt to the panels 'low output voltage under those conditions 

You then used a bigger cable ,the only effect it could have was to REDUCE the voltage drop in the cable ,making more voltage available to charge

All the rest  of your information is somewhat irrelevant to those simple facts

If you can explain how changing to a bigger cable could do anything else than affect cable resistance & therefore  voltage drop in the cable,  please explain in simple electrical terms

Using the only factors that are relevant, Source voltage,  circuit  resistance & current , battery voltage

All your replies  do is explain why the available input voltage was so low.& I have no disagreement with those facts






-- Edited by oldtrack123 on Monday 15th of May 2017 02:50:13 PM

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Aus-Kiwi


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Yes 2.5mm is bloody hard work "CLEANING" solar panels ..

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Baz421


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Well I may as well have my 2 cents worth,,,

480 Watts of panels on van roof, 10 years old,, I clean when dusty etc,,,, they put out 28A one fine day about 7 years ago, but 25A is normally the average max on my control panel.

Sometimes I wash with clean water or use T18 (I think) Truck Wash and they still put out 25A average max on a fine day.

So I'm happy.

We all should be happy we are alive and kicking and enjoying life - aren't we???????

Well most of us are, others just like to carry on like 2 bob watches it seems.

Maybe I'll start another thread on noisy cheap gennies,,,,, ah may be not the last one was closed by crap posts.

Cheers Baz

Maybe I had 10 cents worth there!!!!!



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Aus-Kiwi


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You'll find if you use sp25 it'll keep the sun off the panels ? Less heat build up ! Ahahaha

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Reed


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What is sp25? We just wash panels with hose and soft cloth when we return from Mexico beaches since there is salt buildup. We can get rather dusty rains in New Mexico and then it is necessary to wash again: 0.1 mm of rain and perhaps more than that percipitated dust/dirt. Have never noticed much difference before and after washing. This summer, we should be spending a month or so at 10,300' (3140 m) elevation boondocking/dry camping/dispersed camping/CCC (cheap charlie camping) in Colorado. We do get 100%+ of rated watts on clear days at that elevation.
Reed and Elaine

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oldtrack123


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Hi Terry

Let me start by saying that I believe you have a great job with your lithium work.

But honestly, you do need to get the idea out of your head  that the basic electrical laws such as Ohm's & Kirchoff's do not apply irrespective of the voltage or current type. 

I wish we could sit down side by side so I could go through so many practical examples to help you understand that.

Perhaps a good start would to be to carefully read some of the excellent info on the net such as

http://www.brighthubengineering.com/commercial-electrical-applications/125557-what-you-want-to-know-about-electrical-laws-and-formulas/

Yes I have lost the light of my life after a long illness & her funeral will be tomorrow

 

Thanks for your best wishes

 I have been her full time carer for many years & needing to be constantly near her meant the nett & forums were about the only relaxation I could have & still be near enough if she called

That is why I have spent so much time on various forums

But after the funeral I would be quite happy to assist you in seeing, in detail, why some of your ideas are so wrong or misleading.

Rather than on forums ,I would suggest that we could discuss that by private emails

Would you be interested???

Peter

 



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T1 Terry


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Interesting offer Peter, I would be happy to talk via email rather than going head to head all the time on these forums. We both seem to bring out the worst in each other and sometimes tend to attack the person rather than the subject material. My thoughts will be with you as you say your goodbyes to the light of your life, I have experienced many losses but I can't even imagine the pain associated with the mixtures of feelings you must be going through at the moment.

 

T1 Terry



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oldtrack123


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Hi Terry
Give me a little time & I hope / Will come back to you via email .or PM
Regards
Peter



-- Edited by oldtrack123 on Tuesday 16th of May 2017 04:33:52 PM

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rockylizard


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Gday...

I am a little confused given the comments on this thread regarding the necessity to regularly clean solar panels.cry

Professor Julian Sumner Miller always asked me as a kid "Why is it so?"

In the six years I have had solar panels, I have maybe cleaned them twice but never took any notice of any affect, if any, on their output.

So today, egged on by the positive outcomes all have espoused, I got out the ladder, got up on the roof and saw that all three panels had a fair bit of dust all over ... and due to the slope of the roof where they are mounted, some thick, dry dust in about 10% of one corner of each.

So I climbed down from the ladder, and checked the controller. The panels were showing 20.7V, and as the battery was on Float at 13.4V, 0.00Amps coming down.

So I got all sorted out with my fluffy pad on a stick, connected the hose to the stick, checked the solar monitor again - still 20.7V

Up the ladder - carefully cleaned each panel with the clean water, carefully mopped up the excess water left behind, carefully squeegeed the remaining moisture off the panels.

Climbed back down the ladder and checked the solar panel controller.

It was now showing 20.5V confuse and as battery was still on Float at 13.4V, 0.00Amps coming down.

I will assume the reason for the drop from 20.7V to 20.5V was only the changes in light on the panels while I cleaned the panels.

But what confused me is that my panels usually show between 20.5V and 21.1V 99% of the time during the day - unless it is raining when there is not enough light to charge.

So, given the advice that cleaning panels is critical to obtain a full output from panels ... why don't mine? cry confuse or are they already? hmm confuse

Can someone provide some clarification/advice.

Cheers - John



-- Edited by rockylizard on Wednesday 17th of May 2017 02:04:05 PM

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T1 Terry


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The 20+ volts is open circuit voltage, no current output. The improvement is in the full panel current output, amps, so it needs to be actually charging the battery in boost mode to see the improvement. As for the battery being on float at 13.4v, I'm guessing this system is not in use at the moment and just parked up. A working system where the battery is partially drained over night and then recharged the next day should have a higher float setting as 13.4v will only keep a fully charged battery full, it won't charge up a partly discharged battery, this is known as maintenance mode and is designed not to create any gassing.

T1 Terry

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rockylizard


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T1 Terry wrote:

The 20+ volts is open circuit voltage, no current output. The improvement is in the full panel current output, amps, so it needs to be actually charging the battery in boost mode to see the improvement. As for the battery being on float at 13.4v, I'm guessing this system is not in use at the moment and just parked up. A working system where the battery is partially drained over night and then recharged the next day should have a higher float setting as 13.4v will only keep a fully charged battery full, it won't charge up a partly discharged battery, this is known as maintenance mode and is designed not to create any gassing.

T1 Terry

Gday...

Terry, I rarely see more than  21.9V on my solar controller at any stage during any day- from 320W of panels.

A typical scenario -

Sunrise ... battery showing 12.5V; panels showing maybe less than 5V; 0.00amps coming down.

9am ...  battery anywhere between 12.5V and 14.3V - beginning with Bulk charge and then dropping as panels get more sun and provide more amps down to Absorb charge.

10am ... battery showing 14.3V; panels showing 20V (at least); 10amps (at least) coming down; Absorb charge.

             solar controller shows either Float or Absorb on and off as it continues to keep battery anything between 13.4V and 14.3V -

             amps coming into battery will vary from 7amps down to perhaps only 2amps as the day progresses.

1pm ... battery showing 13.4V; panels showing 20V (at least); maybe 0.9 to 1.1amps coming down; battery on Float charge.

           Battery remains on or around 13.4V for the remainder of the day; panels holding 20V slowly dropping along with the sun ... amps only trickle - until -

6pm ... Battery on 12.9V; panels showing little or nothing V; 0.00amps coming down.

10pm ... off to bed ... battery on (usually) 12.6V. As you can guess, I don't use much power - stingy liddle me. no 

            Although I have at least one LED light on, laptop from van battery for at least 2 hours, radio for at least 4 hours and occasional other small stuff.

Dawn ... off we go all over agen.

[edit: forgot - so cleaning my panels during an afternoon will not usually show any amps (current) coming down .. coz the battery is on float - 13.4V and just 'sitting there'.]

Cheers - John



-- Edited by rockylizard on Wednesday 17th of May 2017 07:11:11 PM

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T1 Terry


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If the battery is still at 12.6 the next morning then I doubt you will actually see and difference, maybe a few amps between 9am and 10 am. If you do use the batteries each night I would suggest putting the float voltage up to 13.8v or even 14v to give the batteries a better chance of actually reaching 100% SOC and clear some of the sulphation out of them.

Your use pattern would match those that tell us they get 7yrs to 10yrs out of their AGM batteries, once you actually notice the battery isn't delivering it would be down to maybe 10% capacity or less. The voltage at the end of charge is always the same, just the length of time a load can be supplied before the voltage drops below 12v changes.

 

T1 Terry



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meetoo


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T1 Terry wrote:

As I said else where Peter, I don't want to go into a head to head battle with you so close to loosing your wife. Please don't attack me to get over your pain
T1 Terry

 Terry, surely you can do better than that here.

Cheers, John.



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rockylizard


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T1 Terry wrote:

If the battery is still at 12.6 the next morning then I doubt you will actually see and difference, maybe a few amps between 9am and 10 am. If you do use the batteries each night I would suggest putting the float voltage up to 13.8v or even 14v to give the batteries a better chance of actually reaching 100% SOC and clear some of the sulphation out of them.

confuse more confused now confuse are you suggesting that my battery, getting to float (13.4V) by 1pm and staying there until sun gone, is not getting to 100% SOC?? 

Your use pattern would match those that tell us they get 7yrs to 10yrs out of their AGM batteries, Battery is five years old - those figures I quoted have been like that for the past five years.
once you actually notice the battery isn't delivering it would be down to maybe 10% capacity or less. The voltage at the end of charge is always the same, just the length of time a load can be supplied before the voltage drops below 12v changes. confuse confused. Are you suggesting that because the battery is down to 12.6V most mornings before sun/solar begin charging, it is losing 'capacity' eg nearly down to X% ... maybe even 10%??

 T1 Terry

Gday...

confuse very confused Terry confuse

Cheers - John



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T1 Terry


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Hi John, it depends what the absorption voltage is and how long it holds that voltage as to how close you get to 100% SOC.

 

9am ...  battery anywhere between 12.5V and 14.3V - beginning with Bulk charge and then dropping as panels get more sun and provide more amps down to Absorb charge.

10am ... battery showing 14.3V; panels showing 20V (at least); 10amps (at least) coming down; Absorb charge.

             solar controller shows either Float or Absorb on and off as it continues to keep battery anything between 13.4V and 14.3V -

             amps coming into battery will vary from 7amps down to perhaps only 2amps as the day progresses.

1pm ... battery showing 13.4V; panels showing 20V (at least); maybe 0.9 to 1.1amps coming down; battery on Float charge.

           Battery remains on or around 13.4V for the remainder of the day; panels holding 20V slowly dropping along with the sun ... amps only trickle - until -

 

The fact that there is still 0.9 amps to 1.1 amps when the charge voltage drops to 13.4v shows the battery has not actually reach 100% SOC yet so the reduced voltage means it will never actually reach 100% SOC. To prove me wrong, reset the float voltage to 14v and see if the amps going in increases, if it remains at 0.9 amps to 1.1 amps then I'm wrong and you can tell everyone I don't know what I'm talking about...... hard to resist isn't it wink biggrin

 

T1 Terry



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Aus-Kiwi


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Having good connections helps .. Even better when connected surprisingly !! Lol

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