Solar Power Calculator

Submitted: Saturday, Jul 11, 2009 at 21:45
ThreadID: 70594 Views:8787 Replies:3 FollowUps:3
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A lot of people ask questions like how many batteries do I need - what size solar panles etc etc ..
I have put together a "rough guide" Solar Calculator on an excel spreadsheet --

Before I put it into the fileswap I was wondering if a couple of the electronic gurus who understand Excel Spreadsheets might have a look at it first and make sure I haven't made any "Ayers Rock sized blunders " ...

If you can help send me an mm and I'll email this small spreadsheet to you for
editing and any extra bits I may have missed etc etc ...

Here's a screen dump of what it looks like ...

Image Could Not Be Found

Cheers

Steve
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Reply By: Member - Clay S (NSW) - Saturday, Jul 11, 2009 at 22:48

Saturday, Jul 11, 2009 at 22:48
Hi Mandrake, your calculator caught my eye! I work with spreadsheets everyday and was previously a qualified electrical engineering technician on power stations so would be more than happy to go over this. I will send you a message with my email address.
Cheers
netsullivc
AnswerID: 374119

Follow Up By: Mandrake - Sunday, Jul 12, 2009 at 09:27

Sunday, Jul 12, 2009 at 09:27
Clay ,

Thanks - I have sent to your email addresses ..

Let me know on any errs

Cheers

Steve
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FollowupID: 641358

Reply By: Maîneÿ . . .- Sunday, Jul 12, 2009 at 01:44

Sunday, Jul 12, 2009 at 01:44
Steve,

The PSH guide would advise the number of "hours of usable light" for different areas in Australia and the hour terminology should be reflected the same way, ie; 6 hours both average and maximum should be either one or the other, it's not likely to be both (average & maximum) - is it??

Google will give you many Solar power calculators so another won't hurt, as I'm sure they are not all correct, or wrong either :-)

But you just can't have too many Amps

When the people ask "how many batteries do I need" and you try and explain to them the more ah the better, they go and put in elcrapo batteries that won't stand up to the torment given to Aux battery systems for long term camping, and then wonder why they only last a few years

Maîneÿ . . .
AnswerID: 374132

Follow Up By: Mandrake - Sunday, Jul 12, 2009 at 09:26

Sunday, Jul 12, 2009 at 09:26
Mainey ,

I only used the word Max on the sheet in the assumptions -
It assumes that you get the Maximum output from the panels over
the average 6 hours of sunlight - It doesn't actually say that 6 hours is
the maximum .. I know the usable time varies from Darwin to Hobart
but I can't factor in every possible variance it would make a simple calculator complicated ..

This is just a basic system calculator nothing more and nothing less -

It will tell Joe Average that his 17aH Jumper will only power is 100 Litre Engel for an hour or two !! And that is all I am trying to do ..

I well add another column in the Days with / without area to cover the maximum cloudy day expectancy - I think dropping the output by 2/3rds would cover that contingency - Would that be about right ?

Cheers for the comments

Rgds

Steve
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FollowupID: 641357

Follow Up By: Maîneÿ . . .- Sunday, Jul 12, 2009 at 12:54

Sunday, Jul 12, 2009 at 12:54
I would not drop output numbers, just stipulate that the numbers shown are relevant in clear conditions and should be expected to be less in overcast conditions, keep it simple with-out stating any %.

Unfortunately different technology used in various panels does give different results in identical light conditions, this will complicate 'simple' and even the overcomplicated Solar calculators.

The light grey (bright) clouds will often give higher Amps (in some panels) than is claimed by their manufacturer, when tested in ideal bright sunshine conditions.
I know this because I've compared my Sharp panel directly with my BP panel under identical 'bad' conditions, the results were vastly different, even when allowing for the different maximum ratings of each panel.

Maîneÿ . . .
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FollowupID: 641391

Reply By: Mandrake - Tuesday, Jul 14, 2009 at 20:27

Tuesday, Jul 14, 2009 at 20:27
Well Its done - with a little help from Clay the Solar Power Calculator has been uploaded to the fileswap area...
its a bit simpler than the other ones that are there and certainly much better looking ( LOL ) -
If anyone would like to check their known system against its findings and let me know how close or not it is that would be useful...

Cheers

Mandrake - 38 days to go or 39 ?
AnswerID: 374550

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