Author Topic: 1500w solar questions newbie.. (Read 10481 times)

dubz · « **on:** August 21, 2009, 02:31:44 PM »

Hi I've had a bit of a search etc.. Please be gentle!

Im currently looking at construction of a 1500W solar array..

My daily usage is 11KWh

I have 1000Ah of 12V...

I'm looking at seting the system up for 24V

so basically my maths are say 7hrs of average 1KW gets me about 7KWh a day..

so at 24V I need 291AH is that right? so the remaining 710Ah is usefull for a rainy day... I read somewhere of a 50% rule.. so really I should never use more than 500Ah

also whats the best way to config the panels... they will be DIY (i undersatnd the pitfalls) would you split the panels with 2 charge controllers? what CURRENt size would they need to be...and what peak current should I espect from my array...

Can you get a seemeles changeover unit??

Im looking at using a 3500KW inverter...

would the syatem work.....? I.e should I expect an average of 7KWh a day with 1500W of panels in the uk..

What if I add a turbine.. say 500w would it be enough to then get me off-Grid?

I welcome all constuctive help..so many questions.... sorry !

many thanks

David UK

Norm · « **Reply #1 on:** August 21, 2009, 09:05:53 AM »

To put it gently ....I don't see any experience

stated....not even mention of a 15 watt solar

panel that you have? or not?

You can't do this yourself unless you are a

licensed electrician....and even then you would

have to be experienced in solar power category.

Unless you have enough money that you don't

need insurance.....

?

electrak · « **Reply #2 on:** August 21, 2009, 11:00:09 AM »

Ok I'll bite

If you can make 1500 watts of panels, and can get 7 hours of full sun a day, at 24 volts you will see about 64 amps, split in two arrays thats 32 amps per array. now batteries, you have 1000AH at 12 volts, if you can reconfigure them to 24volts, you will then have 500AH at 24 volts,

So your math is close, if everything is perfect, no clouldy days, no broken panels, no losses, no other problems,

If you have enough money to throw at it, your close. I would start small, say make a 150watt panel, and use a 100AH battery, and run a room or two, then move up,

You have a plan, so you can make your 150watt at 24 volts, set your battery up for 24volts, get a smallish 24v inverter, then all of your learning parts can be used later,

Oh and where does one get a 3,500,000 watt inverter?

dubz · « **Reply #3 on:** August 21, 2009, 11:07:42 AM »

Thanks for your very helpful reply.....why do i need to state my experience when i ask a question..

I'm a certified part p sparky to bs7671 17th edition... also have ONC/ HNC in electronics.. 2 degrees in RF SYSTEMS, worked in electronics for over 20years.....

and broadcast for 7 with the BBC...I just want some simple re-assurance to some ideas!

You were a newbie once....

anyway.. is there any other helpful people on this forum.... or are you all like this chap?

"Please be nice. Flame wars and rude comments are NOT tolerated here, and the offending comments will be deleted immediately. Keep in mind that sarcastic and cynical comments that you might make in person (with a smile on your face!) often appear to be very rude on a discussion board. "

Im making a 1500W system... not 15w.... Diy panels to make 1500W

tanner0441 · « **Reply #4 on:** August 21, 2009, 11:18:54 AM »

Hi

If you can afford 1500W (best price just over £3 per watt)solar panels and 1000AH batteries,(about £90 per 100Ah) and I assume you meant 3.5KW inverter, and throw a 500W wind turbine in.

Why are you trying to do away with your electric bill, depending on your supplier, UK price about 11P per unit.

Brian

dubz · « **Reply #5 on:** August 21, 2009, 11:31:19 AM »

Just want the reward... that feeling thats its my juice.. not someone elses..Batteries are free !! panels will be diy..! turbine diy... and I've got some money to invest in this..free cable....

yes I meant 3.5 kw inverter... got a 1000va ups im thinking of trying..

thinking of grid tie eventually...

thanks

Dave..

Basil · « **Reply #6 on:** August 21, 2009, 11:37:35 AM »

Please be gentle!

dubz

They gave no slack today. Probably because of lack of information.

I'm currently looking at construction of a 1500W solar array..

I say go for it if you can afford it do it.

I have 1000Ah of 12V...

What are you charging them with now?

I'm looking at using a 3500KW inverter...

You mean 3500 watt inverter I'm sure. As suggested get 24 volt so

you can grow with it.

Good luck

TomW · « **Reply #7 on:** August 21, 2009, 01:02:07 PM »

dubz;

Experience matters in regard to how we answer questions. Your stated need for a 3500KW inverter kind of shows a lack of understanding of RE in general.

So you think you will DIY 1500 watts of solar panels? Please post your results.

Assembling a system is relatively easy once the parts are on hand, building DIY panels is a bit, uh, more ambitious.

You can see our reasons for asking you questions.

You may think you know more about this particular subject than you do.

Its your project but if it was my project I would humbly say thanks to folks for even sarcastic advice rather than pee in their face until I had at least shown some patience for what you misinterpret as nasty. But you know that already being a professional.

What are we supposed to think?

Good luck apolgizing, Norm is a mean old bustard on a good day

And, yes there are literally hundreds of helpful, savvy folks here but being arrogant will not get much useful info.

Just another way of looking at it.

Please note all fees and charges will be refunded immediately.

Tom

Airstream · « **Reply #8 on:** August 21, 2009, 02:18:47 PM »

Your intention of "Seven Hours" is way off mark, with solar the reality is a window of 2-1/2 hours time on either side of Solar Noon is where the majority of power is achieved, calculate for that and anything gotten outside that is a bonus.

Trackers are problematic even if a complete store bought system ie: that extra money would buy more panels so where would the benefit truly be.

Use the calculator provided for your location to get a true picture of energy available!

(**The Gulf Stream warm water currents that keep the UK's temperature mild are cloud makers - I assume opaque cloud cover is calculated into both the following links)

See the "A concrete Example" near the end of the Blog entry.

For 1500W PV array in London England (using http://rredc.nrel.gov/solar/calculators/PVWATTS/version1/)

dubz · « **Reply #9 on:** August 21, 2009, 02:30:48 PM »

My god is it really that bad for the uk?

seems like a complete waste of money...

dubz · « **Reply #10 on:** August 21, 2009, 02:42:45 PM »

My god is it really that bad for the uk?

seems like a complete waste of money...

Ungrounded Lightning Rod · « **Reply #11 on:** August 21, 2009, 04:12:03 PM »

Look up "solar hours". This is the equivalent amount of noontime unclouded sun generation you'll get per day on a panel at your location which is facing the south, tilted at the latitude angle, and not shaded by clouds, trees, nearby mountains, perched birds, or your neighbor's buildings.

Solar hour averages (summer, winter, and spring/fall) are available for most areas. They take into account things like atmospheric attenuation from latitude and typical wind patterns.

Around where I am (latitude 38ish in both California and Nevada) we get about 5ish solar hours per day. You're latitude more like 44 (more atmospheric attenuation, shorter winter days) and have a lot more cloud cover.

Solar power is currently only competitive with mains power in new construction in rural areas, where the cost of the system is low compared to the cost to the customer of running grid power for a few miles. If the panels get down to something like a dollar per watt - or the price of mains power about quintuples - and the new battery technology gets cheap due to its use in hybrids, it may become competitive for sunny suburbs at my latitude. For GB, with its higher latitude and non-clear skys, it will take more.

So don't expect to save any money from your installation (short of more of a financial upheaval than we've had so far). It will cost you something like five times your current power bill for the next seven years. (Which means you could invest the money and run your house on power bough by the proceeds forever.) If you get some other benefit from your installation (fun, green pride points, feeling of self-sufficiency) that is worth four times your power bill for the next seven years, go for it.

zeusmorg · « **Reply #12 on:** August 21, 2009, 06:26:06 PM »

If you're really looking at doing DIY panels, you should do some searches on the ones tried here. The success rate is DISMAL at best! I hate to throw another wrench in your plans, but really, failures are abundant in DIY panels. I was thinking of going that route myself, until I read up on it more.

Figure the cost of building your own, vs a good warranted panel. I think you'll find the savings aren't all that great to begin with. The cost of going RE is quite high as you've probably figured out by now. Payback is in decades even with all the work done yourself. Building all the incidentals yourself is a worthwhile endeavor, and lots have successfully built their own control systems.

I'd look into other ways of saving energy first, and there are a lot! Solar water is probably the best bang for the buck going. Windmills can be good in the DIY area, if you have the wind available.

It's always a lot easier (and more cost effective) saving the energy than producing it!

independent · « **Reply #13 on:** August 21, 2009, 06:38:04 PM »

Great thing about micro solar is you get a really accurate idea of your local insolation (sun time). A plus is your household doesn't rely on it nor your relationships with family members. These past few months in the last NZ Winter we had three weeks where we might have had 5-7 actual hours or sunshine! Let alone in a day. The sun is plentiful in summer and negligible in winter.

Another thing about energy auditing is the advantage of ultra efficient appliances. An 11kWh day might turn into 1.5kWh or less with an efficient fridge and freezer + biomass or solar hot water or heating. A laptop for computing, LEDs (or CFL) for lighting and so on.. It is not worth the effort to make electricity when you can save it.

DamonHD · « **Reply #14 on:** August 22, 2009, 05:06:55 AM »

Absolutely: we went down from gross consumption of ~16--30kWh/day to ~5kWh/day even though we've added two children to our household in that time, by conservation.

Having done that, it has now been possible to generate more than we use over the course of a year (net exporters) with solar PV, and using the most efficient (and expensive!) available panels per unit area, but it would not have been physically possible in terms of roof space without the conservation. Never mind the money.

And the conservation has been considerably cheaper than the generation while saving 5x times the draw from the grid.

And I wouldn't attempt to DIY anything generating enough power to do the above given the mix of water/damp and flammables and and several kW of electricity at peak: serious risk of fire, etc, even if Part-P and thus legally able to do it yourself.

Rgds

Damon

Basil · « **Reply #15 on:** August 22, 2009, 09:12:10 PM »

Ok Look at this. Total

HF Panels 2 sets $440.00 Never agian $440.00 total out of this 4 amps Max

Later 2 100 watt Panels $560.00 Now we are cooking $1000.00 TOTAL 290 WATTS with HF Panels Seen 11 amps Max

38 vodc Motor for a mill $52.00 $1052.00 0 to 17 amps I have seen. 1 to 2 amps Mostly

Hub for mills times 2 $72.00 $1124.00

Linear Actuator for tracking $75.00 $1199.00

Solar controller (15 amp ) $30.00 $1229.00

Solar controller 30 amp (up grade ) $89.00 $1288.00

Batteries 125 amp hr Times 4 + some free $400.00 $1688.00 Total of 680 Amp hrs

Red Rock tracker Think $48.00 But died My fault $1736.00

watt inverter $35.00 Gave away $1766.00
watt inverter Smoked $60.00 $1826.00
watt inverter use some times $100.00 $1926.00

Wire Different size's $100.00+- $2026.00

38 vodc Motor for a ceiling fan $52.00 $2078.00

Forgit Guide wire and other for mill $ 100.00 $2178.00

3 amp didoes Times 6 $6.00+- $2184.00

140 watt inverter (Use a lot ) $32.00 Total $2216.00

Fan controller From G. I Think $ 48.00 Love it.

Added a relay to run it in slow speed when volts drop $2264.00

hours of sun in winter FREE
hours of sun in the summer FREE

Ceiling fan blades FREE

35 AMP Didoes FREE
Relays, 17 ahr Battery and two 1.5 watt panels For tracking FREE

Blades, Pole and other FREE

50 ft # 2 Alum wire from panels FREE

All this to run a ceiling fan 24/7. TOTAL $2264.00+

Yes I have spare power to use but not much.

Getting the idea. BUT IT's FUN.

bob golding · « **Reply #16 on:** August 23, 2009, 01:55:40 PM »

solar hot water, heatpump, a+ rated fridge, led or cfl lighting,low power tv,laptop. that lot should come to the same as 1500 watts of solar on its own. if you have any change and you can get planning permission, go for a home brew wind turbine. should be around 500 quid if you do most of it yourself and pay someone to do the welding. a lot depends on where you are in the UK. i am in Cornwall on the coast and get plenty of wind. you will have to decide between grid tie and islanded, that's where you have batteries and a grid tie inverter as well. can keep the batteries topped up from the grid and sell power back when there is enough wind. i also have a degree in electronics and know a bit about RF but it didn't help much. this is a very small club and you learn from others on here. there are 2 books that will tell you everything you need to know the one on the front page of this site ,and the ones by hugh piggott. good luck.

bob golding

dubz · « **Reply #17 on:** August 24, 2009, 01:47:43 PM »

Thanks ... some excellent advice......

Thinking of doing 500w solar and maybe getting a Hornet 6 blade, with jerry's series rectifier mod...

I want to get one and pur it up to "test" the neighbors reaction, b4 planning....

Are hornets quiet... as the only turbine I've heard was a Windsave, and coln't believe how noisey that peice of crap was....

OuttaSight · « **Reply #18 on:** September 17, 2009, 04:15:45 PM »

7kWh per day from a 1.5kWp array into batteries..? Nope, I don't think so.

I'm running with 1kWp and 440Ah of 12V batteries configured as 220Ah at 24V into a 1kW inverter and can get about 1.5-2kWh per day in the summer months and now the days are drawing in and it's getting hard to use 1.5kW and still get the batteries to go up to their absorption voltage for enough time to get a full charge.

Like others said, peak generation is about 4-5 hours around solar noon.

I still have to judge my evening use of the 28" LCD TV by the next days weather forecast...

You'll find you have to use a chunky grid charger in the winter to avoid the batteries rotting through partial charge. An overcast day (not stormy black) means you'll see about 1/10th the usual peak "sunny Amps". Rainy day? Maybe 1/100th of peak "sunny Amps".

It's perfectly safe to play with some off grid power at home. If you plan on moving house at some point you'd best make things just semi-permanent so it's easy to put things back the way they were for when you have to get the dreaded "electricians safety certificate" for the estate agent. If you never intend to move again then it doesn't really matter at all. All this "Part P" cr#p really annoys me. You can't (in theory) even lift a light switch to paint around it without a certified electrician to undo the screws for you.

If the government was so concerned about public safety, they'd ban home owners from changing light bulbs. After all, you can still stick your pinkie into your "Part P certified safe" unshuttered light bulb socket when it's live and kill yourself.

No doubt a burglar will break into my house at some point and stub his toe on my "unsafe" battery bank and sue me for personal injuries but that's the way things are in the UK these days... GRRRR!

ghurd · « **Reply #19 on:** September 18, 2009, 09:53:19 AM »

You need more battery, maybe double!

G-

OuttaSight · « **Reply #20 on:** September 18, 2009, 02:13:31 PM »

What I really need is 138Ah of lithium iron magnesium phosphate batteries (the Valence U-Charge ones) that can be run down to 100% DoD every day and left for years in any state of charge without them rotting.

News:

Author Topic: 1500w solar questions newbie.. (Read 10481 times)