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Solar for beginners

 
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Kadir



Joined: 16 Oct 2007
Posts: 6

PostPosted: Sun Oct 21, 2007 5:28 pm    Post subject: Solar for beginners Reply with quote

could anybody please point me in the direction of the best value for money inverter on the market? and a great deep cycle battery to go with it! Very Happy
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adam2
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Joined: 02 Jul 2007
Posts: 6555
Location: North Somerset

PostPosted: Sun Oct 21, 2007 5:43 pm    Post subject: Reply with quote

With inverters you tend to get what you pay for, a number of high street suppliers including MAPLIN and HALFORDS have a selection of cheap inverters, these are generally square wave or modified sqaure wave and not suitable for some appliances.
Most cheap inverters have a very limited life if worked at more than 50% of theire rating, they are not normally worth repairing.
Better Quality inverters are sold by renewable energy specialists, the most well known are probably XANTRAX (formerly trace enginering)

As for batteries you again get what you pay for.
For smaller or less demanding applications leisure batteries are fine, costs are about ?50 for a 12 volt 75 amp/hour one. Such batteries are unlikely to last for more than a few years.
Better qaulity batteries can be obtained from RE specialists, but at considerably greater cost. Top qaulity batteries can last 20 years or more, provided they are looked after.
Sealed batteries are also available but tend to be very expensive and are therefore not normally the first choice.
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Kadir



Joined: 16 Oct 2007
Posts: 6

PostPosted: Sun Oct 21, 2007 6:47 pm    Post subject: Thank you Reply with quote

i was really hoping that you would answer my question. as i have seen your previous reply to the question about powering an a/c unit.

thank you for your time.
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kenneal - lagger
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Joined: 20 Sep 2006
Posts: 10303
Location: Newbury, Berkshire

PostPosted: Sun Oct 21, 2007 7:03 pm    Post subject: Reply with quote

Don't forget that batteries only last a long time if they are used gently. In order to make them last you should not discharge them to more than 50% of their rated capacity, 40% is even better.
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Kadir



Joined: 16 Oct 2007
Posts: 6

PostPosted: Sun Oct 21, 2007 7:49 pm    Post subject: solar batts Reply with quote

is there a device on the market that allows you to monitor the batteries charging and discharge rates?
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kenneal - lagger
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Joined: 20 Sep 2006
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Location: Newbury, Berkshire

PostPosted: Sun Oct 21, 2007 9:42 pm    Post subject: Reply with quote

Most decent solar or wind charge controllers will have a setting for DOD, depth of discharge.
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hardworkinghippy



Joined: 16 Aug 2007
Posts: 568
Location: Bergerac France

PostPosted: Mon Oct 22, 2007 9:30 am    Post subject: Reply with quote

Quote:
is there a device on the market that allows you to monitor the batteries charging and discharge rates?


Kadir, yes, that's the controller as kenneil has said controls the charge. You can buy a controller easily or make one yourself. This post gives you a bit more detail on what a good controller will do.

There are two controllers in this photograph, one for the windgenerators going into the other for the solar panels, and another little silver one on top (out of the photo) for a completely different system which we added later and decided to keep separate in the case of a breakdown. The photo shows the controller allowing a high voltage to enter the batteries which makes the acid bubble a bit and cleans the plates to keep them efficient. This is totally automatic.



The controller should do everything to prolong the lives of the batteries.

They can usually detect automatically whether your system s 12 or 24 volts and control the input and output accordingly.

Keep the input to under 13.8 volts. (Except when "cleaning".

Let you know if you batteries are getting low - some beep once at 12V then cut off your supply once the battery is at 11.5. Others beep once the battery is 75%, 50% etc.

Here are some more photos (Which I'll add to next time I add more solar panels) of some of our system, some of this kit is more than 14 years old, and still works well.

http://www.flickr.com/photos/hardworkinghippy/sets/72057594066748877/detail/
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adam2
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Joined: 02 Jul 2007
Posts: 6555
Location: North Somerset

PostPosted: Tue Oct 23, 2007 2:32 pm    Post subject: Re: Thank you Reply with quote

Kadir wrote:
i was really hoping that you would answer my question. as i have seen your previous reply to the question about powering an a/c unit.

thank you for your time.


In view of the many variables involved, I dont think that it is possible to answer your question. Its a bit like asking "what car should I buy" without any idea of budget, location, fuel availability or intended use to be made of the vehicle.

For what pupose is the inverter required ? whole house, or one appliance only.
What capacity is required? any large starting surges?
What input voltage 12? 24? 48? 120?
What output voltage ? 100/120/208/240?

Is least first cost the primary concern, or long term reliability?
Are any additional features required? such as auto generator start, grid power changeover, battery charger etc.
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