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Stuie_k
Newbie

Joined: 18/09/2016
Location: United Kingdom
Posts: 1

Posted: 02:58am 18 Sep 2016

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Hello everyone,
Iv'e been tinkering with electronics for some years now,
I stared by challenging myself to make a green laser from scratch and have developed into making led sculptures cubes etc,
now my enjoyment of electronics has taken a new twist which is to make myself a small wind turbine to charge some 12v batteries which would in turn run some 5v chargers for phones etc,

So iv'e ordered myself a small turbine motor that puts out 5-24v (40v max) with a current of 1500ma
max power of 20 watts (according to the spec sheet)
so not the biggest project but baby steps are always good :)
iv'e got my charge controller that's 12 or 24 v depending which way you set it,
Iv'e got myself 2 x 12v 7AH batteries which should be ample for my needs,

Reading up on a typical wind turbine set up i see that ceramic heaters and heating elements seem to be the standard for dump loads,
but as i'm going to be using this when camping out in tents having hot appliances could be dangerous for the tent,
iv'e got 100's of led's at my disposal so i'm wandering if led's coupled with a hefty resistor would suffice as a dump load?
Iv'e done some online calculations for resistance based on input voltage of 12.6v iv'e had to guess the voltage drop and have estimated 3.4v (blue 3mm led's)
and desired current of 20ma per led,
the calculator says for a parallel chain of 30 led's i'd need an 18ohm 6watt resistor for the 30 leds,this would use 511ma of current,if i made 5 strips of 30 and wired everything in parallel would this be enough to use up the excess electric?
Any advice here would be gratefully appreciated :)
Cheers
Stu :)

fillm

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Joined: 10/02/2007
Location: Australia
Posts: 730

Posted: 01:46pm 19 Sep 2016

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Stuie_k said Hello everyone,

1/ So iv'e ordered myself a small turbine motor that puts out 5-24v (40v max) with a current of 1500ma
max power of 20 watts (according to the spec sheet)
so not the biggest project but baby steps are always good :)
2/iv'e got my charge controller that's 12 or 24 v depending which way you set it,

3/ but as i'm going to be using this when camping out in tents having hot appliances could be dangerous for the tent,

4/ iv'e got 100's of led's at my disposal so i'm wandering if led's coupled with a hefty resistor would suffice as a dump load?
5/Iv'e done some online calculations for resistance based on input voltage of 12.6v iv'e had to guess the voltage drop and have estimated 3.4v (blue 3mm led's)
and desired current of 20ma per led,

Any advice here would be gratefully appreciated :)
Cheers
Stu :)

Welcome Stu,

I have numbered your questions.

1- @ what RPM

2- hope it's not a solar controller

3- What you don't have a portable stove in your tent? If a Dump load is in a correct enclosure it will not be a problem. Not sure if you want to be up all night having LEDs flash ON - OFF .

4- Its not advisable to use lights directly coupled as dump loads, switch them from the stable battery voltage is better but a ceramic resistor is best.

5- when a turbine is switched to dump its at upper charge voltage 14.5V

My 2 cents about what you propose, a wind turbine is not a good portable thing and better to have at home , buy a small solar panel for camping would be a lot easier.

PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits

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