Author Topic: Solar Charger  (Read 1201 times)

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Offline icoms8Topic starter

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Solar Charger
« on: December 11, 2009, 09:54:02 PM »
Im wanting to build some simple, portable things for every day life. And i want to start out with a solar battery charger. If i hook up a solar panel straight to the batterys in a holder. will it charge them? Or do i have to add something?

Offline robojohn

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Re: Solar Charger
« Reply #1 on: December 11, 2009, 10:29:02 PM »
The Answer is "YES" You have to ad a diode between the battery and the Solar panel otherwise the current will leak out of the panel over night or during low sunlight.

A common diode to use is IN4002, Or In4004. You could Salvage one from almost any power supply or Buy one from dick smiths for around 50 Cents or less.

Current can only flow in one direction through a diode and so will allow the current to flow into the battery but not out the other way.

Simply solder it to the red wire.
The direction of flow is identified by a thin white line at one end of the diode.

Offline Soeren

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Re: Solar Charger
« Reply #2 on: December 12, 2009, 05:30:49 AM »
Hi,

Besides the diode, you also have to select a solar panel of the right voltage and current rating.

What are the specs for the battery you want to charge?
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline icoms8Topic starter

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Re: Solar Charger
« Reply #3 on: December 12, 2009, 01:50:44 PM »
I want to charge two AA Nimh batterys.

Offline Soeren

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Re: Solar Charger
« Reply #4 on: December 12, 2009, 02:07:45 PM »
Hi,

What is the capacity of each cell?
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline robojohn

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Re: Solar Charger
« Reply #5 on: December 13, 2009, 10:17:40 PM »
Most off the shelf rechargable AA batterys are 1.2V 650mAh or 700mAh.

Of course higher capacity cells are also available.

Should be written on the side of the batterys or on the packaging.

Offline Soeren

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Re: Solar Charger
« Reply #6 on: December 14, 2009, 10:29:40 AM »
Hi,

Most off the shelf rechargable AA batterys are 1.2V 650mAh or 700mAh.
It's been a couple of decades since I saw AAs that low. The NiMH cells I use on the job is 2700mAh (and AAAs at 900mAh).
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

 


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