Make your own Solar Bag and the sun power will be with you

Posted by Julia at talk2myShirt

on August 27, 2007

We conclude our DIY project ‘Make your own Solar Bag’ by sharing with you our experience by using our Solar Bag for a month now in many different ‘real life’ situations to give you an idea what you can expect (and what you can’t expect) from the solar charging power of solar bags.

We can only speak about the performance of our bag but I would expect that most of the bags using a similar solar panel will have the same performance. Our DIY Solar Bag does not have an on board battery to store energy like many other commercially available Solar Bags have. We plan a version 2.0 of our bag where we will add this function but for the first project we wanted to keep it simple.

Using a solar bag makes of course the most sense when the sun is showing its full face and you plan to be outdoors and not hiding in the shadow. The solar bag will charge behind windows as well as in overcast conditions but the generated power will be less and with it the charging time will go up. How much depends on the actual light conditions.

Walking around in the city on a sunny day gave very good results because of the additional light coming from reflections off glass and bright stone walls. The charging went down when walking around the park with many trees and lot of grass. Going in and out of the trees shadows causes the iPod or cellphone to switch between charging and not charging (in the shadow) that might actually train the battery because each time when the charging starts or stops the display will be switched on which uses quite a bit of power.

As far as I know (but I am not an expert in battery chemistry), the battery will not be damaged or loosing the performance of it by the frequent change of charge and not charging.

If your solar bag is not exposed to the sun for about 70% of the time, I would recommend not connecting the iPod other USB powered devices. In such cases where the sun exposure of the solar bag is less then around 70%, a storage battery would be more effective.

We went also to a beach with our Solar Bag where it could show its full performance, loading at the maximum speed due to lot of reflection from the sand and water. Going to the swimming pool got us similar results of full speed charging. We are far away from any snowy mountain to test our bag but my guess would be our Solar Bag would run there on high speed as well due to the high reflection of snow.

Generally, reflection is not needed for the solar panel to work in overdrive. If the bag is facing the sun fully will give the best results. By carrying the bag like any other bag, the sun is not always fully hitting the solar panel and reflection of the surroundings do help to improve the charging performance.

Although you can recharge a complete empty iPod (G5 for example) in about 6 hours, I do not see a solar bag as my primary charging station but appreciate the convenience to have additional power to top off my energy hungry devices.

Having some additional, free of charge power trickling into the iPod while outdoors (on sunny days) helps extending the playtime. Great and useful when being outdoors on the beach or pool, going on sight seeing tour in the city or exploring the wilderness. As long as there is sunshine the power will be yours.

To place the (sun) power in your hands (bag), you can do the following:

Follow our guidelines on how to make your own Solar Bag part one and part two
If you do not have the time to make your own Solar Bag we can offer you a complete functional Solar Bag (the second bag we made to make all the photos) on our Etsy shop
We made some additional electronic boxes available on our Etsy shop if you want to spend all your time on the bag design but not on the electronic part
More photos of our finished bag can be found on Flickr to get you inspired with your own design

We hope our first DIY project is helpful for your own experiments and creations. If you have any questions on how to make your own Solar Bag or about our experience of using a solar bag, just drop us a line into the comments and we will be more than happy and share our wisdom

Posted in Category: DIY - Corner, Solar | 42 Comments »

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Pingback by Techzi » Blog Archive » HOW TO - Make your own solarbag on August 31, 2007 @ 7:12 am