DIY solar powered-battery powered-mp3-mini boombox thingy


2014-10-28 2:35 pm
1,5W panel is barely enough to charge a phone or tablet battery within the day.

5W would be enough to charge one smartphone like Iphone 5 with full speed.

10-15W is imho the minimum for such a project - if you're using your station very much it's not enough to recharge your battery within the day but it extend your battery life a lot. As said before I'm using 10W (acutally more 13-14W on good weather) for my last box and with it it last a several days longer under heavy usage. If you're using your station for several hours a day it's enough for usual 12V class D amps.

20W-40W should be perfect for any class D amp based project.
My next project for this summer will have at least that.

And yes 9.6V is damn low, a real dead end. Other people say 10.8V is the ultimate minimum, but it depends a bit on the battery model. On my gel-batteries label it says 11.2V min, 14,1V max, I'm using it only between 11,5V and 13,8V (using an mini-voltmeter for checking it every few hours) and it's still working nice with at least 80% of it's original capacity since 8 years, it hope it lasts at least another 5 years.
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