Here is a basic instructional manual that will cover pretty much everything you need to know about the mintyboost you just built.
So, does it work with your gadget? First you can always visit our compatibility list which we keep updated. We have a list for versions 2.x of the kit and 3.x. We try to keep the list updated as much as possible - if something is not on that list then it doesn't mean it doesnt work, just that we dont know. Almost all devices charge fine!
One thing you can always do is try it out! Wait until the battery is halfway drained, then plug your gadget into the USB port and wait a few minutes and see if the battery inches up or if the charging light goes on. You can also feel the mintyboost to see if it's warming up which would indicate it's providing power to the gadget.
Basically, get the best batteries you can. New Lithium or Alkaline 1.5V batteries work great as do fully charged NiMH rechargables. Old, worn out or dead batteries will not work at all.
We have a very detailed tutorial about batteries in case you want a lot of details.
Easy, get a USB charging cable for your gadget, nearly all come with one these days, you can also usually get one for cell phones or games at an accessory shop. Plug in the USB end into your mintyboost and the other end into your device. That's it! The gadget will draw power to charge up the battery.
While charging your device, you may notice the Mintyboost and batteries getting very hot. This is normal, it's because of how much power is being delivered to the gadget! The Mintyboost will cool down as soon as you unplug it. The maximum temperature for the mintyboost chip is over 100 degrees C, that is hotter than boiling water. If you are worried, lick your finger (a little) and touch the tip of your finger to the top of the LT1302 chip. If you don't hear a sizzle (of the water boiling away), it's just fine.
If the mintyboost is getting really hot when it's not plugged in, there may be a short! Remove the batteries and check to make sure there is insulation between the mintyboost PCB and tin.
You may also hear a 'hiss' or 'squeak' coming out of the chip. Sometimes the inductor resonates with the boost converter and that resonance leaks into the audible range. While it's not good for it to always vibrate, it does happen rarely and is not harmful to the charging device. You can try moving the inductor a little with your finger but the noise is electrical in nature so it's hard to stop completely.
Another thing is that it depends on how much power the device is drawing and what kind of batteries are inside.
The mintyboost will charge and charge until the batteries give out and the voltage output isn't 5V anymore. At this point the batteries are toast and you won't be able to squeeze any more power out of them. However, some phones and mp3 players (especially ones that start with an 'i') are not very smart and even if there is no more power coming out of the charger, they stay on, which means they slowly drain back down.
Basically, the best way to avoid this is to not leave the mintyboost plugged in overnight. Just charge for a few hours or while you're using it!
For Apple products, you can also use the charging icon as a hint, while the Mintyboost is still working, you'll see this icon: