I am doing an arduino project that requires wireless charging. I am trying to get all the parts on Amazon because I have giftcards to burn so I had to go with a more complicated but I feel safer than a hack solution.
I have an Arduino Fio that has a built in LiPo USB Charging circuit.
My plan is to use a Galaxy S3 Wireless charging base transmitting to a Galaxy S3 Wireless receiver which I will solder a USB dongle onto and plug into the Arduino Fio (The USB port on the Arduino fio is ONLY for battery charging so this should work)
To keep things consistent I am going to buy a Galaxy S3 3.7v 2100mAh battery to power this device.
Question
So my question is the battery appears to have 4 contacts on it. From research I am assuming that 2 of the contacts are for reading the battery temp and other stats. If I am using the Arduino Fio's lipo charging circuit do I need to connect these other 2 terminals on the battery or can I just use the + and –
This is the battery
http://www.amazon.com/gp/product/B0089VO7OM/ref=ox_sc_act_title_2?ie=UTF8&psc=1&smid=A2DE8N3Z0PUB32
To keep it consistant I plan on using this wireless charger
http://www.amazon.com/gp/product/B00B7LPA42/ref=ox_sc_act_title_7?ie=UTF8&psc=1&smid=A2L77EE7U53NWQ
With this receiver
http://www.amazon.com/gp/product/B00BCC2B1Q/ref=ox_sc_act_title_6?ie=UTF8&psc=1&smid=A2L77EE7U53NWQ
Arduino Fio
http://www.amazon.com/gp/product/B005K0O1PA/ref=ox_sc_act_title_8?ie=UTF8&psc=1&smid=A1LHQ5G6ONPXVT
Best Answer
You can in practice ignore the other pins. The battery will just charge if a suitable voltage and current is applied. One of the pins be connected by a thermistor to another pin, possibly ground. This is to indicate over-temperature. That's not much of a problem unless it's in an enclosed case and you're trying to charge it very quickly.
The wireless charger side of the plan I'm less sure about; it looks like you're supposed to attach it directly to the battery. I'm also unclear about how you plan to hold all this together and make contact with the battery. Note that you MUST NOT solder the battery terminals directly.