Lithium Polymer batteries are the newest and currently one of the best choices for batteries in a portable. They are smaller than other batteries, don't develop a "memory" , and last through more charges/discharges than other types of batteries.
But working with Lithium Polymer batteries can be dangerous and precautions must be observed. Be very careful with polarity when hooking up Li-Po's. Also ALWAYS use a protection circuit (PCB) and a Lithium charger that is appropriate for the number of Li-Po's you will be using.
Lithium Polymer batteries come as single 3.7v cells. These cells can be packed together to get 7.4v , 11.1v, 14.8v , etc Li-Po Packs.
When using a 7.4v pack you will want a 7.4v Pcb and a 7.4v charger. Ditto on the rest.
The following diagrams will be based on wiring the 3.7v cells in series to add their voltages together to get the required voltages we need. Batteries wired in series are wired like so :
This is the typical battery most of us use because it has a relatively high capacity for a very small size and cheap price:http://www.batteryspace.com/polymerli-i ... isted.aspxHere is an example on how to wire the different sets of Li-Po packs you might be using :7.4v pack. (Two 3.7v Li-Po's)
For the Pcb you will need the following :http://www.batteryspace.com/pcbfor74vli ... limit.aspx
For the charger you will need the following:http://www.batteryspace.com/smartcharge ... isted.aspx11.1v pack (Three 3.7v Li-Po's) :
For the Pcb you will need the following :http://www.batteryspace.com/pcbfor111vl ... ocket.aspx
For the charger you will need the following:http://www.batteryspace.com/smartcharge ... isted.aspx14.8v pack (Four 3.7v Li-Po's) :
For the Pcb you will need the following :http://www.batteryspace.com/pcbfor148vl ... ocket.aspx
For the charger you will need the following:http://www.batteryspace.com/smartcharge ... isted.aspx