Ahh good question Ckallday. I have been using Lipo batterys for years. I use two 14.8v 5000mah lipo. Never had a problem. they're light and small and last me for about 3 days without recharching.
Its all water proof and its sits right under my seat.
Here is a pic of my set up.
IMG_20140522_134652.jpg
Just make sure you install a batt monitor.
Hobby King Battery Monitor 4S
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