Half charging lipos?
 

I'm ready to fire up my rebuilt Mugen mbx7r for the first time and have purchased a starter box and lipo batteries for servos/rx and the starter box. For the starter box I have a 4S 5300mah 50c lipo and for the servos/rx a 2S 2400mah lipo.

Since I am only wanting to start the engine and ensure it runs okay, would it be better to fully charge the lipos, or could I half charge them to save time charging/returning to storage voltage? The 4S starter box battery is brand new, however the 2S rx lipo is second hand.

Half charging wouldn't hurt anything.

If the engine is new and tight then I'd charge the lipos to about 4.0v per cell so about 75% charged as you'll need that power to get a new engine started. If it's a well used engine then charging to 3.8v per cell would suffice.