Well I use a very simple, small and quite cheap Turnigy C3 Compact Balance Charger.
I have used this many times over the last 3 years on 2 sets of Lipos. (Obtained from China at an eBay store that Ramesh recommended.) Both still working very well after maybe up to 50 charge cycles.
The key thing is to use a balancing charger (it connects to the little white plug on the LIPO.
Our use is quite different to the main users (flyers) we don't need rapid charging or very rapid discharge. Under these conditions I have found Lipos to be very reliable and trouble free (better than Nicads/Nimhs in my opinion. Much smaller and easier to fit in than lead acids ,say. One 1500mAh Lipo drives my Charlie class, U class (both about 5 feet long)for about 30 minutes.
No fires either! I take the usual precautions:
- in-line fuse to the sub.
- I store the Lipos in the special fireproof bags inside a tin box
- I use a home brewed low voltage alarm to protect the battery. It hasn't been triggered yet because I am quite careful to not sail for too long.