I have used 2 solutions.
1) Astro watt meter. It nice since it shows Amps volts and MAH charged into pack.
2) I made this.. (see link) Cost me under $10.00. By watching volts you know when it is charged. It's a dedicated system for me... I use the Astro for a second system when I want to charge 2 at a time.
http://www.rcgroups.com/forums/attac...mentid=1544395
Thats a $2.99 voltmeter from harbour frieght, wired in paralel near the deans plug.
Thats important as you want voltage near A123 not 15' up towards the Deepcycle.
Total cost was about $7.00 It gets me a charge in about 15 min. Chop 5' off the wire and it would probably be 10 min charge.
Highflier