Need electrical analysis tools

[Steven Bixby]

Hi, all... this isn't strictly GPZ related, but....

I am looking for some kind of gauge-pack for automotive electrics that 
does more than just show red-yellow-green for voltage.  

I have something annoying going on with my ST1300 where the battery 
appears to be losing charge quickly.  After 3-4 days of cool/cold nights 
and not running, I come out and it usually starts after a few seconds of 
cranking, but brings down the voltage far enough to reset the dash 
electronics - which only happens when the battery is low.   What I don't 
know is whether the alternator is dying, the battery is dying (only 15mo 
old, Yuasa), or I have some kind of short in the system.

With that (and other bikes' needs) in mind, I'm looking for something 
decent that I can put in-line with the battery that will indicate 
current movement (charging, discharging) and system voltage, and perhaps 
other useful things like coolant temp in degrees, or the like.  The 
current/voltage is my main need, though.    It should be waterproof 
enough to mount on a bike for an extended period, and it should be 
something I can reasonably move to another bike as needs be.

Anyone got any cool products in mind?