http://bat-pac.com

Has anyone ever tried one ? Opinions?

never even heard of it.  :dunno:

Unless you plan on mounting a kick start on your bike- you'd be wasting time and money.

i want to mount a kickstarter so badly.  what GS motor out there shares the sidecover with Kickstarter to fit the 500?>

Quote from: Blueknyti want to mount a kickstarter so badly.  what GS motor out there shares the sidecover with Kickstarter to fit the 500?>

Sorry, the GS lost its kickstarter for good in 1980, and prior models won't interchange.  Before that, the 400s even had a kickstarter-only/front drum braked "X" model from '76 to '78 (like Honda, Yamaha, and I believe Kawasaki too).  My '78 400 was the deluxe version, and was ridiculously easy to kick over.  I'd kickstart it for effect or in the winter, and used the button when nobody was looking or when I killed it at stoplights.

Marketing data at the time showed consumers equated having kickstarters on electric start bikes as a sign of weak electrical systems.  So, the Japanese took them off for more sales.  On some bikes, they actually upgraded electrical systems to make up for it.  GS's of that era were notorious for electrical problems; blowing stators and voltage regulators with regularity.  My GS never had a failure, but the charging system was weak.  

This might be a case of "if it looks too good to be true it probably is" If it were that brilliant and cheap would'n't the manufacturers be fitting them?

Its not a battery. Its really just a resistor in a metal tube.  They are meant to be used strictly for older bikes with magneto flywheels that produce both their current and ignition current off the generator.
I have one for my little MB5 mini project.

If you really wanted to mount one of these on a GS to replace the battery, you would need to keep the generator and the starter clutch assembly (though you would have to remove the useless starter). The generator weighs as much as a small battery, and produces alot of drag/HP losses on the engine.
I have also heard quite a few times of guys who tried to put a bat-pac on a streetbike complain of bulbs burning out becasue it only prevents over-current, not under like a battery does.

You are much better off going "total-loss" by removing the generator and/or starter gear train and using a small dry cell battery with a trickle charger. And thats only on a race bike. For a street/track day bike, it isn't worth the hassle.