Battery woes....and Battery Bug

So I'm on my second battery since getting my new 08 SD at the end of August. Dealer has worked on bike a couple of times and replaced the battery.

First battery wouldn't seem to hold a charge...2nd battery is losing life slowly but surely. My Battery Bug shows this loss as it is happening:

Battery bug started with 2nd battery showing a starting power at only 40% - now it is down to 32% , even though I leave bike on Battery Tender. With each cranking, the Battery Bug analyzes the remaining crank power...at this rate, I should be needing another battery by spring.

The Battery Bug is really cool - I mounted it in flat spot in cowling (opposite the one where radiator cap is) - while I ride and even while bike sits, it flashes current charging at battery (usually a fairly steady 14.2 volts) and also shows the charge as the bike sits - (interesting to see how the Battery Tender cycles). Although I'm not really sure if this new battery will hold up, the Battery Bug at least keeps me informed so I won't be in the middle of "who knows where" with a dead battery. The only positive I have in all of this is my 2006 Yamaha FZ1 is one of the few bikes that uses the exact same battery as my SD - so I do have an emergency backup if needed.

Grant

Hi, sorry to hear about your battery woes.
I'm a vehicle electrician (they call it a car sparky here) by trade so here some tips.
First borrow a clamp meter (the one that clamps round the cable) from a mate or so that does Amps DC! Take the lower fairing off and clamp the meter round the cable coming out of the bottom of the battery cover going to the main relay. This is the + from the battery.
Switch the meter on DC amps without the engine running and see if there is any current loss, if there is it should be very low, like milliamperes. If not there is something wrong and you probably need to get an electrician to trace the fault. You can try yourself by unplugging fuses and see if it stops.
If this is OK, start the engine and see how many amp's it charges, this should be several depending on the state of the battery. It should come down after a bit and the battery charges. If it's not charging properly the alternator-regulator-diode of the bike is faulty. This should be a warranty issue.
Hope this helps, let me know if you have more questions.
Mine is a 2008 model and the battery is fine even after 2 weeks of sitting in the garage (doesn't happen very often)