I would be testing the ECU connectors, starter relay with the ignition off first and i think your earth cable to the starting motor maybe worth checking.
Did you say in a previous post about a ECU problem :dunno if it was then look at the wiring diagram and check the pins on the connectors.
Sit back and get a beer for a read of this :thumbup
:eatcorn
Lead acid batteries are quite fragile (structurally) and having one in a M/C is just bad news all around. They are constructed of lead plates attached to a honey comb or waffle type grid using a very soft lead paste. Hot n cold cycles, vibration and shocks to the battery will lead to shorter battery life. (Cell failure) Older batteries were constructed slightly differently (better bonding pastes) but that led to more frequent checking/adding of water. Todays batteries also offer more CCA in a smaller size compared to older type too. Many of todays batteries come as "Maint Free" (no vent tube) and generally don't need checking but down side is more prone to internal failures/problems when deeply discharged. Maint free are typically better constructed. Handle vibration and shocks far better but again much more prone to failure if voltages fall too low.
Most would think that deeply discharged is turn key and lights dim or slow cranking of the engine. Deeply discharge, to a 12v battery, is with voltage down to just 12.1vdc for vented or 12.5 for maint free types. This represents a 50% discharge to the battery. A fully charged battery should be 12.6vdc for vented and 13vdc for maint free. As you can see it doesn't take a lot of voltage drop to put the battery in critical condition and prone to problems.
So what leads to poor battery life....? In my opinion its the shop or new owner who fails to properly install and charge a new battery. In the rush to put the bike together and get it sold tothe customer dealers or setup company's don't do whats needed to ensure a long battery life. Customers who come in to purchase a new battery are just as guilty. Either not properly filling, charging and maint the battery. This includes when the battery is first purchased/installed and maint over its life span.
Here is what I do....Dry cell lead acid batteries (vented) have a shelf life of a good 2-3yrs unlike Maint free which you look for the newest available...all batteries are dated on the case. For vented....Pour in the acid to the fill mark then let the battery sit for an hour or so. The acid level will drop. Add additional acid to bring it to the fill level. At this point never add acid to the battery. Always use distilled water if battery levels drop. For maint free be sure the level is up to the fill mark. If not add distilled water. (some maint free are actually gel cell so you can't "add" to them)Hook up a slow rate charger i.e. 2amp or under. Be sure all the fill caps are off. The newer smarter trickle chargers will let you know when the battery is fully charged. Those with older chargers you can use this as a general rule for amount of time needed on the charger. Use a voltage meter to check voltage of the new battery. You already know new and 50% voltages for each type. If the battery is at 50% you need about 30hrs for a 12ah battery, 75% would need about 15hrs and 25% would need 45hrs. Once charged let the battery cool down completely before installing and using. Be sure and use brass, lead or gold plated connections at the battery. Aluminum or steel is not the ideal material. Also you want to coat the connections with dia-electric grease or Vaseline. For those more knowledgeable you can easily check your connections using voltage drops through both the positive and negative leads. Measuring voltage drops is key to diagnosing electrical problems...
Now comes the maint part...all batteries discharge just sitting on the shelf. For vented expect up to 1% a day. For maint free figure about less than half that rate. Gel types are very good overall with less than .3% rate. Now you need to determine at what rate your bike will add to the discharge rate of the battery. Do this by checking current draw with a voltage meter. Ideally it should be under 20ma. At this rate (20ma) your battery will be at 50% within 20days. Please note this doesn't take into account the rate of drop from the battery itself. Griz, as you pointed out it can take as little as two weeks of the bike just sitting there to deeply discharge and possibly ruin the battery. At 10ma you get a good 40 days and so on. A final note about discharge rates...its very temp dependant. Ambient temps at 95F compared to 75F the battery can discharge at twice its normal rate. For those of us living in desert conditions at 105F+ you can deeply discharge a battery in days. And you wondered why your grandparents stored batteries in the refrig? Cold temps reduces discharge rate but it also reduces CCA. Those in cold climates understand this fully.
Checking battery condition...many use a voltage meter but understand this WILL give you a false reading. A sitting battery, even one at a greatly reduced charge builds a "static" charge. The only real way to measure the battery is to use a load tester. If you don't have one then just turn your key on and let the bike sit for 3 or so min then check with a voltage meter. Still not the most ideal way but better than just hooking up a voltage meter.
The battery Griz points out is a better battery, however, knowing what battery you have and how to maintain that battery is more important.
