Battery shows 80% or better charge on "trickle charger", turn key, I hear the FI engage and lights all come on, started once, now I only hear the buzzing from device sitting just in front of battery (house the fuses). I can coast it out of drive and pop clutch in 2nd gear and it starts strong and stays running. But after I shut it down, won't start again. Both fuses appear to be in good order.

I would start by checking the charging system voltage and having the battery load tested.

Tons of possibilities here. Corrosion on terminals builds up over time, causing higher resistance for the electricity going back into the battery from the alternator, causing it to charge more slowly. Moisture (or moisture in dirt) on top of the battery can cause a slow discharge between the poles (worse in humid areas). Short circuits (from bare wires, corroded connectors, etc.). Devices such as phone chargers plugged into power outlets that stay on when the key is off (some do, some do not). Interior lights left on. Remember, also, that alternator recharging will typically not take a maintenance free battery to 100% charge once it has been severely discharged. That means that, even though the car may seem to start fine, it may reach the point of turning the engine slowly (or not at all) much more quickly. It will only reach 100% again if trickle charged (with a battery charger). Probably 4 out of 5 of my battery issues have been solved with a good terminal cleaning and an overnight trickle charge, and my batteries rarely last less than 5 years. My truck battery is still going strong at 9 years. Regardless, though, batteries eventually stop charging, even expensive ones. Hope it turns out to be something simple.

If you hear the starter relay click, but not turn over the motor that's a classic low/dead battery situation. There is only enough power left for the battery to click the starter but is not powerful enough to actually turn the engine over.

three ways you can deal with this issue.
First replace the battery.
Second give the battery a charge using either a battery charger or the more common battery trickle charger (battery tenderizer) which most motorcycle owners use to keep their bikes battery charged over long periods of non use like the winter. If you have a tenderizer just hook it up to the battery, plug it into the wall and let it trickle charge for about 12-16 hours or so and then try again.

If the starter is actually turning over but you arent gettting the engine to fire then it has to be one of the only two remaining variables that we need for combustion, spark and fuel. check you spark plugs for excessive wear, carbon buildup or damage, and then check the spacing or just replace them. if you see a spark when you fire the starter than its not a plug issue.

Finally fuel. Is there gas in the tank? can you hear the fuel pump click on once you turn the key to on? is the line creased or corroded, if you unplug the line do you see fuel being pumped in?

those are your three possibilities.

Another easy thing to try to check if it is a batteyr issue and you don't have a charger is to try push starting the bike

1. First, make sure that your bike isn't starting just because you are out of gas. If you're out of gas, this will not work.
   
2. Make sure the key is in the on position
3. Put the bike in 2nd gear
4. Hold the clutch in and begin pushing, preferably downhill, but it will work elsewhere as well.
5. Once you've gathered enough momentum, apply a minimal amount of throttle (not too much or the bike will get away from you) and hop on the bike just as you release the clutch.
6. Rev the engine a bit so your bike doesn't conk out.
7. Ride away.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_cd01d4e4178e5a11

Have the battery load tested... if low, charge it with a decent charger (overnight type trickle)
If it's not much better in the morning, replace it with a proper fitted battery that has the highest amps rating
If it is better in the morning, keep the existing battery and check for decayed ground cables.

There could be a lose connection somewhere. Anywhere beween the key to the battery or the starter button to the battery.

This is a starter issue.

Rate this fixya

Neither. You have a dead battery. Replace it, and when you store it for the winter get a smart trickle charger and keep your new battery charged over the winter.

Have the battery LOAD tested, a lot of times a battery will show good with no load on it but it can actualy be bad when tested under load. Also make sure your grounds are good clean and tight. Loose grounds is a very common problem with the 1200 sportsters.

You are charging. The meter corresponds to the level of charge in the battery. Try setting to 10 A for 4 hours, battery should be half-way up. To determine if battery id dead.. leave battery off charger once it is fully charged...test with a voltmeter after 10 min.....battery should still be above 12v...after1 hour it should still be above 12v...if not battery is spent.

I’m happy to assist further over the phone at https://www.6ya.com/expert/robert_aad3edb7dfa380b9

No preferences as to charger, as long as it has trickle charge option (slower, but better for battery). Would like to see battery load test done by parts store to see battery condition, but a simple charge may be it. Let me know how it goes, hopefully you will have it up and running soon.