No problem. Its usually something simple.. . However it's not a short ride that it needs its a looknnngggg one.

Its best to test straight from your battery but your tender can be convenient... I've never tried voltage drops tests like that but just as a way to check quickly.

While its started and running... if you have a battery tender pigtail from the battery put the postive probe of your multi meter in the hole and the negative on the pole.... while set to 12 volts... see what it reads. Sometimes in less common cases its not your batteries fault... its the stator/regulator. Prove this functional before buying another battery only to abuse it by running it down because the bike isn't charging it up.

Noco battery chargers have a repair mode that can sometimes save or renew the life of a dying battery... I dont know for how long but I have seen it work. Better to just buy a new battery but if you ever do buy a battery charger instead of just a tender I suggest noco. You can buy a harley battery... or save some money and buy one of the ones you have to activate. (Ar least it will be very fresh)

Don't do what my brother in law did... when you get the battery assume nothing.... test it with a multimeter... right at the dealer is a good idea.... I bought a battery that was sitting at 12 volts... that might not seem low but the useful life of a battery is not from 0 to 12.8.... I can't remember exactly but 12 volts is considered basically completely discharged and requires 13+ hours on a battery tender. Remember to set on lowest setting for charging. A quick charge is a bad charge... like guys on steroids
...looks good but the space between the layers of muscle is too great... low density.... low quality as far as actual strength. Its also like the growth rings of a tree... not sure how accurate my science is but thats the idea. Lol. Ever notice how a fast charge on your phone seems to die quicker? I wouldn't accept a battery that wasn't sitting at a healthy RESTING voltage. Of 12.7 12.8... if you have the option.

After you charge wait half hour to see resting voltage. Once you install the new battery be ready to go... and have someone help you with the multimeter... you want to see the voltage not drop below 10 volts on start up... if it stays above its a healthy battery. Don't start it up and shut it down a few times... go give it a wicked charging. Keep it on a smart charger that will float the charge instead of over charging it. Anytime you go over a week without riding especially.

My brother in law did the opposite of all of this and couldn't figure out why his battery was at 11.8 a week later. I made the mistake of assuming people know this stuff. The battery was probably discharged from sitting on the shelf then he abused it by starting up and shutting down on a bike that was struggling after the winter to start up... didn't change out the bad gas for fresh stuff...forgets to pull the choke... pushed it back in immediately instead of warming up first and then shuts it down... just to do it again later or tomorrow. Wonders why it's having a hard time starting.

We all knew nothing at some point and never know everything ever. No matter what you think you know... PROVE it by testing. Multimeter is your best friend. Like a magic wand... use it to help you understand what you can not see.

It's a bit heady sometimes but you should read zen and the art of motorcycle maintenance. Heavy stuff.

Edit: his battery was also slowly discharging at first even after correcting everything but after a good ride....not the first short one he did... it held true...

Truth is you could probably do none of this and maybe still work out just fine... but its about the longterm life of your battery and the short term frustration of you and your girlfriend or wife or parents or brothers and friends who think you just bought a lemon. Lol

Gotta keep those hecklers quiet