I bought a new battery 3 months ago. I haven't ridden in 2 weeks and the battery died. I bought a battery tender junior on may 19th and it had the red light steady until the next day when it would occasionally flash a green light then go back to steady red. The manual says this means its between 80-100%. 4 days later this battery is still not at 100%. Should i return the charger or is it the battery?

 

Sounds like battery to me - a new one shouldn't die with only two weeks of rest. Maybe your bike is draining it. What bike is it on?

 

2012 1200 Sportster Custom
Im charging the battery disconnected from the bike.

 

Check it with battery tester or voltmeter.

 

Possibly a problem with the tender u bought on the 19th. Easiest first step would be to return/exchange it!

 

Easiest step would be to have the battery load tested at your local auto parts store. You can also try disconnecting it from the bike, and see if the battery tender will fully charge it that way. If so, you probably have a parasitic drain on the bike.

 

5.5 days of charging on the battery tender with the battery not connected to the bike. I reinstalled it and the starter makes 1 click and nothing after that the battery is completely dead. subsequent starts won't even spin up the starter. the battery is measuring at ~11v. if i jump the bike how long should it take to charge the battery? i figure if the battery won't charge off the bike then its definitely the battery

 

I would try another charger - a regular one to see if it charges it. That should only take a couple of hours and then take it to the auto store for testing.

 

A tender is not a charger, no matter how long you leave it on. You need to put the battery on a regular charger and then load test it.

11 volts is too low. You can jump start with a car battery as long as the car is not running. But riding it around will not fully charge it up.
If it's the original battery it's probably toast.

 

He said it's only three months old. A tender does charge - that's what it does but very slowly and maintains. A regular charger, as already recommended, is best for an ailing battery though.