If your bike is going to sit for a bit, either due to not wanting to brave the winter weather or you have it torn apart to do some work or you have more bikes than you can ride at one time, it is important to maintain the battery. Using a battery maintainer will ensure the battery is ready to go when you are and will improve the lifespan of the battery.
I have owned a couple of different Battery Tender brand chargers/maintainers and really have not had very good luck with them. When they worked, they worked fine, they just did not seem to last. Some people love them but every one of them I have owned quit working after 6 months or so. I was looking for another option and came across the NOCO Genius line of battery charger/maintainers.
I have a couple of NOCO Genius G1100 Chargers and a NOCO Genius G3500 Charger.
Both of them will charge and maintain 12 and 6 volt batteries. The only real difference is the amperage (1.1A for the G1100 and 3.5A on the G3500) and the battery repair feature on the G3500 (which I have not used).
If you already have the SAE connector installed on your bike (my 2014 Street Glide came with one installed from the dealer), you can replace it with the connector above or you can get an adapter like the one below which will let you connect the NOCO Genius to the SAE connector.
I use the NOCO SAE adapter on the Street Glide today, but will probably replace the SAE with the NOCO terminal connector when I have to replace the battery.
Will they last? Don’t know for sure, but so far they have outlasted any Battery Tender I have owned. I have had the G3500 for a little over a year now and it is constantly in use. The two G1100 I have are about 9 months old and have been in constant use as well. NOCO Genius keeps the batteries charged and ready.
If you want to give one a try yourself check out the NOCO Genius line of battery charger/maintainers here.