I could not charge the battery on a tender when the battery was connected to the bike. It seems like it would actually drain the battery instead of charge it. But if i disconnected the battery and charged it that way, it would charge with no issues.
I don't think it's the battery tender. Works fine for my track bike and like I said, works fine when the battery is disconnected from the bike.
Anybody have similar experiences?
I have a new battery on the way. Stock one only lasted 2 years and I think it was because of this issue. When I thought I was tendering the battery, I think it was draining it. Leading to a low charge battery sitting idle over the winter.
I have the Battery Minder, so I'm not sure if it's different, but it won't charge at all if the battery is below a minimum voltage. In fact, it will just drain the battery. I have to charge it with a regular charger and then throw the minder on it.
Perhaps one of the cells are failing and having it connected to the bike places it below the minimum voltage required by the Tender or perhaps some kind of parasitic drain?
I use a 15 year old Battery Tender Jr....I think it is 0.75 amp. Have used it on 5 different bikes in that time and it has always worked. Whenever my FZ-10 is not rolling down the road it is hooked up to the Tender. When I plug it in after a ride it will go from 'red' to 'green' in about five seconds and stays that way. My battery is just about three years old, still going strong. Haven't heard of your issue before, strange that it will charge when battery disconnected but not in normal situation. They usually come with the ring terminals and standard alligator clamps, try it with the clamps and see if it works, perhaps you have a bad ring terminal lead.
Last Edit: Jun 10, 2019 16:45:01 GMT -7 by evitzee
Do you have BOTH leads connected directly to the battery? Smart chargers don't like negative to ground, which some recommend... but it's not necessary with less than 5A charging current (motorcycle battery chargers use way less than that). I always connect leads directly to battery terminals on cars and bikes, and zero issues. If you have it that way, it's time for a new charger . I'd try something better. My preferred charger is the Optimate6, which works on all kinds of bike and car batteries (except lithium ones), and also has a desulfating cycle. For heavy desulfating, I use my CTEK MUS 4.3. Oh, and I never leave chargers connected continuously; charge batteries weekly instead, but that's just me. Good luck.