Battery Tender
Seasoned HDF Member
Joined: Jul 2008
Posts: 9,282
Likes: 1,139
From: southeast PA
It can't hurt but it probably won't charge a fully dead battery. For that you'll need a battery charger, not a tender. Depending on the age and condition of the battery it may not take a full charge anyway. A battery that has been completely discharged may be compromised. Get it charged up and then take it to get load tested.
Stellar HDF Member
Joined: Jan 2009
Posts: 2,578
Likes: 463
From: On a Lake, not far from the Gulf
Take it to an auto parts store if you don't have the proper charger. Let them charge it up and load test it. That way you will know if it will hold a charge or not rather than be surprised at a stop while on a ride.
Cruiser
Joined: May 2017
Posts: 156
Likes: 40
From: sacramento, CA
Now I'm curious. Last week my bike, 2016 Deluxe-bought February 2016, wouldn't start. I keep it on the tender all of the time. I thought maybe I hadn't connected it properly. Put it on tender overnight, and started right up. Drove around some. Since then it's been raining, and haven't ridden it. The tender light is now always on green (assume it's still charging). Will riding around charge battery (like cars do) or do i have to use battery charger. i would assume a regular car battery charger would work, put on slow charge. I will still stop by dealer to have it checked out, but what is the determining factor on when to replace the battery (other than it doesn't work!). I would think less than two years is too soon to need to replace, but I'd rather change early than late. I also travel with one of those small "jump packs" so I'll never be stranded. Thanks!
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
As for how long a battery lasts, my worst is 6 months, on a new bike, my longest over ten years. Harleys come with good quality batteries and with your tender I would expect it to last four years or more. I just replaced my original Buell's at six years from new.
Road Warrior
Joined: Mar 2013
Posts: 1,923
Likes: 587
From: Alorton, Illinois
I have stopped using battery tenders. I don't think they put out enough amperage to charge these new bikes, just maintain what is there. I have had great luck with 3 amp chargers that will also go to a maintenance mode.
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Seasoned HDF Member
Joined: Aug 2010
Posts: 5,173
Likes: 177
From: East Coast
I currently have a battery tender on 2 bikes, a tractor (can't even GUESS how old that battery is!), a generator, and a power washer, and would not even consider doing otherwise. I truly do not remember when I bought a batter for anything, though I bought one for my tractor when my 24 year old son was a kid and had no tender on the machine at that time!
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Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
That's what they are for! You are quite right that they won't recharge a seriously discharged battery.
Road Warrior
Joined: Mar 2013
Posts: 1,923
Likes: 587
From: Alorton, Illinois
I don't think .75 -.9 amp is enough for our new bikes. My 09 touring was always slow to start first start of day. Same tender that is on my 99 carb bike. Touring bike has an alarm, radio with memory....... and the first thing that draws the battery when you turn on power. The draw of an electric motor. Went to a 3 amp and bike starts strong after sitting for a couple of days.