As a battery sits, it not only loses it charge at the rate of about 10% but also the plates accumulate a coating of sulfate, which prevents the plates from absorbing and giving off a charge. Then it's new battery time, many times more $$$ than an automatic trickle charger. If you're thinking that occasionally starting the engine during hibernation will overcome that, it won't and for a bonus, it's very hard on the engine. Get the damn automatic trickle charger and save your battery and engine.
I got burned using a couple of Schumacher brand battery tenders that I bought at Walmart about 10 years ago. They worked fine initially but about mid winter the first year both stopped sensing the battery voltage unless you would either unplug the unit momentarily or disconnect it from the battery momentarily. Lost the two batteries connected. To them that year because of that and another friend lost one battery to the same unit purchased the same fall. Maybe a bad batch? I tried a Napa one on the road once, but it had no reverse polarity protection unlike the battery tender brand, and I had a brain fart and killed it. I've had great luck with battery tender brand
I have a slew of battery tenders. Some 15 yrs old. The oldest ones are starting to fail. Probably from voltage spikes. We have crap power where they are mostly used. However as old as they are they don't owe me a thing.. They have saved me from buying many batteries during their lifetime.
Never had one fail in the first 10 years I owned it nor have one fail to keep the battery it was attached to charged as long as the battery was well charged when the tender was attached.
They did redesigned them a few years ago. They now weigh a fraction of what they did. They must have replaced or shrunk the transformer. I've had a few of that style 3 or 4 years and they too have performed well. But I can't tell you if they will last 10 or 15 years like the older style ones did.
To me they are worth the money. But after getting burned early on I haven't experimented with any other brands
My batteries would not last all the years they do without a tender. Having said that I don't typically use it until long term winter storage. I know some that use them year round park bike and plug it in.
Been a Deltran Battery Tender Jr User for many years .. When my Bike sits, it's on the Tender ( Forget now and then ) Always had good life on my Batteries and always figured Starting a Cold Bike at Peak Voltage was an asset .. This is strictly my call and point of view .. Decide for yourself what's best for you ..
A battery tender is a good deal. It only puts in a charge till its full then it shuts off and turns back on when the battery gets low. You more than likely have the tender cord on the battery from the factory
I've used a Schumacher and Battery Tender brands of battery tenders for years on two bikes without problems...except for this one, it killed a battery in about a year being connected 24/7. At that time I owned a Suzuki Volusia and on the Suzuki Forum Site most of the members were keeping their bikes hooked up to their trickle chargers constantly. So I thought that I would try but had a poor result. I have since stopped doing that and now hook up my battery tender every month or sooner if the bike sits and mine rarely does. I keep it on the charger until it shows that it is charged and have had no problems at all. The results for me have been good with most batteries lasting 3-4 years in the Florida heat. I usually replace the battery at that time regardless, rather than waiting to be stranded somewhere.
Have used a Battery Tender Plus for years on both my last two HD's and now my 2014 CC. Purchased in Sep. of '14, it still has the original battery. Put about 300 mi. this past Fri. with several stops and starts for the day. If it's going to sit more than a couple of days without a good charging ride, it goes on the tender. Will likely put a new battery in next spring just cuz it's time but, believe I got my money's worth out of the original.
Since my bike is parked in a CycleShell all winter ( in eastern PA) I bring the battery inside and hook it up to a Battery Tender Jr until the temperature stays above 60 degrees. Then I know it’s going to be ready for that first spring ride.