I have a 2009 with the original battery. I bought the bike new in July of 2010. I use the Battery Tender Jr since I travel frequently and the bike will sit during my time away. I also use the Tender during the Winter when it is not ridden as much.

A trickle charger is harder on the battery than a Battery Tender regardless of where it is made. There is a difference between a trickle charge and a float charge.

I started using a Battery Tender Jr when I had an RC51. The battery on it is very expensive, around $250, so I got tired of replacing it when it died prematurely due to extended periods of sitting while traveling.

Battery Tenders are known to cook batteries when left connected for weeks. They're a very simple tricker charger, and old news by now. The best charger by far (that happens to be recommended by Kawasaki in the manual) is the Optimate4. What kills betteries is SULFATION. And those charges have a very effective automatic desulfation program, which significantly extends the life of any battery. I used to have Schumachers, BT+s, CTEKs, and I like this the best by far. And no modes to choose; everything is done automatically. Plus they have a special CanBUS program for BMW bikes. And they have the same SAE connections, so they worked perfectly with BT terminals. I'd trust this charger much more than a BT to be left connected all the time, but I always disconnect them when the light turns green.

Battery Tenders are known to cook batteries when left connected for weeks. They're a very simple tricker charger, and old news by now. The best charger by far (that happens to be recommended by Kawasaki in the manual) is the Optimate4. What kills betteries is SULFATION. And those charges have a very effective automatic desulfation program, which significantly extends the life of any battery. I used to have Schumachers, BT+s, CTEKs, and I like this the best by far. And no modes to choose; everything is done automatically. Plus they have a special CanBUS program for BMW bikes. And they have the same SAE connections, so they worked perfectly with BT terminals. I'd trust this charger much more than a BT to be left connected all the time, but I always disconnect them when the light turns green.

I guess I'm really pressing my luck then cuz I've been using my BT Jr for 5 winters now with the OEM battery and the tender stays connected for ~two months straight over the winter.

Always knew that you were on the edge..

Batteries age and there no real evidence that sulfation feature works.  Buy one, hope for th ebest, and see what happens.

How about pulling the fuse on the stereo when not in use?

Or drop your bike off at my place for the "winter". I assure you, Ill put some miles on it for you 

Battery Tenders are known to cook batteries when left connected for weeks. They're a very simple tricker charger, and old news by now. The best charger by far (that happens to be recommended by Kawasaki in the manual) is the Optimate4. What kills betteries is SULFATION. And those charges have a very effective automatic desulfation program, which significantly extends the life of any battery. I used to have Schumachers, BT+s, CTEKs, and I like this the best by far. And no modes to choose; everything is done automatically. Plus they have a special CanBUS program for BMW bikes. And they have the same SAE connections, so they worked perfectly with BT terminals. I'd trust this charger much more than a BT to be left connected all the time, but I always disconnect them when the light turns green.

I have had my battery in my other bike for 5+ years and it lives on my Battery Tender Jr. That battery still cranks like the day it was new.

Battery Tenders are known to cook batteries when left connected for weeks. They're a very simple tricker charger, and old news by now. The best charger by far (that happens to be recommended by Kawasaki in the manual) is the Optimate4. What kills betteries is SULFATION. And those charges have a very effective automatic desulfation program, which significantly extends the life of any battery. I used to have Schumachers, BT+s, CTEKs, and I like this the best by far. And no modes to choose; everything is done automatically. Plus they have a special CanBUS program for BMW bikes. And they have the same SAE connections, so they worked perfectly with BT terminals. I'd trust this charger much more than a BT to be left connected all the time, but I always disconnect them when the light turns green.

The Battery Tender is not a simple trickle charger. Believe what you wish. Mine has been plugged in since 2010 and the battery is doing fine. My RC51 did well on it as well.

Looks like I insulted somebody's child . The Battery Tender Jr and + have been around unmodified for ages (although they have new models for newer kind of batteries). It's only a 3-cycle trickle charger, vs 8 for the more modern ones. And the sulfation process helps a lot returning a battery to maximum power, believe it or not. I still have 2 BT+s, plus many others. But mostly use the Optimate4 now. Guess change doesn't come easy for old farts, huh? Ha ha. And yes, I'm one too (in pretty good shape, and feel young at heart, but an old fart nonetheless). Let's see how many people get insulted by that now . This is the same crap as oil, coolant, tires, gear, helmets, etc threads... in which to each his own. Was just trying to help those buying their first charger. Have a great weekend.

I don't remember what charger I used on both my C10 and VoyagerXII, but it did boil out the water on both of those bike's batteries.  I've been very leery of any charger since then and thankfully I haven't had to use any on the C14 but then the longest it sits is about a month during the winter.

Insulted, I think not. I am merely expressing what has worked for me and my others seems to share the same positive results about the Batter Tenders. Reading through the past posts here, It seems that we are trying to help this person buy the correct product. Justt because you read it in a magazine that the Optima charger is the best, is simply one writers perspective.
One more thing I will say, and I am one that is usually the quiet one in this aspect. You are a new member, and your welcomed into the group. We respect you opinion based on knowledge and history. I have seen it before that a person with a know it all attitude, about every subject gets old with many, real quick.

Looks like I insulted somebody's child . The Battery Tender Jr and + have been around unmodified for ages (although they have new models for newer kind of batteries). It's only a 3-cycle trickle charger, vs 8 for the more modern ones. And the sulfation process helps a lot returning a battery to maximum power, believe it or not. I still have 2 BT+s, plus many others. But mostly use the Optimate4 now. Guess change doesn't come easy for old farts, huh? Ha ha. And yes, I'm one too (in pretty good shape, and feel young at heart, but an old fart nonetheless). Let's see how many people get insulted by that now . This is the same crap as oil, coolant, tires, gear, helmets, etc threads... in which to each his own. Was just trying to help those buying their first charger. Have a great weekend.

Not insulted, just trying to point out incorrect information. The Battery Tender isn't a "simple trickle charger." That is all. That is not to say that there are not more advanced chargers out there today. That is also not to say that the Battery Tender is a battery charger that will "cook" a battery, it doesn't.

I just bought a Battery Tender Lithium battery for my Ducati. It was $100 which is much less than a Shorai. I thought it was a good choice for the Ducati because the  OEM battery spec is inadequate for the big twin in my opinion.  Ducati seems to have underspeced to save weight. So far the BT Lithium is working great, has started on first try every time even in cold weather. I also bought a BT JR specifically made for the lithium battery despite the claims the Lithium holds a charge much longer than a lead acid battery. I plan to buy a BT litium for my KLX250 as well since it is a hard starter too..

As for my 2008 C14 I am the third battery (at 134,000 miles) It is a Motobatt and is working fine. The OEM battery did not actually fail, I replaced it, (needlessly) due to issues with my HID headlight which I thought may be battery related. The second battery was an inexpensive Skyrich which did not last long before starting became sluggish.

http://www.batterytender.com/assets/img/static/FLOAT_MAINTENANCE.pdf

http://www.tecmate-int.com/ENG/pdf/TM14xDUAL-PL2-111012_EN.pdf

http://www.batterytender.com/assets/img/static/FLOAT_MAINTENANCE.pdf

http://www.tecmate-int.com/ENG/pdf/TM14xDUAL-PL2-111012_EN.pdf

Good info. Thanks MOB

I don't know what is what (trickle chargers, battery tenders, etc.) or if I should feel insulted or not (I do, just in case  ) but I have my OEM battery, 60K miles and an Optimate3. Every winter I let the battery seat for a month on the bike, then take it out and leave it a couple of days on the Optimate. After a month or two, just a few days before starting the season, I plug the battery once more on the Optimate for a couple of days. After that is back in the bike.
So far, the bike has started the first time, every time. One day it won't, hopefully in my garage and not on a Saturday evening while trying to get to my hotel in Ukrania or something.

I don't know what is what (trickle chargers, battery tenders, etc.) or if I should feel insulted or not (I do, just in case  ) but I have my OEM battery, 60K miles and an Optimate3. Every winter I let the battery seat for a month on the bike, then take it out and leave it a couple of days on the Optimate. After a month or two, just a few days before starting the season, I plug the battery once more on the Optimate for a couple of days. After that is back in the bike.

http://www.optimate1.com/optimate-3

The Optimate3 looks like a decent battery conditioner/charger/maintainer.  Why take the battery off the bike?  You should be able to just connect the Optimate3 anytime you like and for as long as you like.

My '11 will turn three years old next month and still on original battery.
I don't use a battery tender.

My '11 will turn three years old next month and still on original battery.
I don't use a battery tender.

My '11 battery died almost a year ago, but I accidentally let it discharge completely a few times, and batteries HATE that.  Now I have a Tender Jr. so it won't happen again (at least I am pretty sure it won't).

http://www.optimate1.com/optimate-3

The Optimate3 looks like a decent battery conditioner/charger/maintainer.  Why take the battery off the bike?  You should be able to just connect the Optimate3 anytime you like and for as long as you like.

yeap, I could connect the Optimate to the bike without taking the battery out. The trick would be to get a 30 yards cord to the next socket 
It's just that my place is in a block of apartments with a common underground garage for about 100 cars (I own 2 spots) and there's no sockets on the walls in the garage itself. None. The reason is that those would be at everybody's reach and they couldn't meter them individually to whoever uses them. Or that's what I've been told.