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Thoghts on Battery Tenders

7K views 41 replies 25 participants last post by  AK Andrew 
#1 ·
I have a 2009 RT with Gel battery and a BMW "Advanced Charging System" battery tender. Because of the CAN Bus I had the rear auxiliary power outlet reconfigured to work with this charger, i.e., connects directly to the battery. After a ride and putting the tender in service, the red light would blink for awhile and then the red and green lights and then the green when fully charged. Now, only the red light blinks on the tender even after a week of "charging". Any thoughts on whether the battery has gone south or the tender. This is my second battery - I have 17,000 on the bike (I know, I know, 17K on a 4 1/2 year old Beemer is criminally negligent).

There is a highly suspicious dent in the casing of the tender and I suspect foul play from the wife but haven't been able to extract a confession from her as yet. The tender normally rests of the rear seat when charging and it is possible that "someone" may have knocked it off.

If I have to replace the tender, any thoughts on a reliable (less expensive the better) tender.

TIA,

Bob Wood
Oceanside, CA
 
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#2 ·
I have several tenders but the Batteryminder is my favorite. I can't remember the last time I have bought a battery for anything.

I bought my John Deere tractor used in 2006 and the battery is still going strong. I truly believe the desulphate mode on the Batteryminder works. I stored the tractor outside all winter hooked to the Batteryminder. We had a brutally cold winter and it still cranks strong.
 
#3 ·
Hi Bob - I have the same charger, as well as several other Battery Tender products (that's what the BMW charger is), been a good product. Battery Tender Jr. for lawn tractor, other bike, atv, and that's what I'd put on the RT if my BMW branded ACS charger quit.

It sticks in my mind that the symptom you describe (blinking red) indicates that your charger is not properly connected to the battery for some reason- bad plug on the bike, damage to the charger itself, something else? I'd look there first before questioning the battery, though if you've got the original battery, might be time to declare victory and swap that out too while you're at it, rather than trying to squeeze the last volt out. Just the same, from the damage to the charger, the timing, and the blinking red, sounds like the charger might be the culprit.

The Battery Tender Jr. is quite a bit less expensive than the BMW branded unit, and just fine for a gel, agm, or wet battery. About $27 delivered to your door by Amazon.


John
 
#32 · (Edited)
The BMW charger IS a Battery Tender rebranded. In fact I believe it is a Battery Tender Plus which is about $54 on a Amazon.

The Jr. is a .75 A unit, the BMW and the Plus are 1.25 AMP


I have had the BMW Charger for almost 5 years and have my front socket wired directly to the battery and put in an Odyssey Battery about a year ago. Everything works perfectly. Nothing at all wrong with the BMW charger, unless it was damaged.

The blinking red light constant means your battery is not connected properly to the charger. This is printed right on the back of my unit.
 
#4 ·
Thanks for the reply ... the battery was replaced 2 years ago. About the time this problem emerged, my wife complained that the rear seat heater was on even though the control was "off". Had to disconnect the power to it (front seat is fine). Don't know if there is a relationship between these problems.

I just about ready for my 18K service and need to have the fuel pump flange recall performed. I'll have them check the electrical system as well as the rear seat heater.

Bob Wood
 
#6 ·
If that is the original battery (2009), file it under "used and done its duty". Do not buy another GEL battery. Get an AGM Yuasa or some other (lesser IMHO) brand you like. Some folks are using Odyssey and they are very good but expensive. As the man says, get a Volt Ohm Meter, (VOM) and do some quick reading on the web about how to use it. It will become one of your most go to tools. People look at that little black box and think how complicated can it be? But it is and deserves good treatment to live its expected life and performance. Just start reading about batteries and you will spend many nights at it.
 
#8 ·
2011 Rt here. I bought a BMW battery charger but it was not specific for CAN bus, just said something like "BMW Advanced Motorcycle Battery Charger". Recommended for all BMW motorcycle batteries. Would not work through the port and after working with the dealer we found the CAN bus charger but it was very expensive. Although the manual states in several sections that an incorrect charger can damage the electrical system, the top BMW mechanic said this was not the case and they charge all the bikes on the floor with a standard tender using a pigtail to the battery. That is how I went and no problems so far.
 
#9 ·
FYI, or anyone else.......here is a very inexpensive charger that works really well via the auxiliary port (ie. CAN BUS compatible) on both my '07 and '14 RTs!

http://www.amazon.com/WirthCo-20039...F8&qid=1404306477&sr=8-1&keywords=battery+doc



I had paid something like $75 for one when I bought mine in 2012, but as you can see from the above, you can get one for about 1/2 of what I had paid. My RTs are connected to the charger whenever it isn't expected to be ridden for a few days, and of course for the whole winters. The one that I have is still running strong.
 
#10 ·
Also on Amazon is a Tech Inc. Optima 4+ @ $68, says it charges canbus through the 12v port. Anybody know anything about. I'm about to do some google on it. Sounds like the best bargain. As far as not disconnecting battery to charge I would just wait till the canbus shuts down before plugging in charger.
 
#11 ·
Also on Amazon is a Tech Inc. Optima 4+ @ $68, says it charges canbus through the 12v port. Anybody know anything about. I'm about to do some google on it. Sounds like the best bargain. As far as not disconnecting battery to charge I would just wait till the canbus shuts down before plugging in charger.
Sorry, but that is the wrong procedure! Keep the ignition ON, or turn it on, and then connect your charger to the auxiliary port (either front or rear), then you can turn the ignition off! The CAN BUS will stay active while the charger is connected, assuming that your charger is compatible!
 
#15 ·
I guess I'm the odd man out. Here is what I have and do: I have a regular ole Battery Tender SAE lead tied directly to the battery (fused) and that comes out at the tank rails/seat location. I have an SAE lead to heated clothing adapter I use to run my HV. When I need to plug the bike in for storage I use a Redi-Pulse, by Pulse Tech, that plugs into this pigtail. Here is a link to the home version: http://www.batterystuff.com/battery-restoration/12-volt/XC100-P.html

Now if you are on the road with the bike all the time like I am, get this one (this is what I use): http://www.tstonramp.com/~rhinocharge/redipulse.html

If you shop around you may still be able to find the solar panel that works with the aforementioned RediPulse. It is what I use. Here is a solar setup:
http://www.amazon.com/PulseTech-Sol...=8-4&keywords=pulsetech+solar+battery+charger

The pulse technology will bring back a battery from dead in 9 out of 10 instances.
 
#21 ·
Ok, I'm understanding a "bit" better.

well here's what I got............

My uncle was proud to show me and give me a two wire typical "Battery Tender" pigtail with the BMW male socket (powerlet?), and told me he charged using a Battery Tender unit directly through the front power outlet in the fairing, port side. He also had an outlet installed in the rear of the bike.

So I plug one of my three Batt Tender Jr's into the front outlet and the charger light flashes, indicating a no charge state. Same results with one of my other Batt Tender Jr.

I confirmed with my Fluke that the front outlet is hot at all times. The rear outlet is switched via ignition key. I also confirmed that the rear outlet stilled showed voltage after the key was turned off for a period of time.

I guess tonight I will try the key on/off dance to see if that wakes up the system to recognize the charger. Am I thinking right? Because that don't compute to me. I have not physically traced the wiring, yet, but the outlet is providing over 12vdc without any key action. Why would I need to use the key?:eek:
 
#27 ·
It seem that your uncle had made modifications, and you want to make the connection to the outlet that he had wired directly to the battery, whichever one that is. That will be the same as connecting your BT directly to the battery, and if that didn't work, then I would suggest that there is something wrong with your BT! The power on and connect procedure is if your charger is CanBus compatible, and you are connecting to a socket that is under the control of CanBus.

BTW, Dick, I agree with what you said about connecting the charger to AC before connecting it to the bike or battery. The reason is to prevent any possibilities of electrical surges. Edit: Oops, just read your post again! I do NOT connect the charger to bike or battery first, for the reason that I had already stated!
 
#28 ·
Not the Battery Tenders Pad, I tried two different ones and they work fine on my other 3 motorcycles. The only difference being the pigtail with the "BMW male socket" on it.

I thought maybe the female socket on the bike could have chit the bed, but I'm reading good voltage there.
 
#30 ·
Strange isn't it? I am sure that you can see that if the socket is directly wired to the battery, then there really isn't any different to wiring your charger to the battery. I suppose that there is one variation in that the length and size of wires for the pitail will be different to what was used for connecting the socket directly to the battery!
 
#29 ·
Yep, you're doing it right by the RT system, butt the LT and the Battery Tender Plus apparently hookup different. I just go by the BT instructions printed on the BT plate. Hope we (I) haven't confused the OP and Shovel completely- apologies if I stuck my BT where I shouldn'tave. 😉
 
#33 ·
I have about 20 or so batteries around of varying sizes (ATVs, MCs up to diesel tractors and truck) and have tried several different chargers including a few of the recent "smart chargers." The best all-around one I have found is the Optimate 6. Fully automatic and can produce up to 5 amps. It varies the amperage rate from 1 to 5 based on the battery's condition and its current position in the charge cycle. Great little battery charger/"desulfater."

Its around $100 from Ebay or Amazon.

http://www.amazon.com/OptiMate-Ampm...-5&keywords=battery+chargers+12+volt+optimate
 
#38 ·
I bought a packet of 20 (or so) of these Quick-Connects and put them on all batteries (several MCs/ATVs/snowmobiles/lawnmower/etc) that I have that require opening or removing something to access the battery. Just position the quick-connect terminal where you can access it externally.

After installing these, life got a bit easier when making my rounds with the charger.


Battery Tender Fused Ring Terminal Quick Connect Harness Deltran 081 0069 6 | eBay


.
 
#40 ·
#42 ·
I use a $30 battery tender from Walmart. Attach the supplied pig tail, and pug in the bike when ever you are going to go months with out riding. If you are traveling and your battery keeps dying check the loose nut behind the handle bar; the head space and timing might need to be corrected with a swift blow from a big hammer. My can bus BMW and my Yamaha and my Suzuki all are kept charged with $30 Walmart tenders during the winter; I store my bikes in the unheated shed in Alaska during the winter months. 10 years no new batteries.
 
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