Battery Tender Issue - won't fully charge

[RTinNC]

OK .... so here is the issue. I have 2 bikes a 2006 R1200RT and 2012 R1200GSA so both are canbus. I have 2 BMW Gel Battery tenders. These are not the Canbus versions but the ones that actually look bike a Battery tender but day BMW. I have both bikes set up with a wire to the battery and us that to directly plug in the tenders. BOTH of the Tenders will work fine on my RT but neither will get the new GSA up to full charge where the green light will come on. The only thing I get on the GSA is the Red light on and green flashing meaning 80% charge. Other than spending a lot of $$ for the canbus version any suggestions.

[dirtrider]

Morning Ed

 

If your tender has a (for sure) good solid connection to the battery then maybe have your BMW dealer load test the battery & or let the battery sit for about 24 hours then put a trusted (& accurate) voltmeter on it to see if is in fact low or fully charged.

 

Does your GSA have any sort of anti-theft device on it that is continually drawing power?

 

[TestPilot]

The charging curve for Gel chargers is not the same as for wet/AGM chargers. While the float charge voltage at the end of the charging cycle for the two types may be the same (typically 13.2 volts), the absorption, or peak, charging voltage is usually a bit higher for wet/AGM chargers than for Gel chargers. Using a Gel charger on an AGM battery may result in less than 100% charging.

[RTinNC]

Morning Ed

 

If your tender has a (for sure) good solid connection to the battery then maybe have your BMW dealer load test the battery & or let the battery sit for about 24 hours then put a trusted (& accurate) voltmeter on it to see if is in fact low or fully charged.

 

Does your GSA have any sort of anti-theft device on it that is continually drawing power?

 

No theft of anything out of the ordinary drawing power. And the bike is NEW ....well 4 months old with 1000 miles on it. It just seems odd.

[RTinNC]

The charging curve for Gel chargers is not the same as for wet/AGM chargers. While the float charge voltage at the end of the charging cycle for the two types may be the same (typically 13.2 volts), the absorption, or peak, charging voltage is usually a bit higher for wet/AGM chargers than for Gel chargers. Using a Gel charger on an AGM battery may result in less than 100% charging.

 

OK ... so let me add some more info ... the RT had a stock factory batter installed in 2006 and then I replaced with a Bikemaster TruGel and the tenders worked fine on both batteries. The GSA has what ever came from the factory. The confusing issue is the RT has used the same Tenders on both batteries and worked fine.

 

And checked and according the the info the charger should work for all types of BMW batteries.

 

http://www.ascycles.com/detail.aspx?ID=1357

 

This charger has reverse polarity protection; it will not be damaged nor will it harm your battery if it is connected improperly. A 72-hour safety timer also protects batteries from damage. Its versatility allows you to charge and maintain FLA, GEL and AGM batteries

[dirtrider]

Morning Ed

 

I just looked in my parts book & it says the newer GS/GSA comes with an AGM battery. Your link shows that charger for a GEL & Lead acid but doesn't mention AGM.

 

All my chargers work good on AGM batteries but you just don't know if the BMW charger is an outlier.

 

[TestPilot]

And checked and according the the info the charger should work for all types of BMW batteries.

 

A Gel charger won't hurt an AGM battery; it just may not completely charge it.

[na1g]

At 80% charge the bike should start-up. When running it should charge the battery fully in a short time. So after a ride, hook-up the battery Tender and see what it shows. You should get the green light (fully charged) after a couple of minutes. (It takes the Battery Tender a short time to go green even if the battery is fully charged)

 

And just because its a new(ish) battery doesn't mean it if good. Have it load-tested.

 

pete

[RTinNC]

Morning Ed

 

I just looked in my parts book & it says the newer GS/GSA comes with an AGM battery. Your link shows that charger for a GEL & Lead acid but doesn't mention AGM.

 

All my chargers work good on AGM batteries but you just don't know if the BMW charger is an outlier.

 

Check my link again and also the quote on the bottom of the post .... that is from the BMW site that says Gel and AGM batteries.

[RTinNC]

At 80% charge the bike should start-up. When running it should charge the battery fully in a short time. So after a ride, hook-up the battery Tender and see what it shows. You should get the green light (fully charged) after a couple of minutes. (It takes the Battery Tender a short time to go green even if the battery is fully charged)

 

And just because its a new(ish) battery doesn't mean it if good. Have it load-tested.

 

pete

 

That is what I always do! I take a day ride, get home clean the bike and put it on a Tender. The Tender always goes red then Red w/green flashing and what I have found is that the newer bikes take overnight to get the green or float status. That is fine ... but on the GSA it never goes green. Oh ... and yes the bike always starts right up.

 

This is just very odd! Have been doing this routine for 10+ years on all my bikes no matter what type battery. And that is why I got the actual BMW brand tender to make sure no issues. And until the 2012 GSA all has been fine.

[dirtrider]

Evening RTinNC

 

Thought I would run the part number of the charger you posted above. Sure enough it came up in my parts manual complete with pictures.

 

As you can see in the picture, BMW says it ALSO for the AGM battery.

 

Given this info I believe your charger is OK & should work on your new bike. You might call your BMW dealer tomorrow to verify.

 

 

[Alan in BC]

In relation to this...

 

After all of this discussion, I am wondering if the charging system in the bike itself is "set up" to charge a specific type of battery?

In a bike supplied with a certain battery, does one always have to buy the exact type of replacement battery to ensure proper charging by the bike?

[dirtrider]

Evening Alan

 

The alternator/generator charging system voltage is pretty standard across all modern bike lines. Battery type or construction isn't a concern as the bike's charging system is highly regulated & the bike's electrical system demand is handled by the alternator (or generator) with the engine running.

 

Unlike a battery tender type charger that can run continuous for hours or weeks on end the bike's charging system only operates when the bike is being ridden.

 

Some of the older bikes with internal 2 or 3 phase stator type charging systems are a little less controlled as they don't regulate the alternators power output but instead just allow the alternator to output about all it can then dump the excess to ground through resistance (heat). My old GoldWing is like that & so are a couple of my dirt bikes. On my GoldWing the charging output runs from around 13.9 volts to just about 15 volts depending on engine RPM, temperature, & charging load. For that reason a Gel battery would be a very poor choice for that bike. But I have been running AGM batteries in that bike for years with absolutely no battery issues.

 

The modern BMW's are pretty tightly regulated at close to 14.0- 14.2 volts so about any (production type) battery you put in them should be just fine.

 

The real issues are in trying to use an older battery charger with a lead acid Desulfation cycle on a newer Gel or AGM type battery. The desulfation cycle can wreck a modem Agm or Gel battery in a single charging cycle.

 

[RTinNC]

OK ... so it looks like this will just be one of those "unsolved mysteries". After having the bike on the BMW charger for a week with the Red light on and green blinking indicating 80+ charge ... Friday night I checked and to my shock the green light was on! WTF? So yesterday I took a 200 mile ride, returned home, detailed the bike and hooked back up the the charger. Red light on solid as normal and then green flashing as normal ... this morning solid green just like god intended it. So it seems to be working just fine now. I did buy an Optimate charger posted in the classified section and will see if that works any better. But for now it appears as though the issue is solved .... not by any action on my part though!

[tallman]

"detailed bike"

 

any water involved?

[RTinNC]

Nope. Spray Polish & Cleaner.