I'm gonna beat a dead horse here, but...........

.............now that its "winterizing" (ew ew, bad word) season, all the shop websites and elsewhere are discussing battery tenders. bmw seems absolutely committed to the idea that you MUST NOT DANGER DANGER charge a gel battery with a conventional battery tender. i say BS, for reasons outlined in the past (search it, i'm gonna be the lazy one here) there is no reason that older style tenders with a cut off voltage of below 14.7V should cause any damage to the battery.

(steps off soapbox)

Bubba, if you say "BS," I say, "Go for it"!

Fred

BTW - I'm gettin' a glass mat battery this winter to avoid this BS!

BubbaZanetti said:

.............now that its "winterizing" (ew ew, bad word) season, all the shop websites and elsewhere are discussing battery tenders. bmw seems absolutely committed to the idea that you MUST NOT DANGER DANGER charge a gel battery with a conventional battery tender. i say BS, for reasons outlined in the past (search it, i'm gonna be the lazy one here) there is no reason that older style tenders with a cut off voltage of below 14.7V should cause any damage to the battery.

(steps off soapbox)

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Yep, I agree with Fred, go for it. Oh, and let us know how it works out in a couple of months, ok? It's always kind of nice when the experiment is done on someone elses bike.

I'm in agreement too. I've been using a BMW Advanced Battery Charging System, 12v 1.25amp "Tender" which I bought for my Lead Acid 'Liquid' Battery. Since they replaced my battery with a new gel type 3-years ago. I checked all the literature and it said don't use this charger, I say BS.

I checked the charge at full charge, trickle charge and sustainment charge with DCV meter and it fit within the maximum allowable charging voltage and amperage. According to the battery manufacture.

I think they post this stuff so you spend more money.

My bike is either pluged in or being ridden, all year long.

Rich said:

Yep, I agree with Fed, go for it. Oh, and let us know how it works out in a couple of months, ok? It's always kind of nice when the experiment is done on someone elses bike.

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i've already done it, i brought a dead gel battery back from a complete state of discharge in one night..........with a standard 29 dollar battery tender jr

The alternator will work.

BubbaZanetti said:

i've already done it, i brought a dead gel battery back from a complete state of discharge in one night..........with a standard 29 dollar battery tender jr

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The issue was that the GEL battery made by Exide shouldn't be charged with a voltage higher than 14.2 volts. If it was, the issue is shorter lifetime, not whether it could be charged and for all practical purposed look charged without any shorter lifetime. That would surface later. The BT plus charges at 14.4 volts and what's more has a soak cycle at 14.4V. The soak cycle is the most suspect to not be recommended for the Exide Gel. The BT jr doesn't have the soak cycle so would be the best charger for the Exide GEL if you don't buy the GEL specific charger from Deltran (Battery Tender) or the same charger they market through BMW for the gel ($80).
BMW makes a GEL (and AGM) charger ($115) which has a desulfating cycle and does not harm the GEL, supposedly, and addresses the most damaging condition for any gel battery where sulfate crystals prevent the layers of cell material from contributing to the battery's capacity by having a desulfating cycle at the beginning of the charging cycle. This charger also keeps the ZFE electronics on so the charger may charge thru the later bike accessory jack. The only thing that bothers me about this charger is that they say it is ok for both GEL and AGM. And, the AGM is ok and would like to be charged with 14.4 volts. It does not have a switch on it so I guess they may use 14.3 or 14.4 and just go with it for the GEL. Kind of like using a BT jr.
BMW makes a $250 charger now which does it all and seems to address the GEL, AGM differences in that it has a switch on it to select AGM or GEL. It also does other neat stuff like read out charge condition of the battery, etc. It's pretty neato.
I definitely would not use a standard BT Plus, would use a BT jr or either of the three BMW chargers for the GEL. Preferably the BMW ones that have the desulfating cycles.
In any case, I don't leave the chargers on the whole winter. I only turn them on with an outlet strip every two weeks or so until they go thru the whole charging cycle, go green or what ever, and then off. I have seen wet batteries go dry during the so called float time. The instructions say to check the fluid periodically. How many of us do that during the storage months? And, I usually ride one bike or the other during the winter, but still charge them if they sit for two weeks or so.

"BTW - I'm gettin' a glass mat battery this winter to avoid this BS!"

What is a "Glass Mat" battery??

Thanks in advance!

cjack said:

The issue was that the GEL battery made by Exide shouldn't be charged with a voltage higher than 14.2 volts. If it was, the issue is shorter lifetime, not whether it could be charged and for all practical purposed look charged without any shorter lifetime. That would surface later.

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The question is - does the alternator on the bike never get above 14.2v? Because, I don't see any notices not to put a gell cell in an older oilhead.

Eureka said:

What is a "Glass Mat" battery??

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I'd rather Jack answer this in depth, because he has the knowledge. A glass mat battery is commonly known as an absorbed glass mat (AGM) battery. My lay understanding is it is chemically similar to lead acid batteries, though physically different, having the advantage of not requiring special chargers or tenders; I can use the ones I already own. If I can get reliability, low maintenance and longevity in a battery without buying a bunch of extra equipment for the gel or dry-cell types, then I'll go for it, and my research lead me to the AGM battery.

Here is the battery I plan to buy: Westco 12V20P

Here is one of many websites that came up when I "googled" AGM batteries": AGM battery.

Fred
'02 R1150R

Fred Rydr:

Thanks for the prompt answer.

MarkF said:

The question is - does the alternator on the bike never get above 14.2v? Because, I don't see any notices not to put a gell cell in an older oilhead.

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This is what really got me. Before this logic I was like "oh, okay, different tech in the batt, so new charger, blah blah blah, someone smarter than me says... blah blah blah."

But then someone mentioned putting a newer gell batt in an older bike...

yeah, wtf? Why do I need a new charger if my alternator is the same?

-Xaque- (knows nothing about charging batts)

Xaque said:

This is what really got me. Before this logic I was like "oh, okay, different tech in the batt, so new charger, blah blah blah, someone smarter than me says... blah blah blah."

But then someone mentioned putting a newer gell batt in an older bike...

yeah, wtf? Why do I need a new charger if my alternator is the same?

-Xaque- (knows nothing about charging batts)

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Because the alternator charging system does not put out the higher voltage that the battery charger does in order to completely charge the battery in about 10 to 20 hours. If it did, the battery would be toast in the space of a day's ride. The alternator puts out a voltage which is more or less the float voltage required for the battery...the voltage that the battery tender drops to when the battery is "fully" charged.

cjack said:

Because the alternator charging system does not put out the higher voltage that the battery charger does in order to completely charge the battery in about 10 to 20 hours. If it did, the battery would be toast in the space of a day's ride. The alternator puts out a voltage which is more or less the float voltage required for the battery...the voltage that the battery tender drops to when the battery is "fully" charged.

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Thank you cjack! I really appreciate your explanation!

Phew... okay, now I need to find something else to get all worked up over.

-Xaque-

I'd like to hear from some riders about battery life. How long are AGM, lead acid, sealed or not lasting. Is anybody getting multiple years ,like 3, from proper maintanence and normal use?
18 months ago I had to buy 3 batteries for 3 bikes I am riding that all died in spring time . One BMW (expensive) one cheapest (Grueber) and One Ducati sealed. They are all still working fine and get periodic charges at 2 amps with a controlled and deduced slow charge as it builds.

macman320 said:

I'd like to hear from some riders about battery life. How long are AGM, lead acid, sealed or not lasting. Is anybody getting multiple years ,like 3, from proper maintanence and normal use?
18 months ago I had to buy 3 batteries for 3 bikes I am riding that all died in spring time . One BMW (expensive) one cheapest (Grueber) and One Ducati sealed. They are all still working fine and get periodic charges at 2 amps with a controlled and deduced slow charge as it builds.

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I have gotten 8 (eight) years out of two (in our K100RSes) wet batteries and then only 3 years out of two again in the same bikes the next time. So it's hard to say.
The AGM and GEL are too new for that kind of test but I would say that 3 years should be a for sure with maintanence. I would charge them with a battery tender, or gel specific charger every two weeks or so when sitting unused and remove the charger (turn it off with an outlet strip) just after it turns green showing "full" charge. If you are using a 2 amp trickle charger, then leave it on for about ten hours for a 19 amp hour battery and no longer. It will go from 2 amps at the beginning and trickle down to about 1 to 3 hundred milliamps when it is near or at full charge. You might feel the battery and it can be warm but not hot like it would be if sitting out in the sun. That would be overcharging. The Battery Tender is the way to go. You can get the $30 ones which are called Battery Tender JR. They work fine. Make sure the led is red, not orange, when charging. I have noticed that the led goes sort of orange if the two pin SAE connector is not making a good connection to the charging pigtail on the battery or BMW plug.

Wow 8 years! that might be the record for a motorcycle battery. You must have been doing sonething right. Thanks for response.

BubbaZanetti said:

BMW seems absolutely committed to the idea that you MUST NOT DANGER DANGER charge a gel battery with a conventional battery tender. I say BS, for reasons outlined in the past.

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And that is exactly what it is...pure BS in an attempt to make $$$.

The gel cells have a cut-off of 14.4V according to the brochure that came with my factory BMW/Exide battery...and most automatic battery chargers cut off at that voltage anyways...ie: flooded lead acid batteries fully charged are 2.4V per cell x 6 = 14.4V...Hmmmmm.

I've charged my BMW/Excide gel cell for three years now using my $29 YUASA 12V, 900 mA Hot Shot battery maintainer...battery still works fine.

macman320 said:

Wow 8 years! that might be the record for a motorcycle battery. You must have been doing sonething right. Thanks for response.

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Nothing abnormal about that.

My original battery BMW/Mareg lasted 8 full years and slowed down in the middle of the 9th before I replaced it.

My other BMW/Mareg battery lasted 7 full years with unknown maintenance (bike is parked overseas).

The factory original Panasonic batteries that came in my 1990 Toyota Tercel and 1999 Honda CR-V are just over 15 and 6 years old and still operate as new.

And by the way, I still think traditional batteries are better than gel cells.

These should be stickies:
YUASA Technical Manual in PDF

Battery University

GlobalRider said:

Nothing abnormal about that.

My original battery BMW/Mareg lasted 8 full years and slowed down in the middle of the 9th before I replaced it.
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Oh yeah...well my battery lasted 10 years. I was just kidding with the 8 years.