Battery Tender on a 2006 1200RT

[Deek]

I understand that my BMW might have either the standard battery or the newer gel type. I poked around in there yesterday as I installed a BlueSea fuse panel, and really can't see much info on the battery without taking it out, which I don't plan to do. However, if the angle is just right I can see "Pb" on the battery side, which leads me to believe I have the standard, lead acid battery. I sure hope so; I connected the battery tender this morning about 10 minutes ago.

 

Any ideas what symptoms I'm going to get if I made a horrible mistake?

[Boffin]

First of, all automotive batteries are lead-acid cells. They come in three flavours: "Flooded Cell" - the old 'standard' batteries; GEL, where a silicone gel is added to the liquid electrolyte turning it in to a jelly-like substance; AGM (absorbed-glass-mat), where the lead plates are clamped together around glass-fibre matting which has the liquid electrolyte soaked into it. Any battery sold in the EU will have Pb on it as it contains lead.

 

The only way to be sure of which battery type you have is to take it out and look at the part number and then google it...

 

BMW Exide GEL batteries have the word Gelbatterie near the BMW logo. Some AGM batteries have AGM written on them, though many just have VSLA (vented, sealed-lead-acid)

 

GEL bateries are prone to damage from over-charging, especially being held at too-high a 'float' voltage. If you use the charger to top-up the battery then disconnect it, you will probably have no issues.

 

Symptoms will be as for any defective battery - it will not hold charge properly and will not crank the bike.

 

My approach for laying-up bikes is to remove the battery and put it on a wooden shelf in a frost-protected area. I then give it a top-up charge once a month.

 

Andy

[rglassma]

Here in the US, I believe it is rare to get a recent RT with anything other then the Gel Battery. Do yourself a favor and purchase the Gel Battery compatible Charger. If you don't want to buy the canbus compatible version, use a direct connection to the battery for charging.

 

No use taking unnecessary chances. One of the nice features of the battery tender is that you can leave it on the bike.. I would want one that was compatible with my bike. If you are that worried about the cost, you should be able to pick one up on one of the online forums second hand..

[T__]

I understand that my BMW might have either the standard battery or the newer gel type. I poked around in there yesterday as I installed a BlueSea fuse panel, and really can't see much info on the battery without taking it out, which I don't plan to do. However, if the angle is just right I can see "Pb" on the battery side, which leads me to believe I have the standard, lead acid battery. I sure hope so; I connected the battery tender this morning about 10 minutes ago.

 

Any ideas what symptoms I'm going to get if I made a horrible mistake?

 

 

Deek, more than likely it is a GEL Cell battery (most of the later BMW ones are)..

 

Overcharging a GEL Cell battery using the incorrect charger can (not will but sure can) decrease the battery’s life & can lower it’s cranking performance.. Overcharging can allow gas bubbles from in the GEL so that can decrease battery performance.. Overcharging can also dry out the electrolyte by forcing the oxygen and hydrogen out of the battery through the safety valves (need to be a gross overcharge for this to happen though)

 

The good news is most GEL type battery’s have a shelf life depletion of less than 2% so you can just remove them,, fully charge them then they can sit on the shelf for months with little depletion or damage.. On my GEL battery’s I just remove them from the bike & store them in a cool dry above freezing place then charge them once every coupel of months (if needed)..

 

I agree with Boffin in that you can probably just use your battery tender then disconnect it soon after the full charge light comes on.. The GEL Cell on my new BMW is right at about 12.93volts fully charged & sitting dormant so during storage I just check it once a month with my voltmeter & if it drops much just bring it back up to 12.9..

 

In fact I have lots of bikes (therefore lots of batteries) that I winter store batteries on so when I remove the batterry I charge them until the tender light comes on,, then allow to sit dormant for 3 days,, then measure the voltage & write that on the battery case with a paint pencil.. That way I can monitor them & track the voltege depletion over the storage time..

 

I have an old AGM battrey that is over 6 years old now & it started out when new (remember I write the voltage on the battery case) at 12.86 volts .. The battrey shelf voltage is now down to 12.62 volts after the 3 day sitting but it still cranks the bike strong (I would imagine it is getting near it’s life end though)..

 

Twisty

 

[Koop]

The problem with using a standard Battery Tender on a gel battery lies in the software and voltages. The standard Deltran Battery Tender during the constant current phase of charge can go as high as 14.9 volts. Gel batteries won't tolerate that voltage for long. The Deltran Battery Tender Plus for gel batteries (P/N 021-0156) is optimized for charging gel batteries and never exceeds 14.2 volts.

 

Once I learned this, I ordered the correct charger for my RT.

[1analguy]

The correct Battery Tender part number for their GEL cell charger is: 021-0156. My dealer offered to sell me one for about $80. Instead, I went to batterymart.com and paid $47. Wire the supplied harness directly to the battery and leave the charger connected full time. When I'm not riding, mine's plugged in, period. No problems so far. The BMW-brand charger that plugs into the accessory socket will be shut permanently off by the CAN buss after it initially reaches full charge, allowing the battery to bleed down during an extended storage period.

[JayW]

The problem with using a standard Battery Tender on a gel battery lies in the software and voltages. The standard Deltran Battery Tender during the constant current phase of charge can go as high as 14.9 volts. Gel batteries won't tolerate that voltage for long. The Deltran Battery Tender Plus for gel batteries (P/N 021-0156) is optimized for charging gel batteries and never exceeds 14.2 volts.

 

Once I learned this, I ordered the correct charger for my RT.

 

So is the onboard electrical system of the RT specially engineered to meet the charging needs of a GEL battery? If not, then what's the big deal about using an external charger that uses a special algorithm? If yes, then maybe a non-GEL battery would not be happy as a replacement.

 

Jay

 

'05 RT with 46K and original GEL battery still going strong (no maintainer ever used)

[Koop]

The problem with using a standard Battery Tender on a gel battery lies in the software and voltages. The standard Deltran Battery Tender during the constant current phase of charge can go as high as 14.9 volts. Gel batteries won't tolerate that voltage for long. The Deltran Battery Tender Plus for gel batteries (P/N 021-0156) is optimized for charging gel batteries and never exceeds 14.2 volts.

 

Once I learned this, I ordered the correct charger for my RT.

 

So is the onboard electrical system of the RT specially engineered to meet the charging needs of a GEL battery? If not, then what's the big deal about using an external charger that uses a special algorithm? If yes, then maybe a non-GEL battery would not be happy as a replacement.

 

Jay

 

'05 RT with 46K and original GEL battery still going strong (no maintainer ever used)

 

My guess (and it's only a guess at this point) is that the BMW alternator is voltage regulated to 14.2 volts or lower. No special charging engineering, just voltage regulation.

 

The Deltran battery tender switches from constant current to constant voltage, depending on the state of charge of the battery it's connected to. During the constant current phase, voltage will vary depending on the internal resistance of the battery it's connected to.

[Deek]

One reason I do not want to pull the battery to check its type is I do not know what that will do to resetting any settings? I figure I'd loose the radio memory buttons and clock setting for sure, which is not much risk, but are there other things that would reset with the battery out?

 

Great tips from all you guys on the Battery Tender and Battery. I read them, of course, after I charged the battery yesterday using my Battery Tender. This is the model for a regular battery, not specific for a Gel type.

 

Anyway, it was only on the battery (in the bike) for maybe 2 hours before I checked on it. The BT light started out solid red, and was solid green after 2 hours. I disconnected it and went riding - no problems. However, I probably don't need a BT on this bike as it rarely will go over 2 weeks without a good 200 mile ride. Lucky me!

 

I believe I will use my current BT for the truck and lawn tractor, both of which go much more than 2 weeks without a run, and get a Gel BT for the BMW if it looks like it will be sitting more than 3 weeks or so and I can verify the battery type. I'm not too worried about it now. I was a little concerned when I did the fuse panel install and was fiddling around with my XM radio and MP3 player with the ignition on but the bike not running.

 

Again, thank you gentlemen.