Charging battery with Battery Tender

[dan90638]

Hello, folks. I need some advice on charging the battery on my 06 R12RT. This morning, when I tried starting the bike, the engine turned a bit, but it didn't start. After doing a few times, it started. After riding to work, it started without any problems after work. I'm assuming the battery is a bit low as I've been using the heated grips and seats lately.

 

If I hook up the Battery Tender directly to the battery, is it really necessary to disconnect the battery? Or could I just do it while it's still connected? The manual says it could damage the electronics if I do so with the battery connected. I could use your expertise here.

 

Thanks in advance.

[T__]

Dan, most people don’t disconnect the battery to use a Battery Tender or similar newer electronic battery charger.. Probably should but most don't..

 

The caution in the manual is mainly to preclude any onboard electronic damage from high voltage spikes.. That is very unlikely when using new electronic regulated stable voltage control type battery chargers.. If you have an older manually set charger or a starting cycle type charger you probably should disconnect the battery before charging as you could possibly get a voltage spike or surge.. Probably shouldn’t use that type of charger on the newer Gel or AGM batteries anyhow even if disconnected..

 

I think BMW is worried about 15.5 volts plus as a damaging voltage spike..

 

Twisty

 

[dan90638]

I just connected the Battery Tender and it looks like my battery isn't that low. Although, I'm still charging it to full capacity.

 

So could it be worn out spark plugs that made the engine turn over and over without starting the first few tries? It hasn't been that cold in So Cal, so I doubt it's the weather. The bike has about 7400 miles on it now, and it had the 6K service just under 6K miles.

 

What do you guys think?

[Ken H.]

You will be fine. Literally 1000s of us are doing it that way.

[hopz]

dan... I do not think your spark plugs would wear out on an 06RT... unless you have a whole lot of miles... like 30,000 or so.

 

My battery tender goes straight to the battery and nothing is disconnected. I replaced my battery last year... mine is an 05RT. It never actually failed to start but it was weak and slow. Batteries only get one chance around my house. They either work right or get replaced.

 

Which reminds me... what is our advice on bump starting? Can we do that or is that old school?

[Silver Surfer/AKAButters]

I run my battery tender through one of the accessory outlets. No problems yet.

[Koop]

If you have the OEM Exide Gel battery, then be careful of which battery tender you use. The standard Deltran Battery Tender Plus (P/N 021-0128) is not recommended for this application, you should use the Battery Tender Plus that is optimized for Gel batteries (P/N 021-0156).

 

The difference is in the maximum charging voltage. During the constant current charging phase the standard Battery Tender Plus can reach 14.9 volts. The Gel version never exceeds 14.2 volts.

 

I just learned this info on another site and contacted Deltran to verify.

[dan90638]

Thanks for the feedback, guys. I charged it with the Battery Tender Plus, and the engine started well this morning.

 

Hopz, that was my twin brother on the BMWLT website.....

[Deek]

If you have the OEM Exide Gel battery, then be careful of which battery tender you use. The standard Deltran Battery Tender Plus (P/N 021-0128) is not recommended for this application, you should use the Battery Tender Plus that is optimized for Gel batteries (P/N 021-0156).

 

....

 

Does anyone know if the 2006 used that Gel battery? I asked about a Battery Tender Jr and was told it would work fine, but I didn't know there was more than one model of Tender.....or of batter for that matter.

[RTinNC]

If you have the OEM Exide Gel battery, then be careful of which battery tender you use. The standard Deltran Battery Tender Plus (P/N 021-0128) is not recommended for this application, you should use the Battery Tender Plus that is optimized for Gel batteries (P/N 021-0156).

 

....

 

Does anyone know if the 2006 used that Gel battery? I asked about a Battery Tender Jr and was told it would work fine, but I didn't know there was more than one model of Tender.....or of batter for that matter.

 

All BMW's from 2005 and later have gel batteries. You can get a BMW gel tender from Chicago BMW for about $69 or DelTran makes a "gel" tender ..... they usually can be found for about $45-50. With either of these you will need to run them off the battery and not the power outlet. The only way to use the factory power outlet on the bike is to buy the special canbus tender that lists for something like $150! I have been using a BMW gel tender directly off the battery for a year now and it works fine.

[Nice n Easy Rider]

If you have the OEM Exide Gel battery, then be careful of which battery tender you use. The standard Deltran Battery Tender Plus (P/N 021-0128) is not recommended for this application, you should use the Battery Tender Plus that is optimized for Gel batteries (P/N 021-0156).

 

....

 

Does anyone know if the 2006 used that Gel battery? I asked about a Battery Tender Jr and was told it would work fine, but I didn't know there was more than one model of Tender.....or of batter for that matter.

 

All BMW's from 2005 and later have gel batteries. You can get a BMW gel tender from Chicago BMW for about $69 or DelTran makes a "gel" tender ..... they usually can be found for about $45-50. With either of these you will need to run them off the battery and not the power outlet. The only way to use the factory power outlet on the bike is to buy the special canbus tender that lists for something like $150! I have been using a BMW gel tender directly off the battery for a year now and it works fine.

 

+1 . One of our board members, Quinn, lent me his to keep my battery charged while I recuperate from my back surgery. It is a piece of cake to hook up and I left the battery in (per my dealer's instructions).

[Deek]

"..All BMW's from 2005 and later have gel batteries. .."

 

Thanks. Oh Jeez, another mc product (Battery Tender JR) I cannot use on this motorcycle! I guess I'll just have to ride even more to make sure the battery doesn't get low.

[marcopolo]

I'm not sure all BMWs have gel batteries; I think it depends on the model. I'm recalling having read a BMW tech service bulletin that someone posted some time ago which had a table showing bike model and battery type.

[TestPilot]

I'm not sure all BMWs have gel batteries; I think it depends on the model. I'm recalling having read a BMW tech service bulletin that someone posted some time ago which had a table showing bike model and battery type.

 

My 2007 ST came with an AGM battery, not a gel battery. AGM and gel are not the same and have different charging requirements.

[Deek]

I'm not sure all BMWs have gel batteries; I think it depends on the model. I'm recalling having read a BMW tech service bulletin that someone posted some time ago which had a table showing bike model and battery type.

 

I guess I don't know the difference in the two types. What I have in my 06 RT looks like the same one I had in my Venture and Suzuki. Might it be the non-gel type, and how could I verify that? Thanks.

 

 

[RTinNC]

You guys may be correct .... but I know that my 2005 LT had a gel battery and my '06 RT has a gel battery and when it came time to replace my 6 year old battery in my R1150GS last may my dealer said all BMW is selling now is gel. Therefore, probably may be an incorrect assumption that all newer BMW's were gel but I am quite sure ALL R1200RT's are gel. When I replaced my '02 GS's battery this past May I wanted the SAME lead acid battery since it had lasted 6 years and was actually functioning fine but was 6 years old and I had a 2400 mile trip planned and did not want to tempt fate. That is when the dealer told me they (BMW) does not sell a lead acid battery any more. So far the gel is working fine. By the way I ALWAYS have by bikes on a tender. Am a believer. Have never had a battery failure and have gotten over 5 years out of every battery.

[Boffin]

I'm not sure all BMWs have gel batteries; I think it depends on the model. I'm recalling having read a BMW tech service bulletin that someone posted some time ago which had a table showing bike model and battery type.

 

I guess I don't know the difference in the two types. What I have in my 06 RT looks like the same one I had in my Venture and Suzuki. Might it be the non-gel type, and how could I verify that? Thanks.

 

 

The GEL battery has the word "Gelbatterie" printed on it.

 

Andy

[Deek]

"The GEL battery has the word "Gelbatterie" printed on it."

 

Hmmmm. Not sure if you're trying to pull my leg........but I'll still check it out.

[T__]

I’m not sure all the batteries will say what type of battery they are.. My Harley is a AGM & says nothing on the battery itself as far as construction goes.. Same with the battery in my Ducati it just says battery on it..

 

Might be best to get the battery info off the battery in question (make, model, numbers) then Google the battery manufacturer & see what specs the battery manufacturer has to offer about the battery..

 

Twisty

 

[Deek]

"Same with the battery in my Ducati it just says battery on it.. "

 

Ah, the Italians, they can be laconic sometimes, si?

 

I'll try your suggestion of Googling any model number I can find on the battery; thanks.

[Dietrich]

With the proper charger it makes no difference if the battery is hooked up or not. As previously mentioned the electronic charger prevents spiking which could be harmful to the electronics of the bike.

I have the extra rear outlet on my 1200RT which I rewired directly to the battery via a fuse. This way I can plug in the charger without removing the seat etc. and I have constant power with the bike switched off, just in case I want to connect a light or whatever without the bike running.

Last winter I left the tender on all the time during the cold months. In spring the battery was charged and the bike started right up.

[stubblejumper]

All BMW's from 2005 and later have gel batteries

 

My 2007 R1200ST has an AGM battery.

[TedG]

My 2007 R1200ST has an AGM battery.

 

Well, I guess that means my 07 R12ST does, too. All I know is I use a Battery Tender (one that I've had for years) to keep things charged and nothing has blown up, melted, shorted, died, or otherwise disturbed my serenity so far.

 

I'm sure there are compelling reasons (errr, besides the customary anal retentiveness of some folks) for using just the "right" charger, but as long as the battery holds a charge and the bike starts, I'm more than willing to be a slack jawed ignoramus.

[TestPilot]

AGM batteries have the same chemistry as standard lead-acid batteries, so the same charger should work. Gel batteries require slightly lower charging voltages and are more susceptible to overcharging, so a lead-acid charger should not be used on a gel battery. A gel charger could be used on a lead-acid battery without damaging the battery, but it wouldn't bring the battery up to full charge.

[Unhofliche_Gesundheit]

minor hijack- speaking of battery tenders.... anyone have any bad stories about the incredibly inexpensive battery float charger from Harbour Freight?

 

i previously asked this - people had opinions that 'they would not use the cheap HF unit' but no-one had a story in which they had an actual problem.

 

Chicago electric power tools sku 42292, less than 10$

voltage output 13.5 V (per the paper instructions.. back of box says 12.5 v). claims good for flooded and gel-cells.

thx

 

 

 

 

 

[Koop]

AGM batteries have the same chemistry as standard lead-acid batteries, so the same charger should work. Gel batteries require slightly lower charging voltages and are more susceptible to overcharging, so a lead-acid charger should not be used on a gel battery. A gel charger could be used on a lead-acid battery without damaging the battery, but it wouldn't bring the battery up to full charge.

 

What makes you believe a gel charger wouldn't fully charge an AGM or lead acid battery?

[TestPilot]

Lower voltage.

[smiller]

A gel cell battery charger will charge at a lower rate (current) and perhaps a slightly lower absorption charge voltage than other lead-acid chargers, but the finishing/float voltage of a gel cell charger is plenty high enough to fully charge any lead-acid battery. The charge cycle will just take a little longer.

[Sailorlite]

I've seen the Exide BMW battery that comes on the 1200's described as a gel battery and as an AGM battery. Which is correct, or are both correct? Are all AGM's gel?

 

Anyway, I use the Battery Minder (not Tender) through a fused SAE connector to the battery and it seems to be fine. ('08 RT).