How long does the BMW battery last?

[Eh2Zee]

I seem to have a battery that is not taking a full charge. Measures 12v, and my charger no longer thinks it has applied a full charge. It's never been allowed to go flat.

 

I bought this BMW battery 2+ years ago for my '04 R1150RT. Should they last longer or is this acceptable/predictable?

 

TIA,

[SinNH]

The first thing I would do is test it with a battery load tester.

I put digital voltmeters on all my bikes, for me the first indication of a failing battery is when the voltage drops below 11 volts or so on starting--which is the same thing a load tester does.

 

[Eh2Zee]

I will try to start it with the meter on. Thanks for the tip.

 

Is two years life acceptable, in your experience? It is a genuine BMW battery.

[philbytx]

Do you have it on a Battery Tender type charger?

 

Did you check the battery resting and then tested following a full charge. 2 years really isn't a "good" life. However, like the other poster stated, you need to check the battery with a load test.

 

HERE is a useful link on motorycle batteries.

 

 

 

 

[NavyDad]

Genuine BMW doesn't mean squat. BMW doesn't make batteries or oil or brake fluid, you get the picture. I have had expensive batteries give up in a year and I have had inexpensive batteries go for five or six years. I use a tender and all of the other stuff you are supposed to do and sometimes the battery gods smile upon me and sometimes they don't. A voltmeter is the first "farkle" that is installed on any bike I buy.

[11101110]

My OE battery is going on 7 years.

[AndyS]

My OE battery is 10 years old.

[Bud]

My OE battery is 10 years old.

 

That has to be a new world record!

[AndyS]

Thanks!

Shame the tyres and brake pads don't have a similar penchant for longevity

[4wheeldog]

Is two years life acceptable, in your experience? It is a genuine BMW battery.

 

BMW batteries do not have an exceptionally good reputation (Actually, quite the opposite). But how they are treated before you get them has more to do with longevity than anything else. It may have sat on the shelf (Filled with acid, but not fully charged) for months before you got it. Then, it could have been installed with a less than full charge. These are bad things for a lead acid battery. Or, it could just have failed, as many batteries do, because it was poorly manufactured, and is breaking down internally.

 

BTW, did you check the acid level?

[Dave Parry]

I've had my R1100RT for four years and have just replaced the battery, I don't know how old the battery was when I bought the bike,

 

Dave.

[Rogue_Trader]

Hi, Dave,

 

I'm not sure which battery exactly you have...I'm fairly certain there are several types.

 

I have the gel battery and have been getting 5 years on those. I think that is pretty good for a vehicle batter.

[Dave Parry]

The one I've just fitted is a Numax AGM (absorbed glass mat)type, the pevious one was a different make but I think the same type,

 

Dave.

[Nathan Margolis]

I replace batteries as part as maintenance about every four years.

 

Have a new RT and battery access is good but on my '02 RT, forget it.

 

The S bike that I own has jumper cable lugs where you can jump start. Old RTs do not.

 

Don't want to get stranded on a trip.

 

If you can afford, every four years, replace in my opinion with a good aftermarket. No need to go back with BMW. BeemerBoneyard usually has some great Westco prices.

 

[g_frey]

2 years would only be acceptable if it were abused IMO. Most of mine go about 5.

[roger 04 rt]

Doesn't the stock alternator slightly overcharge a GEL type battery? Does that not shorten their life?

[gmcjetpilot]

Genuine BMW doesn't mean squat. BMW doesn't make batteries or oil or brake fluid, you get the picture. I have had expensive batteries give up in a year and I have had inexpensive batteries go for five or six years. I use a tender and all of the other stuff you are supposed to do and sometimes the battery gods smile upon me and sometimes they don't. A voltmeter is the first "farkle" that is installed on any bike I buy.

FARKLE? I had to go to Urban Dictionary, where English goes to die.

 

1. farkle

 

accessory.

 

The word is generally accepted to mean a combination of "function" and "sparkle", hence, farkle.

Motorcycle enthusiasts may install accessories, called farkles (also spelled farkel), to customize their machine.

 

The term is well known in the sport touring community.

 

An enthusiast may be in the process of "farkling". The completed motorcycle would be all "farkled up". Radar detectors, Global Positioning System receivers, heated grips, and satellite radios are some of those farkles. Other accessories could be aftermarket seats, side and/or top cases or bar risers, which make the motorcycle more suitable for long miles.

[Bud]

Thanks!

Shame the tyres and brake pads don't have a similar penchant for longevity

 

Andy,

 

You can get the same 10 years out of your brake pads and tires. But you can only ride 500 miles per year.

[gmcjetpilot]

The one I've just fitted is a Numax AGM (absorbed glass mat)type, the pevious one was a different make but I think the same type,Dave.

The only issue with AGM is their MIN recommended charge voltage is about 14.1-14.2 volts, and it's hard on them if you go more than 14.8 volts, down right damages them at over voltage of 14.8-14.9 volts. 14.3-14.4 volts would be ideal for an AMG battery.

 

The 2004 R1150RT I have, charges at 13.8 to 13.9 volts, which is plenty for a Lead Acid Battery. Typical operating voltage for old school electrical systems, was around 13.5 volts. AGM will charge at lower voltages, but very slowly, and in fact will never get to 100% full charge at those voltages.

 

It is physics and battery chemistry. Measure voltage of a late model car running, the system is at or around 14.3-14.5 volts. Even though most cars still used flooded lead acid technology (even if no maintenance sealed) the manufactures upped the voltage for better efficiency of the electrical system. Actually the higher voltage is kind of hard on lead acid car batteries, boils off the electrolyte, but what battery makers did, was increase the internal resistance slightly to allow safe operation at higher voltage. Old lead acid batteries did great at lower voltage because they had inherent lower internal resistance. Again higher operating voltage from 13.5 to 14.5 voltage is more efficient. Remember cars use to be 6 volts.

 

You need a charger that is designed for AGM. I have a Schumacher charger that has different settings for lead acid, gel and AGM. Gel and AMG are similar, but Gel will charge fully at lower voltage. This is analogous to small batteries, NiMh vs NiCd vs Li-Ion, they all have different charging requirements to get Max capability and life from them. Good NiMh chargers will condition the battery and go through some complicated voltage schedule during charging as well as monitor temperature and rate of charge, delta of measured voltage of battery over time. As a NiMh gets to full charge it will charge more slowly. Some times temperature is a limiting factor or charging rate. SHORT battery life is sometimes due to abuse by chargers, either the vehicles charging/operating voltage or your bench charger.

 

The resting voltage of a "12 volt battery" is about 12.6 volts at 100% charge, ideally. To charge any battery you need higher voltage to overcome the internal resistance. Bottom line the AGM has more resistance and needs higher differential voltage. It also is NOT tolerant of over voltage or near over voltage for long periods. Ideally you would want higher voltage to charge and then lower voltage to maintain. Except for marine applications with very fancy voltage regulators, vehicles have a voltage regulator that regulates to one voltage. With that said AGM is awesome no spill technology, but does have special needs and requirements.

 

I thought about changing out the alternator voltage regulator, to one that puts out a few more 1/10ths or is adjustable. Most VR's now are sealed in potting and fixed. I don't want to fry the bikes computer(s). However BMW electronics should have internally regulated voltage supplies, that can handle wide range of input voltage, say 11 volts to 16 volts. If they made electronics with out regulated voltage protection, that would be incompetence on BMW's part.

[AndyS]

Doesn't the stock alternator slightly overcharge a GEL type battery? Does that not shorten their life?

Well the stock battery in the 1150 is a GEL battery and it hasn't killed mine early.

[azccj]

I just replaced my RT's battery with one that I got from http://www.wunderlichamerica.com/motorcycle/6151913.html a couple of years ago when they had them on sale for less that $20.00 each. I bought two for that price. Now I know it's not a gel or AGM battery but let me tell you, that old tech lead acid battery turns my RT over faster than the AGM style one that it replaced. Now I wouldn't pay the $90.00 Wunderlich wants for one now, but for $20.00 it was worth it.

[Dave Parry]

Bit of a bugger to get access for topping-up though isn't it?

 

Dave.

[AndyS]

But, in the defense of the traditional battery (re maintenance), the tupperware comes off for a service, so checking and adjusting electrolyte levels at that frequency is not a problem anyway.

[GMC]

I just replaced my BMW battery when it turned 7yrs old (last winter), and it still load tested pretty well. Just was making me nervous. It lived on a tender, even during the riding season when I was riding it regularly. At least whenever it was home.

 

 

[GMC]

To add more, now that I think of it, all my bikes are going 5-7 yrs on a battery now, and none of them have been replaced due to failure, but rather for preventative maintenance.

They are all gel cells, and all live on a regular tender all winter, and usually for most of the summer when they are in the garage between trips. I ride the RT year round, while the other 3 machines mainly get seasonal/summer use.