[Motard_Blr]

Originally Posted by ashwinprakas

If only life was that simple, eh?

On any modern motorcycle the 310 and my P220 included, the alternator's sole purpose is to charge the battery, as in literally, nothing else.

Here's a picture of the 3 Phase stator coil on the Versys 650;

Attachment 1927084

There is literally one huge primary winding that feeds the RR unit which again feeds the battery.

Everything else draws current from the battery, be it the starter motor or the horn or the lights or even primarily the ECU(In your case) and DC CDI(In my case).

The only motorcycles to ever beat the system(yet, partially) are the pre 80's ADV's and the current small motorcycles like my CT100B which feeds the lighting and ignition charge directly from the stator.

Attachment 1927088

As you can see the windings can be separated into primary ignition coil winding that feeds AC CDI, lighting coil that feeds the headlight, and the rest that feeds the battery which still does feed the electrical's.

So to put things simply, graaja was dead on point.

Regards,
A.P.

Long post so please bear with me and thank you for reading.

All electrical power on an internal combustion vehicle (they're was no need to specify that before the advent of battery electric vehicles) comes from the alternator. The battery only serves as an energy reserve to be used when the alternator cannot supply the required amount of current.

Obviously, when the engine is not running, the battery is the sole source of electric current. But, the battery will also need to supply current whenever the alternator output is insufficient, as in these 2 cases:

- The engine speed is low and alternator voltage is low

- The load is temporarily high. For example, powerful, high current horns are operating

- The load is continuously high. For example, a lot of electrical accessories are operating and the total load is more than the alternator output. In this case, they battery will be discharging faster than the alternator can charge it and the battery will eventually be depleted.

The best analogy I can offer for this is a hydroelectric power station fed by water stored in a reservoir. The water comes from a river. If the power consumption is too much, too fast, the reservoir will be depleted. If the power consumption matches what the water inflow from the river can provide, then that rate of power consumption can be sustained indefinitely. Even if the river is dry but the reservoir has water, electricity can still be generated until the reservoir is depleted.

Batteries for engine starting applications are rated both in terms of continuous rate ampere-hour and cold cranking amps (CCA). The CCA figure denotes how much current the battery can deliver to start the engine when cold.

Older battery technology had a relatively low CCA figures for a given ampere-hour rating. This is why old Enfield Bullets (with electric start) had 14 Ah batteries flooded lead-acid batteries and newer bikes have 8 Ah or 9 Ah sealed VRLA or AGM batteries. Both those batteries have the same CCA of about 120 amps, which is amazing!

Although new bikes have smaller capacity batteries, their electrical load is higher than in an old generation Bullet because of higher power headlights, fuel injection, etc. To supply the higher electrical current requirement, they have higher rated alternators - 308 W in the case of the BMW G310. I expect that old bullets must have had alternators of about 120 W to 150 W (if someone can confirm).

[Turbanator]

Some info.

https://www.motorcyclecruiser.com/ho...-fundamentals/

https://www.tvsmotor.com/blog/motorc...ts-volts-bike/

[ashwinprakas]

Originally Posted by Motard_Blr

The battery only serves as an energy reserve to be used when the alternator cannot supply the required amount of current.

The following part of your reply answers why the 'only' part carries way too much weight than what we credit the battery for.

- The engine speed is low and alternator voltage is low

- The load is temporarily high. For example, powerful, high current horns are operating

- The load is continuously high. For example, a lot of electrical accessories are operating and the total load is more than the alternator output. In this case, they battery will be discharging faster than the alternator can charge it and the battery will eventually be depleted.

With most emphasis given to the first point.

Because from experience the difference in alternators output takes a noticeable rise/dip at about the 4~5k RPM range depending on motorcycle.

And practically you cannot be expected to generate the maximum rated output at all times, hence why the manufacture determines battery size depending on draw and we enthusiast determine draw depending on battery size.

Else its just a matter of time before your horn stops working or on more modern motorcycles the battery warning light starts blinking, a concern which the lesser informed enthusiast tries to rectify by plonking in a bigger battery but which only ends up delaying the inevitable.

Which for a matter of fact is proof that the Battery cannot be dismissed as merely a reservoir for the alternator, because if it were so then CCA aside the size would more or less be irrelevant, which to reiterate is not the case as in this scenario bigger has never proved to be better.

The best analogy I can offer for this is a hydroelectric power station fed by water stored in a reservoir. The water comes from a river. If the power consumption is too much, too fast, the reservoir will be depleted. If the power consumption matches what the water inflow from the river can provide, then that rate of power consumption can be sustained indefinitely. Even if the river is dry but the reservoir has water, electricity can still be generated until the reservoir is depleted.

For a simpler understanding I see the charging system as a Tap, the battery as a Bucket and draw as different Mug's.

No point increasing size of Bucket as the flow of Tap determines the quantity of water available in the Bucket, at the same time caution is advised while increasing the size of the Mug just to make sure that when the flow of the Tap is at its least the Bucket would not run out which would hinder our intended activities.

Please do share your thoughts, I'm basically a Commerce student with only miles to back my understanding, hence please feel free to educate me.

No Pun Intended.

Regards,
A.P.

[Motard_Blr]

Originally Posted by ashwinprakas

The following part of your reply answers why the 'only' part carries way too much weight than what we credit the battery for.



With most emphasis given to the first point.

Because from experience the difference in alternators output takes a noticeable rise/dip at about the 4~5k RPM range depending on motorcycle.

And practically you cannot be expected to generate the maximum rated output at all times, hence why the manufacture determines battery size depending on draw and we enthusiast determine draw depending on battery size.

Else its just a matter of time before your horn stops working or on more modern motorcycles the battery warning light starts blinking, a concern which the lesser informed enthusiast tries to rectify by plonking in a bigger battery but which only ends up delaying the inevitable.

Which for a matter of fact is proof that the Battery cannot be dismissed as merely a reservoir for the alternator, because if it were so then CCA aside the size would more or less be irrelevant, which to reiterate is not the case as in this scenario bigger has never proved to be better.



For a simpler understanding I see the charging system as a Tap, the battery as a Bucket and draw as different Mug's.

No point increasing size of Bucket as the flow of Tap determines the quantity of water available in the Bucket, at the same time caution is advised while increasing the size of the Mug just to make sure that when the flow of the Tap is at its least the Bucket would not run out which would hinder our intended activities.

Please do share your thoughts, I'm basically a Commerce student with only miles to back my understanding, hence please feel free to educate me.

No Pun Intended.

Regards,
A.P.

You are right that alternator output varies. But only alternator voltage increases with RPM. Alternator output is voltage multiplied by current. Maximum output in Watts is got at maximum engine RPM. Current in amps does not increase as that is linked to the strength of the magnets and wire used in the winding.

When the alternator is designed or specified for a particular bike, the designer must take into account various factors such as total continuous electrical load, average road speed, etc. So the total CONTINUOUS load in an average single cylinder bike would be:
Headlight 60W + other lights 30 W + fuel pump 20 W - 30 W + ECU 20 W + ignition 20 W + radiator fan 60 W + miscellaneous 30 W = 250 W.

If the bike above is going to be running in city crawling speeds, say 2000 to 3000 RPM in first or second gear, the alternator output at that engine RPM should be at least 250 W. If it is less than 250 W, the current required by the load will be drawn from the battery and the battery will discharge. Since the speed is not constant, there will both charging and discharging alternately. The trick is to ensure that on the whole, the battery voltage remains above 12.8 or so.

As I mentioned in my previous post, the size of the battery is mostly driven by the cranking amps it can supply. Take the following examples with battery sizes as specified by the manufacturer:
- Honda Activa 125 carburettor: 3 Ah
- Honda Activa 125 fuel injected: 5 Ah
- Yamaha R15: 5 Ah
- BMW G310: 8 Ah
- KTM 390: 8 Ah
- BMW F850: 10 Ah
- Ducati 1290 Multistrada: 12 Ah
- Triump Rocket 3: 18 Ah

The biggest battery in the list above is in the Triumph Rocket 3 which has a 2300 cc, 3 cylinder engine. That large engine requires more current to start it and battery with the required CCA rating to start it is larger.

You might note that small Indian bikes without electric start have 2.5 Ah batteries with lead wires instead of fixed terminals. These have relatively low CCA rating and cannot be used to start engines.

In summary, if you stick to an unmodified vehicle, the battery capacity in ampere-hour is irrelevant and only the CCA rating of the battery is important. However, if you have added a lot of electrical accessories operating continuously, such as auxiliary lights, heaters, air compressors, etc., the battery capacity in Ah is important to ensure that you have sufficient reserve charge.

This is very off-topic so it would be best to take this discussion offline if you want.

[Sutripta]

Originally Posted by Motard_Blr

This is very off-topic so it would be best to take this discussion offline if you want.

Why do you think it's OT?

Regards
Sutripta

[RSimonS]

Originally Posted by Motard_Blr

In summary, if you stick to an unmodified vehicle, the battery capacity in ampere-hour is irrelevant and only the CCA rating of the battery is important. However, if you have added a lot of electrical accessories operating continuously, such as auxiliary lights, heaters, air compressors, etc., the battery capacity in Ah is important to ensure that you have sufficient reserve charge.

Though it is true that Nasir's bikes had aux light installed and the battery failed while on an out of station ride, many of the battery / alternator failure cases had been with bikes without any modification. I believe it is some design flaw that is causing the problem, not the accessories that are installed on the bike.

Yes, dealers are known to arm twist customers to increase their accessory sales in terms of accepting warranty claims.

[shajufx]

Originally Posted by Turbanator

Doesn't BMW uses Indian batteries on these bikes in which case, one can simply talk with the brand directly.

Unfortunately, the stock batteries are claimed to be imported from US, somewhere I found a Mexico label too, it could be a China product routed to India via US. No idea why a German brand has to do this circus. But the cost of the stock battery was always quoted as Rs.7k+ whereas the Exide alternative costs under 3k here !! End of the day it's all put together at Hosur TVS plant !!

Originally Posted by Haroon

Warranty most times with BMW bikes goes out of the window with their well articulated fine print....and from personal experience and seeing a lot of international forums, BMW is one company that seems to follow it very diligently....

Warranty is void at the drop of a hat but varies dealer to dealer. In my group of riders, I heard more than 6 or 7 warranty void comments due to simple light/USB point etc. Interestingly, none of them could be the battery drain reason. Plenty of battery issues are reported on bikes that have no accessories fitted !!

Latest I heard is the replacement batteries sourced from Exide. Hope that is the end of this dark tunnel !!

[ashwinprakas]

Originally Posted by Motard_Blr

This is very off-topic so it would be best to take this discussion offline if you want.

True, hence taking this discussion to the following thread;

Understanding & troubleshooting Motorcycle Charging Systems

[Red Liner]

Originally Posted by Turbanator

My apologies, I implied Battery. Doesn't BMW uses Indian batteries on these bikes in which case, one can simply talk with the brand directly.

that was funny. AP has got to be less trigger happy with the keyboard.

Yes, the batteries are imported. I saw that it was made in France or something. And had a BMW badge on it.

However, recent news emerges that BMW is replacing these expensive 7k inr import batteries with Exide, probably the xlrz9 8ah batteries.

What's interesting is i have read on the skoda threads of early battery failures on the new RS too (imported varta units i think?). Could it be that these imported batteries are not able to handle the extreme heat in our tropics? Batteries do tend to fail in hot weather conditions and in extreme cold too.

On the other hand, imported jap bikes with the standard yuasa do manage to breach the two year mark but still seem to fall shy of an exide doing duty on many other local motorcycles. My own yuasa is still going strong but only because i did full recharges of the battery every other month with a wall charger after i checked the voltages and did a cranking voltage test.

Maybe there is a correlation here.

[JayKis]

Originally Posted by Red Liner

On the other hand, imported jap bikes with the standard yuasa do manage to breach the two year mark but still seem to fall shy of an exide doing duty on many other local motorcycles. My own yuasa is still going strong but only because i did full recharges of the battery every other month with a wall charger after i checked the voltages and did a cranking voltage test.

Maybe there is a correlation here.

My Ninja 250R Original Yuasa battery lasted 50,000 kilometers and 5 years! So Maybe its the Yuasa brand.

[gauravanekar]

My experience with automotive battery at various organisations is that the most critical thing about batteries is that it has to assembled and the automobile has to reach the customer ASAP.
The more idle a battery is more changes of discharge. If you assemble a battery with less SOC in a new machine and crank it the cold cranking will further discharge the battery.

{One should note that a newly manufactured engine won't start right away with a single cranking action (like one would experience in a brand new car/bike off the dealer shelf)}

Generally all motorcycles/cars are briefly tested by test driving/riding it ( during which period battery gets charged back to desired level)

The time period of testing is crucial too, some companies have a short testing period whereas some have longer test drives.

Consider the following scenario:
An imported battery come to India on a ship and gets assembled to a new bike ( 2+ months on sea and factory inventory). The battery is already low on charge. During the first crank the battery charge is further depleted. After that the bike is tested briefly for 2-3 km ( hardly 5-10min) which is very less time for battery recharging ( out of which intial 1-2 min will spent in switching on all lights and accessories to inspect at idle engine speed, in this scenario the battery is still getting discharged)

Other reasons for depleted battery is someone forgetting to turn of the ignition key during tea time or end of shift in the factory.

Hence it's very important for manufacturers to source battery locally, maintain lean inventory in the factory and follow FIFO religiously. They also need to check CCA of battery before assembly and before despatch of the machine.

Generally in car industry situation is better due to better processes and long test driving requirements. In two wheelers the boon is that the volumes are high which directly reduced the battery inventory and local sourcing. The bane of the two wheeler industry is that there is hardly anything to test drive ( few lamps, engine noise observation, brakes, clutch and nothing much)

[shajufx]

A General Update on the topic : The number of battery issues have come down drastically in the last 30 days. Newer replacements are from Exide and they seem to work well in our weather conditions. Hopefully the issue will be history very soon.

As an end user, being part of a huge group of owners, its always a worry on the health of our batteries. Ideally Motorrad should atleast have the courtesy to call a friendly campaign to check the battery health and replace them if needed. It will bring a lot of relief to riders who plan to take their machines to outstation rides

[nasirkaka]

WHOA! So much discussion on the battery warranty issue. And so informative as well. Was on a ride for the Diwali weekend and returned to work today to see all the discussions.

OK, to continue with the story, got the bike back after service last week when the warranty issue happened. Service cost was 7.2K, for a general service, a bit expensive in my opinion. Bike felt better and smoother as it usually feels after and oil and air-filter change, except two concerns. One is that both the brakes are making noise when engaged and the other is that the bike does not start in first attempt in the morning. Prior to service, it always started at first go, now it required few attempts and a bit of throttle input as well to hold the idle. Brakes i am not much concerned, but not sure on why this cold start issue suddenly?. Anyhow, we went on our planned ride towards munnar side along with two more 310GS and a 390 duke. The ride was good except that on an extremely isolated off-road location, one of the GS 310 suddenly refused to start. we were all stuck in wet mud and the path was so narrow with deep tyre ruts, it was impossible to even turn the bike around. We somehow managed to push the bike for about 500 mts in slush to a point where the track had a downward slope. We tried starting the bike on slope in 2nd gear and for our good luck, it fired. Post that the AOH headlamp was disconnected to save the battery drain, and bike did manage to reach Bangalore without further starting issues.

Coming back to the battery issue, i do understand that technically BMW has all right to refuse warranty as i have installed aux lights which is against the books. The only point i was trying to stress was that the 310s are known for battery issue, even on stock bikes, and in my case, there was no visible link between aux and the battery failure, so on these grounds, it would have been nice of BMW to have offered to replace the battery.


Post my mail to BMW and others, they did call me with an assurance to try and help with my concerns. And just today, they called again saying that as per BMW policy, they cannot replace my battery under warranty due to the aux lights fitment, but as a goodwill gesture Tusker BMW would offer to replace my battery. I told them what i have been trying to say since day 1 that its not the battery replacement i am looking at but for BMW to be more reasonable and flexible when it comes to after-market accessories, like other brands are. Please treat the issues on case to case basis instead of a blanket ban. Do penalize where a link is detected with an accessory fitment, but asking riders to stay away from any modifications is a bit harsh as customizing ones ride to suit ones requirement is important in motorcycling world. A blanket ban would push customers towards other brands who are more understanding and not as rigid. They did say they will share the feedback with concerned team, hope there is some positive outcome from all this for the riders.
Sharing some pics from this weekends ride.

[ani_meher]

Originally Posted by nasirkaka

Sharing some pics from this weekends ride.

In the first picture, the red GS has some top box mounted on it. Is it yours? Do you have any information about its make and review?

[nasirkaka]

Originally Posted by ani_meher

In the first picture, the red GS has some top box mounted on it. Is it yours? Do you have any information about its make and review?

Yes!The red one is my bike only! Its a plastic top box from "Hepco & Becker" and this design series is called ORBIT. Its 52 liters volumetric capacity and is large enough for 2 helmets side by side. I had originally purchased the top box for versys 650, hence it visually feels a bit big for the 310gs. It costed 16k including the base mounting plate. Its pretty strong and had a rubber gasket making it water tight and also reduce vibes/rattles. The box flew off my bike twice on the ride at decent speeds and survived both the falls without breaking. it bears scratches etc from the two falls but overall intact. It flew off as i had forgotten to lock it and had left the key in the box lock. Overall happy with the box, almost use it every day to work carrying my bag, lunch-box etc and its been close to 4 years now.
If you are looking at economical alternatives do check out a company called ASG, they have some decent products at reasonable price. Can vouch as one of the grey GS has them.