Does the Alternator fully charge the battery? My Battery Research & results - anyone else run into this?

[Nokesy]

I was reading an article about batteries in vehicles and what the alternator does to charge it. The article stated that the alternator on a vehicle was not to charge the battery to full capacity but to charge it to a minimum voltage so a vehicle will start. Many people have said that when your battery has died and after they jump start the vehicle, they say drive it for a while and it will charge the battery.

So, I decided to see what happens. I bought a battery analyzer and when my wife's car would not start, I jump started her car and drove it for half an hour and then checked the battery with the analyzer and found that the battery was at about 70%, but her car started no problem. After running it a few days without a problem I checked it again and found that it was about 80%. Then I attached the analyzer and set it to repair (this applies a pulse charge to the battery at low amperage). It took a whole day to bring the battery to 100% and then shut off. The car started quicker, the lights were brighter, and it's still going strong after two weeks.

Then I said, let's see what it does to the RT - the analyzer said the battery was at 40% but the bike still started. I did the same thing as I did with the car and put it on repair. Again it took all day to bring the battery up to 100%, but now the bike starts faster and I feel it performs better electronically.

I feel more confident in the battery now than I did before. It also makes you understand how important the battery condition is.

Anyone else run into this?

 

[racoon]

Then I attached the analyzer and set it to repair (this applies a pulse charge to the battery at low amperage). It took a whole day to bring the battery to 100% and then shut off.

So will you tell us the name of the "analyzer" you used?

 

[Peter Aawen]

I was reading an article about batteries in vehicles and what the alternator does to charge it. The article stated that the alternator on a vehicle was not to charge the battery to full capacity but to charge it to a minimum voltage so a vehicle will start. Many people have said that when your battery has died and after they jump start the vehicle, they say drive it for a while and it will charge the battery.

...

Anyone else run into this?

If you read thru some more of the multitude of threads about Spyder batteries here on the Forum and on the need to keep them in good nick, I know that it's been mentioned before and by more members, possibly much better qualified, than just me - but yes, if your battery's state of charge gets too low, your alternator will not be able to fully recharge it, and since these Spyders ARE extremely power hungry, this becomes an issue much sooner than it might on any other vehicle.

BTW, the '100%' reported by your 'analyzer' is not very likely to be actually 100%, it's more likely to be just at 'State of Charge' that's reach something above about 12.6 volts. Few analyzers and fewer chargers, let alone alternators, can actually determine or reach a true 100% State of Charge in a battery.

 

[jzeiler]

Actually the alternator is not there to charge your battery but rather provide for the current demands of the bike's electrical system ( ignition, lighting and other electrical loads ). Any thing left over after covering the loads presented is available to charge the battery. That is why start and stop short trip travel will take the life out of your battery as it does not allow the time to replace the energy that was removed during cranking. Starting the bike and driving for more than an hour should provide ample current to replace the starting draw of energy.

 

[Nokesy]

Actually the alternator is not there to charge your battery but rather provide for the current demands of the bike's electrical system ( ignition, lighting and other electrical loads ). Any thing left over after covering the loads presented is available to charge the battery. That is why start and stop short trip travel will take the life out of your battery as it does not allow the time to replace the energy that was removed during cranking. Starting the bike and driving for more than an hour should provide ample current to replace the starting draw of energy.

That's wat I always thought, but I hear mechanics all the time say just run it and It will charge it up. Ive always used a trickle charger to keep the bike battery up when not in use, so never had a problem with the battery. The comments and the analyzer just confirmed it.