Post by Deleted on Dec 5, 2011 20:21:51 GMT 10
There have been a few threads recently about how to diagnose whether a battery is dying or defective. Here are some simple things to look for:
Using a digital voltmeter, there are a few easy tests you can do. After a ride or when you've had the battery on a tender/smartcharger, it should read 12.8-12.9 volts after it has been sitting for a half-hour or so. If it reads about 10.5 volts, it has a shorted cell.
There's always a chance that it's losing its charge due a parasitic current draw, such as a GPS left on, or a light that's lit, etc. These would slowly draw down the battery. The best way to diagnose this is to measure voltage over a period of several hours while the battery is still in the bike. If the voltage decreases over time, it might be a parasitic draw rather than a defective battery. Then remove the battery and fully charge it, and repeat the voltage measurements over several hours. If it isn't losing charge when removed from the bike, but is when it's installed, you've got a parasitic current draw somewhere on the bike.
Cranking slowly is another symptom of a failing battery. When the battery is fully charged and in the bike, run the engine with the petcock (tee hee) turned off, so the bike stalls from lack of fuel. Then pull the seat and put the voltmeter across the battery terminals, and measure the voltage while the bike is being cranked over (it shouldn't start, due to fuel starvation). If the cranking voltage measures 9.6 volts or more, the battery is OK.
Using a digital voltmeter, there are a few easy tests you can do. After a ride or when you've had the battery on a tender/smartcharger, it should read 12.8-12.9 volts after it has been sitting for a half-hour or so. If it reads about 10.5 volts, it has a shorted cell.
There's always a chance that it's losing its charge due a parasitic current draw, such as a GPS left on, or a light that's lit, etc. These would slowly draw down the battery. The best way to diagnose this is to measure voltage over a period of several hours while the battery is still in the bike. If the voltage decreases over time, it might be a parasitic draw rather than a defective battery. Then remove the battery and fully charge it, and repeat the voltage measurements over several hours. If it isn't losing charge when removed from the bike, but is when it's installed, you've got a parasitic current draw somewhere on the bike.
Cranking slowly is another symptom of a failing battery. When the battery is fully charged and in the bike, run the engine with the petcock (tee hee) turned off, so the bike stalls from lack of fuel. Then pull the seat and put the voltmeter across the battery terminals, and measure the voltage while the bike is being cranked over (it shouldn't start, due to fuel starvation). If the cranking voltage measures 9.6 volts or more, the battery is OK.