What is the best way to check if I need a new battery before it actually dies?

I have an 09 street glide with original battery. Keep it on a trickle charger and find that it is slower to turn over. Volt meter on the bike shows above 14v. When I press the start button it drops below 8v and tries hard to start.

If i hook up my own volt meter, what should I be looking for?

 

Sounds like you need a new battery but the only sure fire way is to test the battery itself with a volt meter. Should be at about 14.6 or so running and 12.5 not running. That is subject to change after I have some coffee.

 

When mine start cranking slow I replace them - peace of mind.

You could have the cranking amps tested to know for sure.

 

The best way is to use a load tester. If it passes, it will be good, if not, you'll need a new battery.

 

Volt and load test will do it. If its dropping down to 8v when cranking its weak or has a bad cell.

 

I replaced my 09 battery this past winter....It's time.....batterymart.com for the Big Crank....

 

Take the battery to an autoparts store and have it tested.

 

After a good 24 hour low amp controlled charge and the battery has set about 2 hours voltage should be about 12.8 volts.

12.8 = full charged

12.6 = 75%

12.3 = 50%

12.0 =25%

With a DC volt meter hooked across the battery terminals and reading 12.8 or so, crank motor and while its cranking it should not drop below about 9.6 volts and as soon as it starts and throttled up to 2000 rpm or so should read around 14.8 volts. The crank check shows a rough check of the reserve amperage capacity of the battery while cranking with a 150-200 amp load on it. The 14.8 shows a good alternator and if you leave it on a while as the regulatory will drop the voltage a little showing itself working. However, with the lights and stuff always on it will never drop back much.
When a battery wears out a good charge will show fairly good voltage, but the battery can still have very low amperage capacity which will show in the crude crank test above, but it really should be checked after a good charge by removing it from bike and getting a free check at a place like AutoZone that has a fancy load meter check that gives you a print out of the battery health. Battery MUST BE CHARGED to check it. Be sure they set their meter to correct cold cranking amperage stated on the battery. Never charge the AGM absorbed glass mat battery with a regular car battery charger. Also by taking battery out you know you have good connections. Vibration tends to loosen the connections or a little corrosion will prevent charging or cause starting problems. Using the maintenance charger can get 5 years from a battery but be careful here. You do not want the last start 5 miles from home. After a few years, charge and pull battery and have it checked for cold cranking amperage ever spring. If they have one, Wal-Mart's AGM absorbed glass mat battery is just as good as any one's for half the money. Do not jump, push start or run bike with a half dead battery. It will kill alternator stator or the voltage regulator or both. Probably a $500 repair.

 

+1 on the load test.

 

Personal experience story. I was getting the less than peppy cranking and had my battery checked at Auto Zone or Oreilly, I don't remember specifically and it passed. When I tried Ripsaw's in bike test, the batt dropped to around 7.5 volts during cranking. That made it easy to decide, battery was gone even though it passed the "professional" load test. Yes, it was topped off by a charger/maintainer before I tried the in bike test.