News Feature

Battery Testing and Maintenance

May 26, 2015

By Bob Gregor


Nothing quite like walking out to your garage on a beautiful weekend morning, all pumped up for the big ride with your buddies, and you find your motorcycle is as dead as your latest relationship ... Or worse, being stranded alongside Highway 14 going to Lancaster on the Fourth of July.

If you've never experienced a battery-related problem, chances are you just haven't been riding that long. With proper care most if not all battery problems can be avoided with the added bonus of getting a decent service life out of your battery.

G E T T I N G  S T A R T E D

It starts with the purchase of the battery (or a new bike). I have always found the best value to be the top-of-the-line Yuasa batteries. I see a lot of early failures on the cheaper off-brands.

It is very important for the battery to get a proper initial service. Sadly this is seldom the case, even in motorcycle shops and especially in auto parts stores. So you end up getting screwed out of the maximum battery life. You can do a much better job yourself. Start by identifying what kind of battery your bike uses. The two main types are the older open cell lead acid type:

... and the newer maintenance free (a minor misnomer) AGM (Absorbed Glass Mat) style .

Lithium-Iron-Phospate is another type of battery starting to pop up occasionally in specialty applications. I expect to see more of these in the future as price drops.

The old style lead acid battery needs to be filled with the correct electrolyte and left on a charger four to 12 hours depending on battery size. What is vitally important is that the battery is not charged at more then 10 per cent of its ampere rating. For example a YB14L-A2 battery gets charged with less then a 1.4 amp current. Charging with too high a current can either ruin or cut down on the battery life-span. During the charging process it is important to make sure the battery vent cap has been removed. A cheap $20 trickle charger is the best bet for charging these kind of batteries.

The newer and more common AGM battery gets charged in a completely different manner. Looking at the label on the battery you will see the initial charging specs. A typical label will read '1.2 amps at 5 hours or 4 amps at 1.5 hours.' The first number is called the standard charging rate. You want to charge your battery as close to that number as possible without going below the 1.2 amp spec. Charging at a lower rate will shorten your battery life.

You need to use a constant current style charger that puts out more amps then a trickle charger. We have been using the Schumacher 3 Amp model on all types of batteries with good results.

After your battery is charged and ready to install clean up your connecting lugs with a file or sandpaper and coat them in a conductive grease that you can buy in the electrical department at Home Depot or OSH. Make sure the terminals' fasteners are tight. We see a lot of battery problems caused by dirty and loose terminals.


Take some time once a month for battery maintenance chores. If you have the open cell type, make sure the fluid levels are correct. If they are low, top up the cells with distilled water. If you have an AGM battery you are off the hook on this job. Next toss your battery on the charger for a few hours. This monthly conditioning is really important to getting max life.

After your battery is charged, let is sit for at least an hour and test its condition. For open cell batteries the cheapo mini-hydrometer you can buy in most auto parts stores for a couple of bucks does a great job.

Testers for AGM batteries are more expensive. We found a $50 motorcycle carbon pile tester online that works perfectly. If you don't want to spend the money you can do a half-ass test using a voltmeter. With the ignition turned off, the battery should register a minimum of 12.8 volts. Now turn the bike on and hit the starter button without starting the engine (leave the choke off and hold the throttle wide open). You want to see the 'cranking voltage' at 10 volts or more.

While you have your voltmeter out, now is a good time to test your charging. Check your manual for exact specs, but as a general rule you want to see the voltage across the battery increase by at least a volt when you rev from an idle to around 4,000 rpm.

Once your battery nears the end of its life, don't screw around and try to stretch a few more months out of it. A marginally performing battery can wipe out expensive charging system components, cause poor running and leave you high and dry waiting for the tow truck.


DISCLAIMER: The methods in this article are guidelines, provided and performed by a trained mechanic. If you are not comfortable performing routine maintenance on your bike, it is recommended you get a trained mechanic to complete these and more difficult tasks on your bike.



  Master Links & Chain Breaking
  Chains and Sprockets: R & R
  Switched Accessory Wiring
  Drive Chain Clean, Lube & Adjust
  Tool Guide for the Home Motorcycle Mechanic – Part 2
  Tool Guide for the Home Motorcycle Mechanic – Part 1
  Tire Inspection & Maintenance
  The Cold Hard Facts about your Cooling System
  Clutch Cable Free Play Adjustment
  Hydraulic Brake System Maintenance
  Belt Drive Adjustment & Care
  Charging System Inspection

  Getting Started
  Chain inspection, adjustment and lubrication
  Battery testing and maintenance
  Checking your controls PT 1
  Checking your controls PT 2
  Tires and Wheels

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