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My Battery Machine Dies in 15 Minutes now....

We see this more and more.  There are several reasons for this and you'll just have to work through the possible problems.  Unfortunately many customers purchase parts thinking it is the batteries or charger only to find out it is the another part.  I've included a few basic tests with tools you can find at any auto parts center or Wal-Mart to narrow the problem.

If the machine used to run for a couple of hours and now it dies in 15 minutes or whatever and you are thinking that your batteries are weak, start with the basics.  Does the battery pack get fully charged?  The ONLY way to know this is to use a battery hydrometer tester.  I prefer the style with the lever as opposed to the floating balls.  Voltage meters, and the fact that it ran through a complete charging cycle DO NOT guarantee a fully charged pack.  Run a charging cycle and then let the battery pack cool back to room temp.  Test EACH cell with the hydrometer and look for the electrolyte figure to be about the same across all cells and to show a full charge.  If the cells are not showing full charge, the problem is with the charger not the batteries.

If any of the batteries have plates exposed when looking in the cell through the top, the battery typically is defective.  Generally adding distilled water and executing another charging cycle will not bring back the battery to a functioning state, but you can try.

If the batteries check out, do a load test with a battery load test meter.  The load test meter puts an extremely high load onto the battery for a short period of time, typically about 10 seconds.  You'll want the battery to take the load and the needle to drop and stabilize but then to hold at the stabilized level during the test.  If the needle continues to drop the battery needs to be replaced.  This same tool is used to check the voltage of the battery.  If the voltage is not in the correct range (6V or 12V) for the battery it needs to be replaced.

If the batteries checkout, it is time to check the amp draw on the batteries.  This test will require a DC clamp on style digital amp meter.  An AC amp meter meter will not work.  The meters are typically are a more expensive tool.  The the tool is clamped around only one of the leads at a point going into the machine, run the machine in full operating mode (brush in contact with the floor, vacuum motor on, and moving the machine forward).  Look at the load being drawn.  Cycle through running only various motors under a typical load.  Run the vacuum, the brushes, and the drive system separately.  Typically a singe motor will draw about 12-20 amps, or no more than about 75% of the circuit breaker rating for that motor.  Look for a motor with a spike, maybe that's the issue. 

Look at wiring VERY CAREFULLY for arcing marks, heated areas, insulation burns, tinged copper wires, melted anything.  Concentrate on connectors and places where wires go into a terminal connector.  Corrosion, high amp loads, etc will damage the wire causing high resistance shorts draining battery life.  Replace damaged components as necessary.

If your not sure about the charger, then use a car 12V automotive charger to charge batteries in groups of 12 volts.  Two 6 volt batteries in series can be charged together as a unit.  Charge all batteries this way, run the machine.  If the machine now works normally, the charger is the issue and not the battery pack.

Make sure the charger is on the proper setting for the type of batteries you have.  AGM or Maintenance Free require a different charger setting than conventional wet acid batteries.  Incorrect settings will damage the battery pack quickly.  Typically there is a dip switch or small recessed switch to change this setting.

If you need further assistance, please give us a call.