My alternator has failed.  What should I do?    It is most likely your alternator has not failed.  All of our units are built with the highest quality, highest performance components and are checked on our high performance testers at the factory, prior to shipment, and verified for performance.    

First check your battery.  (Do not charge the batteries first with a charger.  Check batteries as is, in service state).   With the engine off and the ignition off check the voltage across the front battery red and black terminals with a volt meter.  The reading should be at least 12.3. volts DC.   If there are dual batteries, disconnect the positive of the front battery,  then measure front and rear batteries voltage with a VOM,  one at a time.  If voltage is below 12.3 volts DC replace battery.  If there are dual batteries, even if one is below 12.3 replace both. 

Second,  ensure there is a heavy gauge wire (about 3/8" thick) running from the red post on the alternator to the red post on the battery.  

Third ensure that there is a heavy gauge (again 3/8" thick) ground wire running from the alternator mount to the negative side of the front battery OR the vehicle chassis if the battery is also solidly grounded to such.  Ground to the engine is not sufficient.  Flat braided ground wire is not acceptable.  Also insure there is no paint on the alternator mounting bracket. In some instances paint may be thick enough on the mounting bracket that a good ground is not obtained by the alternator.

Fourth, belt alignment is critical.  Verify that the belt that runs the compressor and alternator is on the correct grooves.  The compressor will usually have eight grooves and the alternator will have six grooves.  The belts should be aligned correctly either using a belt alignment laser or review of operations manual.  Typically,  but not always,  the belt should ride on the rear most six grooves of the eight groove pulley.

Fifth, download the alternator checklist and run the tests as described.    This should correct most problems associated with apparent alternator "failure".

Does leaving a chassis sit for awhile without running the vehicle hurt the batteries?   Yes.  It is imperative that vehicles do not sit for over a week without running the motor or driving the vehicle.  Vehicle overhead loads that exist on the chassis, even when the vehicle is not running,  will deplete the battery beyond damage level.  It is important that the battery or batteries be put on a trickle charger or dashboard-cigarette lighter trickle charger if the vehicle will not be run for extended periods of time.  

What is your warranty policy?   Our warranty depends on the type of client you are.  If you are a dealer/end user the warranty is  12 months in service life.  If you bought your vehicle with an APS alternator installed,  your warranty would be 18 months from inservice date of the vehicle or 75,000 miles.

My battery just blew up from another manufacturer's alternator.  Does your power system do this?   Battery issues are usually caused by one thing........BATTERY DISCHARGE BEYOND RECOMMENDED LIMITS.  When batteries discharge this low they will not be able to be recharged due to heavy sulfide buildup.    Most alternators do not spike or send over voltage to a battery, due to modern internal regulator design.  But alternators will try to charge a depleted battery back to normal state.  The table below indicates the lowest recommended voltage under load, or cut-off voltage, for lead acid batteries at various discharge rates. In general, lead acid batteries are damaged in terms of capacity and service life if discharged below  1.69 volts per cell (10.14VDC for whole battery).   It is widely recognized that the lead acid style batteries are susceptible to over discharge damage. For example, if a lead acid battery was discharged to 9.6 volts, and left standing in either open circuit or on load for a long period of time, severe sulphation would occur, raising the internal resistance of the battery to an abnormally high level. In such an extreme case, the battery would not accept charge from any source.  Trying to recharge a battery that has been discharged  to this point will result in an exploding battery due to excessive current from the alternator trying to get the battery back to a 14.2 voltage float.  The battery would bubble or bulge out and then after several days explode.   It is necessary to avoid the over discharge situation as much as possible. To prevent this from happening, for some applications, it may be possible to incorporate a low voltage alarm and cut off circuit.  We recommend our 4013 battery seperator.   For the relation between discharge current and final discharge voltage, the following table should be reviewed. The battery should never be discharged to less than the predetermined final discharge voltage shown below; it could result in over discharging the battery. Repeated over discharging may cause permanent damage, to an extent that it may not be possible to recover the battery.

Do you have a diagnostic chart to tell me if my alternator is working correctly?    Yes, click here.

Do you recommend a certain battery?   Yes.  Hawker PC1700 AGM.

Do you have specific installation schematics for power wiring?  Yes, click here.

Service bulletins for Cutaway chassis.

1   GM Topkick OEM wiring issue

2    Upgrade ground

3    Upgrade wiring

4    Installation Tips

5    Dual Battery Isolator Wiring

6    Load Profile Calculation Sheet

7    Diagnostic Checklist

We just changed our batteries out after we thought we had an alternator problem.  Now the alternators are working fine.  What is going on?   Batteries are the primary source of chassis power problems.  In 90% of all power problems,  the batteries have been discharged beyond damage level and cannot be recharged.   The alternator system will still try to charge the battery even though the battery will never charge up beyond 10.3 volts.   Attempting to continue to charge depleted batteries will cause excessive overload and power robbing current that could otherwise be used for other electrical loads, and eventually destroy the alternator and explode the battery. 

© Copyright 2006 American Power Systems, Inc.