Copies from NH Dealer Technical Concerns Web Site
Series TC SERIES TRACTOR CLASS 3
Group Electrical systems - 55
Summary Description BATTERY BOILING OVER
Symptoms Battery boils over
Excessive corrosion of front end components from battery electrolyte emitting from battery vents.
Causes 1. Alternator is overcharging battery.
2. Battery is overfilled with electrolyte.
3. Battery composition
Solutions 1. Connect a charging system tester to check alternator output. Start the engine and operate at 1200 - 1500 ERPM. When the charging rate has dropped to less than 10 amps, the system voltage will be stabilized. Stabilized voltage will be approximately 13.2V at 100 degrees F to 15.2 volts at 32 degrees F.. Average voltage at 70 degrees F. will be 14.2 volts. If the charging rate is less than 13.7 volts or more that 14.7 volts at moderate temperatures (70 degrees F.) there is a fault with the charging system. In a overcharging situation, be certain to check the battery ground attachment point at the front frame of the tractor for resistance. Remove the battery ground at this point and remove the paint to bare metal for a better connection.
2. Electrolyte level should be 1/8" to 1/4" below fill ring in each cell. Due to overfilling, temperature and vibration the electrolyte may vent out of the fill caps, onto the top of the battery. If necessary drain electrolyte from the battery until it is at the proper fill level. Wash the battery with a water and baking soda solution to remove any excess acid.. Clean and/or replace any tractor parts that were exposed to electrolyte. Check alternator for proper output (max) 14.7 volts.
3. Batteries used on TC series tractors are an agricultural type (antimony charged and rated for rough service). Typically agriculture machinery use is seasonable and equipment may go for extended periods of time without being run and without the battery being charged. An antimony charged battery will maintain charge over longer periods of inactivity than standard automotive type batteries, however, agricultural type batteries (antimony charged) will however produce more corrosive/acid vapor. For units in continual use where periods of inactivity or rough usage/service is not a concern consider a maintenance free automotive battery.
