Hand-Held
Walnut Moisture Meter
Battery Pack
Premature Failure
09/27/01

We have observed several premature battery pack failures this year. We designed the Hand-Held Meter with a large battery pack so that it would only require charging once or twice during harvest season for most customers. These large Ni-Cad battery packs have a lifetime of about 500 charge cycles and a shelf-life of at least 10 years. Consequently the battery pack lifetime should be limited only by the shelf-life. (If anyone is expecting to be around for 250 years to test this theory would you please let us know your secret.)

All batteries self-discharge slowly just sitting on the shelf. As batteries age this self-discharge rate increases. We believe that battery packs over 5 years old may sometimes discharge so much during the off-season that one or two cells will reverse polarity and will no longer accept any charge at all.

To avoid this problem we now Strongly recommend that you charge the battery pack fully at the end of harvest season before putting the meter in storage.

Hand-Held
Walnut Moisture Meter
Battery Pack
Improper Charging
09/27/01

We have identified two problems with charging the battery pack.

It is very important that you use ONLY the battery charger supplied by us or an EXACT equivalent. Our charger is rated at 14V DC at 200mA with an open circuit volatge of 21 VDC. Using any other charger can cause the battery pack to fail. Chargers cost about $25.00. Battery packs cost over $300.00 and must be installed by us.

Our charger provides the correct current and voltage to charge the battery pack in 12 to 15 hours. The charging current tapers down correctly as the pack charges but it does NOT turn off when the pack is fully charged. You MUST unplug the charger when the battery pack is charged. Overcharging the battery pack will seriously reduce its lifetime and may also cause the charger to overheat and fail.

Please remember that these meters were built and in-service before all those fancy battery-management chips that are in your cell-phones were ever designed. These prehistoric (by dot-com standards) meters still require that you be the brains of the device.