Battery Percent and Charge Time

This charger adjusts the charging time in order to charge the battery com- pletely, efficiently and safely. The microprocessor automatically makes the necessary decisions. However, this section includes guidelines that can be used to estimate charging times.

The duration of the charging process depends on three factors:

1.Battery State – If a battery has only been slightly discharged, it can be charged in less than a few hours. The same battery could take up to 10 hours if very weak. The battery state can be estimated by using the built-in tester (see page 10). The lower the reading the longer charging will take.

2.Battery rating – A higher rated battery will take longer to charge than a lower rated battery under the same conditions. A battery is rated in ampere-hours (AH), reserve capacity (RC) and cold cranking amps (CCA). The lower the rating the quicker the battery will be charged.

3.Charge rate – The charge rate is measured in amps. This charger provides charge rates of 2A, 15A and 40A. The 100A rate is for engine start only. The 2A rate is for charging smaller batteries such as those used for motorcycles and garden tractors. Such batteries should not be charged using the 15A or 40A rate. The 15A and 40A rates are for charging larger batteries. In the 40A mode, the charger begins at a low charge rate and increases the charge rate if it is determined that the battery can accept the higher rate. All charging modes will decrease the charge rate as the battery approaches maximum charge. After the charging process has started, the digital display can be used to determine charging progress by selecting the BATTERY % mode.

There are some important facts to keep in mind when charging a battery.

•When the display indicates 77% charged, the battery has been charged enough to start most vehicles and has already been charged as much as by many other battery chargers.

•When the display indicates 85% charged, the battery has already been charged at least as much as by most other battery chargers.

•The battery % shown in tester mode is an estimate based on the battery voltage and the Battery Council International scale. The battery % shown in charger mode is an estimate of the relative charge in the battery compared to the charge it should have if the charging process is allowed to complete.

•The battery % shown in tester mode can be used to estimate the relative charge time.The lower the % shown, the longer the charge time for a given battery.

•The battery % shown in charger mode is an indication of the relative progress of the charging process. The higher the battery % displayed, the less charge time remains.

•The more a battery is discharged, the faster it absorbs charge from a charger. That means that the battery % increases faster at the beginning of the charging process than at the end. In other words, it takes longer for the battery to absorb the last few percent of charge than the first several percent.