Battery Charging
Amps | | | | | | |
50 | | | | | | "Bulk Charge" |
| | | | | |
40 | | | | | Freedom | Constant Current |
| | | | Charger | "Acceptance Charge" |
| | | | | |
30 | | | | | | Constant Voltage |
| | | | | |
| | | | | | Finish "Float" |
20 | | | | | | Charge |
10 | | | | | | Equalizing |
Traditional | | | | | |
| | | | | 100 Amp |
| Charger | | | | |
| | | | | | Taper Charger |
11 | 12 | 13 | Volts | 14 | 15 | 16 |
| | | | | Quicker, more complete recharging, safe long-term charging |
| | | | | and battery rejuvenation through an equalizing charge. |
Figure 3-7Benefits of the Freedom Charger vs. the Traditional Taper Charger
The battery charger stages are:
•Stage 1—Bulk Charge. During the bulk charge stage most of the charge current is delivered to the battery bank. This phase is engaged as soon as the battery charger is activated. Full rated charger current is delivered to the battery bank until the bulk charge voltage limit is reached. This results in a relatively rapid recharge.
It is generally agreed that a wet cell battery bank should not be charged up to the gassing point at a rate that exceeds 25% of its capacity. In other words, a 12-volt battery bank of 520 amp hours should not be charged at over
130 amps.
Gel cell batteries can accept a higher rate of charge. Consult the manufacturer for details.
•Stage 2—Acceptance Charge. The acceptance stage immediately follows the bulk charge stage. During this stage, the battery voltage is held constant at the bulk charge voltage limit and the current gradually ramps down. During this stage the battery is accepting its final amount of charge current and the last of the sulfate on the plates is removed.
The acceptance stage lasts until the charge current reaches about 6 to 7 amps (3 to 4 amps for a 24-volt system). A timer will terminate the acceptance stage if this current level is not reached. This timer is set automatically when the DIP switches for battery type are set. Maximum acceptance time is 1 hour for wet cells and 3 hours for gel cells. Gel cell acceptance time can be increased because the battery is not gassing. Expect wet cell batteries to gas somewhat during acceptance. This is a necessary part of the charging process.
