THE PROBLEM :
When charging 6V batteries connected in series, there is no guarantee that the batteries will receive the same charging voltage. Therefore, a lower voltage (e.g. 6.8 V) is applied to one battery and a higher voltage to the other.
(e.g. 7.6 V) will be applied to the other battery at the same charging current.
RESULT:
This process is self-exciting and leads to premature failure of both batteries. The undercharged battery will gradually lose capacity due to the formation of a sulphate layer, while the other battery will fail due to dehydration caused by regular overcharging and then cell flooding.
Operating principle:
The equalizer measures the total charging voltage and calculates its average value. If the charging voltage of one battery exceeds this value by more than 0.1 Volts, it diverts part of the charging current from that battery to another. Thus the total charging voltage is not affected.
Operating conditions:
Stops if any battery is below 5.2V.
During shutdown, the consumption is reduced to 2mA.
To demonstrate the operation of the rectifier, we connected two batteries in series and measured the charging voltage across them.
Stage 1: Without charging and equalisation, we connected the batteries in series and measured the unloaded terminal voltage (6.3 V and 6.3 V respectively)
Stage 2: Without equalisation, they were connected to a constant voltage charger of 14.4 V (6.8 V and 7.6 V) (undercharge and overcharge respectively).
Stage 3: The equalizer was also connected to the batteries (7.18 V and 7.22 V).
Stage 4 : Again, we charged them without the equalizer.
(6,8V and 7,6V)
LED indications:
- steady light - the device is operating, the rectifying current is greater than approx. 5A
- flashing light - rectifying current greater than approx. 0.5-5A
- LED flashes less frequently, faintly - batteries are balanced
Result:
- Decreasing charging voltage on overcharged battery
- Increasing charging voltage on undercharged battery
- Increased starting ability and capacity due to the resulting equal charge level
- Longer battery life
Application:
- Vehicles equipped with 6V batteries
- Cleaning machines
- Anywhere where two or more 6V batteries in series provide the voltage.
