General; A) The Patented Reflex Charging Process - Voltcraft Rlg 7008 Bedienungsanleitung

4. General

a) The patented reflex charging process

The Reflex charging process is based on a patented process for quick charging of NiCd and NiMH
accumulators. If such accumulators or accumulator packs are charged exclusively with the Reflex
charge process, no previous discharging is necessary up to the final discharge voltage for partly
discharging accumulators. The memory effect is safely avoided nevertheless.
An important advantage of this process is that extremely short charging times of only 15 minutes are
possible without the connected accumulators being damaged by this. On the contrary, through the
Reflex charging process, the performance of the accumulator is maintained as coarse crystal
formation does not occur with the chemical active substances.
With the Reflex charging process, high charging currents are always used and charging times of
more than 4 hours are not envisaged. Correspondingly, the charging device has to be able to supply
high output currents.
Just in the modelling area, the Reflex charging process has advantages when discharged accumula-
tor packs have to be available fully charged again within the shortest of times without full discharging
up to final discharge voltage being necessary.
The so-called memory effect for NiCd accumulators arises if these accumulators are frequently
charged in part-discharging condition with conventional charge technology, with very small charging
and discharging currents and for a longer storage period without use.
More or less large potassium hydroxide crystals form on the nickel electrode here which
lead to a reduction in the effective electrode area. Through several discharging/charging
cycles, the memory effect can be eliminated again in most cases.
In general, discharging of the accumulator up to final discharge voltage for prevention of the memory
effect for NiDc accumulators at regular intervals (every 5th to 10th charge cycle) is recommended.
If the accumulator to be charged is stressed with a very high charging current, small oxygen bubbles
arise through the electrolysis processes on the electrodes which lead to a reduction in the electrode
area and thus to internal resistance. The charging effectiveness deteriorates through this and the
accumulator heats up more and more as the energy cannot be taken up completely.
The pressure within the accumulator can then reach impermissibly high levels
which lead to outgassing through the safety valve. Such accumulators are a case
for environment-friendly disposal.
Even with the Reflex charging process, the oxygen bubbles arise on the electrodes due to the at first
high charging current. Through periodically arising discharging impulses with reversed power flow,
the small bubbles are dissolved in this charging process and then recombined. The 5ms (0,005
seconds) short discharge impulses must hereby show a current which corresponds to the 2.5 to
3-fold value of the charging current!
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