Q. What is an acceptable test reading relative to the stated capacity rating of the battery?
A. As most new nicads will test out to a capacity slightly greater than that
printed on the side of the case one must aim for a value equal to or no more
that 5% lower than this value. Don’t assume that a 1000mAh rated pack that
checks out to 500mAh is actually as good as a 500mAh pack. It is already 50%
gone and the rest of its capacity will die soon!
Receivers will cause greater variations in battery loading due to servos operating at different times. As such, it is even more requirement to have a good nicad with the Rx than with the Tx.
Q. How often should nicads be cycled?
A.Cycling nicads is only necessary as part a true capacity, peace of mind
checks.. If nicads are used heavily for long flying sessions there is less need
to cycle. However, if a battery has been stored for several months, say during
a winter lay-up, it is a good idea to cycle/test them a couple of times before
use. Normally cycle checks should only be necessary four to five times a year
on each battery. More often than that is considered of little benefit.
Remember, it is always better to highlight pending faults at home rather than
on the field. . .
Q. Can the analyser be arranged for dual voltage supply i.e., 240 & 120 volt supplies?
A.Yes, if required. Please state when ordering. Use of a 60 hertz mains
frequency does not cause a problem either. All timings and ranges are processor
controlled by quartz crystal and not dependent on any supply characteristics.
Q What happens if there is a diode (one way circuit) at the transmitter charge socket?
A.Certain transmitters have a diode in the charge connection. This will not
allow a discharge through the socket. In this case it will be necessary to
arrange the analyser to connect directly to the nicad battery itself. It is
quite customary to add your own purpose connector to the nicad and keep this
neatly tucked away under the battery cover.
Q. Does the analyser cycle/test two batteries at the same time?
A.No. The analyser goes through a complicated operation & test programme.
It is not practical to arrange this for a dual battery function. As nicad
analysis is a routine but casual function the need for checking more than one
battery at a time causes no concern in practice.
Q. What other uses can the analyser provide?
A.Using the instrument to test batteries several days after they have been
charged gives valuable insight to their shelf storage properties. Good nicads
can retain 95% of their useful working capacity for long periods.
Q. How often am I able to use the Delta 4 charger?
A. It is quite in order to use the charger all the time with no ill effect to
the batteries. It has been designed with this in mind. However, if your nicads
do not get discharged, (not run down significantly during activity sessions) at
least 5 times a year. then it is advisable to provide this discharge purposely
yourself by one means or other. For similar reasons Delta 4 may be reluctant to
charge either brand new or long-term stored battery packs. In these events an
initial slow charge and couple of controlled cycles will allow D4 to be used
satisfactorily from then on.
Q. Does Delta 4 give a full charge?
A. The Digital Delta Peak system used with the charger is very precise. As soon
as the prescribed delta voltage occurs, for any particular battery pack, the
charge will shut down. It may be noticed by those who use our analyser, that
Delta 4 gives a marginally lower, (2 to 3% less) ‘test result’ than
that obtained from a traditional overnight charge. This is due to the fact that
D4 does not overcharge. A more realistic charge is obtained with the D4.
Overnight trickle charging can cause a pronounced cusp in the finally charged
voltage. In practice this slight apparent ‘extra’ has been shown to
correspond to mere seconds of additional usage.
Q. How does Delta 4 cope with worn out or faulty nicad packs?
A.Where there are serious problems with a nicad Delta 4 chargers will reject
those nicads, i.e., not charge. This will normally be apparent within half a
minute of starting a charge. The added bonus from D4 in being able to detect
pending failures over more simple forms of charging may just save that
expensive model! Remember, overnight trickle charging will conceal nicad faults
from an unsuspecting user.
Q. How long should I expect my nicads to last with prolonged use with the Delta 4?
A.Our extensive tests over many years have shown that the type of useful quick
charge given by Delta 4 will have no ill effect whatsoever on the life of
nicads. In fact, because the unit will tend to only used when it is needed
rather than for repeated aborted sessions, batteries will generally be more
reliable and last much longer than with repeated trickle charges. We can cite
several instances where standard nicads with R/C equipment have lasted for as
many as 2,000 full charges using D4 techniques.
Q. Would we use Delta 4 chargers on our own equipment?
A.Here at Mainlink, we are modellers too. Personally owned transmitters, (one
of which is now over nine years old the other five), both have original nicad
packs on board. Neither Tx has ‘seen’ a slow charger since new, other
than the casual routine cycle-test four times a year. The oldest Tx has now had
well over 1600 charges and still performing as new. . .
Q. Is there any advantage in choosing to use a lower charge rather than any higher rate that may be available?
A.No. Actually there may be a disadvantage. Ideally we should chose an output
at no more than a 2 to 3C rate, i.e., 2 to 3 times the battery rating. Delta
peak charging does have a relationship with cell temperature. If charging is
done too slowly ambient changes in room or day temperature can influence the
‘end of charge’ drop-out. In theory a 600mAh nicad can be charged at
well over 1 amp on our system but generally the wiring used with R/C equipment,
(especially that in the Tx), cannot take a higher current. We regularly charge
150mAh nicads at 200 or 400mA. Even a 50mAh pack has been shown to suffer no
ill effects when charged repeatedly at 200mA using Delta 4. At the other end of
the scale a 2Ah pack can be charged at the 200mA rate over its required 12 hour
period but this does defeat the object of having the charger in the first
place!!
Q. Do the cells have to be vented?
A.No. Vented cells are a only a safeguard against overcharge. Once a cell has
vented its performance will be seriously reduced. We have tested over 10,000
charges using our digital delta peak system on totally standard type cells. The
technique has been shown so consistently reliable that overcharge and venting
does not come into the equation. We do advise that Delta 4 is used only with
normal cylindrical cells. We cannot offer any advice with its use with button
cells.
Q. Can the cigarette lighter socket be used to run the Delta 4?
A.Basically the answer is yes. However, it is not unusual for these sockets not
to provide the best ‘all-time’ connection. It can be annoying to find
the cigar plug has fallen out when this was not expected. Our advice is always
to fit your own purpose connector to the car battery which will give the best
results.
Q. Some transmitters have a diode in the charge connector. Does this matter?
A.No. the Delta 4 will still work correctly with or without a diode style
transmitter. The circuit has been designed around this feature.
Q. Will the mains/12 volt Delta 4 still work the same from a car battery as with the mains?
A.Yes. The voltage boost takes car of battery voltage requirements and no
difference will be found between either type of supply.
Q. Is there protection against supply battery or nicad reverse connection?
A.Yes. The 12 volt supply has total protection and the charge will not work if
this has been done. No harm will come! Each battery output is similarly
protected with any accidentally reverse connected nicads refusing to start.
Other correctly connected outlets will continue to work normally. Each outlet
is similarly protected against accidental shorting. However, note that the
nicads themselves are not. . .
Q. How much power is consumed from the 12 volt supply battery during use?
A.This depends only on the number of cells in the pack being charged. The DDP
contains a voltage booster that starts to operate only as required. For a
6-cell pack there is no boost. For a 7-cell pack there is some boost towards
the end of the operation. Up to 14-cell packs the boost is introduced
accordingly to maintain the charge current. Charge output is nominally at two
and a half amps for all time. It is thus that up to 7-cell packs will cause a
drain of approx. two and three quarter amps. When the booster is operating
current drain can rise up to just below five amps for the maximum number of
cells.
Q. Can two 7-cell packs be charged at the same time?
A.Yes. It is advisable to ensure that both packs are in the same condition, -
state of charge. Packs should be wired in series so looking like a single
14-cell pack.
Q. Does it take any longer to charge a 14 cell pack than a 7 cell pack?
A. No. Essentially the charge current stays the same throughout the running time. Run time relates to the actual capacity of the battery being charged.