| Graphs produced with Microsoft Excel from
CSV files output by Pro-Trak. |
| |
| Why
re-invent the wheel when there are programs ideally suited
for graphing and sorting out data. |
| |
|
|
|
Discharge curves of fully charged cells
which have stood for 12 hours before being discharged |
|
|
|
The raw CSV data output by Pro-Trak was collected by
terminal .exe program and graphed in Microsoft Excel |
|
|
|
As can be seen the voltage of the NI-Mh
cells drop quite low before increasing in volts, especially the standard
cells. It can be seen the Ni-Cd cells do not have this characteristics.
|
|
|
|
When selecting discharge before charge ( to
enable the lockout facility of Pro-Trak) the discharge cut-off is set to
Number of Cells * 0.9 ie if the number of cells is set to 6 the discharge
cut-off is set to 5.4 volts. This has proved to be quite
satisfactory and was introduced in Pro-Trak version 10.08 and above
( over a year ago)
|
|
|
|
|
|
|
| |
|
Below is the same graph with the scaling set between 5
and 7 volts to exaggerate the voltage swing of Ni-Mh cells |
| |
 |
| |
|
|
| |
| Multi cycles on
Pro-Trak Sanyo3300HV
cells. |
| |
The
following graphs are a pack of
Pro-Trak Sanyo
3300HV cells cycled 9 times with a time
between cycles of 2 hours. |
| This cycle took 24 hours to complete. |
|
| |
The graph shows the
pack charging, discharging then resting for 2 hours before charging
again.
The charge data is sent every 8 seconds, every 1 second during discharge
and every 120 seconds during the rest period. This is why the rest period
looks very short for the 2 hour rest period. |
| Multiply the
temp by 10 for the correct temp. |
|
| |
| The cycle was
started at 22.00hrs in a workshop, this is why the first 3 cycles have a
lower starting temperature than those towards the end of the cycles. |
| The time between
the start of charge and the start of another charge is approximately
3 hrs. |
| |
| |
| The cells were
temperature charged to 40`C |
| |
 |
Cycles started at:
1st at 22.00 hrs
2nd at 01.00 hrs
3rd at 04.00 hrs
4th at
07.00hrs
5th at 10.00hrs
6th at
13.00hrs
7th at 16.00hrs
8th
at 19.00hrs
9th at 21.00hrs |
|
| |
| As can be seen from the graph
below the discharge
curves line up one on top of the other indicating very little |
| degradation
in cell performance even though they were cycled 9 times over 24 hours. |
| The following graph
is the discharge portion of the graph above |
| |
 |
| |
|
| Following
is the Pack data sent at the end of each discharge. |
| Note: the
TIME and the CYCLE have been put in manually and is not sent with the
pack data |
|
| D/CAP |
CCAP |
TIME |
A/V1 |
P/V1 |
POWER% |
PEAK/V |
F/BACK |
TEMP |
TIME |
CYCLE |
| 3261 |
3682 |
586 |
7.22 |
6.99 |
96 |
9.53 |
0.07 |
0.19 |
10.00 |
1 |
| 3250 |
3620 |
585 |
7.23 |
6.99 |
96 |
9.57 |
0.10 |
0.17 |
1.00 |
2 |
| 3238 |
3578 |
582 |
7.22 |
6.99 |
95 |
9.60 |
0.12 |
0.15 |
4.00 |
3 |
| 3244 |
3584 |
583 |
7.23 |
6.99 |
95 |
9.60 |
0.11 |
0.2 |
7.00 |
4 |
| 3288 |
3585 |
591 |
7.24 |
7.02 |
96 |
9.52 |
0.04 |
0.23 |
10.00 |
5 |
| 3277 |
3550 |
589 |
7.24 |
7.03 |
96 |
9.50 |
0.01 |
0.23 |
13.00 |
6 |
| 3261 |
3550 |
586 |
7.23 |
7.02 |
96 |
9.50 |
0.00 |
0.23 |
16.00 |
7 |
| 3277 |
3571 |
589 |
7.24 |
7.03 |
96 |
9.52 |
0.02 |
0.23 |
19.00 |
8 |
| 3272 |
3592 |
588 |
7.25 |
7.03 |
96 |
9.50 |
0.01 |
0.24 |
21.00 |
9 |
|
| D/CAP = Discharge capacity |
|
MATCH% = "Not
applicable as remote leads not fitted" |
| TIME = Discharge
Time |
|
PEAK/V =
Peak volts at end of charge |
| A/V1 = Average pack
volts over 5 minutes |
|
F/PEAK =
False Peak in first 60 seconds |
| P/V1 = Pack
volts at 5 minutes |
|
F/BACK =
Fallback of pack at end of charge |
| POWER% = "Punch" |
|
CCAP
= Charge Capacity |
| TEMP = Ambiant
temperature |
|
TIME
= Start time of each cycle |
|
|
|
| From
the data above a number of charts can be produced as below |
| |
| The following chart
shows the discharge time varies only 9 seconds over the 9 cycles |
| |
 |
|
|
|
| Pack
Fallback |
| Now
this one is interesting, the fallback of the pack varies from 0.00 to 0.12
volts over the 9 cycles!! |
| Remember
the pack was temperature charged to 40`C but
Pro-Trak still records the fallback |
|
| We are
in the process of testing the same pack over the same time period
but |
| are
going to use PEAK detect at 0.08 volts instead of temperature detect. |
| We will
post the results here as soon as we have them!! |
|
 |
|
|
| The
following graph is the ambient temperature plotted with the fallback |
| Note
the temperature is divided by 100 to keep it on the same graph |
| Looks
like the cooler the cells are, the higher the delta fallback has to
be to get maximum charge |
|
|
 |
|
| More
information will be posted here as we continue our testing |
|
| We have
noticed a great deal of discussions on cells, charging and chargers on rcracechat.co.uk |
| We hope
this helps and will continue to post information here as we gather it |
| If you
wish for a particular test on cells we will try to accommodate you and
post the results here. |
|
| ENJOY
YOUR RACING
Phil |
|
| 05/02/03 |
|
| Well
here's some more information |
|
| Tests
on Pro-Trak Sanyo 3300 HV cells |
|
| The
following graphs are of 2 packs of
Pro-Trak Sanyo
3300HV cells cycled 9 times with a time |
|
between cycles of 2 hours. |
| This cycle took 24 hours to complete. |
| One
pack was peak detect charged to 0.08 and the other temperature charged to
40`C |
|
| It
looks like everyone has it wrong about temperature
charging. |
| It was
thought, the temperature cut-off of the cells should be altered
according to the ambient temperature. |
| The
following graphs show this not to be the case and in fact it is the
delta fallback which has to |
| be
altered according to the ambient temperature. |
|
|
| The
graph below shows that if charged to a Delta fallback of 0.08
(F/Back) the input |
| capacity
(C/Cap) and the discharge capacity (D/Cap) vary according to the ambient
temperature. |
|
|
|
Graph Key |
| F/BACK
= Delta fallback ( set to 0.08) |
| Ambient
Temp * 100 = Ambient temperature |
| D/Cap
* 10000 = Discharge Capacity |
| C/Cap *
10000 = Charge Capacity |
| Pack Temp
Chrg * 100 = Pack Temp Charged |
|
 |
|
|
|
| The
following graph shows that if temperature charged to 40`C the input
capacity (C/Cap) and |
| the
discharge capacity (D/Cap) do not vary over the ambient temperature range. |
| It does
however show that the Delta fallback is dependant on the ambient
temperature. |
|
 |
|
|
Conclusion |
|
| Temperature
charging |
| Gives consistent
charge and discharge times irrespective of the ambient temperature. (in
the range 10 to 18 `C) |
|
| Peak
detect charging |
| To
achieve consistent charge and discharge times the delta fallback has to be
altered according to the ambient |
| temperature. |
|
| From the
above graphs and previous tests it can be seen that to achieve maximum
charge using peak |
| detect,
a suggested fallback would be. |
|
|
Ambient
Temperature
10`C
18`C
20`C 24`C |
|
Fallback (Delta
volts)
0.20v
0.10v
0.04v 0.01v |
|
|
| Note
the above tests were carried out over a temperature range of 10 - 24 `C |
|
|
| Below
is our tests on temperature and peak charging put back to back |
|
Peak detect |
| The ambient
temperature was increased to > 20 `C between cycles 13 and 16
which resulted in a dramatic increase in pack temperature. |
| of
over 50`C when using a fallback of 0.14v. The data before this
time when the fallback was set to 0.08 would still suggest |
| the
pack temperature would be more than 40`C |
|
|
Temperature detect |
|
Temperature detect produces
more consistent charge and discharge figures than peak detect. |
|
The ambient temperature was
increased between cycles 31 and 34 to > 20`C which resulted in a drop
in input capacity but only a small drop |
|
in discharge capacity. |
|
|
The graph would suggest a
temperature cut-off of 40`C up to an ambient temperature of 20`C should be
used. |
|
and a temperature cut-off of 45`C
should be used with an ambient temperature of > 20`C |
|
|
 |
|
|
Graph Key |
| F/BACK
= Delta fallback |
| Ambient
Temp * 100 = Ambient temperature |
| D/Cap
* 10000 = Discharge Capacity |
| C/Cap *
10000 = Charge Capacity |
| Pack Temp
Chrg * 100 = Pack Temp Charged |
|
|
|
The following graph plots the
Average voltage (Av1) over the first 5 minutes, Pack voltage (Pv1) at 5
minutes and the discharge |
|
times for a pack of Sanyo 3300
Ni-Mh and a pack of Sanyo 2400 Ni-Cds over an accelerated charge and
discharge cycle. |
|
The packs were tested side by
side on 2 Pro-Trak chargers, 80 cycles were performed with a 2 hour
rest period between cycles. |
|
It can be clearly seen that
the Ni-Cd cells maintain a consistent Average volts, Pack volts and
discharge time over the 80 |
|
cycles, however the Ni-Mh cells
were showing signs of deterioration even after the first 40 cycles.
The 3300s start with a |
| discharge
time of 600 seconds but finish with at time of 525 seconds. The
2400s start with a discharge time of 425 and finish with a
discharge time of about 420. |
|
|
|
Average volts = Av1 * 10 |
|
Pack volts = Pv1 * 10 |
| Discharge
Time = Dis Time * 1000 |
|
|
|
|
|
|
| You will
notice the graphs going up and down slightly over the 80 cycles, this coincides
with the ambient temperature. |
|
|
|