GasClam 2 Instrument User Manual
Ion Science Ltd.
Unrivalled Gas Detect
ion.
ionscience.com
13
Li Long Life
7.2
19.0
0
–
50
na
2937
2937
24
98
The average number of samples for each logging interval is shown (1). This value can vary depending on operating
temperature, the number and type of gas sensors fitted in the GasClam 2 and the state of the filters. These values
are for temperatures at 20 °C with the maximum number of sensors and clean filters.
The “Nominal Battery Life” (2) is a conservative calculation of the number of days a battery will last under
“nominal” conditions (battery is fully charged at the start of logging, operating te
mperature is 20 °C, the filters are
clean) and using all the sensors. This value is 80% of the average value for 15min and 1 hour logging intervals.
Other factors such as relative humidity can also affect the battery lifespan (see below).
Alkaline Batteries
The GasClam 2 is fitted with Alkaline batteries for initial testing and checks. However, for normal field work it is
recommended to use either the Ni-MH rechargeable or Li long-life battery packs. The Duracell batteries can be
stored in the instrument case as a reserve and can be used when the rechargeable battery has not been charged
and the GasClam 2
must be deployed immediately. Alkaline batteries have a long “shelf life” but do not use after
the date shown on the battery. Short logging intervals will reduce the maximum number of samples taken.
Ni-MH Rechargeable
The Ni-MH rechargeable battery packs should be fully charged using the charger provided (see instructions) and
used for logging as soon as possible. Rechargeable batteries do
not have a long “shelf life” as they will self
-
discharge over time.
This also means that battery life is not proportional with an increase in logging interval, e.g. if the logging interval
is increased from 1 hour to 12 hours the nominal battery life will not increase 12 times to 276 days (9 months).
The NiMH batteries self-discharge at a rate of 15% - 20% per month.
To obtain the maximum working life from the Ni-MH battery packs it is recommended that they are always first
fully discharged and then charged using the charger provided (see Charger instructions). Also Ni-MH battery packs
should be charged at least once every 6 months even if they are not being used.
Li Long-Life
The Long-life battery pack will last up to 3 months at an hourly logging interval. Only the Li battery pack has a
restriction on the minimum logging interval that can be used and that is 15 minutes.
The Li battery pack has a built-in fuse to maintain intrinsic safety and if the GasClam 2 is switched on/off rapidly
using the Push-button cable in rare cases this can cause the fuse to blow. If the GasClam 2 does not react with a Li
battery pack first check the battery using a voltmeter.
Adhere to the conditions of use and safety instructions enclosed with the Li battery packs.
The Effects of Temperature and Humidity on Sample Count
To ensure that the gas sample is dry before measurement by the CH
4
and CO
2
sensors a Moisture Filter is fitted in
the GasClam 2. Over time this will hydrate and its ability to remove moisture will decrease. If moisture is not
successfully removed, concentration readings can be affected. The amount of samples that can be taken will
depend on temperature and humidity. The table below shows how many samples can be taken at 90% Relative
Humidity (RH) at different temperatures (90% RH is assumed to be worst case).
Temperature °C
1°C
5°C
10°C
15°C
20°C
25°C
30°C
35°C
38°C
Samples at 90% RH
3455
2620
1850
1320
950
700
520
390
330
