Section 2: Description of SBE 19plus V2
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Moored Mode Examples
A 19plus V2 with strain-gauge pressure sensor and standard alkaline batteries is set up to sample autonomously every
10 minutes (6 samples/hour). How long can it be deployed?
Example 1 – SBE 5M pump on for 0.5 sec/sample (MooredPumpMode=1), no auxiliary sensors,
1 measurement/sample
(NCycles=1):
Sampling current = 70 mA * (2.5 sec + 0.5 sec) = 0.21 amp-sec/sample
In 1 hour, sampling current = 6 * 0.21 amp-sec/sample = 1.26 amp-sec/hour
Pump current = 100 mA * 0.5 sec = 0.05 amp-sec/sample
In 1 hour, pump current = 6 * 0.05 amp-seconds/sample = 0.3 amp-sec/hour
Quiescent current = 20 microamps = 0.02 mA
In 1 hour, quiescent current ≈ 0.02 mA * 3600 sec/hour = 0.0.072 amp-sec/hour
Current consumption / hour = 1.26 + 0.3 + 0.072 = 1.63 amp-sec/hour
Capacity = (10.5 amp-hours * 3600 sec/hr) / (1.63 amp-sec/hour) = 23190 hours = 966 days = 2.6 years
However, Sea-Bird recommends that batteries should not be expected to last longer than 2 years in the field.
Example 2 - optional SBE 5T pump on during sample (MooredPumpMode=2), 15 sec delay before sampling
(DelayBeforeSampling=15), auxiliary sensors drawing 100 mA, 4 measurements/sample (NCycles=4):
On-time = 2.5 + 15 (delay before sampling) + (4 – 1) * 0.25 (additional measurements/sample) = 18.25 sec
Sampling current = 70 mA * 18.25 sec = 1.28 amp-sec/sample
In 1 hour, sampling current = 6 * 1.28 amp-sec/sample = 7.7 amp-sec/hour
5T Pump current = 150 mA * 18.25 sec = 2.74 amp-sec/sample
In 1 hour, pump current = 6 * 2.74 amp-sec/sample = 16.4 amp-sec/hour
Auxiliary sensor current = 100 mA * 18.25 sec = 1.82 amp-sec/sample
In 1 hour, auxiliary sensor current = 6 * 1.82 amp-sec/sample = 10.9 amp-sec/hour
Quiescent current = 20 microamps = 0.02 mA
In 1 hour, quiescent current ≈ 0.02 mA * 3600 sec/hour = 0.072 amp-sec/hour
Current consumption / hour = 7.7 + 16.4 + 10.9 + 0.072 = 35.1 amp-sec/hour
Capacity = (10.5 amp-hours * 3600 sec/hr) / (35.1 amp-sec/hour) = 1076 hours = 44 days = 0.12 years
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