Power Options
MagneFlow loggers are designed to function with minimal power draw, making possible deployments of weeks to months, and even for more than a year. Actual battery life depends on amount of data logged (e.g., logging a meter with constant flow draws more power than logging a meter with only sporadic flows). Battery chemistry and environmental factors will affect a battery’s internal discharge rate.
Our loggers can run on any DC power supply between 3V and 15V, making possible a wide array of power options. A standard 4-AA battery pack is included with each logger. In field tests, this typically powered the logger for more than three months. In addition to recording flow through the water meter, MagneFlow loggers also record ambient temperature and battery input voltage. Thus, while downloading data, one can quickly check battery voltage over time.
For longer battery life we recommend rechargeable lithium ion batteries in waterproof cases and cable connections. We offer case/cable options for:
- 4 Li-ion batteries, 2 parallel sets of 2 batteries in series
- 6 Li-ion batteries, 2 parallel sets of 2 batteries in series
| Case Option | Battery type | # of batteries | Cost |
| 1 | AA (1.2 – 1.5V) | 4 | 1 Included, $30 |
| 2 | Li-ion 18650 (3.7V) | 4 | $35 |
| 3 | Li-ion 18650 (3.7V) | 6 | $40 |
Some example chemistries and capacities are:
| Number & type of batteries | Rechargeable?* | Configuration | Capacity (mAh) | Power (Wh) |
| 2 9V alkaline | No | 2 in parallel | 1,100 | 9.9 |
| 2 9V NiMH | Yes | 2 in parallel | 500 | 4.2 |
| 4 1.5V AA alkaline | No | 4 in series | 9,600 | 14.4 |
| 4 1.2V AA NiCd | Yes | 4 in series | 3,200 | 3.84 |
| 4 1.2V AA NiMH | Yes | 4 in series | 8,000 | 9.6 |
| 4 3.7V Li-ion 18650 | Yes | 2 parallel sets of 2 in series | 13,600 | 50.32 |
| 6 3.7V Li-ion 18650 | Yes | 2 parallel sets of 2 in series | 20,400 | 75.48 |
Monsoon Metrics does not sell or ship batteries, nor do we recommend sources. However, we are aware of the problem of counterfeit and substandard batteries sold over the Internet. For 9V and AA batteries, we recommend buying name-brand batteries from local brick-and-mortar stores.
For Li-ion 18650 cells, we make no recommendation, but we do note that independent reviewers concluded that the following company rigorously sources, inspects and tests its Li-ion batteries:
LIION Wholesale, www.liionwholesale.com
Note that for rechargeable 18650 Li-ion batteries, there often is a tradeoff between battery capacity and its ability to rapidly discharge. Because MagneFlow loggers draw such a low current, we recommend you ignore the published discharge rate and focus on battery capacity. We also recommend buying overcharge protected batteries.