Choosing the Right Batteries for Your Data Logger

Battery selection plays an important role in determining how well a data logger performs in the field. This is especially important in challenging thermal environments or in scenarios where the data logger needs to power demanding sensors. 

The Hawk (our extremely flexible data logger) can be powered by a large variety of different sources. 

On the market, there are countless different battery sizes, chemistries, and constructions. In this article, we will focus on which batteries are suitable for the Hawk depending on your application. 
 

Summary of Battery Chemistries 

The Hawk Pro can be powered by D-cell batteries (minimum 3V), by a LiPo battery, or by external power. The Hawk Lite is designed to be powered by Alkaline D-cell batteries. 

Here's a quick summary table on the different battery chemistries, but please read on for more detailed explanations. 

1 Energy Density: The amount of energy a battery can store relative to its size or weight. 

2 Discharge Rate: The batteries' relative ability to output high amounts of current in a short period of time. Higher is better, allowing the battery to cater to high “peak” currents. 

When you’re trying to decide on your battery choice, the decision tree looks like this. 

Hawk Lite 

Alkaline Batteries 

Nominal voltage of 1.5V 

Alkaline batteries are widely used, low-cost, non-rechargeable batteries. For the Hawk Lite, we suggest the Procell Intense D Cell. 

Alkalines provide low discharge rates and have a limited operating temperature range, so caution should be taken when selecting these as the battery of choice. 

For most applications, we would recommend the Hawk Pro with LTC or LiMnO2 batteries over Alkaline batteries. 

Hawk Pro 

Lithium Polymer (LiPo) Batteries 

Nominal voltage of 3.7V 

A lightweight rechargeable battery that can support high discharge rates and can be shaped to fit a variety of compact designs. These batteries fit under the Hawk Pro PCB in the Hawk LiPo Housing. The LiPo battery we use is from Uniross, and is the UB2529. 

LiPo batteries have a standard operating temperature range of approximately -20° to 60°C degrees. They have quite a high self-discharge rate and therefore are suited to applications where they can be frequently recharged via mains power or solar. 

Lithium Thionyl Chloride (LTC) 

Nominal voltage of 3V 

LTCs are phenomenal batteries with high energy content, plus they are extremely robust. There are two main LTC options, bobbin and spiral. 

Bobbins have a higher capacity but have a much lower discharge rate. This makes them a poor choice for the Hawk. They sometimes struggle to provide the “pulses” of current that the device needs to power sensors and transmit data in challenging environments. 

Spiral cells have a slightly lower capacity than bobbins but have the ability to discharge at much higher rates. This makes them a much, much better option for a device like the Hawk Pro. 

Lithium Manganese Dioxide (LiMnO2) 

Nominal voltage of 3V 

A lesser-used, non-rechargeable battery chemistry that has a better safety reputation than some other lithium-based options. 

Lithium manganese dioxide batteries are more thermally stable and have a greater resistance to thermal runway than some other lithium battery types. 

They have quite high discharge rates, and thus should be suitable for higher current applications such as powering sensors in the Hawk Pro. 

They also have an excellent operating temperature range, typically from –40°C to 85°C 

LiMnO2 vs Lithium Thionyl Chloride (LTC) 

Our development team has conducted some thorough testing comparing the performance of numerous LTC and LiMnO2 batteries to determine the differences and to better provide guidance on the battery choice. 

The above 4 batteries were tested from –30°C to 60°C, performing GPS fixes, BLE scans and Modem transmissions at each interval. 

The batteries were assessed to determine the change in current consumption over the temperature range, and the voltage drop over the same range. 

From the above, the Saft LSH20 (the only LTC tested) performed the best over the temperature range, with the lowest change in voltage and current consumption. 

The best performance per $ are the EEMB LiMnO2 cells. Their performance is comparable to the Saft LM33600 for 1/3 of the price. 

Bottom Line - Which Batteries to Choose for Your Data Logger 

If you have access to external power, whether solar or mains power, the Hawk Pro with a rechargeable LiPo battery is the best option. It should provide you with almost indefinite battery life, and the ability to power demanding sensors. 

If you have a very low power application, the Hawk Lite is your best bet. It is less expensive than the Pro, and the industrial alkaline batteries deliver a good balance of power and performance. 

If external power is not available or appropriate, and you have a demanding application, the Hawk Pro with D Cell batteries is the best bet. It becomes a choice between LiMnO2 batteries, and LTC batteries. 

If performance is your priority, the SAFT LSH20 (LTC spiral wound cell) is our suggestion. Otherwise, for a balance of performance and price, the EEMB LiMnO2 would be a great option. 

Conclusion 

The best battery for your Hawk depends on your application needs, from low-power Alkalines to high-performance LTC or LiMnO₂ cells, or rechargeable LiPo for solar and mains-powered setups. 

Selecting the right batteries ensures reliable performance and longer device life in the field. For tailored recommendations, get in touch with the Digital Matter team.