A note on batteries
Digital Matter battery powered devices offer world-leading performance and battery life.
However, it should be noted, with any battery powered device, the ultimate performance and battery life is largely down to the batteries themselves. Our devices make the best use of the energy available from the batteries. But if the batteries underperform, so will the entire solution.
Cheap batteries can be found, but great care needs to be taken. Using low quality batteries can lead to early battery failure, and short battery life.
Often, the cost of going out to an asset to replace batteries will FAR exceed any marginal cost saving on batteries, and any reputational damage with your customers.
This is why we have left no stone unturned in designing the Oyster3 to achieve it's 'Deploy Once' battery life.
Some examples of batteries and suppliers are given in this article. DM has not tested all models and partners should conduct their own testing to verify the batteries are suitable. Many batteries will be 'suitable' according to their datasheet but not perform later on after some time in the field.
If you are unsure on battery selection, contact our support team.
1. Fresh Batteries
It has been shown that batteries deteriorate over time. Make sure that the batteries that you are buying are as fresh as possible. You can usually check the batch manufacture date or the expiry date on the battery to get an idea.
Ideally each battery should be tested using a battery tester before being installed.
You would think every battery is exactly the same size. But they can vary slightly and affect the fit of the battery in the device. It is important to check the fit of your batteries in the device's battery holder.
The Oyster3 has the following requirements for batteries:
|Battery Size||3 x AA|
|Input Voltage Range||4V → 16V|
|Pulse Current Capability Required|
About Pulse Current Capability
Some batteries are available to provide small amounts of current, over a long life - whereas others can supply relatively higher peaks but do not last quite as long. The Oyster3 is very low power, but it does require some higher spikes of current when running the modem and GPS. As such it requires the pulse current capabilities listed above.
These values can be found on battery datasheets. It is advised to leave a margin of safety here. Some datasheets overstate or provide 'best case' figures, and the pulse current capability can degrade over the battery's lifetime, meaning it can't properly power the device for an upload even when some capacity is left.
In general, go for Spiral (High Power) versions over Bobbin Type batteries.
Resellers should conduct their own testing to ensure the listed batteries meet their requirements.
|Battery||Where to buy?|
|Energizer Ultimate Lithium L91 - AA||Hardware stores|
|Green Energy ER14505M AA||Stocked by DMA|
|FANSO ER14505M AA||AU - Batteries Direct|
AU - Master Instruments
NZ - SIMPower
Common Battery Concepts
For more information about batteries, head to Battery University - this is an excellent resource providing to the point information about various battery types.
Most batteries will perform the best at room temperature. It is why most of the time their capacity (and other characteristics) will be specified at room temperature (25 or 27°C ). All batteries will specify an operating temperature range (which they can be safely used within) - i.e. -20°C to + 60°C. However in general exposing batteries to excessively high or low temperatures at the edge of this range for extended periods will lead to reduced life.
All batteries, when sitting around unused will slowly degrade and lose capacity. This is referred to as 'self-discharge' and is expressed in % per year. Batteries have a limited shelf life and as such the freshest possible batteries should be used where possible.
The Oyster3 supports different battery chemistries. Each has it's pros and cons, summarized below.
|Voltage||1.5V per cell||3.7V per cell|
|Self Discharge||3% per year at 25°C||1% per year at 25°C|
|Shipping||Restrictions apply - Dangerous Goods||Restrictions apply - Dangerous Goods|
|Typical Operating Temp||-40°C to +60°C (Energizer)||-55°C to +85°C|
|Availability||Readily available consumer product||Industrial|