As my sensor will be located in a hard-to-reach location, it is crucial that it can be powered for as long as possible with a battery (no recharging). The average current draw of the sensor is in the range of 200 to 400µA, though sometimes with peaks at around 200mA. Currently I use a 3.7V 2A LiPo battery, but after some calculations the lifespan at best is only around 7 months or so. I need something that can charge it for way longer than this, preferably in the range of 2-3 years minimum.
I don’t have a background in electronics so I’m largely uneducated when it comes to specifications. Would you guys recommended a larger-sized LiPo battery (e.g. 6A, 8A) or a different type of battery? It doesn’t need to be rechargeable; temperatures can get to minus 20 Celsius in the winter, up to plus 50 degrees in the summer. Size dimensions are not an issue. Voltage input of the sensor board should be around 3.7V. Price per battery should preferably be less than about $15.