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There are various solutions for powering communications nodes. The cheapest, with extremely low consumption, use primary cells (non-rechargeable batteries). For a longer life, applications are being developed that will use batteries based on various technologies (Pb-acid, NiMH, NiCd, Lithium cells, etc.). But all batteries have a limited number of charging-discharging cycles: a few thousand, at comfortable temperatures (between 15°C and 25°C) and incomplete discharge. The storage capacity decreases with each cycle, and is greatly accentuated in the case of over-discharge. In addition, the performance of standard batteries at low temperatures is low (limited capacity, low charging and discharging rate, increased internal resistance). In addition, the price limits the use of cells designed to operate at extreme temperatures (-40°C to + 80°C), in isolated locations that remain in hard-to-reach areas. New power systems are moving towards the use of supercapacitors (EDLC) which are becoming cheaper and cheaper with increasing energy density. They are very reliable passive devices, which exceed the battery life, the number of cycles and the robustness of any battery on the market today, without feeling the effects of low temperatures. The number of cycles reaches hundreds of thousands, and at the end of them to a doubled internal resistance (which remains in the range of millions) and to a slight reduction in capacity (10% -20%). Since a good capacitor has a lifespan of about 20 years, a carefully designed communications node outperforms any network with nodes powered by standard batteries. Under these conditions, hybrid power solutions are required, which, in addition to a small capacity battery, power supply, includes supercapacitors to improve the performance of the power system.
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