I'm wondering what type of batteries to use on a project I'm building, it's a wireless temperature data logger.
- It spends 15 mins asleep drawing 15 microAmps of current.
- And about 10 seconds awake drawing between 70 and 200 milliAmps of current.
- The board is tolerant between 2.5v and 3.7v.
I've currently got it running off 2 primary Zinc Chloride Dry cell AA's as they were to hand and it's been on a month so far and it's down to 2.70v now, but I'm wondering what would give the longest life.
I don't mind if it's rechargeable or disposable batteries but I want to get the longest life span between having to change them as it won't be in a convenient place to do so.
I realise using C or D cells would give more life than AA's but this is more of a question about chemistry and self discharge rates, high current discharge rates etc. Once I have decided on the most appropriate battery chemistry I will choose the largest capacity that I can to fit the solution.
I also don't want to have to have any additional regulation circuitry to keep the complexity down and also the standby current low.
I'm concerned about using a LiPo as it's over 3.7v after initial charge plus needing cut off circuitry to prevent damage to the battery, also some NiMh & NiCd can be 1.4v after initial charge so 3 of those would 4.2v
Anyway any help appreciated.