I am designing an electronic device that will be powered by a battery, and I am trying to keep my device's current draw in standby to a minimum. Specifically, I would like to keep the current just low enough that it is insignificant compared to the battery's own self-discharge. In other words, I would like to determine the maximum current which, if constantly drawn from a particular battery, still would have no noticeable effect on the charge life of the battery. My device will be powered from 4 AA NiMh cells, although I would like to be able to figure this out for any cell size and chemistry I may encounter.
Electronic – Maximum load current that is still indistinguishable from battery self-discharge
batteriescurrentdischargeload
Related Topic
- Circuit Design for Managed Draining of NiMH Cells
- Electronic – 5V USB backup for long time usage
- Electronic – Is voltage an accurate metric for testing the charge of an NiMH battery
- Electronic – Which battery chemistry to use in a project
- Electronic – Very long battery life with rechargeable lithium ion batteries
Best Answer
The only way to know the actual self-discharge rate of any given battery/cell, is by measuring from a fully charge state to a discharged state, over a given time period. Aside from that, a look at the datasheet, or an educated guess based on battery chemistry is required.
Standard NiMH Rechargeables for example, have a high discharge rate, noted of up to 4% per day, or 40% per month, when stored at room temperature. It is higher at higher temperatures, and lower at lower temperatures. That means a regular 2300mAh 1.2V AA sized NiMH cell discharges in the mid to high double digit milliamp range per day!! Alkaline batteries on the other hand, have a 5 year shelf life. The same 2300mAh AA battery but with Alkaline chemistry discharges at 1mA or less per day.