Loose electrical connections cause items in a circuit to heat up. The Naked Scientists cite an example of an electrical cord that gets warmer near a wall socket if it is a loose fit. The reason for this is the poor connection increases the resistance, causing some power to waste as heat. Excessive warming during recharging also indicates battery efficiency is low.
Things to Know About Rechargeable Battery Efficiency
Battery efficiency is a measure of the amount of energy we get out of a battery, compared to how much energy we put in. Battery input is invariably greater than battery output, because some power is consumed in the process.
There are two ways with which we can measure battery efficiency:
- COULOMBIC EFFICIENCY, whereby electrons shuttle during charging and discharging, including the proportion lost.
- VOLTAGE EFFICIENCY, being the voltage difference between these two operating modes, caused by over-potential.
Five Key Factors Affecting an Efficiency Rating
- The rating of the INPUT CURRENT during the recharging process is best kept constant for lead acid batteries. Many users of lithium-ion batteries depart from this standard, because they value shorter charging time over efficiency according to Flux Power.
- The STATE OF CHARGE affects battery cell efficiency too, because the voltage output gradually reduces as the remaining charge falls. However, temperature, surface charge, and age also play a role too, meaning this measure is not entirely reliable.
- INTERNAL RESISTANCE in a battery depends on size, age, current, and chemistry. Low resistance produces a higher-performing battery. Manufacturers try to encourage this positive trend with electrolyte additives. These may be among their best-kept secrets.
- BATTERY TEMPERATURE is another critical factor, especially with lithium-ion batteries, where high temperature causes cathode-electrolyte-oxidation, which can result in sudden loss of capacity. Battery efficiency is lower in cold lead-acid batteries, and may cause old ones to fail.
- BATTERY AGE serves to prove, once again, that nothing lasts forever. Over-charging, fast-charging, and extreme temperatures all help accelerate battery aging. Treat your batteries responsibly, and they should reward you with longer, more reliable lives.
The amount of energy we get out of rechargeable batteries is always going to be less than what we put in. Spending more on quality products up front, should repay you with more efficient battery performance in the long term.
More Information
Lead-Acid Versus Lithium Battery Performance
