Explanation of Battery Terms
1. Storage Capacity:
Storage capacity, often measured in ampere-hours (Ah), is a measure of how much energy a battery can store. Think of it as the fuel tank of a car — the larger it is, the further you can travel on a single fill. For example, a battery with a storage capacity of 100Ah can deliver 5A of current for 20 hours before it runs out. Applies to both lead-acid batteries (typical car batteries are 40-100Ah) and lithium batteries common power tool batteries are 1.5-5Ah).
2. Nominal Voltage:
This refers to the electrical potential difference maintained by the battery. A higher voltage can deliver more power — think of this as the pressure propelling the water in a hose. The nominal voltage for a single cell is typically 2V for lead-acid and 3.7V for lithium-ion.
3. Lifecycles (Battery Lifespan):
This is the number of complete charge-discharge cycles a battery can undergo before its capacity falls below 80% of the original. Lithium batteries often last for 3000-5000 cycles, while lead-acid batteries typically manage 200-1000 cycles depending on the usage and maintenance.
4. Power:
Power measured in watts, calculated as voltage x current. High voltage and/or current result in higher power wattage. Both lead-acid and lithium-ion batteries operate at similar power levels.
5. Operating Temperature:
A battery's functioning temperature range. Lead-acid batteries usually operate between -20℃ and 50℃; lithium batteries have a wider range, often functional between -20℃ to 75℃.
6. Discharge Voltage Curve:
A graph representing how voltage output changes during the discharge. Lithium-ion batteries maintain a fairly constant voltage during discharge providing steady power, while lead-acid battery's voltage slowly drops, reducing performance.
7. Peak/Continuous Charge:
Peak is the maximum instantaneous charge a battery can handle, while continuous is the sustained charge rate permissible without harming the battery. These rates are higher in lithium batteries compared to lead-acid batteries due to greater charge acceptance.
8. Max Charge/Alternator Size:
Refers to the maximum charging power that an alternator can provide. The bigger the alternator, the faster it can charge the battery. Both battery types have this specification, but lithium batteries often have a higher acceptance rate, which allows them to charge faster.
9. Reserve Capacity:
The amount of time the battery can run on its own power without the engine and still perform essential functions. This metric is important for both types of batteries, but lithium batteries generally have higher reserve capacities because of their higher energy density.
10. BMS:
Stands for 'Battery Management System'. BMS is critical in lithium batteries to manage the charging/discharging process and safeguard the battery. Lead-acid batteries don’t normally have BMS as their chemistry is more tolerant to overcharge and over-discharge.
11. Internal Even-Heat:
Refers to the distribution of heat within battery during operation. Lithium batteries often have better thermal management than lead-acid batteries.
12. Waterproof Rating:
Waterproof ratings are depicted by IP ratings — like IP67, where the first digit indicates solid particle protection and the second denotes liquid ingress protection. Lithium-ion batteries in outdoor equipment often need high IP ratings, while lead-acid car batteries do not as they are usually installed in well-protected areas.
13. Constant Current Charge:
This is the initial stage of charging where the charger delivers a constant current to the battery, causing the battery voltage to increase. During this phase, a lithium-ion battery typically takes in about 70% of the charge. Lead-acid batteries also use this charging method, however, it results in a lower percentage of total charge compared to lithium-ion batteries.
14. Constant Voltage Charge:
This stage comes after constant current charge when the battery has reached its peak voltage. The charger reduces the current, maintaining the voltage at a constant level to prevent overcharging. This phase fills up the remaining 30% of a lithium-ion battery's capacity at a slower pace. Lead-acid batteries are also charged using the constant voltage method, but at different voltage and current settings compared to lithium-ion batteries.
15. Boost Charge:
Typically associated with lead-acid batteries, it's an increased charge applied to 'boost' the battery capacity after the battery has been discharged to a certain level. It's not a typical term in the lithium-ion battery field as they have different charging specifications.
16. Charging Rate:
This term denotes the speed at which a battery is charged. It's usually expressed as C-rate (e.g., C/5 means a battery will be fully charged in 5 hours). Charging rates vary greatly between lead-acid and lithium-ion—lithium batteries tend to support higher charging rates.
17. Equalizing Charge:
Mostly relevant to lead-acid batteries, equalizing charge is an intentional overcharge causing the cells to reach an equal charge level. This preventative maintenance prevents the acid from stratifying and sulfation from forming on the plates. Lithium-ion batteries do not require equalization, as they have a better ability to balance the charge on their own.
18. Trickle Charge:
This is a method of charging a fully charged battery under a rate equal to its self-discharge rate, thereby enabling the battery to remain at its fully charged level. Trickle charging is common in lead-acid batteries, especially those kept in storage for long periods. Lithium-ion batteries do not usually require trickle charging and may be damaged by it.
Each battery type has different charging requirements and behaviors under each of these terms. The key takeaway is that an appropriate charging regimen is necessary to maintain battery health, functionality, and longevity.
