Terminology
The average Voltage a battery will hold throughout one cycle, measured in Volts (Vdc)
- Nominal Voltage along with Rated Capacity are the two main characteristics that will define your battery system’s operating limits by defining the overall power (Watts) your system holds.
- Nominal Voltage of a system can be increased by adding batteries in series.
The total amount of power a battery is capable of providing in one full discharge cycle, measured in Ampere hours or Amps per hour (Ah)
- Rated Capacity along with Nominal Voltage are the two main characteristics that will define your battery system’s operating limits by defining the overall power (Watts) your system holds.
- Rated Capacity of a system can be increased by adding batteries in parallel.
The process of discharging a battery and subsequently charging it back up, returning the Energy consumed. It is commonly accepted that one cycle is complete when %50 of the battery Energy is expended then returned to the battery.
- The depth of discharge (DOD) to which you cycle your batteries directly relates to the overall lifespan (Cycle Life)of the battery. Typically less depth of discharge per cycle equates to a longer battery lifespan.
This is a measure of the usable Energy remaining in the battery. The percentage of available battery charge, relative to its Rated Capacity.
SOC = Remaining Capacity/ Rated Capacity
Q. You have a 100Ah rated capacity battery and have used 20Ah total to power a pump. What is the battery’s SOC?
A. 100Ah – 20Ah = 80Ah remaining
SOC = 80Ah/ 100Ah = 0.80 or 80%
80% capacity
- Battery SOC can be roughly monitored with a Volt meter or more accurately with Shunt meter circuit.
This describes the amount of Current (A) being drawn from the battery as a percentage of total Rated Capacity. C rate (C) is helpful to determine the proper charge and discharge rates for LFP batteries.
0.2C states that Current (A) is being drawn at a rate of 20% per hour relative the total battery capacity. For a 100Ah rated battery, 0.2C equates to a 20A discharge rate per hour.
Q. A 200Ah rated battery is discharging at 100A. What is the C rate (C)?
A. C = 100A/ 200Ah = 0.5/h
50% C or 0.5C
The amount of charge and discharge cycles a battery can perform while retaining at least 80% of it's initial rated capacity. One method of maximizing cycle life for your battery is by limiting DOD per Cycle.
- A few other factors must be considered in order to help prolong cycle life ; maintaining safe SOC during storage and use, limiting C Rate while charging and discharging, BMS Protections, Cell Balancing, usage and storage in the proper Temperature range, proper usage and storage environment.
The percentage a battery is discharged in relation to it's fully charged state. If 70Ah have been consumed from a 100Ah battery, %70 of the Energy has been drained - %70 depth of discharge (DOD). This also means the state of charge (SOC) is 30%.
- Limiting DOD from 50% - 80% in general will help preserve battery Cycle Life.
An electronic system designed to manage the individual cells and battery pack as a whole. All of our battery management system's are mounted internally in our batteries, control Cell Balancing and serve protection functions for safety and performance of the pack. SOC calculation, secondary data communication, protections, environment control and monitoring are other functions they serve.
An electronic device that changes Direct Current (DC) to Alternating Current (AC).
- In a solar grid system, solar panels produce DC power to charge batteries. In order to power any devices that require AC power (any household appliances - common 120Vac wall outlets) an inverter must be used to change the DC power into AC power.
An electronic device that produces Direct Current (DC) from either an Alternating Current (AC) source or another Direct Current (DC) source at a different Voltage.
AC-DC Converter
Example: A standard 120Vac input is converted to a 12Vdc output. This can also be called a converter charger if the output is suitable for battery charging.
DC-DC Converter
Example: A 24Vdc input is converted to a 12Vdc output. This can also be called a converter charger if the output is suitable for battery charging.
To properly charge LFP batteries from an Alternator, a DC-DC converter charger can be used. This is a 12Vdc - 12Vdc converter charger that outputs the proper charge profile.
This device acts as a regulator between the solar panel and the battery. It ensures that the battery is charged properly when the sun is up, and that the battery does not discharge through the solar panel when the sun is down.
- Typically, in many off grid solar setups, a solar charger is used alongside solar panels, an inverter and a battery bank to store all the produced energy. Talk to us about our complete off-grid solar packages!
Here's an example of a solar controller working in a simple solar charging setup:
A device that pulls and measures a fraction of the current running through a circuit, in order to allow you to measure amps, amp hours and total power of your system.
- We at Lynac, utilize shunts in order to run monitoring systems, like LCD screens as well as Bluetooth Monitoring. This allows us and customers to view the SOC of batteries.
Equalizer’s should be used when connecting multiple batteries in one system. The function of an equalizer is to ensure all batteries in one system are maintained at the same voltage. This is needed as one or more batteries may be discharging at a slightly faster rate than the others.
Not using an Equalizer will lead to battery systems cutting out before it’s full DOD once a single battery is discharged fully, while the other batteries may still have usable power.
Same thing goes for charging. One battery might reach full charge before the others, triggering a stop to the battery charger, while the other batteries are still not at SOC.
These problems can all be avoided by simply using an Equalizer in your setup.
Here's an example:
