From our long experience of providing industrial battery charger solutions to our customers and partners, we have seen that there are some basic questions that are always asked. One of the basic questions we are always asked by our valuable customers is “what are the formulas needed to do the battery charger sizing calculations?” Here we are sharing the basic formulas for your convenience. .
CHARGER SIZING FORMULAS:
1. Calculating charger requirements
A = 1.1C / H + L
2. Calculating hours to recharge
H = 1.1C / A - L
3. Calculating charger losses (BTUs)
BTUs PER HOUR = ((1 / EFF) – 1) x Wdc X 3.42
4. Calculating charger input current drain:
Single-Phase chargers
IIN = EOUT x IOUT / EIN x EFF x P.F.
Three-Phase chargers
IIN = EOUT x IOUT / EIN x EFF x P.F. x √3
Here,
A = DC output rating of charger in amperes
1.1 = Efficiency factor to return 100% ampere-hours removed from a lead-acid battery. Use 1.4 for NiCad batteries.
C = Calculated number of ampere-hours discharged from battery. (Time in hours x load)
H = Number of hours recharge time
L = Load on system in amperes
Wdc = Output volts x output amperes
IIN = Input current (amperes ac)
EOUT = Output voltage (volts dc)
IOUT = Output current (amperes dc)
EIN = Input voltage (volts ac)
EFF = Efficiency (e.g. 88% = 0.88)
P.F. = Power Factor (E.G. 92% = 0.92)
√3 = 1.7321
Conclusion: