juancarlos2003
Member
At the downstream side for a battery charger I have 150 A @ 24 VDC (Commercial value after load DC calculation). How I calculate the conductor size for the upstream side of the battery charger for 120 VAC
wire size for a battery charger
- Thread starter juancarlos2003
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electricman2
Senior Member
- Location
- North Carolina
- Occupation
- Retired Electrical Contractor
Re: wire size for a battery charger
The nameplate or manufacturers instructions should give the current at 120volts. 150A at 24 volts would be 30A at 120 volts not taking losses into consideration. Depending on the efficiency, you will need more than 30A. You may need a 40A circuit with #8 conductors.
The nameplate or manufacturers instructions should give the current at 120volts. 150A at 24 volts would be 30A at 120 volts not taking losses into consideration. Depending on the efficiency, you will need more than 30A. You may need a 40A circuit with #8 conductors.
juancarlos2003
Member
Re: wire size for a battery charger
THANKS A LOT JOHN
THANKS A LOT JOHN
brian john
Senior Member
- Location
- Leesburg, VA
Re: wire size for a battery charger
distance distance distance
Voltage drop is a major concern and must be figured into all electrical calculations but especially when the voltage is lower.
What is the charger/rectifier supplying, besides a battery?
What is the Low Voltage Drop out of the DC power board.
What is the float voltage?
Does the customer have a minimum acceptable VD for the installation.
distance distance distance
Voltage drop is a major concern and must be figured into all electrical calculations but especially when the voltage is lower.
What is the charger/rectifier supplying, besides a battery?
What is the Low Voltage Drop out of the DC power board.
What is the float voltage?
Does the customer have a minimum acceptable VD for the installation.
Re: wire size for a battery charger
If you are talking about what size the AC supply conductors should be, simply look at the manufactures recommend breaker and wire sizes. All I have ever designed is based on the OCPD. The AC supply is not that important since you are working with a self regulating SDS device.
The DC supply conductors is a completely different story. They are based on voltage drop from the battery terminals to the load. The industry loop voltage drop levels are:
48 VDC Plant = 2 VDC
24 VDC Plant = 1 VDC
12 VDC plant = 1/2 VDC
You have to divide the sections of the system up to end up with the maximum VD. Example on a 24 VDC plant is usually divided into three sections. Battery Terminal-to-Charge Bus, Main Power Board-to-Breaker Bay, Breaker Bay-to-Load device. Typical voltage drop for each section may look like this:
Battery Terminal-to-Charge Bus = 1/8 VDC
Main Power Board-to-Breaker Bay = 1/4 VDC
Breaker Bay-to-Load Device = 5/8 VDC
Voltage drop is calculated by:
(22.2 * L * I) / VD = CM
Where
22.2 = Constant for copper @ DC
L = Length in feet one-way distance
I = Maximum Load Current In Amps
CM = Circular Mills Of Copper Cable Needed
Once you figure the conductor sizes, cross-check with table 310-16 to make sure the conductors are at least the minimum recommended. This is not usually a problem unless very short distances are encountered.
The other important thing is connector resistance all connectors should be irreversible compression connectors two-hole tongue type, and "NO-OX" should be used on the wire skinner and between contact surfaces.
Hope that helps.
If you are talking about what size the AC supply conductors should be, simply look at the manufactures recommend breaker and wire sizes. All I have ever designed is based on the OCPD. The AC supply is not that important since you are working with a self regulating SDS device.
The DC supply conductors is a completely different story. They are based on voltage drop from the battery terminals to the load. The industry loop voltage drop levels are:
48 VDC Plant = 2 VDC
24 VDC Plant = 1 VDC
12 VDC plant = 1/2 VDC
You have to divide the sections of the system up to end up with the maximum VD. Example on a 24 VDC plant is usually divided into three sections. Battery Terminal-to-Charge Bus, Main Power Board-to-Breaker Bay, Breaker Bay-to-Load device. Typical voltage drop for each section may look like this:
Battery Terminal-to-Charge Bus = 1/8 VDC
Main Power Board-to-Breaker Bay = 1/4 VDC
Breaker Bay-to-Load Device = 5/8 VDC
Voltage drop is calculated by:
(22.2 * L * I) / VD = CM
Where
22.2 = Constant for copper @ DC
L = Length in feet one-way distance
I = Maximum Load Current In Amps
CM = Circular Mills Of Copper Cable Needed
Once you figure the conductor sizes, cross-check with table 310-16 to make sure the conductors are at least the minimum recommended. This is not usually a problem unless very short distances are encountered.
The other important thing is connector resistance all connectors should be irreversible compression connectors two-hole tongue type, and "NO-OX" should be used on the wire skinner and between contact surfaces.
Hope that helps.
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