• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

:)urgent urgent urgent ; Heating element voltage

Status
Not open for further replies.

alhumaidi

New Member
Hello
I have 220v 1200watt water heating element and I want to convert it and use 12v battery about 120watts 10 amps . our heating element is different I guess from yours but the idea is connecting the 12v wires dirictely to the copper pipe , it didn't work no heat any ideas?
Another thing I added another copper pipe small one ; and connected the two wires (+)(-) in the top of the copper pipe it gets heated but also the wires get heated and burns ; so I saw some subjects about adding resistors ; what kind of resistors I can use and how can I attach them to the heating element so I can use 12v battery 120 to 150watts and what I can use for automatic switch off when it get heated enough
Waiting for your replies
 

Les Jones

Well-Known Member
Most Helpful Member
You will need a heating element with a resistance of 1.2 ohms to provide 120 watts of heating from a 12 volt power supply.

Les.
 

Les Jones

Well-Known Member
Most Helpful Member
The heating element you have will require 69.6 volts to provide 120 watts of heating. To use a 12 volt supply you need an heating element with a resistance of 1.2 ohms. Your existing heating element has a resistance of 40.33 ohms so with a 12 volt supply would provide 12 x 12 /40.33 watts = 3.57 watts. The only way you could use the existing element would be to use a step up converter to convert the 12 volts up to about 70 volts. The converter would only be about 90% efficient so you would be using about 132 watts from the 12 vollt supply to get 120 watts of heating.

Les.
 

MikeMl

Well-Known Member
Most Helpful Member
And you will have to explain to us why this is so URGENT?
 

alhumaidi

New Member
The heating element you have will require 69.6 volts to provide 120 watts of heating. To use a 12 volt supply you need an heating element with a resistance of 1.2 ohms. Your existing heating element has a resistance of 40.33 ohms so with a 12 volt supply would provide 12 x 12 /40.33 watts = 3.57 watts. The only way you could use the existing element would be to use a step up converter to convert the 12 volts up to about 70 volts. The converter would only be about 90% efficient so you would be using about 132 watts from the 12 vollt supply to get 120 watts of heating.

Les.
OK ; if I convert the 12v to 70v it will use more amps of the battery I mean if I use 100ah battery how much time until it needs to be recharged
I'm not expert in electricity so I have to ask you the Resistance that you are taking about is it some component On the heating element ? If it's ,,, where in the element cause our heating elements doesn't have much components
 

Les Jones

Well-Known Member
Most Helpful Member
The heating element IS a type of resistor. It will probably be made from a coil of resistance wire inside a stainless steel tube which is packed with an insulating powder (Probably aluminium oxide.) to insulate the element (Electrically. ) from the tube and to provide a good thermal path from the element to the tube. If we ignore the fact that the converter is not 100% efficient then the current drawn from the battery will still be 10 amps. NOTE the current trough the element will be 120/70 = 1.7 amps. The time taken to charge the battery will depend on the charging current. The maximum charging current would have to be found from the specifications of the battery.

Les.
 
Last edited:
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading
Top