100amp current regulator

[Disco]

Hi people,

I was hoping someone could help me,

I need to somehow regulate an electrode to only drawing 100amps from a 12v battery power source. It is currently drawing about 300amps which is too much.

Hopefully someone out there can help?

Thanks

 

[Someone Electro]

Put some long wire in to add some resistance?

 

[Disco]

it will still draw 300amps at the moment I am using 55mm2 wire anything else melts. I think I need to use a circuit driving some mosfets to only allow 100amps to be drawn by the electrode?

 

[Nigel Goodwin]

it will still draw 300amps at the moment I am using 55mm2 wire anything else melts. I think I need to use a circuit driving some mosfets to only allow 100amps to be drawn by the electrode?

Even doing that, the excess power is dissipated in the MOSFET's as heat, unless you use PWM to control it - where the heat will be much less, but it will be far more complicated to do.

The obvious solution is to use a different battery!. Lead acid batteries are made of 2V cells, and you can buy them as single cells - 12V uses six cells, using only two will probably drop your current to about 100A.

I would expect anything designed for such high currents to be made of single cells anyway? - you need pretty substantial batteries for those currents!.

 

[Disco]

sorry for my lack of knowledge but what is PWM???

and how complicated would it be?

 

[Nigel Goodwin]

sorry for my lack of knowledge but what is PWM???

and how complicated would it be?

PWM is 'Pulse Width Modulation' - for your purposes you would switch the power ON for 1/3rd of the time, and OFF for 2/3rd's. This gives an average of 100A.

You do this fast enough so it seems continuous, as you're switching 300A it's not particularly simple!.

The simplest method is a current limiting resistor, which needs to be a low resitance and VERY high wattage - as suggested a LONG wire would be a simple method! - keep it all in clear air to help heat dissipation!.

 

[Someone Electro]

Meaby if you coil the wire and have an fan on one side to push air trough to keap it cool.

 

[Russlk]

If you take apart an electric heater rated at 10 amps, 120 volts and cut the resistance element into 10 pieces, the parallel resistance will be rated 12 volts,100 amps.

 

[chemelec]

Hi people,

I was hoping someone could help me,

I need to somehow regulate an electrode to only drawing 100amps from a 12v battery power source. It is currently drawing about 300amps which is too much.

Hopefully someone out there can help?

Thanks

I Doubt it really matters because at 100 Amps you will sill fry your battery.

This Sounds like another Hydrogen Electrolysis Generator for running a Car?

 

[Oznog]

What are you trying to do? This question cannot be adequately answered without knowing this. For one, the problem might be better addressed by making changes to the power source itself or the load.