chassis resistor build

Thread Starter

96y

Joined May 8, 2019
38
I want to make a 200 watt 1/2 ohm resistor in a housing. I guess 2- 1 ohm in parallel is the way to go. I want to make it
very inexpensive.In some kind of heat sink and rugged. What would you use ??Similar to those gold colored Uxcell chassis units but less expensive. thanks
 

Thread Starter

96y

Joined May 8, 2019
38
too big....I thought 2 cement 200 watt 1 ohm next to each other, I thought I saw those available...
maybe I was wrong?? Is their a cheap IC that could do this?
 

dendad

Joined Feb 20, 2016
4,637
How accurate and stable do you need?
A lot depends on your application. Is it a load or a measuring resistor?
Whatever you do, the heat sinking to get rid of the heat will have to be taken into concideration. An element made from stainless steel or fencing wire could work, with a cooling fan.
 

jpanhalt

Joined Jan 18, 2008
11,087
too big....I thought 2 cement 200 watt 1 ohm next to each other, I thought I saw those available...
maybe I was wrong?? Is their a cheap IC that could do this?
I think you are headed in the right direction. A 200W resistor dissipating 200W gets pretty hot. Since the current divides equally between the 2x200W resistors, each will dissipate only half the total heat or 100W each.

Does it have to be accurate? I have used spiral wound heating elements for high power. Also, as posted, high-power resistors can be quite expensive new. In Cleveland, we have a surplus/used dealer. Many cities have them. Things can be cheaper there and negotiable.
 

Thread Starter

96y

Joined May 8, 2019
38
this is for a super capacitor starting module, starting an engine....the resistor needs to go between the battery and the caps
(5,3v caps in series 400 farad caps) It will throttle down the draw on the battery. But I guess even 1 ohm is too big. Has to be no more than .5 ohm. But I am open to any way of doing it..even somewhat primitive ways as long as it works. Some builders dont even use a resistor but it seems like a good idea..
 

Thread Starter

96y

Joined May 8, 2019
38
If you HAD to put a resistor in this thing ,what is the minimum watts you would go with at 1/2 ohm?
or would 1 ohm really be too big??I saw some 100 watt 1/2 ohms for about 15$ I think..
remember the caps discharge about 14v,400 farad caps 5 in series and the battery would be a small
AGM ATV battery like Odysey would make.. I am just trying to get a general idea...
 
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