I am in the process of building a replica of the BB smack dry cell. I need a PWM for this cell and I would like to get a good deal. If anyone could lead me to a website or someone that sells these for a low cost, please let me know. I think i need a 30a but people tell me that the solder will melt if you run it close to 30amps. Any advice is helpful. Thank you
There is a PWM unit on ebay for at the time of this writing at $.99 cents.
This unit uses a modified Zero's PWM portion that maintains constant current, and has an additional voltage sensor that turns the unit on when the engine is running. Very cool feature.
Search for "PCU PWM" to find it.
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Check Shanes thread in the for sale section, he is building exact models of ZFF's current sensing PWM for a very reasonable price.
Has anyone used the PWM from Hydrogen Garage?
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I have never used that PWM but at the price with you having to install all those components I would recommend against unless you just like that kind of work. If it is an inexpensive PWM you are looking for try Google and look up MX066. You can find and buy a completed 30 amp PWM for under $30.00. Also check out Shane Jackson in this forum. He is offering a great quality product at a very good price.Originally Posted by Steamo
Well actually I bought it quite a while ago and have already assembled it. I was just curious if anyone else had tested it because I have not gotten a chance to. It seems pretty nice thought and it is quite compact.
Most of the inexpensive PWM's don't offer constant current. With a constant current PWM, as the cell heats up it adjusts the duty cycle to limit the cell and keep it from going into runaway mode. Of course if you have an amp meter in the car and your cheap PWM you can adjust it from time to time while you are driving. But hope your wife knows what to do when she has the car.
A better solution is to use a constant current PWM like ZeroFossileFuels, and I believe Shane's unit is also based on this, and of course so is mine. Zero sells his for around 200 bucks on his website and there are others on ebay for around 150, but I've been selling mine for the price of $50 - 60 bucks (sometimes less than those other cheap PWM's but mine has more features than all of them).
I have a current sensing switch that will shut the cell down if the voltage drops. This is a good feature because if your cell is drawing too much power it will protect the Alternator. All you have to do is fry your alternator once to realize how important this feature is.
So check mine out, they are up on ebay just search for "PCU PWM"
My modified design doesn't need the large capacitor. The circuit is also designed to give better drive for the MOSFET.
Has anyone purchased a PWM from Arizonavideo on eBay?
I'm not sure his PMW's are constant current, but he has very good feedback and decent prices. Does anyone have any experience with his products?
I've seen ArizonaVideo's PWM's on ebay. They are motor controllers similar to the MX066. Although you can use a motor controller PWM to control your HHO cell, we don't recommend it. Your cell can still go into thermal runaway with those PWM's because they don't adjust the current draw as your cell heats up.
For a few dollars more you can get a constant current PWM, and the little extra you pay will save you a lot of hassle.
I build the PCU-2 PWM you can find on e-bay and the way our PWM keeps the current constant is there is a wire that runs from the box to the heat sink. This wire acts as a shunt. The current is measured by the processor and adjusts the duty cycle automatically. So as your cell starts to heat up, it will try to draw more current. When the processor senses this change it rolls back the duty cycle to keep the current the same. This will also keep the cell from overheating.
http://motors.shop.ebay.com/merchant/billabuckhi?_rdc=1
You can turn the current knob to adjust the production just like a dimmer switch. However, what you set it at, will stay that way, and its way cool.
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