This is a true Constant Current PWM. That means that even if temperature changes, or electrolyte concentration changes, or any number of other current affecting factors change, the amperage will be maintained at a constant rate. The amperage is set using the Amps Knob on the front of the PWM. Fully clockwise is full amperage, or 40 amps. Fully counter-clockwise is 0 amps. Anywhere in between will give the proportional fraction of 40 amps.
It's best if you understand how a PWM works. You can get a good understanding by reading What Is a PWM? The conditions for making HHO must exist in order for the PWM to be able to do it's job. So after connecting your PWM, if you do not get HHO production, or if the production is too low, even with the Amps Knob set to maximum, then you'll need to debug the HHO system. Often you will find that you you just need to add more electrolyte. Or in some cases, you'll find that the cell is filled with air so electrolyte is not contacting the plates. Bad electrical connections can exist. Whatever it is, it will need to be found and handled. The PWM cannot correct these kinds of things.
The main terminal block is the large black terminal block at the rear of the PWM. It takes the high current connections to the battery and the HHO cell. See the diagram. We provide connectors for these wires so you can make the connections to the PWM. Crimp the connectors onto the wire, and use the included heat shrink so that the connectors are unable to short to the case of the PWM. We also recommend soldering the connector to the wire, prior to using the heat shrink. See the following short video which shows how to make these connections. In a pinch, you can purchase some #8 ring terminals for 10/12 gauge wire at your local auto parts store. Those can just be crimped on. But we prefer the more professional connection as shown in the video.
We use 10 gauge cable for these high current wires for nearly all installations. But if you anticipate long cable runs or higher amperages, then you should use this chart to calculate the wire gauge that is appropriate.
You can use 12 or 24 volts at the Batt+ terminal. But please realize that if you have a 24 volt system you also need to have your cell set up for 24 volts. This means 11 neutral plates. If you have a cell that was built for 12 volts (5 neutral plates), then you'll need 2 of those cells in series. The following diagrams will show various wiring schemes for different voltages
In the first image, use parallel cell wiring for 12 volt systems and series wiring for 24 volt systems. In these examples, the cells are 12 volt cells with 5 neutral plates. The next 2 images show how to wire a double stack cell. The white and green lines represent HHO+ and HHO- . 3 wires are used for a 12 volt system. Notice that there are 5 neutral plates between each of the wire connections. For a 24 volt system, the last image is used. Notice that in this case there are 11 neutral plates, because the center tabbed plate is not connected, and therefore becomes the 11th neutral. Failing to get the correct number of neutral plates for the voltage of your system can lead to failures. 12 volt systems wired for 24 volts will not get any amperage. 24 volt systems wired for 12 volts will get too much amperage, and very poor efficiency. Most of your energy will be used to make heat and steam, not HHO.
PWM Front Connections
On the front of the PWM is a green terminal block with 4 positions. This is a pluggable terminal block, in that the terminal block can be unplugged from the PWM, making it easier to make your wire connections. Then you plug the terminal block into the PWM, and secure it in place with 2 screws. You can use 24 gauge, or larger wire for these connections. Phone or computer wire is fine for this purpose. The use of each terminal is described below:
12/24 Volts In: This is what powers the PWMs control circuitry. It is very low current, about 100 milliamps. We recommend connecting this to the output of the Fuel Pump Relay of your vehicle. The Fuel Pump Relay only activates when the engine is actually running. Therefore, if your key is on, but the engine isn't running, the PWM is not powered and your system is not making HHO. This is an important safety point. But the point of this wire is that it can be used to trigger the PWM on or off. It will be up to you to be sure that the PWM is only triggered on when the engine is running and consuming the HHO that is produced.
Float Switch: This is for use with a reservoir water level indicator, or float switch. If you have a float switch, then connect one wire to this terminal, and the other wire to ground. If the switch is activated, it will cause the PWM to sound a warning beep that will let you know you need to add water to your reservoir. If you use this function, you'll also need to see the part about the float switch in the Programming Instructions below.
Amps Adjust: This is a pretty cool feature if you have a way to use it. Some users and developers would like to have automatic control of the PWM's output. The knob sets the constant current amps for the PWM. But, this port can also control the amps with a 0 to 5 volt signal. If you put 5 volts on this wire, then you'll get the full amps as determined by the position of the Amps Knob. Lower voltages will cause proportionally lower amps. For instance if the Amps Knob is set at the center (20 Amps), and you put 5 volts on this port, then you will get 20 amps output of the PWM. If you put 2.5 volts on this port, you'll get 10 amps, and if you put 0 volts on this port, you get 0 amps. If you don't connect any wire to this port, it will not be use.
12V Out (.5A): This port can be used to power such things as an EFIE or MAP Enhancer. It is fused for 500 milliamps which will handle devices of this type. It is best to power your EFIE from here as you don't want them running unless your HHO system is also running. Further, for 24 volt systems, this output is always 12 volts no matter what the input voltage is to the PWM.
To program the PWM you must first remove the bottom cover. You will see the switches and program pot exposed (see image). There are 2 modes of programming. Notice the "Run/Pgm" switch. When you first open the cover you will see that is in the "On" position. Look closely and you'll see the word "ON" written at the top of the switch. This means the PWM is in Run mode. The PWM must be in Run Mode to operate. While in Run mode, there are several things you can change about how the PWM operates:
Disable Float Switch: If you are using a float switch with your reservoir, then turn this switch off. On means that the float switch will not be monitored.
Float Switch NC: This sets the PWM for the type of float switch you have. When this switch is On, then then the PWM expects the switch to be "Normally Closed". In other words, since the other end of the float switch is connected to ground, it expects to see ground at the float switch port except when the reservoir is empty. In this case the PWM will signal an error if ground is removed from the port. Turning this switch to the "Off" position will cause that logic to be reversed, and is used with a normally open float switch.
External Amps Normal:This switch is only used in conjunction with the External Amps Adjustment port described above. "Normal" means that 0 volts at the port will cause 0 amps to be produced, while 5 volts at the port will cause full amps to be produced as determined by the Main Amps Knob. Turning this switch to the "Off" position will reverse the logic. Low volts will mean high amps and vice versa.
The above changes were made in Run Mode. We did not need to go into Program Mode to make those changes. The following changes are made in Program Mode. Before using Program Mode, you should write down your switch positions for Run Mode. In program mode we will change those switches to send information to the programmable chip. When you complete your changes in Program Mode, you will need to restore all 4 switches to their original positions.
There are 4 switches. The Run/Pgm switch and 3 others. In the picture, I have labeled them "1", "2", and "3". This is to make clearer that their Run Mode functions have no meaning in Program Mode. All 4 switches in the photo are in the "On" position. In the instructions below, if you are told to make the switch positions "On On Off", then you will put switch 1 in the "On" position, switch 2 in the "On" position and switch 3 in the "Off" position.
Each operation in Program Mode is done the same way:
- Put the "Run/Pgm" switch in the "Off" position. The LED will start blinking red. This means the PWM is in Program Mode.
- Make changes to the switches, and if necessary, the "Program Pot" as detailed below.
- Put the Run/Pgm switch back into the "On" position. You will hear 2 beeps and after a few seconds, the LED will turn green again. The 2 beeps tell you the program instruction was accepted. 1 beep means no change was made, because the switches were not in a valid configuration. This doesn't hurt anything, but you'll have to do the procedure correctly to get the changes you want.
- If you have further programming changes to make, go back to step 1. You can only make one programming change at a time.
- Very important: After you have completed all programming changes you want to do, put the switches back in their original run positions. The Run/Pgm switch of course must be in the Run position. But the other 3 switches must also be restored to their correct positions. The default position for all 4 switches is "On". However, you may have changed some of them, such as activating float switch monitoring as covered earlier in these instructions.
Program Pot: You will need a small screwdriver that can turn the pot. You will notice that the range of the pot is from about 8:00 (fully counter-clockwise) to about 4:00 (fully clockwise). 12:00, or straight up and down, is the center of the pot's travel. When using the pot, you will estimate its position based on the range you are given. For instance the instruction to set the frequency up to 500 Hz has a range from 3 to 500. Fully counter-clockwise will set 3 Hz and fully clockwise will set 500 Hz. Putting the pot straight up and down will set it for 250 Hz. Half way between 12:00 and 4:00 will set it to 375 Hz. The program pot is not used in Run Mode, so can be left in any position when you are done.
Hint: If you need to be more exact on a setting, you can measure the voltage of the top pin of the Program Pot while you are making changes. 5.0 volts is 100% clock-wise, and 0.0 volts is 100% counter-clockwise. 2.5 volts is when the pot is fully centered. You can calculate the exact voltage you need, and then turn the pot until you see that voltage. This will make for more accurate settings if high precision is needed.
Go ahead and try making some changes. If you mess things up, you can always restore the factory default settings. The supported functions are shown below:
Set Frequency up to 500 Hz: On Off Off - The Program Pot selects from 3 Hz to 500 Hz.
The factory default is 100 Hz. Fully counter-clockwise is 3 Hz. Fully clockwise = 500 Hz.
Set Frequency from 0.5 to 6.5 KHz: Off On Off - The Program Pot selects from 0.5 KHz to 6.5 KHz
Fully counter-clockwise is 500 Hz. Fully clockwise = 6.5 KHz. Take care when using higher frequencies. They can generate more heat in the PWM. Keep an eye on the heat generated by your PWM for a while when selecting frequencies in this range.
Set Ramp Up Time: On On Off - The Program Pot selects from 0 to 60 seconds.
The factory default is 10 seconds. This setting changes the "Ramp Up" time. When you first turn on power to the PWM, it will "ramp up" to it's full constant current setting. For instance, the default is 10 seconds. Lets say you have the Constant Current Knob set for 10 amps. This will mean that you will get 1 amp 1 second after power up, 2 amps after 2 seconds, and so on, until after 10 seconds, you get the full 10 amps.
Calibrate Amps Sensor: Off Off On - The Program Pot is not used.
This will run the calibration procedure. You'll hear a number of beeps of different durations. You normally don't have to do this step because we calibrate the unit at the factory.
Set Float Switch Shutdown Time: Off On On - The Program Pot selects between 0 and 40 hours.
If you are using a float switch in your electrolyte reservoir, and the float switch activates, the PWM will alert you with a beeping sound. However, it won't shut the PWM down immediately. When the float switch first goes on, there is still quite a bit of water left in the reservoir. This setting tells the PWM to shut down after the float switch error has been active for the selected number of hours. Full clockwise = 40 hours. Full counter-clockwise = 0 hours (the PWM will shutdown within one minute). The default setting is 10 hours. The PWM will keep track of your run times even when the PWM is powered off.
Increase Amps Knob Sensitivity: On Off On - The Program Pot selects between 1 and full amps.
This setting allows you to set the range of the Amps Knob to a more workable range for your needs. For instance, if you are trying to use 6-8 amps, it is very difficult to make adjustments for 1/2 amp, when the full range of pot travel is for 40 amps. Instead, you can set the maximum amps for the Amps Pot to 10 amps (for instance), so that when you turn the Amps Knob to maximum you will get 10 amps, not 40 amps. Now you can more easily make fine adjustments in the range of 6 to 8 amps. We recommend doing this modification to make it easier for you to make fine adjustments in the range of amps that you will actually use. Note, if you later need more amps, just do this procedure again and set it for the amps you now need. Turning the pot fully clockwise will restore the PWM to it's rated amperage (20 or 40 amps). Resetting to the factory defaults will do the same thing.
Reset to Factory Defaults: Off Off Off - The Program Pot is not used.