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Background
I spent some time converting John Bedini’s Battery Switching (BBS) concept from toggle switches or relays to a fully MOSFET controlled circuit. I found the key lies in the use of diodes. MOSFETs only have 3 legs; Gate (control), Source (input), and Drain (output). When the Gate is > Source (N-MOSFET) the Source is connected to the Drain like a relay.
The BBS places 3 energy storage devices (batteries, capacitors, etc) in a rotation. In one rotation, C1 may have its positive tied to Output Positive (“P”) and its negative tied to C2 Positive (“X”). Later, C1 Negative may be tied to Low (“G”) with its Positive tied to Output Negative (“N”). The complication arises in putting both the Positive of each capacitor in one of 3 places and the Negative in one of 2 places, while connecting the Positive of one to the Negative of another. At any given time, the Negative of one capacitor may be at or above the Positive potential of another cap/battery. Back-feed and cross-feed makes the straight-forward use of MOSFETs impossible.
To begin, it becomes necessary to map out all possible combinations for both the Positive and Negative connections for each battery/capacitor. Referencing the attached image below, we can call the positive of Batt 1 “P”. The negative of Batt 2 and Batt 3 are “G”. The positive of Batt 3 is “N”. Where 2 batteries are connected in series, we’ll call “x”.
Since we’re rotating positions of each battery (capacitor), positions “P”, “N”, and “G” will need a MOSFET connection to each of the batteries/caps. In addition, we will need a MOSFET to tie batteries together at position “x”. In reality, position “G” is a negative voltage in reference to output (or even input).
Connecting the negative side of any of the 3 batteries to “G” requires an N-channel MOSFET. N-MOSFETs are anchored to “ground” through the Source & Drain pins. Whenever the Gate is >0.6 volts (dependent on individual part numbers) of Source, the Drain is connected to Source. In other words, put a positive voltage on Gate, then Source & Drain are shorted together like a relay. That one is rather easy.
P-channel MOSFETs connect the output to a “positive” source. By lowering the Gate voltage >0.6 volts below the Source potential, the Source & Drain are shorted together. Every connection outside of connecting the Negative side of the batteries to “G” is accomplished with P-MOSFETs!
Connecting the Positive of one of the batteries to “P” is easy with a P-MOSFET. Connecting the Positive of one of the batteries to “N” is easy with a P-MOSFET. The challenge arises when trying to connect the Negative of Battery 1 to the Positive of Battery 2 using either a P-MOSFET or N-MOSFET. The Gates of unused MOSFETs suddenly start to connect things we didn’t anticipate, or want! That concept is integral to the functionality of the whole Bedini circuit and can’t be skipped over.
Diodes are like electrical “check valves”. Try to push voltage through them in one direction and they act almost like a dead short. However, reverse the polarity and they act like an open circuit. That electrical principal allows us to make connections between the Negative of one battery to the Positive of another, without triggering unwanted connections elsewhere in the circuit.
The Circuit
Referencing the attached schematic, C1 is equivalent to Battery 1, C2 = Battery 2, C3 = Battery 3. Additional components include C4, which is nothing more than a buffer that maintains the power supply during switching; U1 is a 5-volt regulator for a microprocessor; D15 allows an external energy to top off the battery/capacitor system as energy is consumed. D16 allows for an initial charge to the system sufficient to power up a microprocessor.
The schematic shows a couple of rails; “Rail+” is tied to the Positive side of the load (“P” in the first drawing). “Rail-“ is tied to the Negative side of the load (“N” in the first drawing). “Sys Gnd” is the negative voltage potential, representing the lowest voltage potential in the system (“G” in the first drawing). Sys Gnd = “G”, Vplus = “P”, and “Vgnd” = “N”.
If you are using a 1.5 volt battery(s) as your energy source with a 5-volt microprocessor, then you can trigger P-MOSFETs directly with your processor. Otherwise, you will need an N-MOSFET to trigger your P-MOSFET’s (not shown in the schematic). Q23, Q24, and Q25 are N-MOSFETs that can be triggered directly by virtually any means (including directly from a microprocessor). The P-MOSFETs will most likely require an N-MOSFET or NPN transistor to trigger them.
Below is a Truth Table for what is active (=1) or disabled (=0) for each of 3 rotations:
Rot1 Rot2 Rot3
C1P 1 0 0
C2P 0 0 1
C3P 0 1 0
C1N 0 0 1
C2N 0 1 0
C3N 1 0 0
C1G 0 1 1
C2G 1 1 0
C3G 1 0 1
C12 1 0 0
C23 0 0 1
C31 0 1 0
In the first drawing we have Batts 1_2_3. For the sake of illustration, let’s call the positions held by those batteries Positions 1_2_3. Rot1 would place C1 in Position 1, C2 in Position 2, and C3 in Position 3. Rot2 drops C1 to Position 2, C2 to Position 3, and C3 to Position 1. Put another way, the Batteries/Capacitors are rotating in a counter-clockwise direction based on the first drawing. This is important if you want to use a 9 volt battery (or 12 volt, or wallwart of whatever voltage) to keep the system charged. D15 allows for that function.
Circuit Description
The Bedini Battery Switching principle calls for a rotation of batteries, capacitors, or whatever power storage device, to occupy a position for a period of time, then rotate to a different position. This rotation process allows electrons to be cycled through a load numerous times, thus applying an unpublished nuance of the Laws of Conservation of Energy. Since most of you reading this are already familiar with the Bedini concept, I’ll skip the elementary basics.
The Truth Table shows what to connect (1) or disconnect (0) to create a connected circuit that resembles image1 in a functional manner; and to be able to rotate batteries or capacitors to other positions within the image1 framework. I used a PIC processor to develop this principle. You may use PICAXE, Audrino, or some other logic controlling type device.
The critical component is the diodes placed between the capacitor (battery) and MOSFET connections for “x”, which then requires diodes between the Rails and MOSFETs. Reversing diodes won’t work. Placing diodes on the wrong side of MOSFETs won’t work. HOWEVER, what you use for diodes and MOSFETs should be tailored to your application. For diodes, if you have a portable device powered by a 9 volt battery, 1N4001 will probably be all you need. If you have a moderate amp rating, you may need 1N5408. If you are pushing 20+ amps, you may need a bunch of MSCS3460’s. For low amps, N-MOSFETS can be 2N7000’s and P-MOSFETs TP2401’s. Moderate loads; N-MOSFETs = BUZ11, P-MOSFETs = IRF5305…and so forth.
I spent some time converting John Bedini’s Battery Switching (BBS) concept from toggle switches or relays to a fully MOSFET controlled circuit. I found the key lies in the use of diodes. MOSFETs only have 3 legs; Gate (control), Source (input), and Drain (output). When the Gate is > Source (N-MOSFET) the Source is connected to the Drain like a relay.
The BBS places 3 energy storage devices (batteries, capacitors, etc) in a rotation. In one rotation, C1 may have its positive tied to Output Positive (“P”) and its negative tied to C2 Positive (“X”). Later, C1 Negative may be tied to Low (“G”) with its Positive tied to Output Negative (“N”). The complication arises in putting both the Positive of each capacitor in one of 3 places and the Negative in one of 2 places, while connecting the Positive of one to the Negative of another. At any given time, the Negative of one capacitor may be at or above the Positive potential of another cap/battery. Back-feed and cross-feed makes the straight-forward use of MOSFETs impossible.
To begin, it becomes necessary to map out all possible combinations for both the Positive and Negative connections for each battery/capacitor. Referencing the attached image below, we can call the positive of Batt 1 “P”. The negative of Batt 2 and Batt 3 are “G”. The positive of Batt 3 is “N”. Where 2 batteries are connected in series, we’ll call “x”.
Since we’re rotating positions of each battery (capacitor), positions “P”, “N”, and “G” will need a MOSFET connection to each of the batteries/caps. In addition, we will need a MOSFET to tie batteries together at position “x”. In reality, position “G” is a negative voltage in reference to output (or even input).
Connecting the negative side of any of the 3 batteries to “G” requires an N-channel MOSFET. N-MOSFETs are anchored to “ground” through the Source & Drain pins. Whenever the Gate is >0.6 volts (dependent on individual part numbers) of Source, the Drain is connected to Source. In other words, put a positive voltage on Gate, then Source & Drain are shorted together like a relay. That one is rather easy.
P-channel MOSFETs connect the output to a “positive” source. By lowering the Gate voltage >0.6 volts below the Source potential, the Source & Drain are shorted together. Every connection outside of connecting the Negative side of the batteries to “G” is accomplished with P-MOSFETs!
Connecting the Positive of one of the batteries to “P” is easy with a P-MOSFET. Connecting the Positive of one of the batteries to “N” is easy with a P-MOSFET. The challenge arises when trying to connect the Negative of Battery 1 to the Positive of Battery 2 using either a P-MOSFET or N-MOSFET. The Gates of unused MOSFETs suddenly start to connect things we didn’t anticipate, or want! That concept is integral to the functionality of the whole Bedini circuit and can’t be skipped over.
Diodes are like electrical “check valves”. Try to push voltage through them in one direction and they act almost like a dead short. However, reverse the polarity and they act like an open circuit. That electrical principal allows us to make connections between the Negative of one battery to the Positive of another, without triggering unwanted connections elsewhere in the circuit.
The Circuit
Referencing the attached schematic, C1 is equivalent to Battery 1, C2 = Battery 2, C3 = Battery 3. Additional components include C4, which is nothing more than a buffer that maintains the power supply during switching; U1 is a 5-volt regulator for a microprocessor; D15 allows an external energy to top off the battery/capacitor system as energy is consumed. D16 allows for an initial charge to the system sufficient to power up a microprocessor.
The schematic shows a couple of rails; “Rail+” is tied to the Positive side of the load (“P” in the first drawing). “Rail-“ is tied to the Negative side of the load (“N” in the first drawing). “Sys Gnd” is the negative voltage potential, representing the lowest voltage potential in the system (“G” in the first drawing). Sys Gnd = “G”, Vplus = “P”, and “Vgnd” = “N”.
If you are using a 1.5 volt battery(s) as your energy source with a 5-volt microprocessor, then you can trigger P-MOSFETs directly with your processor. Otherwise, you will need an N-MOSFET to trigger your P-MOSFET’s (not shown in the schematic). Q23, Q24, and Q25 are N-MOSFETs that can be triggered directly by virtually any means (including directly from a microprocessor). The P-MOSFETs will most likely require an N-MOSFET or NPN transistor to trigger them.
Below is a Truth Table for what is active (=1) or disabled (=0) for each of 3 rotations:
Rot1 Rot2 Rot3
C1P 1 0 0
C2P 0 0 1
C3P 0 1 0
C1N 0 0 1
C2N 0 1 0
C3N 1 0 0
C1G 0 1 1
C2G 1 1 0
C3G 1 0 1
C12 1 0 0
C23 0 0 1
C31 0 1 0
In the first drawing we have Batts 1_2_3. For the sake of illustration, let’s call the positions held by those batteries Positions 1_2_3. Rot1 would place C1 in Position 1, C2 in Position 2, and C3 in Position 3. Rot2 drops C1 to Position 2, C2 to Position 3, and C3 to Position 1. Put another way, the Batteries/Capacitors are rotating in a counter-clockwise direction based on the first drawing. This is important if you want to use a 9 volt battery (or 12 volt, or wallwart of whatever voltage) to keep the system charged. D15 allows for that function.
Circuit Description
The Bedini Battery Switching principle calls for a rotation of batteries, capacitors, or whatever power storage device, to occupy a position for a period of time, then rotate to a different position. This rotation process allows electrons to be cycled through a load numerous times, thus applying an unpublished nuance of the Laws of Conservation of Energy. Since most of you reading this are already familiar with the Bedini concept, I’ll skip the elementary basics.
The Truth Table shows what to connect (1) or disconnect (0) to create a connected circuit that resembles image1 in a functional manner; and to be able to rotate batteries or capacitors to other positions within the image1 framework. I used a PIC processor to develop this principle. You may use PICAXE, Audrino, or some other logic controlling type device.
The critical component is the diodes placed between the capacitor (battery) and MOSFET connections for “x”, which then requires diodes between the Rails and MOSFETs. Reversing diodes won’t work. Placing diodes on the wrong side of MOSFETs won’t work. HOWEVER, what you use for diodes and MOSFETs should be tailored to your application. For diodes, if you have a portable device powered by a 9 volt battery, 1N4001 will probably be all you need. If you have a moderate amp rating, you may need 1N5408. If you are pushing 20+ amps, you may need a bunch of MSCS3460’s. For low amps, N-MOSFETS can be 2N7000’s and P-MOSFETs TP2401’s. Moderate loads; N-MOSFETs = BUZ11, P-MOSFETs = IRF5305…and so forth.
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