DIY Voltage Stabilizer

g4i8y0t

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g4i8y0t

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Hi guys. I would like to share my experience building a voltage stabilizer for my old Civic. The purpose of this device, as with all automotive voltage stabilizers, is to reduce electrical noise and distortions within the vehicle. Electrical noise comes from distributor, alternator, automatic transmission solenoids, certain relays etc.

Okay, back to the main story. First, after figuring out the space available under the bonnet and taking the measurements, I design the circuit using a circuit design software. The only suitable place I can find is between the battery and intake manifold. I want to have around 100,000uF of total capacitance. After researching on the internet, I found out that in order for the voltage stabilizer to 'absorb' or dampen many types of electrical noises within the car, it is also important to reduce the ESR (equivalent series resistance) so that the currents from the electrical noise can easily flow in and out of the device. So in this case, instead of using some big capacitors like the 50,000uF monsters, I use many smaller ones.



3D view of the design:



It turns out I can only fit 14 units of 4700uF 35V caps and 11 units of 2200uF 35V caps within the space available. The total capacitance is 90,000uF, pretty close to my target. Next, I use a rapid prototyping CnC machine to fabricate the printed circuit board (PCB). Modern tech certainly made life easier. No more messing around with the nasty ferric chloride PCB etching solution. :thefinger:





The completed bare board:



After the caps are soldered:



I put a 20 amp fuse for protection:



Hot glue is applied between the caps to make them more rigid. Engine vibrations can make solder joints crack.



The main copper tracks are soldered with extra layer of lead to lower the resistance and improve current carrying capacity:



I made up the casing using some wood planks. Hopefully the low heat conductivity of wood will increase the life of the capacitors. Living under the bonnet sure will suck the life out of them. :rolleyes:



I drill some holes for the PCB stand and put some industrial resin there to support it.



After the + and - wires are soldered, the board is put into the wooden box.



After the connectors are put to the wire ends, I use some heat shrink tube to secure them. The device is now completed. :love:



I secure it to the battery using cable ties. The box is actually supported by the battery holder.



I haven't got time to test this device yet. I'll let you guys know the results later. :listen:
 
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g4i8y0t

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g4i8y0t

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Ok, here's the review. While driving to work this morning, I noticed the pick-up and lower end response have improve a bit. Usually when I put in the reverse gear, I need to depress the throttle or the engine would stall. Small Honda engines in general are not known for their low end torque. :sleep: After installing this device, I still need to give a bit of throttle but not as much as before. Can't comment on top end response yet as the drive was quite short.
 

g4i8y0t

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g4i8y0t

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Nice. How are the lights and especially your ICE?
I didn't notice any changes to light brightness. My audio unit is currently under repair, so can't comment on that yet. :tongue: One thing that I notice is when the aircond compressor kicks in, the jerking is less noticeable. Much less. Overall, I'm quite satisfied with the result. I spent only about RM1++ in buying parts. If any of you want to try building this on your own, send me your email and I will send the parts needed and circuit schematics.
 

vr2turbo

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vr2turbo

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I bought a pivot unit long time ago. Lights like you say not noticeable but my ICE did sound better. The high was clearer and bass was more solid.....:driver:
 

g4i8y0t

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g4i8y0t

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I bought a pivot unit long time ago. Lights like you say not noticeable but my ICE did sound better. The high was clearer and bass was more solid.....:driver:
I also bought that Pivot VS some time ago, installed it in my previous car. The blue unit with blue LED isn't it? That one only has about 4 caps inside, forgot the capacitance. Bought it for RM150. After installing that damn thing, I couldn't notice any improvement, what a waste. :mad:
 

vr2turbo

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vr2turbo

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I also bought that Pivot VS some time ago, installed it in my previous car. The blue unit with blue LED isn't it? That one only has about 4 caps inside, forgot the capacitance. Bought it for RM150. After installing that damn thing, I couldn't notice any improvement, what a waste. :mad:
Yup, the blue one that is attached to battery one......lol:biggrin:
 

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what a great project and one that is well documented. great work there g4i8y0t, you may want to make more to sell
 

g4i8y0t

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g4i8y0t

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what a great project and one that is well documented. great work there g4i8y0t, you may want to make more to sell
Thanks Tom. I have thought about selling this VS, but I'm too busy with work at the moment, no time to do many sets. By the way, I'm still testing its durability. So far no problems.
 

g4i8y0t

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g4i8y0t

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My concern now is the caps that I use are only rated to 85 degree C. The 105 degree ones are very hard to find. I worry that they may not last very long as the air temperature under the hood can reach 60-65 degree C on a hot day, in stop and go traffic :confused:. The 85 degree C rating is the absolute temperature limit, it doesn't mean that the caps can withstand that temperature for extended time.
 
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Hello fellow petrol heads.

I too have developed my own voltage stabilizer (VS) but I've been quiet about it because of how the public reacts to these devices. No it is not a miracle device that will solve all your electrical stability problems, however it does help.

I built one of these devices because my friend basically threw his broken VS at me and told me to fix it. So I took it apart, analyzed it and figured I could make it better. Having solved his device, I then began designing my own. It is hard to emulate this device with software as a 12V car battery undergoes charging upon acceleration of the throttle (it supplies current and recharges). After going through many analogue builds and testing, I came up with my own device.

Here are some specifications of the device and the capacitors (Japan made) that I use:
- Total capacitance: 18000uF ± 20%
- Operating max temperature: 105°C
- Operating min temperature: -55°C
- ESR per capacitor: 0.104Ω
- Voltage rating of capacitor: 16V
- Current consumption: 7 - 8mA

Now let me begin to explain my device:
Let us begin with a YES; it is only 18000uF but its basically all you need. 16V as a voltage rating for capacitors is all you need as the battery will never reach this value. At a max operating temperature of 105°C, the capacitors will last longer in a car's engine bay as operating conditions can get hot. ESR stands for equivalent series resistance; typically the lower the resistance the better the flow of charge.

Let me explain and show my data behind it (I will try to make it as simple as I can to be understood):

Read this to make sense of the data:
The y-axis is the voltage of the battery and the x-axis is the time. The battery's 12V is attenuated to 1/4 (0.25) of its value to be measured. Example: 3.8 on the y-axis is 15.2V.
The time is sampled with a resolution of 500ms (half a second). Example: 120 on the time scale is 60 seconds in reality.

Test conditions:
The first 120 on x-axis (60 seconds) the car's engine is kept at acceleration or left to idle. From 120 to 360 on x-axis (the next 120 seconds) the car's engine is kept at acceleration or left to idle, the air con is on full, the lights are on full, and the radio is blasting music. This is the excitation period.

Here are two images of the 12V battery under acceleration and stationary conditions without device and grounding cables:

Figure 1 - Acceleration condition where the engine is kept at 2.5k rpm.

Under acceleration conditions, the oscillations are 200mV or less which is fine. You'll notice a dip between 248 and 251 on the x-axis. This is when the air con fan turns on.


Figure 2 - Stationary condition where the engine is kept at idle, typically around 0.9k rpm for stock cars.

Upon the excitation period, you'll notice huge jumps of the curve. These oscillations are 1.59V and are bad for power supply applications.

After plugging in my device and grounding cables:

Figure 3 - Acceleration condition with device and grounding cables where the engine is kept at 2.5k rpm.

As you can see, the curve with and without the device and grounding cables are pretty much the same. Even recovery from the fan excitation is the same. This is good.


Figure 4 - Stationary condition with device and grounding cables where the engine is kept at idle, typically around 0.9k rpm for stock cars.

Now you notice the oscillations before the device and grounding cables have been smoothened in this data set. This is because the device is doing its job by absorbing and releasing charge evenly to obtain a good power supply.

Overall explanation:
As you can see from the before and after, my device and grounding cables does smoothen the power supply. Now to debug some notions the public has regarding these products.

1) Having a higher capacitance doesn't make your device better. Yes the device stores plenty of charge and smoothens the system. However under acceleration, the induction coil is the highest current consumer. As the engine revs higher and higher the demand of charge by the induction coil increases till red line. Hence its a varying load. Now the VS is a load in the system as it stores charge. This is basic electrical engineering. Now what you must consider is the time response of the device. With high capacitor values used and a large capacitance, the response time of the VS becomes the bottle neck of the system under high rpms.

V(t) = Q(t)/C, where V(t) is voltage with relation to time, Q(t) is charge with relation to time and C is capacitance formula.

This formula explains what I'm referring to because it takes a capacitor time to charge, the higher the capacitor value and total capacitance value, the longer it takes to charge. Dispersing the charge is not in question, only charge time; and you can easily find the curve for this if you google "charge time of capacitor". So for low rpm revving situations, a device with high capacitance will suit you well; however at high rpm levels, you will notice your engine begins to slow its revving capability.

To put it simple, at low rpm you will notice slight improvement in torque and speed. However at high rpm, you will notice your car is slower than without the device and grounding cables. My device, helps the bottom end of the rpm without having to affect the top end of the rpm response. This is why I don't use high capacitance or large capacitor values.

2) Devices sold in the market do work. However they don't tell you how to make the most of it. As known in basic electronics, components perform best at room temperature and not high temperature environments (unless designed to do so). Hence always store your VS in the coolest place that is closest to your car battery. I know this for fact because I have had the misfortune of plugging my device close to the back of the radiator fan which disperses high heat. This reduced the stabilizing ability of my experimental VS system.

3) "You'll notice big changes" is a horrific notion that has entered the minds of consumers. Yes, there is an improvement however it has been heavily overplayed and marketed. Now... where to begin... right, your car's current consuming items are typically designed to operate with specific voltage and current. Without a VS device they do work, however their not working at 100%. VS systems and grounding cables help stabilize the voltage which stabilizes the current supplied bringing it closer to its designed operation point.

V=IZ, where V is voltage, I is current and Z is impedance.

Impedance is the current consuming items. Assuming impedance is a constant, voltage and current are directly proportional. Thus, stable voltage equates to stable current supplied. In reality impedance isn't constant because of the induction coil in a car which varies in load depending upon which rpm state the engine is at. However, despite this, the relationship between voltage and current is very close to proportional (If this confuses you, let me know and i'll try to explain it better. I lack sleep at the moment...).

Now let me tell you realistically the improvements that you will notice:
- You will notice that the acceleration becomes smoother, though its a very small change. I will advise for you to drive you car before installing the device and grounding cables in order to notice this difference because it can be very subtle for certain people. For petrol heads, they'll probably notice it straight away since they know exactly how their car accelerates.

- Your bottom end speed and torque increase because of the smoother acceleration. Assume an increase of 1 - 2.5bhp and 1.5nm, it varies from car to car.

- Audio improvements. Now this should be the easiest to tell. Pay attention to the bass of your car, you'll notice it becomes pronounced and depending on your speakers, you'll notice sub bass which was probably very low beforehand. Sometimes, depending on the speakers, clarity is improved and so is overall loudness.

- The lumens of your lights don't increase, however you'll notice the varying brightness of it will reduce. When your car's aircon fan kicks in, the lights begin to dim and slowly increase back to its normal brightness. With a VS and grounding cables, this recovery time will improve. Typically with a new battery, VS and grounding cables, you shouldn't observe this problem.

- Yes the aircon does improve but only slightly. This is because the system is receiving the current it was supposed to obtain under design conditions.

4) Always use a VS with grounding cables. Period. The VS can only do so much on its own but with grounding cables, it really does improve the power supply response and I have tested this with data collected. However, don't do silly things like 10 points grounding cable because that is simply marketing nonsense. What grounding cables do is help earth the electrical systems on the car. Typically connect, the grounding cables between other electrical grounding connections, engine casing, throttle body and the car's metal chassis. Do not, I repeat, do not touch your car's alternator. This is only asking for trouble both physically and electrically you aren't connecting to its ground circuit, which is pointless. At most (if your paranoid like me), a 5 point grounding system can be recommended but even this is one connection too many.

Conclusion:
Hopefully I have managed to make sense to some people on here. If you do disagree, kindly explain what it is you have a problem with, with physics and an engineering perspective ideally. Warning: I don't handle well with stories or non-factual responses as it is utterly pointless and nobody learns anything from it. We all just get really angry and upset.
Keep spreading engineering and physics, its what makes our world a fun one.

For those of you who are interested in my device, I do take orders to build and install my device into cars. I use 6mm squared copper cables which are more than enough for grounding cables and I custom install the wiring depending upon your car's engine bay to maximize the application of the VS system. My fee for the device + grounding cables + installation is RM200 and I only operate around Kuala Lumpur and Selangor. For more information or if you would like to place an order, kindly contact me via email as seen below.

Contact information:
superpineapple@gmx.com

Oh and one last thing. The device is called The Cyclops.

Cheers,
G
 

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vr2turbo

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vr2turbo

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My concern now is the caps that I use are only rated to 85 degree C. The 105 degree ones are very hard to find. I worry that they may not last very long as the air temperature under the hood can reach 60-65 degree C on a hot day, in stop and go traffic :confused:. The 85 degree C rating is the absolute temperature limit, it doesn't mean that the caps can withstand that temperature for extended time.
I think will help if you wrap your unit in aluminum foil......:biggrin:
 

g4i8y0t

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g4i8y0t

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Clutch_Shift_Accelerate, thanks for the detailed explanation and knowledge you share. I have not thought about this before. However, I was intrigued by what you said about the VS becomes a load at higher RPM. I didn't notice any changes to my engine's willingness to rev at high RPM. Maybe my total capacitance of 0.09F is not considered that big for my car's charging system? Also, the battery itself is a large capacitor, many times larger than the VS. It should present itself as a far bigger load to the charging system, isn't it?
 
Sep 8, 2013
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Hey g4i8y0t, that's a good question. The best way for you to tell, is to drive the car without the VS + grounding cables at high RPMs and then with the VS + grounding cables. Conduct this test with the radio blasting music, lights on full and air con on full. Sadly I have not recorded any data to show my test results of this experiment.

Upon driving the car towards red line or close enough (5k RPM), you'll notice the acceleration output (wheel speed) will be ever so slightly affected. Also, when oscillating the throttle response, you'll notice a hick-up in the response time compared to before installing the VS + grounding cables.

Now for your circuit design. If you'd like to improve it, I'd recommend using lower capacitor values with low ESR and a larger array of them to get the total capacitance that you desire. The individual capacitance of a capacitor is far more important than the total capacitance of the VS. Typically they follow a charge time curve, that being said, the larger each individual capacitance of a capacitor the longer it takes to charge them. It would appear I didn't make this clear in my above explanation. Thank you for pointing it out.

Also, capacitors and batteries are not the same thing. A car battery produces energy through a chemical reaction. A capacitor stores charge between its plates and releases charge when certain conditions are met. It does not produce energy. Rather than make this super long and technical, just have a read about capacitors on Wikipedia. That ought to help give a good idea of how they function. If you still have questions, do let me know.

Finally, a total capacitance value of 90000uF is actually alright and it does not mean it will automatically prove to be a heavy load on the time response of the electrical system. This comes down to the selection of individual capacitors used in combination, the orientation of the circuit, ESR of the entire circuit and the health of the 12V battery. It would be ideal to build a VS system close to that value. However due to costing, circuit orientation and build dimensions, I've designed my VS to do as much as it can with a mere 18000uF. I have explored a bigger capacitance system, however it makes it difficult to mount in the engine bay and increases the cost of the product significantly because of the number of capacitors used. Japan made capacitors are not cheap sadly, especially with the increase in their currency recently.

I can design and build a VS of higher capacitance that would in theory smoothen the power signals response even further, if people are willing to pay for it. However, I feel that most users already question the functionality of VS + grounding cable systems, so I do not enforce this onto them especially due to its increase in price (an estimated total of RM340 for VS + grounding cable + custom installation).

Hope my reply helps~
 
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