Electret Capacitor Based Battery Charging System

Bedini Trifilar energiser

Apologies for the picture size, larger files would take too long to upload for some.

You can see the Bedini Trifilar energiser driven by a mains powered 25V PSU through a 300,000uF capacitor bank with the output fed to a standard car ignition coil. This is then rectified by a string of 10 off 4kV diodes.

You’re probably here simply because of simple curiosity and, similarly with the Bedini page, wondering what this has to do with anything.

Again this hinges around lead acid batteries but in this case it is, potentially, another way of charging them.

Electrets are unique man-made materials that can hold an electrical charge after being polarised in an electric field or alternately a solid electrically insulating, or dielectric, material that has acquired a long lasting polarization.

I wanted to trial something which could be done fairly simply using a tried and tested method.

As fas as I’m aware this method of producing an electret was developed by Mototaro Eguchi, a Japanese gentleman circa 1925. The initial ‘discovery’ was made by a Japanese Navy Captain Kawao Wantachi in 1919. He experimented with a mixture of carnauba wax and rosin. To be historically correct Oliver Heaviside apparently first used the phrase electret.

The make-up of the base substance is one used by a guy called Oleg Jefimenko (now Professor) in electrostatic experiments he conducted in South Africa. This mix is 45% carnauba wax, 45% water white rosin and 10% white beeswax.

Bag of flakes

One of the raw products as it arrives as a bag of flakes.

This is relatively easily heated in a Pyrex dish in a saucepan of water but make sure you don’t use your bestest kitchen utensils as they don’t clean too well on completion!!

I cut a length of 4” plastic drain pipe about 2” long and cut out two 4” diameter aluminium discs. These latter had a 4mm hole drilled in the centre and had a brass bolt and nut put in to act as an electrical contact point.

Next I needed an HV source. I had a choice of a 230V AC mains driven simple dimmer switch (triac driven), capacitor , car ignition coil and a suitable diode(s) or a 12V car battery based 555/ 2N3055 driver circuit again to a car ignition coil or a Bedini trifilar energiser.

Initially I went with the former but forgot to include a diode and thus the cooling electret was being 'zapped' with AC rather then DC!!!

I have now acquired the necessary HV diodes. This consists of 10 off 4kV diodes in a 'string'.

Water white rosin

The next main constituent, the water white rosin. This arrives as rock like lumps. It is very sticky stuff as it melts and takes by far the longest of the three constituents to do so.

You will see from the attached photo that I have gone for the more sophisticated option of using a Bedini trifilar energiser to charge a 10uF HV electrolytic capacitor which is discharged using a neon triggered SCR which in turn drives a normal car ignition coil to provide the necessary level of HV.

I sealed the bottom aluminium disc in to place and attached the HV cables to the bolts. I then poured the molten mixture into the plastic pipe, pressed the top disc in to place, connected up the mains and retired to a safe distance.

I left this running overnight to cool down before gingerly approaching it to disconnect it all.

Now to detect an electret you can build a device as per Bill Beatty’s site – http://www.amasci.com/emotor/chargdet.html. It doesn’t get much simpler than this and it does work.

OK so this first attempt didn't work because I was using HV AC. My MkII attempt using the Bedini energiser was much more successful.

White beeswax

White beeswax is the refined product of the more normal tan coloured stuff you might be familiar with.

See the series of pictures at the bottom of this page.

Having made it then what do you do with it. What you don’t do is leave it NOT shorted out as it will accumulate a charge continuously.

Well you connect it to a suitable neon lamp triggered thyristor, this allows the electret capacitor to build up/ store a charge of some 70V DC prior to the neon activating and switching a pulse of power in to a standard lead acid battery.

Thus you have a very handy battery charging system independent of any such requirement as the sun for a solar panel or wind for a small turbine and which will operate 24 hours a day all year around.

This is currently work in progress but I’m hoping to have a marketable system available some time soon.

When I have a model up and running I will post a picture and some results for you to make your own judgement.

Mk II attempt

Here is my MkII attempt after removal from the mould. A word of warning the product in this state is quite brittle and you need to handle it carefully. If you drop it is very likely to split apart. This example is probably too thick and my MkIII attempt will be at least half this.

Red LED is on

Armed with Bill Beatty's detector you can see (if you look carefully) that the red LED is on with the detector held away from the electret.

LED is off

If you look carefully here you can see the that the LED had gone out.

LED is on again

This shows that LED on again when the electret is turned over showing there is a different charge present either side of the electret (which is as it should be).

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