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# CBC and CT Corrections

I recently purchased the plans for the Capacitive Battery Charger and Transformer and there are some things that I just can’t understand.

1. Does the CBC stops loading batteries when they’re full

No.  Most battery chargers don’t.  You can add that feature using electronics.  I plan to offer such a circuit when I get time.

or I have to figure it out by some mysterious ways.

Most people who recharge batteries know how to determine if the battery is charged.
Stop charging when the voltage is full or peaks, whichever comes first.
For example, a fully charged 12 Volt lead acid battery is fully charged when it’s somewhere between 13.5 VDC and 14 VDC when being charged.  Once the charger is removed the state of charge shouldn’t drop to less than 12.6 VDC.

If the battery is sulfated it may go as high as 80 VDC to push one amp across the sulfation.  As the sulfation dissolves the voltage will drop, to as little as 5 VDC, then the battery will charge normally.  The CBC’s ability to reach higher voltages (if needed) is what gives it the capability to recharge sulfated batteries.

If you charge it above 14 VDC, like to 15 VDC and the voltage starts to drop, stop the charger immediately or battery damage will occur (plates will start to decompose).

2. What do the symbols DC amp and DC volt (both with arrows) mean (CT, page 1, figure 1).

Those are amp and volt gauges.

3. What does F1 mean?

Fuse.

4. What does the A on the Bridge Rectifier stand for (CBC, page 3, figure 1)

Weird font issue, a typo.  It’s supposed to say AC.

5. It says that “amperage will increase with the increase of capacitance” but it doesn’t say the way how to calculate the increase.

There are comments to help you calculate the capacitance needed for amperage.

The increase may be parabolic or linear.

It’s linear.

In my case, I would like to get 12 VDC and 25 ADC from 220 VAC (European standard). What formula do you use to calculate the capacitance necessary.

You’ll get about 1 amp for every 12.5 uF with 220 VAC at 50 Hz.

Below is a correspondence that corrects mistakes we made when converting the Capacitive Transformer document to it’s electronic version.  The CT drawing is correct, just in the wrong place; it was put in Figure 1 instead of Figure 2.

On 2012-07-07, at 11:55 AM, Jed wrote:George,

The document I got off your website is contained in the attachments
Doc1-1,Doc1-2,Doc1-3,Doc1-4

The document that came with my order is contained in the attachments
Doc2-1,Doc2-2,Doc2-3,Doc2-4

I can no longer find the document I originally found on your website, but I noted that the copyright date was October 1996.

Your Doc1 is a copy of the original paperback book and has the correct Capacitive Transformer circuit schematic,  description and figure numbers.  So you already have the ‘corrected’ version.  The paperback is correct.

The only change I see is that I no longer recommend using electrolytic capacitors for the secondary (lower voltage) capacitor.  Electrolytics are NOT rated for continous duty AC and will fail in a fairly short time.  I didn’t know that when I originally tesed them.

Your Doc2 is the download of our conversion of Doc1 to an electronic version.  It is supposed to be IDENTICAL to your Doc1.  In the process of conversion there were several errors that have caused your appropriate confusion.

1. The drawing that was supposed to be figure 1 (the simplest Capacitive Battery Charger) was accidentally deleted altogether (but is still in the CBC book).

2. The drawing that was supposed to be figure 2 (example of Capacitive Transformer) is currently in the place of figure 1 (so where it says ‘fig. 2’ in the document, refer to fig. 1).

3. The drawing that is currently labelled figure 2 is the ‘Capacitive Battery Charger, with options’; which wasn’t supposed to be in the Capacitive Transformer document.  However, it doesn’t matter because neither it or the simple CBC drawing (original fig. 1) were CT circuits anyway.  The ONLY CT circuit is labelled correctly (as the Capacitive Transformer), even if it’s figure number and placement are currently wrong.

I will put a note up in the Capacitive Power Supply Resources about these errors.
In the meantime you can now proceed with your project.
I thank you for bringing this matter to my attention.The error I believe is on attachment Doc2-4. The figure 2 is obviously the “Capacitive Battery Charger, with options,” and it should be the picture of the “Capacitive Transformer.”

You are correct.and also any insight where I can buy the parts to build a charger for a 115 VDC battery pack.

I get my capacitors from surpluscenter.comI appreciate the work you’re doing. It’s encouraging. I’d love to be on your subscription list.

You’d need to subscribe yourself; it’s part of double opt in requirements by my ISP. Subscribe to the Eagle-Research newsletter at the bottom of our home page (if you haven’t already) to be informed when new information is available.

For faster notification of updates, you can also follow me on twitter
Fuel Saving Tweets ( FuelSaverGuru )
Eagle-Research Tweets ( Eagle_Research )
Personal Tweets ( ecopegasus )I also want to note that if you are charging a vehicle battery while it is in the vehicle, it is a good idea to at least disconnect the ‘positive’ battery terminal; so that the charging voltage from the CBC will not go into the vehicle’s electrical/electronic system.  Safest is to disconnect both battery terminals. I had two experiences with my RV that show the importance of this cautionary measure. 1. My RV had been parked for some time and the chassis (engine) battery had drained (I now disconnect the chassis battery when I park the RV).  When I went to charge it there must have been some sulfation because the initial battery voltage rose to 22 VDC.  I heard a pop inside the RV and discovered that my inverter had fried (it couldn’t take that high a voltage).  Cost to replace \$200.  I’ve also subsequently upgraded my ‘charging relay’ circuit so that the coach batteries (and inverter) are not connected to the chassis battery unless the engine is running. 2. My CBC had developed an internal short, but it was still working at half power so I hadn’t bothered to fix it.  There was no problem charging ‘normal’ vehicle’s batteries or even the RV battery EXCEPT that this particular time I had the RV coach plugged into the Grid (so the RV would have electrical without using its storage batteries and inverter).  The electricity (from the Grid) that was feeding the CBC was on an opposite ‘leg’ of the 240 VAC, so (because of the CBC internal short circuit) I had a 240 VAC direct short back through the RV’s 12 VDC electrical system to the Grid.  This fried a bunch of things in my chassis electrical/electronic systems (primary fuse box, gauge cluster, ABS, headlights, etc.).  Estimated cost to repair by Ford was 2 weeks time and parts, in the range of \$8000.  Since I’m a mechanic and know how to buy parts off eBay I repaired it for \$600 in two working days.   So… I recommend disconnecting the positive lead of your battery.  Generally I still don’t if I know the battery is good (no sulfation) and I know my CBC is good (no shorts).  But I’m telling you this story now so you can be aware of the potential issues.