Another Cap Pulser

[Peter Murray]

Hi All,

I finally got my cap pulser to work as designed, I got through lots of mosfets on the way.

I am testing it on a 12V system on a bike wheel first.
The caps charge to 29.6V before discharging down to 18.2V into the battery. These voltages can be changed
by replacing the 3 resistors in the terminal blocks.
These resistors can also be changed to use the cap pulser on a 24V system.

6 x 10 000uF 100V caps
2 x IRFP260 mosfets
1 x dual mosfet driver.

I have charged/discharged a battery a few times to get the battery ready for COP tests which I will be starting
next week.

Regards
Peter

[Ed_Morbus]

Thanks for sharing have you schematics

[John_Koorn]

Hi Peter, looking good! I would reduce the dump voltage to about 25v. Keep an eye on heat in the FETs and they should also be matched.
What are the spikes on the scope?

John K.

[Peter Murray]

Cap Pulser Circuit

Ed,

here is the circuit as requested.



Peter

[Peter Murray]

John,

The spikes are around 52V. I agree the dump voltage could be lower, I was so pleased at getting it working that I did not want to change anything until I was certain it was working properly.
During testing I was using 1 FET without a heat sink and the FET temperature was not much above ambient.

Peter

[Ed_Morbus]

Peter Thanks

[Mike Swanson]

Thanks for posting, that looks very nice. I am interested in how it does .

Mike

[Peter Murray]

An easier to read diagram

Glen,

Circuit diagram in pdf format.

Peter

[Peter Murray]

Hey Peter Thanks for the diagram. I am the new kid and just beginning to grasp the need for such High/Low circuitry. My dump is not so automatic so if the amp draw is changed on the primary the operator must reset the controls. Now that I have used a 555 timer based chip with basic frec and duty cycle controls I see the benefits. Like in the cast of varying inputs from a tiny wind turbine or solar panel.Mikey

Mikey,

check out this Avago spreadsheet, it calculates the resistor values.

http://www.avagotech.com/docs/HCPL-3700_3760-Tools

When I down loaded it at was password protected so I copied the relevant worksheets into a new spreadsheet to get it to work.

Peter