Ashley wrote:
> Hi Richard,
>
> Thanks for the quick reply. Actually I wasn't aware of the original
> ratings, in fact until Tuesday night I didn't even know what the heck
> L1 and L2 were on the circuit diagram (refer earlier comment about me
> being an electronics ignoramus).
>
> I got desperate (the sulphated batteries are in an EV and it's
> basically useless until I recover them) and ordered the parts anyway.
> I think they'll be ok.
>
> I got the 200uH choke from Jaycar:
>
http://www.jaycar.com.au/productView.asp?ID=LF1276&CATID=&keywords=choke&SPECIAL\
=&form=KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=\
&SUBCATID=
> and the 1000uH choke from RS:
>
http://www.rsaustralia.com/cgi-bin/bv/rswww/searchBrowseAction.do?Nr=avl%3aau&N=\
4294918384&name=SiteStandard&forwardingPage=line&R=0228551&callingPage=/jsp/brow\
se/browse.jsp&BV_SessionID=@@@@0405384956.1173848947@@@@&BV_EngineID=ccdladdkgih\
ljdlcefeceeldgkidhgn.0&cacheID=aunetscape
>
> Based on what you've said they should be ok...I think. I'm not sure I
> have much choice.

The Jaycar 220 uH looks good. Can't see the RS 1000 uH,
but if its the 1.6 A unit it will be fine.

On electrolytic capacitors - you can use caps with a higher
voltage rating than specified in any electronic circuit.
It is not necessary in this circuit, but if you have
difficulty getting one rated at 25V, for example, you
can use one rated at 35V or more. The 16V caps specified
in the original article are too low - use 25V or higher.
16V units work, but by going to a higher voltage rating
you have a safety margin. And the value of C1 - 30 uF
in the original - can be increased with no problem.

>
> I also got the IRF9Z34N from RS:
>
http://www.rsaustralia.com/cgi-bin/bv/rswww/searchBrowseAction.do?obs=sObs&name=\
SiteStandard&No=0&N=0&Ntk=I18NAll&Ntt=irf9z34n&Nty=1&D=irf9z34n&Ntx=mode%20match\
partial&Dx=mode%20matchpartial&callingPage=/jsp/line/line.jsp&BV_SessionID=@@@@0\
405384956.1173848947@@@@&BV_EngineID=ccdladdkgihljdlcefeceeldgkidhgn.0&cacheID=a\
unetscape&Nr=avl:au
>
> At least I know that bit is 100% correct.
>
> My EV has 4 12V 50Ah AGM batteries so the voltage of C4 at 25V should
> be right on the money since I plan to do each battery individually.
> Speaking of money, I hope this works or I will be coughing up a *huge*
> amount on some new batteries...
>
> I'll throw a zenner in there too as you suggest. Thanks again!
>
> I'm off to DSE (http://www.dse.com.au/) to pick up a pack of 1N4004
> diodes as that was what was suggested to me to use for D1.

That's not good for D1. 1N4004 is fine for general use, so
having some on hand won't hurt. For this circuit, you want
a very fast diode, such as RS 2509061830, which is a MUR2020CT.
That is an ultrafast doide which should work very well in this
circuit. It contains two diodes in one TO-220 package - you use
only one of them. Connect the center leg of the MUR2020 to the
Mosfet, and either one of the outside legs to battery (-). See
page 6 of:
http://www.irf.com/product-info/datasheets/data/mur2020ct.pdf
for the schematic of the diode.

> I might
> also get a board etching kit and have a go at making my own boards
> using the traces from this site:
> http://members.shaw.ca/pferlow/desulfator.htm

You may need to adjust the traces to fit your components.
The traces and the drilled holes have to line up with the
actual components you use - and your L1 and L2 likely do
not match the L1 and L2 in the drawing. Also, if you use the
MUR2020 that's a 3 legged part and the traces don't match
that.

There is a free program that you can use to draw circuit boards:
http://www.cadsoft.de/

There are several options, regardless of what you use to
draw the board(s) on the PC, to transfer the "artwork"
from the PC to the blank copperclad PC board prior to
etching. It would be a good idea to read a bit about
making PC boards before buying the kit.

Two general comments on making PC boards:
1) Ferric Chloride *stains*. (I'm not against it -
I use it. But be forewarned - get it on your clothes,
and the stain is permanent.)
2) You will break drill bits. You are drilling very small
holes, with a very thin bit, which you will have to buy.
It is not part of a "standard" drill bit set.
The best drill bits are dental burrs, used with a Dremel
tool. I use a drill press attachment with the Dremel
tool, and haven't broken a bit since I started using
that with dental burrs. Maybe you can get your dentist
to give you some old burrs.

I think you might be better off doing point to point
wiring for your first desulfator.

Ed


>
> Cheers,
> Ash
>
> --- In randrdesulfatorforum@yahoogroups.com, "linesrg48"
> <courtiestown@...> wrote:
>
>>Ashley,
>>
>>As you're probably aware the original API-Delevan inductors were
>>rated;
>>220uH was 2.025A
>>1000uH was rated 0.39A
>>so this gives you a clue as to the 'minimum' you should be looking
>>for.
>>You can go above this, but as others more knowledgable than me will
>>tell you, everything kind of impacts on everything else and a balance
>>has to be achieved.
>>I would look at what Jaycar or similar has or try looking at say the
>>Coilcraft range (I don't know who might stock it in Aus) as they will
>>have something to suit.
>>You could go for 100uF/ 25V at C1 and anything up to 6,800uF for C4,
>>the voltage arting of C4 should be at least double the battery
>>voltage.
>>
>>For prtection youi should also put a 15V zener parallel to C1 to
>>protect against spikes.
>>
>>Regards
>>
>>Richard
>>
>>--- In randrdesulfatorforum@yahoogroups.com, "Ashley" <tty07@>
>>wrote:
>>
>>>Hello, I'm glad to find this group as I've been reading the ezboard
>>>web forum but it appears to be more or less deceased. I'm in the
>>>process of building the basic, simple, original Alastair Couper
>>>desulphator comprising 13 components.
>>>
>>>I either already have, or can order all of the components but the
>>>chokes are throwing me for a bit of a loop. I've consulted with
>>>someone much cleverer than I (I'm an electronics ignoramus) who
>>>advised that two chokes I'd selected as potential candidates would
>>
>>be
>>
>>>unsuitable as they're only rated for 155mA.
>>>
>>>I can get the 220uH choke rated for 5A, and a 1mH (which I presume
>>
>>to
>>
>>>be the same as 1000uH) rated at 1.6A. Would this be sufficient? If
>>>the lower current ratings will do that would be great because
>>
>>they're
>>
>>>significantly cheaper, but since I'm only making 4 it probably won't
>>>matter that much.
>>>
>>>Also, will it be ok to substitute a 33uF 25V for C1 (should be 30uF
>>>16V) and 100uF 25V for C4 (should be 100uF 16V)?
>>>
>>>Any advice gratefully received.
>>>
>>>Cheers,
>>>Ash
>>>
>>
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