Re: Fast zener diode substitute

How will you know if they work or not?

The pulsed desulphator sounds bogus to me.

John

Yvan a écrit :

Like John said you, just go for a similar power zener and you'll be OK.

Also, as you app seems to be single pulse, and have a very low duty ratio, you can slow down the FET turn off quite a bit without any pb. You could probably reduce the over voltage to the point of not needing any clamp at all.

Ditto

--
Thanks,
Fred.

Nedavno John Larkin napisa:

I have two old, unused car bateries. I'll connect desulphator to it, and wait for a month to see if it works.

--
      ___   ____
     /__/  /    \      ** Registrovani korisnik Linuksa #291606 **
    /  / \/  /\  \     ** Registered Linux user #291606 **
   /__/\____/--\__\    ** http://counter.li.org/ **

They actually do work, but may take more than a month and the battery will have reduced capacity. Discharging and charging during desulfation seems to help the sulfur to get reabsorbed back into the electrolyte.

Cheers

after looking at the GIF, that is not a zener that he's looking for. its just a Fast recovery diode of 6 amps with a Vr(rms) of 70v, Tr(recovery time) of 150nS with 100pf

This is nothing special..

If D2 is the diode you are referring too, it's not a zener.. it's fast recovery diode of 6 amps.

I am going by the image of the GIF you posted earlier as you stated it was the connected to the FET.

Nedavno Jamie napisa:

You are looking at the wrong link. Look at my first post, and there is a link to PDF file, and there in the parts list:

D5 = fast zener diode, e.g., BZT03 24V, 27V or 33V)

--
      ___   ____
     /__/  /    \      ** Registrovani korisnik Linuksa #291606 **
    /  / \/  /\  \     ** Registered Linux user #291606 **
   /__/\____/--\__\    ** http://counter.li.org/ **

"Yvan" schrieb im Newsbeitrag news:hkloda$n61$ snipped-for-privacy@news.eternal-september.org...

I also think this circuit can be dangerous. If there goes something wrong and that FET keeps conducting...

ciao Ban

To desulphate a lead acid battery, one must cycle it (charge, discharge) and it is wise to do that in such a manner to have a net (or long term average) charge rate at least equal to the trickle charge rate. One needs to force the current without regard to voltage across the battery. One time i took a motorcycle battery that was made for the Army in

1945 that was made dry-charged and zero electrolyte; the idea was that addition of electrolyte would give one a fully usable battery. Well, by the time i bought it (surplus) it was in the 1980s and the battery would not pass more than a milliamp at 6V (its rating); it was "hopelessly" sulphated. I used a 120v/120V isolation transformer, a series current limiting resistor, and a reverse polarity protection diode across the battery and let it run a week; reduced the transformer drive to half and ran another week, etc until i was using a mere 12VAC for a 50mA peak current. Then i could use a standard charger, and cycled it twice to get almost full rating. Lead sulphate is a good insulator, and you need to RIP it apart, but keep the current down to create small lead particles for "re-plating" and thus be able to be a regular part of the charging/discharging chemistry.

You will wind up with fully discharged batteries ASS-u-ME-ing they had any charge in the first place. You might be able to get them to charge slightly better afterwards than before treatment.

Nedavno Robert Baer napisa:

I will monitor the process, and charge the battery when needed, or connect a trickle charger (when I find / make one). Perhaps it will not work, bat as the batteries are written off it can only get better.

--
      ___   ____
     /__/  /    \      ** Registrovani korisnik Linuksa #291606 **
    /  / \/  /\  \     ** Registered Linux user #291606 **
   /__/\____/--\__\    ** http://counter.li.org/ **

The way to keep batteries from sulphating is to discharge and recharge them occasionally. So a single resistor will work as well as this circuit.

John