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Re: Fast zener diode substitute

Nedavno Ban napisa:

> I can not find this diode where I am, so can you suggest a >> substitute? I guess I can not just put regular 27V zener diode here? >> > > Yes put a 3-5W 27V zener.

Local parts store only has ZY 27 (27V 1,3W), and ZX 27V (27V 10W) which is to expensive to buy for making something that may not work, just as a pastime.

If diodes use the zener effect, they are always very fast, because no > charge needs to be removed. This is valid for z-diodes above 8V > rating. The circuit discharges the battery, in one year with more than > 30Ah, together with the self discharge rate there will be 0 capacity > left after a year for a normal 45Ah, this is certainly not a good idea > and won't prolong battery life at all.

I wouldn't let it connected for a year. Perhaps a month or two, and then recharge it. I used to do that, but as soon as the battery is out of the car, unused, it dies quickly. I tried to connect my charger to a timer that switched it on for a 20 min three times a week. Unfortunately timer died while I was away for a three weeks, car battery got charged all that time, and it died.

Better to get a trickle charger > and keep the battery fully charged during the storage time.

What sort of voltage / current do I need? Do you have any links to a good proven trickle charger design?

I've found different ones from small ones (like the ones for mobile phone), to 1A. But isn't 1A (when battery is fully charged) cause electrolyte to boil?

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     /__/  /    \      ** Registrovani korisnik Linuksa #291606 **
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Yvan
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"Yvan" schrieb im Newsbeitrag news:hklqa4$hhp$ snipped-for-privacy@news.eternal-september.org...

The batteries have a self discharge rate which is dependent on temperature, age and condition. If we assume 10%/month we have to replace 4.5Ah which means a continuous trickle charge of only 6.5mA. You can use any small supply with higher voltage and calculate the resistor value (Vout-13.8V)/10mA if you have 15V then use a 120 ohms 1/4W resistor. This won't hurt the battery.

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Ban

Nedavno Ban napisa:

But how does that work? Surely it is not the same if I connect charger capable of delivering 10A, and the one capable of delivering only 10mA with the same voltage.

What determines the current flow, 10mA or 10A or whatever?

And what happenes if, for some reason, battery discharges faster than the charger can charge? Current flow rises, and charger dies?

When I connest my charger to partially discharged battery it starts charging at ~5A, and gradually drops down.

I also decided to try this:

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It should start charging below 12.5V, and stop at 13.8V (adjustable).

What do you think? Good alternative to trickle charger?

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

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