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Re: Unsmoothed car battery charger - is it crap?

My car battery is oversized for the car. =A0The battery is a bit old

> but usually works fine. =A0The battery is flat (I left the lights > on). =A0 > > My fancy new modern charger senses a poor battery and only puts in > very little charge. > > I used to use a really old charger to charge this battery > successfully. =A0I opened up the old charger and saw it was only a > transformer and a big rectifier. That's it. =A0No soothing. > > Is this ok for a car battery or is it way too crude?

A related question....

What should the open circuit voltage on a battery charger be?

And when one's charger has its rectifier fail, how should a person repair the charger?

Thanks

TMT

Reply to
Too_Many_Tools
Loading thread data ...

How long is a piece of string? With a crude transformer/rectifier one, depends on the transformer design. And the type of rectifier. And the device measuring the voltage. ;-) What matters is the voltage under load.

These days silicon diodes. Suitably heatsinked.

--
*Money isn?t everything, but it sure keeps the kids in touch

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.
Reply to
Dave Plowman (News)

TMT is a troll who usually hangs around rec.crafts.metalworking

--
You can\'t have a sense of humor, if you have no sense!
Reply to
Michael A. Terrell

oad.

=A0 London SW

Thanks...again...what would a recommended OC voltage be for a battery charger for lead acid batteries?

TMT

Reply to
Too_Many_Tools

load.

LOL...TMT is a poster who doesn't take crap from idiots like Michael.

Post any conservative drivel today Michael?

TMT

Reply to
Too_Many_Tools

Depends on the charger, but usually a few percent higher than the voltage rating of the batteries it's meant to charge. It will drop under load, by how much depends on the design.

When the rectifier fails, you replace the rectifier...

Reply to
James Sweet

Thanks.

The reason why I ask is when I was a kid I repaired a battery charger that had lost its selenium rectifiers with a couple of diodes. I seem to remember it being 14 volt something. While I would have thought it sufficient, the charger seemed to overcharge batteries from then on.

TMT

Reply to
Too_Many_Tools

Of course it overcharges and this has already been discussed in this very thread.

The voltage drop across a modern diode is much less than that across a selenium rectifier so you have to add some resistance to reduce the current.

John G.

Reply to
John G.

oad.

=A0 London SW

IT SEEMS THE PROBLEM WITH THIS CHARGER IS FILTERING IN OTHER WORDS OUTPUT WAVE FORM ATTENUATION RECTIFYING IS NOT AN ISSUE OR IT WOULD NOT ADJUST TO THE CHARGE AT ALL

I AM PROTEUS

Reply to
Proteus IIV

load.

-

AND THAT MAKES YOU THE RESIDENT EXPERT ON TROLLS ????

I AM PROTEUSD

Reply to
Proteus IIV

Who apparently can't even shout his name correctly.

--

*When a clock is hungry it goes back four seconds*

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW To e-mail, change noise into sound.

Reply to
Dave Plowman (News)

His teletype obviously needs adjusting.

Reply to
Jules

r

nt.

And adjust the OC voltage to what?

TMT

Reply to
Too_Many_Tools

And adjust the OC voltage to what?

TMT

A resistor will not change the opencircuit voltage it will only change the current delivered and you will have to decide what is correct for your transformer and your battery.

If this requires some basic training in electricity well so be it.

John G.

Reply to
John G.

Wrong, you just have to add a diode or three to create a voltage drop.

Dave

Reply to
Dave

You just need the right resistor in parallel :-)

Reply to
Duncan Wood

Selenium rectifiers have a much higher voltage drop than silicon diodes. When you replace them with modern diodes, you need a resistor in series for most applications, the value of which depends on the design load.

Reply to
James Sweet

You don't adjust the OC voltage, you adjust the *amperage* into a load, IE, a battery that you wish to charge.

Reply to
James Sweet

That depends on the battery & how you're charging it, taper charging a lead acid with an upper voltage limit is the normal procedure.

Reply to
Duncan Wood

.

der

ry

rent.

Why the hang-up over the OC voltage? Read what p[eople are saying.

MBQ

Reply to
Man at B&Q

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