[EE] what kind of battery charger are you using?

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[EE] what kind of battery charger are you using?

microsoftwarecontrol
Today, is my third trying to build a
universal battery charger.
I don't have one, that can charge
my pile of batteries!!!!

I tried lm3647, max713 both have
-dV termination. But I never got
even once to have my battery
fully charged! They seems always
terminated far early than 1/10 of
whole time.

After check and check, I realized that
-dV sensoring is such high demanding
circuit. There are plenty of -10mV signal
come as interference. To, -dV performance
of battery charging, only exists on paper.

I prepare to give up using -dV termination.
I can only try to build a pic time-current accumulating
charger. that should be better immune to noisy.

So, what are you guys using now?
never saw the question been raised,
or you all have never being bothered
by charging battery?

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Re: [EE] what kind of battery charger are you using?

Dave VanHorn

>
>So, what are you guys using now?
>never saw the question been raised,
>or you all have never being bothered
>by charging battery?

Well, I did it, but I used an AVR. :)

Tiny-26 running from internal 8 MHz R/C clock, PLL'd up to 64 MHz
internally to run the buck switch regulator PWM at 500kHz with good
resolution.

After that, there's a bunch of things you need to know about NIMH
cells, you can look at the Panasonic and Sanyo data sheets, and the
Cadex docs, plus the Galaxy power docs, and get there.


There are temperature limits, lockouts on certain trip conditions...
A lot to consider.


BTW: The max chips all provide rather a lot of trickle charge for
NIMH cells. Some NIMH can't tolerate ANY trickle, some are almost
like Nicads.  

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Re: [EE] what kind of battery charger are you using?

John Ferrell-2
In reply to this post by microsoftwarecontrol
I use quite a few different chargers on NiCads and NiMhs. I have found that
a peak detecting charger is just about useless for getting a full charge.
All I have tried either shut down early or miss the peak altogether and try
to cook the pack. Especially if you try charging at the max ratings. My
temporary solution is to use chargers that display the amount of charge that
the battery accepted and restart the charger until it appears to have
accepted an adequate charge.

Charging and monitoring individual cells looks like a better way than trying
to charge a four cell pack.

NiMh cells are harder to keep track of the state of charge.

My principle application is Radio Control Model airplanes. A battery failure
can cost several thousand dollars.

My digital camera uses AA NiMh cells. I keep them in pairs to help keep
track of performance. If I restart the charge process 4 times, I seem to get
good service from them. Anything less gives less performance.

I use only Sanyo cells just to reduce the number of variables.

The best reference for NiMh I am aware of is at
http://www.dvanhorn.org/NIMH/Index.php

The Sanyo datasheets are also good.

When you get to LiPo's be aware that all of the safety warnings are
understatements.
They may be useful repurposed as detonators!

With Nicads, a C/10 charge for 17 hours will work if anything will, but does
not give a clue about the quality of the pack.
John Ferrell
http://DixieNC.US

----- Original Message -----
From: "microsoftwarecontrol" <[hidden email]>
To: <[hidden email]>
Sent: Tuesday, June 14, 2005 12:44 AM
Subject: [EE] what kind of battery charger are you using?


Today, is my third trying to build a
universal battery charger.
I don't have one, that can charge
my pile of batteries!!!!

I tried lm3647, max713 both have
-dV termination. But I never got
even once to have my battery
fully charged! They seems always
terminated far early than 1/10 of
whole time.

After check and check, I realized that
-dV sensoring is such high demanding
circuit. There are plenty of -10mV signal
come as interference. To, -dV performance
of battery charging, only exists on paper.

I prepare to give up using -dV termination.
I can only try to build a pic time-current accumulating
charger. that should be better immune to noisy.

So, what are you guys using now?
never saw the question been raised,
or you all have never being bothered
by charging battery?

--
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist


--
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist