Fast Universal Battery Charger (S/C June/July 2001)

[Franc Zabkar]

Has anyone built this "Fast Universal Battery Charger":
http://www.siliconchip.com.au/cms/A_101728/article.html

It is based on the TEA1102 IC from Philips:
http://wwww.ges.cz/sheet/t/tea1102.pdf

My reading of the datasheet suggests that the fast charge current is
3A, but DSE's assembly manual specifies "nominally 6A".

The formula for calculating the fast charge current is:
Ifast = Rb/Rsense.(Vref/Rref)

This gives:
Ifast = 3K3 / 0.05 x (1.25 / 27K) = 3.06A

If the actual figure is 3A instead of the design target of 6A, then
this would affect all the fast charge timeout settings. For example, a
timeout of 15mins for a 1.2Ah battery would allow it to fast charge to
only 0.75Ah (62%) before switching to top-up mode.


- Franc Zabkar

 

[Phil Allison]

"Franc Zabkar"

Has anyone built this "Fast Universal Battery Charger":
http://www.siliconchip.com.au/cms/A_101728/article.html

** Better that that - I had to de-bug two non working kits for a friend.

He made simple assembly errors - but SC put in the real doozies.

It is based on the TEA1102 IC from Philips:
http://wwww.ges.cz/sheet/t/tea1102.pdf

My reading of the datasheet suggests that the fast charge current is
3A, but DSE's assembly manual specifies "nominally 6A".

** Even the SC article is ambiguous on the point - in one place they say "
nominally 6 amp " in another it is stated to be 4.58 amps on test - see
page Fig 5 on page 30, SC, June 2001.

The problem is that the input to the switching regulator is unfiltered, full
wave rectified AC - not smooth DC. The battery charging current is
pulsing at a 100Hz rate - which makes the rms value higher than the
average value by about 52% - according to SC. The actual values will vary
with the ESR of the particular battery and its state of charge.

Be aware - a battery charges in proportion to the AVERAGE value of the
current it is fed - the rms value is irrelevant to a battery charger. So
the 4.5 amp figure is the real one - the 6 amp figure is the "fake" rms
one.


BTW

The data and examples supplied for the TEA1102 assume that it is being fed
with smooth DC - so that formula is out the window here.




................ Phil

 

[Franc Zabkar]

"Franc Zabkar"


** Better that that - I had to de-bug two non working kits for a friend.

He made simple assembly errors - but SC put in the real doozies.




** Even the SC article is ambiguous on the point - in one place they say "
nominally 6 amp " in another it is stated to be 4.58 amps on test - see
page Fig 5 on page 30, SC, June 2001.

The problem is that the input to the switching regulator is unfiltered, full
wave rectified AC - not smooth DC. The battery charging current is
pulsing at a 100Hz rate - which makes the rms value higher than the
average value by about 52% - according to SC. The actual values will vary
with the ESR of the particular battery and its state of charge.

Be aware - a battery charges in proportion to the AVERAGE value of the
current it is fed - the rms value is irrelevant to a battery charger. So
the 4.5 amp figure is the real one - the 6 amp figure is the "fake" rms
one.


BTW

The data and examples supplied for the TEA1102 assume that it is being fed
with smooth DC - so that formula is out the window here.

I would think that the timing formulae should still apply, though. For
example, the fast charge timeout values of 15min, 30min, and 60min
appear underrated.

The formula is:

Ttimeout = 2^26 x POD x PTD x Tosc

For Tosc = 43.25kHz, this gives timeout settings of about 26, 52, and
104 minutes.

I also find it strange that the construction addendum suggests that
the charger can be modified to handle 6V+ "low capacity" battery packs
of less than 1.2Ah by changing the value of the loop stability
capacitor rather than the Rb resistor.


- Franc Zabkar

 

[Phil Allison]

"Franc Zabkar"

( snip complete non sequitur reply)


** Dear Franc,

how about you actually build one of these POS first and post queries
afterwards.

Perhaps you will then speak from some experience instead of just blowing it
out your wog backside.






.............. Phil

 

[Franc Zabkar]

"Franc Zabkar"

( snip complete non sequitur reply)


** Dear Franc,

how about you actually build one of these POS first and post queries
afterwards.

I'll build it when I'm ready. And I'll be ready when I understand how
it works so that I can modify it beforehand to charge the "low
capacity" batteries that I want it to charge. If I need to drill the
front panel for an extra switch, then I'd like to do it now, before
the unit is assembled.

Perhaps you will then speak from some experience instead of just blowing it
out your wog backside.

Just the kind of schoolyard taunt one would expect from a pathetic,
lonely, old, frustrated, demented, bigoted, sociopathic, dropout
loser. Get a life, Phil. There's still time.


- Franc Zabkar

 

[Phil Allison]

"Franc Zabkar"
"Phil Allison"

I'll build it when I'm ready. And I'll be ready when I understand how
it works so that I can modify it beforehand to charge the "low
capacity" batteries that I want it to charge.

** Then why the **** didn't you post **that** as your question ????

Just the kind of schoolyard taunt one would expect from a pathetic,
lonely, old, frustrated, demented, bigoted, sociopathic, dropout
loser. Get a life, Phil. There's still time.

** Dear Franc,

I went to some trouble to post a clear and precise reply to your original
post, I used my first hand experience of the design, checked the original
SC article and downloaded the PDF on the IC to check that again too.

You rudely and completely ignored it - since you are nothing but a
arrogant, wog pig.

You will never get any help from me again.




.................. Phil

 

[budgie]

(snip)

Get a life, Phil. There's still time.

I seriously doubt that.