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Muti chemistry charger..

C

cafm

Jan 1, 1970
0
Hi guys,

i am doing my 4th year..7th sem... garduate degree in Electronics and
Communication and am looking to do a good project that will have some
practical use.
on of the peojects i studied the feasibilty was of a a multi chemistry
charger. I read up on the chemistry of batter charging and here are
some points.
(*)Intended Chemistry
(1) NiCd
(2) NiMH
(3) Li Ion
The reason for excluding SLA sealed lead acid is the ratings that i am
planning to build for is around 15v tops (+2 differential) and around
2-3 A.

(*) Smartness
some pretty straight forward chargeing and discharging sampling should
allow for chemisty detection but this is currently a stumbling block
since there are no experiment data available

(*) Efficieny...plan to get the constat current by PWM switching in a
feedback control sytem with uC as intelligentce....should be enough

(*) Cost???...
(*) Noise...Swithcing noise will be eliminated using a proper filter..
(*) Battery life...may implement pulse charging to increase life
(*) Speed Fast charging with proper EOC...

currenlty the only charger that i could find that indentifies and
charges properly is
bq2000 Programmable Multi-Chemistry Fast-Charge Management IC
a similar thread is "Battery Charger IC's"
i plan to improve on any of its trade offs

cost for this is about 1.7 $ per KU but requires external switching
supply

dicrete implementaion may not present a cost saving though


currenly i am trying to figure out chemistly identification part.

any suggetions are welcome in any area

any other good projects ideas are also welcome...i have some free time
on my hands and dont want to waste it all up on football manager 2005
and Age of conqurors...lol

thank you
cafm
 
M

martin griffith

Jan 1, 1970
0
Hi guys,

i am doing my 4th year..7th sem... garduate degree in Electronics and
Communication and am looking to do a good project that will have some
practical use.
on of the peojects i studied the feasibilty was of a a multi chemistry
charger. I read up on the chemistry of batter charging and here are
some points.
(*)Intended Chemistry
(1) NiCd
(2) NiMH
(3) Li Ion
The reason for excluding SLA sealed lead acid is the ratings that i am
planning to build for is around 15v tops (+2 differential) and around
2-3 A.

(*) Smartness
some pretty straight forward chargeing and discharging sampling should
allow for chemisty detection but this is currently a stumbling block
since there are no experiment data available

(*) Efficieny...plan to get the constat current by PWM switching in a
feedback control sytem with uC as intelligentce....should be enough

(*) Cost???...
(*) Noise...Swithcing noise will be eliminated using a proper filter..
(*) Battery life...may implement pulse charging to increase life
(*) Speed Fast charging with proper EOC...

currenlty the only charger that i could find that indentifies and
charges properly is
bq2000 Programmable Multi-Chemistry Fast-Charge Management IC
a similar thread is "Battery Charger IC's"
i plan to improve on any of its trade offs

cost for this is about 1.7 $ per KU but requires external switching
supply

dicrete implementaion may not present a cost saving though


currenly i am trying to figure out chemistly identification part.

any suggetions are welcome in any area

any other good projects ideas are also welcome...i have some free time
on my hands and dont want to waste it all up on football manager 2005
and Age of conqurors...lol

thank you
cafm
Excellent subject.
http://www.seabird.com/pdf_documents/manuals/NiMH_001.pdf
section 5
These people actually measure the Kjoules charged, rather on A/H. Many
users need a reasonably accurate measure of how much battery life is
remaining. This, I think, is quite a challenge.
Have a look at www.TI.com for INA138, or similar at www.linear.com

Many laptop batteries have EEPROMS embedded in them, mainly to prevent
us using non original replacements. Consider putting an open source
"charge status" in something similar. It's probably been done, but
worth investigating


martin
 
C

cafm

Jan 1, 1970
0
thank you...will follow up on that....and post what i get....
 
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