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Using a Li_Ion charger with Ni-MH
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steve
May 20, 2013, 6:44:47 AM5/20/13
to
I was wondering whether a 4.2V li-Ion charger could be used to charger 3 series NiMH batteries, assuming appropriate current limits where in place. I understand that they may not achieve full charge, but could be charged to 80% I think. This is because I use NiMH batteries in my product and have to design the charging circuit and there is a lot more choice in Li-ION charging ICs.
Any thoughts would be appreciated.
Steve
Any thoughts would be appreciated.
Steve
mike
May 20, 2013, 6:47:20 AM5/20/13
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If you don't have to ask, you shouldn't do it.
Use the chip designed for the task.
steve
May 20, 2013, 9:27:24 AM5/20/13
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Glenn
May 20, 2013, 11:08:35 AM5/20/13
to
http://en.wikipedia.org/wiki/Low_self-discharge_NiMH_battery#Low_self-discharge_cells
Standard NiMH self-discharge rather quickly.
-
http://www.ti.com/lit/sg/slyt420/slyt420.pdf
Look at:
bq2002/C/E/F
bq2004/E/H
bq2005
bq24400/1
http://www.ti.com/battery
Coulumb counter and measure four cells voltages (multichemistry):
http://www.ti.com/product/bq2060a
Glenn
Glenn
May 20, 2013, 11:11:29 AM5/20/13
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Paul Rubin
May 20, 2013, 11:21:30 AM5/20/13
to
Glenn <glen...@gmail.com> writes:
>> I was wondering whether a 4.2V li-Ion charger could be used to
>> charger 3 series NiMH batteries, assuming appropriate current limits
>> where in place.
I wouldn't advise this, unless you can reprogram the li ion charger and
>> I was wondering whether a 4.2V li-Ion charger could be used to
>> charger 3 series NiMH batteries, assuming appropriate current limits
>> where in place.
get a little more voltage from it. Charging NiMH cells in series in
general isn't a great idea. If you do it, you have to be very sensitive
to slight changes in the pack voltage, if you want to fast charge. You
could alternatively use a dumb, slow trickle charger, but even then you
have to be careful.
Glenn
May 20, 2013, 12:29:49 PM5/20/13
to
(Answer to: comp.arch.embedded )
On 20/05/13 12.44, steve wrote:
Hi Steve
Please read about this, while designing:
http://www.linear.com/products/battery_charger_ic
https://www.google.dk/search?q=Smart-Battery-System+%28chip+OR+IC%29
Fast, High Efficiency, Standalone NiMH/NiCd Battery Charging:
http://cds.linear.com/docs/en/design-note/dn380f.pdf
Quote: "...
The LTC4010 (16ben) and LTC4011 (20ben) are NiCd/NiMH battery chargers
that simplify Nickel-based battery charger
design and include power control and charge termination for fast
charging up to 16 series-connected cells using a synchronous buck topology.
..."
http://cds.linear.com/docs/en/product-info/10_Most_Asked_LTC4011_Questions.pdf
LTC1759 - Smart Battery Charger:
http://www.linear.com/product/LTC1759
LTC1760 - Dual Smart Battery System Manager:
http://www.linear.com/product/LTC1760
"...
The LTC1760 implements all elements of a version 1.1 �Smart Battery
System Manager� except for the generation of composite battery information.
..."
LT3652 - Power Tracking 2A Battery Charger for Solar Power
http://www.linear.com/product/LT3652
"...Resistor Programmable Float Voltage Up to 14.4V Accommodates
Li-Ion/Polymer, LiFePO4, SLA Chemistries..."
Complete NiMH/NiCd Charger for 1 to 16 Cells:
http://www.linear.com/product/LTC4100
http://www.linear.com/product/LTC4101
http://en.wikipedia.org/wiki/Smart_Battery_System
http://www.sbs-forum.org/specs/
New:
http://en.wikipedia.org/wiki/Power_Management_Bus
http://www.avrfreaks.net/wiki/index.php/Documentation:NGW/TinyFirmware
http://pmbus.org/
http://en.wikipedia.org/wiki/Battery_balancing
http://en.wikipedia.org/wiki/Battery_management_system
http://en.wikipedia.org/wiki/Battery_charger
http://en.wikipedia.org/wiki/Charge_controller
http://en.wikipedia.org/wiki/System_Management_Bus
Glenn
On 20/05/13 12.44, steve wrote:
Please read about this, while designing:
http://www.linear.com/products/battery_charger_ic
https://www.google.dk/search?q=Smart-Battery-System+%28chip+OR+IC%29
Fast, High Efficiency, Standalone NiMH/NiCd Battery Charging:
http://cds.linear.com/docs/en/design-note/dn380f.pdf
Quote: "...
The LTC4010 (16ben) and LTC4011 (20ben) are NiCd/NiMH battery chargers
that simplify Nickel-based battery charger
design and include power control and charge termination for fast
charging up to 16 series-connected cells using a synchronous buck topology.
..."
http://cds.linear.com/docs/en/product-info/10_Most_Asked_LTC4011_Questions.pdf
LTC1759 - Smart Battery Charger:
http://www.linear.com/product/LTC1759
LTC1760 - Dual Smart Battery System Manager:
http://www.linear.com/product/LTC1760
"...
The LTC1760 implements all elements of a version 1.1 �Smart Battery
System Manager� except for the generation of composite battery information.
..."
LT3652 - Power Tracking 2A Battery Charger for Solar Power
http://www.linear.com/product/LT3652
"...Resistor Programmable Float Voltage Up to 14.4V Accommodates
Li-Ion/Polymer, LiFePO4, SLA Chemistries..."
Complete NiMH/NiCd Charger for 1 to 16 Cells:
http://www.linear.com/product/LTC4100
http://www.linear.com/product/LTC4101
http://en.wikipedia.org/wiki/Smart_Battery_System
http://www.sbs-forum.org/specs/
New:
http://en.wikipedia.org/wiki/Power_Management_Bus
http://www.avrfreaks.net/wiki/index.php/Documentation:NGW/TinyFirmware
http://pmbus.org/
http://en.wikipedia.org/wiki/Battery_balancing
http://en.wikipedia.org/wiki/Battery_management_system
http://en.wikipedia.org/wiki/Battery_charger
http://en.wikipedia.org/wiki/Charge_controller
http://en.wikipedia.org/wiki/System_Management_Bus
Glenn
steve
May 21, 2013, 8:39:08 AM5/21/13
to
Thanks, what a great lot of information.
The reason I thought NiMH would be a good battery technology is that is is relatively safe if slow charged, easy to ship via air and customer installed if need be and AA NiMH batteries can be purchased anywhere if required. The unit requires a 5V rail of around 1.5amps, either from a Micro USB or via the batteries with smooth switch over, also the batteries will need charging. We are a host device with 3 USBs and a Micro USB wall power supply input. I did think of some variation of USB OTG such as the bq24195, however the Boost mode start up time is too long (200mS)and because it uses current termination for charging cannot fully charge NiMH battereis. If there is some Li-Ion battery pack with in built safety circuitry of a similar size and cost to 3 AA batteries please point me in the right direction.
Thanks again for all your advice and pointers
The reason I thought NiMH would be a good battery technology is that is is relatively safe if slow charged, easy to ship via air and customer installed if need be and AA NiMH batteries can be purchased anywhere if required. The unit requires a 5V rail of around 1.5amps, either from a Micro USB or via the batteries with smooth switch over, also the batteries will need charging. We are a host device with 3 USBs and a Micro USB wall power supply input. I did think of some variation of USB OTG such as the bq24195, however the Boost mode start up time is too long (200mS)and because it uses current termination for charging cannot fully charge NiMH battereis. If there is some Li-Ion battery pack with in built safety circuitry of a similar size and cost to 3 AA batteries please point me in the right direction.
Thanks again for all your advice and pointers
Glenn
May 21, 2013, 5:38:58 PM5/21/13
to
On 21/05/13 14.39, steve wrote:
> Thanks, what a great lot of information.
...
> Thanks, what a great lot of information.
> If there is some Li-Ion battery pack with in built safety circuitry of a similar size and cost to 3 AA batteries please point me in the right direction.
> Thanks again for all your advice and pointers
Hi Steve
> Thanks again for all your advice and pointers
This might be interesting. But the AA LiFePO4 has only
3.2V*400mAh=1280mWh, they are cheap, the LiFePO4 chemistry is very
robust, might have very long life - it depends on how gas-tight the
accumulator is made. I do not know their self-discharge rate. If water
disappears the internal impedance go up.
(LSD-NiMH has 1.2V*2000mAh=2400mWh. May last 1-3 years)
US$8 (4 pieces)
4pk Solar Tech 3.2V AA LiFePO4 Rechargeable Batteries:
http://www.amazon.com/Solar-Tech-LiFePO4-Rechargeable-Batteries/dp/B008UZEOHW/ref=sr_1_3?ie=UTF8&qid=1369170893&sr=8-3&keywords=lifepo4+aa
3.2V; 400mAh
AA Size battery
LiFePO4
(Search for lifepo4 aa at amazon. The same product can have different
prices)
-
A123Systems M1-cell 2.3Ah 3.2V is as far as I can remember, laser welded
(therefor very gas/water-tight) so it is estimated to last more than
10-15 years - even at high temperature (60�C) according to their
brochure. More than 3000 full cycles:
http://www.rc-netbutik.dk/getdoc.asp?id=100&md5hash=9810C237586CF6B4325753101E37DAE1
You can overcharge LiFePO4 chemistry, discharge to zero volt; then
overcharge, overdischarge it (high ampere), reverse charge it, it won't
explode according to many tests, but it will of course diminish the
battery-life. (FYI: I have currently no shares in any battery firm ;-)
br,
Glenn
Glenn
May 21, 2013, 5:52:50 PM5/21/13
to
More about LiFePO4 batteries/accumulators:
SANDIA REPORT
SAND2008-5583
Unlimited Release
Printed September 2008
Selected Test Results from the LiFeBatt
Iron Phosphate Li-ion Battery
Thomas D. Hund and David Ingersoll
Prepared by
Sandia National Laboratories
Albuquerque, New Mexico 87185 and Livermore, California
http://www.lifebatt.com/sandiareport.pdf
Quote: "...
Test results have indicated that the LiFeBatt battery technology can
function up to a 10C discharge rate with minimal energy loss compared to
the 1 h discharged rate (1C).
...
The majority of the capacity loss occurred during the initial [!] 2,000
cycles, so it is projected that the LiFeBatt should PSOC cycle well
beyond 8,394 cycles with less than 20% capacity loss.
...
[See graph pdf-page 23]
[ Read: 48% capacity available at -30�C. ] [ very useable! ]
[ Read: 65% capacity available at -20�C. ]
[ Read: 74% capacity available at 0�C. ]
...
3.8 Over Voltage/Charge Abuse Test
In Figure 16 the events in an over charge/voltage abuse test are
documented. Initially, as expected, the cell voltage increases quickly
while being charged at 10 A, but then slowly increases after 4.7 V. The
cell voltage slowly increases for about 30 minutes while the cell
temperature continues to slowly rise to about 100 �C at which time cell
voltage spikes to the maximum value of 12 V. At about 110 �C the cell
vents liquid electrolyte without any fire or sparks and then
open-circuits at 116 �C. After open-circuiting and a loss of
electrolyte, the cell looses all voltage at 120 �C. The data acquisition
shuts down due to a no voltage condition, but temperature is manually
monitored until the cell reaches its maximum value at 160 �C about 20
minutes after the cell open-circuited.
..."
Nail penetration testing A123 Li-ion [ one of the best LiFePO4-batteries ]:
http://www.youtube.com/watch?v=rb_J2QQ0k-4
-
-
Compare with the other Li-ion (non-LiFePO4):
Exploding Laptops on Good Morning America:
http://www.youtube.com/watch?v=zvTRKKS0wpo
Nail penetration testing Standard Li-ion:
http://www.youtube.com/watch?v=f30fBFitkSM
Spark, Smoke & Boom!: World's Most Dangerous Battery!:
http://www.youtube.com/watch?v=8vdOC8dN3_I
Modify Li-Po Battery Nail Penetration Test:
http://www.youtube.com/watch?v=8vdOC8dN3_I
br,
Glenn
SANDIA REPORT
SAND2008-5583
Unlimited Release
Printed September 2008
Selected Test Results from the LiFeBatt
Iron Phosphate Li-ion Battery
Thomas D. Hund and David Ingersoll
Prepared by
Sandia National Laboratories
Albuquerque, New Mexico 87185 and Livermore, California
http://www.lifebatt.com/sandiareport.pdf
Quote: "...
Test results have indicated that the LiFeBatt battery technology can
function up to a 10C discharge rate with minimal energy loss compared to
the 1 h discharged rate (1C).
...
The majority of the capacity loss occurred during the initial [!] 2,000
cycles, so it is projected that the LiFeBatt should PSOC cycle well
beyond 8,394 cycles with less than 20% capacity loss.
...
[See graph pdf-page 23]
[ Read: 48% capacity available at -30�C. ] [ very useable! ]
[ Read: 65% capacity available at -20�C. ]
[ Read: 74% capacity available at 0�C. ]
...
3.8 Over Voltage/Charge Abuse Test
In Figure 16 the events in an over charge/voltage abuse test are
documented. Initially, as expected, the cell voltage increases quickly
while being charged at 10 A, but then slowly increases after 4.7 V. The
cell voltage slowly increases for about 30 minutes while the cell
temperature continues to slowly rise to about 100 �C at which time cell
voltage spikes to the maximum value of 12 V. At about 110 �C the cell
vents liquid electrolyte without any fire or sparks and then
open-circuits at 116 �C. After open-circuiting and a loss of
electrolyte, the cell looses all voltage at 120 �C. The data acquisition
shuts down due to a no voltage condition, but temperature is manually
monitored until the cell reaches its maximum value at 160 �C about 20
minutes after the cell open-circuited.
..."
Nail penetration testing A123 Li-ion [ one of the best LiFePO4-batteries ]:
http://www.youtube.com/watch?v=rb_J2QQ0k-4
-
-
Compare with the other Li-ion (non-LiFePO4):
Exploding Laptops on Good Morning America:
http://www.youtube.com/watch?v=zvTRKKS0wpo
Nail penetration testing Standard Li-ion:
http://www.youtube.com/watch?v=f30fBFitkSM
Spark, Smoke & Boom!: World's Most Dangerous Battery!:
http://www.youtube.com/watch?v=8vdOC8dN3_I
Modify Li-Po Battery Nail Penetration Test:
http://www.youtube.com/watch?v=8vdOC8dN3_I
br,
Glenn
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