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Apr 30, 2001, 12:36 PM
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Spin_Doctor's Avatar

Universal Battery Charger for Li-Ion, Ni-MH and Ni-Cd Batteries


Ok Take a look at this any ideas on it. I came across it on the net you can get an evaluation bord for 100 bucks

General Description
This is a charge controller for Lithium-Ion (Li-Ion), Nickel-Metal Hydride (Ni-MH) and Nickel-Cadmium (Ni-Cd) batteries. The device can use either a pulsed-current charging or a constant-current charging technique. The device can also be configured to discharge before charging. Throughout the charging sequence monitors voltage and/or temperature and time in order to terminate charging.

Charge termination methods are:

Negative delta voltage (-[Delta]V)
Optional: Delta temperature/delta time ([Delta]T/[Delta]t)
Backup: Maximum temperature
Backup: Maximum time
Backup: Maximum voltage
If both voltage and temperature fail to trigger the termination requirements, then the maximum time (configured by external hardware) steps in which terminates the charging.

In Ni-Cd/Ni-MH mode, four different charging stages are used:

Soft-start charge
Fast charge
Topping charge
Maintenance charge
In Li-Ion mode, four different charging stages are used:

Qualification
Fast Charge Phase 1, Constant Current
Fast Charge Phase 2, Constant Voltage
Maintenance charge
The charge current is configured via external resistors, which in turn controls the duty cycle of the PWM switching control output. For cost-sensitive applications, charge controller cab be configured to use an external current source and no temperature sensor.

When using an external current source, the current is controlled by the charger which turns the current source on and off. The charger automatically detects the presence of a battery and starts the charging procedure when the battery is installed. Whenever an error occurs (e.g., short circuit, temperature too high, temperature too low, bad battery, charge time over, etc.) the charger will stay in error mode until the battery is removed or it gets within the allowed charging temperature range.

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Features
Auto-adaptive fast charge
High-resolution, accurate voltage monitoring prevents Li-Ion undercharge or overcharge
Fast charge, pre-charge and maintenance currents are provided. Different currents are selectable via external resistors.
Fast-charge termination by [Delta] temperature/[Delta] time, maximum voltage, maximum temperature, negative [Delta] voltage and maximum time
Dynamically detects battery insertion, removal, short circuit and bad battery without additional hardware
Supports charging of battery packs with 2-8 cells of Ni-Cd/Ni-MH or 1-4 cells of Li-Ion (1 cell of NiCd/NiMH can be supported by added external 2x voltage amplifier)
Three optional LED indicators and Buzzer output indicate operational modes
Ni-MH/Ni-Cd charge mode, Li-Ion charge mode or discharge mode can be selected manually
Supports control of current feedback power supply and constant current power supply

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[This message has been edited by Spin_Doctor (edited 04-30-2001).]
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Apr 30, 2001, 02:04 PM
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Ralph Weaver's Avatar
I've got one of those. You need to supply your own constant current power supply to go with it.
Apr 30, 2001, 02:29 PM
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Please post a link of where this board can be found. - Thanks
Apr 30, 2001, 02:30 PM
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Spin_Doctor's Avatar
How good does it work
Apr 30, 2001, 03:24 PM
rebmeM roineS
MrBungle's Avatar
LM3647
Universal Battery Charger for Li-Ion, Ni-MH and Ni-Cd Batteries :
http://www.national.com/pf/LM/LM3647.html

Evaluation board is available from National for US$59

MrB
Apr 30, 2001, 04:35 PM
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Spin_Doctor's Avatar
Cool eveb cheaper but how will does it work anyone know
Apr 30, 2001, 10:16 PM
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Ralph Weaver's Avatar
Works fine if you have a constant current source.
May 04, 2001, 10:34 AM
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The link to the $59 just point you to Digi-key, which is $75.

Any way to actually get it for $59?

May 04, 2001, 12:52 PM
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A friend of mine here in town works at a custom electronics and fabrication shop. He came across some 12 volt 12 amp power supplies for around $30. Would this work to power this charger?
What about when you're in the field?
May 04, 2001, 05:37 PM
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Ralph Weaver's Avatar
Quote:
Originally posted by sf_247:
A friend of mine here in town works at a custom electronics and fabrication shop. He came across some 12 volt 12 amp power supplies for around $30. Would this work to power this charger?
What about when you're in the field?

You have to have a constant current charger and set it for the cell you're charging. The power supply would need a current adjustment knob.
Jun 04, 2001, 04:40 PM
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is the evaluation baord already assembled? and does anyone have any links for cheap constant current power supplies? thanks
Jun 04, 2001, 06:52 PM
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Fly_joy's Avatar
Go to maxim-ic.com. They will send you samples of thier chips upon request. They have plenty of differnet types of charger chips. Free!
Jun 05, 2001, 12:54 AM
Registered User
National, Linear Technology, Maxim, TI all make battery charge controllers, and provide samples. Also you can get some of them from Digi-key in small quantities. I've tried the BQ2002 from TI; works very well. I use a simple switcher from National to raise my 12V car battery input to 24V for charging cells > 10. Most of them also supply evaluation boards with all the components already soldered in for around $50 - $60, and will probably save you a lot of time.
Jun 05, 2001, 01:03 AM
Registered User
To get the National board for $59, try this link:
http://store.national.com/natsemi/lm3647eval.html

The constant current supply can be built with one regulator (LM317), a couple of resistors and a diode. You can get details of this by going to:
http://www.ti.com/

enter bq2002 in the search window and click go

Then at the bottom, under
TOP TECHNICAL HITS, find and click

"DV2002L2/TL2 Fast Charge Development System Control of LM317 Linear Regulator" (PDF:


The pdf file has schematics.
Sorry about the lengthy instructions - The single URL was almost a page long!



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