SmartBatteryPack
From [WearLab]
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Smart Battery Pack
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Features
Lithium-Polymer batterypacks with integrated charging circuitry and fuel gauge IC.
Recharge connector: Low Voltage Plug, internal diameter 2.1mm.
System Connector: Micromatch 4-Pin; Voltage, GND and One-Wire communication
Recharge LED goes OFF when charging is finished.
2 Cell-System: 7.4V average; charging voltage 9V ( absolute minimum, might result in only partial charge ) to 12V ( recommended ), 15V absolute maximum of onboard charging circuit, Charging time about 2h.
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Versions & Notes
SBP V3R0:
- Polarity of recharge-connector reversed to all later models: positive outside, negative inside.
- No onboard On/Off switches, thus permanent power-supply to connected devices.
- Design flaw 1: Fuel-Gauge measurement-resistor RSNS does not fit it's pad - manual fitting by rotating it around 90°.
- R6 ( Optional ) not to be fitted.
SBP V4R0:
- Corrected soldering-pad for Fuel-Gauge measurement-resistor RSNS removes Design Flaw 1 from V3R0
- On-Board On/Off switches ( switching on/off positive power supply to Micromatch-connector )
- Power-interrupt on Micromatch-connector upon inserting of recharge-jack ( cutting off GND )
- Polarity as expected on most german devices: positive terminal inside, negative terminal outside.
- Secondary LED showing state of Micromatch Terminal ( On / Off ), overridden by charging-plug ( Thus secondary might be on, but lacking the GND a connected device should be off ).
- Protector-Diode to prevent damage from wrongly polarized recharging-plugs.
- Design flaw 1: Voltage-supply to On/Off circuitry ( PIC12F508 ) is by layout 3.3V, but PIC needs 4V at least. Hand-fixed on all exsting V4R0 boards by rewiring the MAX1615 voltage regulator to provide 5V instead of 3.3V
- Design flaw 2: PG-DATA, PG-Clock and MCLR-Lines laid out nicely, but forgot to provide +5V and GND pins to have at least the GND-reference. Once programmed irrelevant, but programming V4R0 needs to connect GND manually to a contact of the PIC12F508.
- R6 ( Optional ) not to be fitted.
SBP V4R1:
- 5-Pin programming-connector providing +5V and GND removing the Design Flaw 2 of V4R0
- Corrected configuration of MAX1615 voltage regulator, now providing 5V to the PIC12F508
- Enhanced Routing and Layout, enhanced soldering pad for Fuel-Gauge measurement-resistor RSNS
- R6 ( Optional ) not to be fitted.
SBP V4R2:
- enhanced routing, no unnecessary components anymore ( = R6 ( Optional ) removed )
- SBP V4R2 not yet ( 2006.July.05 ) produced.
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Pinout
Recharge-Connector: Polarity as given in 'Version & Notes';
- V3R0 inner pin negative, outer pin positive
- V4R0 onward: Inner pin positive, outer pin negative
Micromatch-Connector: Pin 1 is the pin adjacent to the drill in the PCB for the polarity-guard of the Micromatch-plastic-frame
- Pin 1: positive terminal; +7.4V average; disconnected upon switching of the battery pack using the 'off' button
- Pin 2: ground / negative terminal; disconnected upon inserting the recharge-jack
- Pin 3: Not used
- Pin 4: 1-Wire communication line
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Charging of the Smart Battery Pack
The battery packs can be charged with DC voltage from 9V to 15V. Caveats apply:
- Depending upon the given power-supply charging with 9V may not always result in a 100% fully charged battery ( Voltage-drop under load on the powersupply's side, losses over the circuitry of the batterypack ), but in any case battery should remain quite cool whilst charging.
- Charging with 12V will charge the battery to 100%, but the circuitry will get quite hot, as about 0.6W to ~1W of electric power is dissipated as heat. Consider removing the battery from cases, wrappings or other heat-blocking encasements.
- Charging above 12V ( 13.8V / 14.4V as for example from a car's 12V cigarette-lighter-jack during drive ) should work, too, but it is not tested yet, and it will produce even more excessive heat, which in itself could lead to problems - Lithium-cells don't like temperatures above 60°C.
