by Solarcycle @ instructables.com:
Power Stacker is a portable, modular, USB rechargeable lithium-ion battery pack. Stack them together for power hungry projects or separate them for smaller projects with this modular system. The Gerber, BOM, and .STL files are available below.
Power Stacker does what other USB rechargeable batteries have failed to do, and that’s the ability to combine together for increased battery capacity or separate in to many small batteries for smaller projects. You can literally use the same Power Stacker batteries for many years across many applications!
Stackable USB Rechargeable Battery System - [Link]
by Jim @ jimlaurwilliams.org:
I got a couple of cheap ($1.29) 1A USB LiPo chargers since I’m doing more and more LiPo/LiIon powered stuff. I mostly discharged a recycled 18650 cell for a test load and it looks like it does charge at nearly 1A. Two LEDs – red charging, green (mine is blue) fully charged. Seems like a pretty ideal cheap device.
Cheap USB LiPo charger notes - [Link]
A battery charger is a device used to energize a rechargeable battery by driving an electric current through it. The charging protocol depends on the size and type of the battery being charged. Some battery types have high tolerance for overcharging and can be recharged by connection to a constant voltage source or a constant current source; simple chargers of this type require manual disconnection at the end of the charge cycle, or may have a timer to cut off charging current at a fixed time.
The MCP1631HV multi-chemistry reference design board is used to charge one, two, three or four NiMH batteries or one or two cell Li-Ion batteries. The board uses the MCP1631HV high speed analog PWM and PIC16F883 to generate the charge algorithm for NiMH, NiCd or Li-Ion batteries. It is used to evaluate Microchip’s MCP1631HV in a SEPIC power converter application. As provided, it is user programmable using on board pushes buttons. The board can charge NiMH, NiCd or Li-Ion batteries. It provides a constant current charge (Ni based chemistry) and constant current / constant voltage (Li-Ion) with preconditioning, cell temperature monitoring (Ni based) and battery pack fault monitoring. Also, the charger provides a status or fault indication. It automatically detects the insertion or removal of a battery pack.
The MCP1631 multi-chemistry battery charger reference design is a complete stand-alone constant current battery charger for NiMH, NiCd or Li-Ion battery packs. When charging NiMH or NiCd batteries the reference design is capable of charging one, two, three or four batteries connected in series. If Li-Ion chemistry is selected, the board is capable of charging one or two series batteries. This board utilizes Microchip’s MCP1631HV (high-speed PIC® MCU PWM TSSOP-20). The input voltage range for the demo board is 5.3V to 16V.
Multi-Chemistry Battery Charger from Microchip - [Link]
Dilshan Jayakody has published a new build, an automatic car battery charger:
This is modified version of commonly available automatic car battery charger system. I obtain original layout of this charger from one of the commercially available Chinese car battery charger and modified some of the sections of original schematic to improve the performance and stability of the system. This charger is mainly based on LM311 comparator and 2×12V 4A transformer.
Simple automatic car battery charger - [Link]
The LTC®4121 is a 400mA constant-current/constantvoltage (CC/CV) synchronous step-down battery charger. In addition to CC/CV operation, the LTC4121 regulates its input voltage to a programmable percentage of the input open-circuit voltage. This technique enables maximum power operation with high impedance input sources such as solar panels.
An external resistor programs the charge current up to 400mA. The LTC4121-4.2 is suitable for charging Li-Ion/ Polymer batteries, while the programmable float voltage of the LTC4121 is suitable for several battery chemistries.
LTC4121/LTC4121- 4.2 – 40V 400mA Synchronous Step-Down Battery Charger - [Link]
by Superbender @ instructables.com:
Winter just arrived. The enemy of all batteries. Last year this was the season the auxiliary battery of my T3 VW camper bus bit the dust. This likely happened because I neglected to take care of it over the winter months during which the bus is typically parked in my garage. When the auxiliary battery is really dead dead, aka croaked, it is not only not working, but it also prevents the main battery used for starting/driving of the bus to be properly charged when driving. Not a good situation if you are somewhere out in the woods and eventually need a ride back to civilization. After almost getting stuck in the boonies, I decided to build a two-channel battery cycle charger that is supposed to keep both batteries happy and healthy for these winter months. You can see this project documented here.
ATtiny85 Two-Channel Lead Acid Battery Charger - [Link]
In this project, we are building a programmable single/multi cell lithium battery charger shield for Arduino. The shield provides LCD and button interface which let the user set the battery cut-off voltage from 2V to 10V and charge current from 50mA to 1.1A. The charger also provides the ability to monitor the battery status before and during charge.
The charger is based on LT1510 Constant Current/Constant Voltage Battery charger IC and controlled by Arduino UNO. The display on the shield is Nokia 5110 LCD which is very simple to use and still available on the market. There are two different battery connectors available on the shield, a two contact screw terminal block and a right angle 2mm JST-PH connector.
DIY Lithium Battery Charger Shield for Arduino - [Link]
The bq2510x series of devices are highly integrated Li-Ion and Li-Pol linear chargers targeted at space-limited portable applications. The high input voltage range with input overvoltage protection supports low-cost unregulated adapters.
The bq2510x has a single power output that charges the battery. A system load can be placed in parallel with the battery as long as the average system load does not keep the battery from charging fully during the 10 hour safety timer.
BQ25100 – 250-mA Single Cell Li-Ion Battery Charger - [Link]
A USB port is a great power source for charging a single cell Lithium-Ion battery. It is capable of supplying a maximum of 5.25V and 500 mA. The circuit above is a USB powered single cell Li-Ion battery charger. LM3622 is used as the controller. This special purpose IC has a precise end-of-charge control and low battery leakage current about 200nA. S1 and S2 select the low voltage detect enable/disable. The low voltage detection is handy for conditioning a deeply discharged battery with a low current stage, to prepare it for the full charge cycle.
LM3622 Li-Ion USB Battery Charger - [Link]
This Arduino Nano controlled solar battery charger can charge a standard lead acid 12V battery and runs with 90% efficiency under 70ᵒC (158ᵒF). The circuit can take up to 24V input from the solar panels. The maximum power point tracking is implemented in the circuit by measuring the output voltage and current from the solar panel to get the maximum possible power from it.
Solar battery charge controller - [Link]