|Experimental Alternator Controller - Here is the schematic for the automatic charger I have been using for my kids' battery cars. The charger is a small molded unit that probably doesn't supply more than an amp and this circuit would have trouble with much more. No current limit is provided by this circuitit relies on the charger for that. The circuit could be modified to provide more current by scroll down to find this one __ Contact: Charles Wenzel of Wenzel Associates, Inc.
Fast Charge Circuits for NiCad Batteries - Linear Technology AN37 __ Designed by Jim Williams Feb 1st, 1990
Fast Charger for NiMH
& NiCad Batteries This is a truly versatile charger. It can charge up to 15 identical NiMH
or NiCad cells. You can build it to suit any size cells or cell capacity and you can set the charge rate. It can fast charge, trickle charge and has safeguards, including temperature sensing, to prevent overcharging.__ SiliconChip
Fast Charges for NiCad Batteries - AN37 Safe, fast charging of NiCad batteries is attractive in many applications. This note details simple, thermally-based fast charge circuitry for NiCads. Performance data is summarized and compared to other charging methods. __ Linear Technology/Analog Devices
Fast High Efficiency Standalone NiMH
/NiCd Battery Charging - DN380 Design Notes__ Linear Technology/Analog Devices
Fast PIC NiMH
/ NiCd Battery Charger - This battery charger charges a NiMH
5-pack battery used in the BiPed robot in less than 1 hour, and charges the 10-pack NiCd used in the Snuf robot in about 30 minutes. To prevent overheating of the battery, the charging current is turned off when the slope of the battery-voltage turns from positive into negative. A second termination-criterion of the charging process is provided for safety: the charge time is limited to about 1 hour.
Fast Universal Battery Charger: Part 2 - Second article has all the constuction details. This unit will solve all your charging problems once and for all.__ SiliconChip
Fast Universal Power Charger - It chargers NiCad, NiMH
, lithium-ion and SLA batteries as well as a conventional car and bike lead-acid batteries. Build it and solve all your charging problems in one hit.__ SiliconChip
Fireflies_In_Jar_Solar_Light - When I was a kid, growing up in Illinois, I remember catching fireflies and putting them into a jar. I loved watching them flashing away at night. Later, I would let them out to live another day. . . . Hobby Circuit by David Johnson P.E.-September, 2017
Friendly Charger for Mobile Phones - Most mobile chargers do not have current/voltage regulation or short-circuit protection. These chargers provide raw 6-12V DC for charging the battery pack. Most of the mobile phone battery packs have a __ Electronics Projects for You
Gel cell Battery Charger - Recently, a fellow amateur was looking for a gel cell charger which would first charge at a fixed rate and then later switch to a trickle charge when the cell was fully charged. After reviewing several catalogs and web sites, the MAX712 IC was discovered. This IC meets all the requirements for almost any type of battery charging system. The circuit in Figure 1 was designed specifically for 12 volt gel cells __ Designed by Radio Amateur Society of Norwich
Gel-Cell Charger I - This high-performance circuit first quickly starts (Tony van Roon's and holds) the charge at 2 amp, but as the voltage rises the current will consequently decrease. When the current falls below 150mA, the charger automatically switches to a lower 'Float' voltage to prevent overcharging. At the point that a full charge is reached, Q1 will bias and the LED will light. __ Designed by Tony van Roon VA3AVR
Gel-Cell Charger II - This circuit needs a regulated 10V-DC front end capable of supplying 2 Amps. Starts the charge cycle at 240mA and at full charge switches automatically to a float condition (trickle charge) of 12mA. __ Designed by Tony van Roon VA3AVR
Gell Cell Lead Acid Battery Charger - This high-performance circuit first quickly starts (Tony van Roon's and holds) the charge at 2 amp, but as the voltage rises the current will consequently decrease. When the current falls below 150mA, the charger automatically switches to a lower 'Float' voltage to prevent overcharging. At the point that a full charge is reached, Q1 will bias and the LED will light. __ Designed by Tony van Roon VA3AVR
High Current Regulated Power Supply - The high current regulator below uses an additional winding or a separate transformer to supply power for the LM317 regulator so that the pass transistors can operate closer to saturation and improve efficiency. For good efficiency the voltage at the collectors of the two parallel 2N3055 pass transistors should be close to the output voltage. The LM317 requires a couple extra volts on the input side, plus the emitter/base drop of the 3055s, plus whatever is lost across the (0.1ohm) equalizing resistors (1volt at 10 amps) , so a separate transformer and rectifier/filter circuit is used that is a few volts higher than the output voltage __ Designed by Bill Bowden
High Speed NiCd Charger for Electric R/C - A few years back, I published a design for a Low Cost Thermal Peak Detection Charger. Since then, I've designed several other chargers, in my ongoing quest to avoid having to spend money. Of course, in building all these designs, I've probably spent more than a really good commercial charger would have cost me. But designing and building is half the fun __ Designed by Stefan Vorketter
Homemade "B" Battery - I recently purchased a couple of old battery-powered tube radios on eBay with the idea of using their cases to house a transistor radio project. But these radios were so nice that I couldn't bring myself __ Contact: Charles Wenzel of Wenzel Associates, Inc.
Homemade battery packs for Canon S100 digicam - In January 2001, I had just received a Canon S100 "Digital Elph" camera for Christmas. This camera was, and still is, a marvel of miniaturization for what it does. But a serious downside of the small size is that the batteries don't last very long. A brand new battery pack will operate the camera, with the LCD viewfinder on, for about an hour, but after a couple of years' use, that same battery pack will give less than 10 minutes of such operation (although it may still take a hundred pictures if used carefully with the LCD mostly off) __ Designed by Markus Wandel
IC Controlled Emergency Light with Charger - White LEDs are replacing the conventional incandescent and fluorescent bulbs due to their high power efficiency and low operating voltage. These can be utilised optimally for emergency lamp and vehicle turning __ Electronics Projects for You
Improved Solar Path Light - The circuit below was designed to replace the guts of an existing path light assembly with one which has a much better performance. I suggest using a quality 10 cell solar panel with at least a 4 square inch area. Buy a panel with solar panels that fills . . . Hobby Circuit designed by David Johnson P.E.-March, 2011
Indicate Health of Lithium-Ion Batteries - 05/14/09 EDN-Design Ideas A simple inexpensive circuit quickly indicates a battery pack's health Design by Fritz Weld, Friedberg, Germany
Indicates Battery Charge Current - This circuit turns on a LED whenever it detects at least 25ma of battery charge current . . . Hobby Circuit designed by David Johnson P.E.-July, 2006
Inexpensive Charges Lithium-Ion Cells - DN188 Design Notes__ Linear Technology/Analog Devices
Battery Charger - this will top-up your motorbike battery in 2-3 hours and switch off __ Contact: P. Townshend EduTek Ltd
Intelligent NiCad Battery Charger - "Connect and Forget" unit fast charges 702-14.4V battery packs from power tools and model cars. A PIC processor simplifies the circuit.__ SiliconChip
Battery Charger - This cheap and easy to build NiCd/NiMH
Battery Charger is suitable for automatically charging a wide range of batteries for many applications. Proper chargers are usually expensive and cheap chargers supplied with the original equipment often incorrectly charge the cells and dramatically shorten their life.
Charger/Cycler with 128x64 Graphical LCD - The accu cycler project presented here is an excellent solution for charging and discharging NiCd and NiMH
accumulators for R/C modelers and others who make use of these accumulator types. With its performance it is very close to the many of the commercial products available on the market.
Interfacing 5 volt CMOS
to 12 volt loads - The circuit above is designed to be used with the bi-directional lamp sequencer shown above on this same page. Two additional transistors are used to increase the current from the 74HCT138 decoder to control 12 volt 25 watt lamps. A 6.8 volt/1 watt zener diode is used in series with the ground connection of all the CMOS
ICs (74HC14, CD4516 and 74HC138s) so that the total voltage across the CMOS
devices will be about 5.2 volts and the outputs will move from +12 to about +7 when selected. The 2N2905/PNP transistor stage is connected as an emitter follower which provides a high impedance to the __ Designed by Bill Bowden
iPOD Charger 1 - MP3 Player Charger|
iPOD-MP3 Player Charger - Portable iPod charger that you can use while away from your computer. The circuit is based around an MC34063 switchmode regulator. This has high efficiency so that there is very little heat produced inside the box, even when delivering its maximum output current. The circuit is more complicated than if we used a 7805 3-terminal regulator but since the input voltage could be 15V DC or more, the voltage dissipation in such a regulator could be 5W or more at 500mA. and 5W is far too much for a 7805, even with quite a large heatsink.
Keep Away Ni-Cd From Memory Effect - Here is a simple circuit that discharges the cell to a level of 600 mV, ensuring that the cell is correctly discharged without the risk of polarity reversal. __ Electronics Projects for You