If your portable receiver, player or camera runs on batteries, try replacing them with rechargeable batteries. Unlike batteries, they can be recharged many times. Even in one year, you can save two to three thousand rubles in this way.
Instructions
Step 1
Never try to charge batteries that are not designed for this by any means. Always charge lithium-ion, lithium-polymer, and lithium-iron batteries only with factory-made devices. Make your own chargers only for rechargeable NiCd and NiMH electrochemical systems.
Step 2
Calculate the charging current for one battery. To do this, divide its capacity by ten. If the capacity is in milliampere-hours, the charge current will be in milliamperes.
Step 3
Take a power source so that its output voltage exceeds the nominal voltage of the battery by at least four volts, and the load current exceeds the sum of the charging currents of all batteries (they will be charged separately to reduce wear).
Step 4
Purchase as many LM317T voltage regulators as the batteries will charge at the same time.
Step 5
Please note that, despite the similar appearance, the LM317T stabilizer differs in pinout from the well-known stabilizers 7805, 7809 and similar. Namely, the first output is regulating, the second is the output, and the third is the input.
Step 6
In order for the LM317T microcircuit to start stabilizing the current strength instead of the voltage, go to the trick. First, reduce its output voltage to the minimum. To do this, use the regulating output of the stabilizer as a common one, in the same way as it is done when using the 78xx series stabilizers. The output voltage will be equal to 1.25 V. Secondly, connect a load to its output so that at 1.25 V it consumes a current equal to the charging current of one battery. To calculate its resistance, use divide the number 1.25 by the charge current, expressed in milliamperes. Resistance will be in kilo-ohms. The power that will be allocated to the load, determine by multiplying the number 1.25 by the same current. It will be expressed in milliwatts.
Step 7
Please note that the regulator's own current consumption is very low. Therefore, the current that it consumes at the input will be practically equal to the load current. Use this property to stabilize the current through the battery. To do this, connect the input of the stabilizer to the power source through the battery, observing the polarity (plus of the source to the plus of the battery, minus of the battery to the input of the stabilizer, the common wire of the stabilizer to the minus of the power supply).
Step 8
Collect as many stabilizers as there are batteries. Place all microcircuits on separate heatsinks that are not electrically connected to each other. Shunt the inputs and outputs of the microcircuits with oxide and ceramic capacitors of small capacity. Connect oxide capacitors with correct polarity. Their operating voltage must be at least 10 V.
Step 9
Turn on the power to the charger, and after 15 hours, turn off and remove the charged batteries.
