Charger for car batteries
Scheme charger is shown in the relative complexity of chips. Created
this just for one condition: to adjust the current should be from 0
to maximum. Usually, even a factory car chargers have the initial
leap from 2,5-3 A and to the maximum. In the charger used thermostat,
which includes a radiator cooling fan, but it can be deleted. This
was done in order to minimize the size of the charger. Charger
consists of a control unit and the power section.
Fig.1. Charger for car batteries. Scheme
The voltage from the transformer Trr, approximately 14 V, enters the
diode assembly KTS405. Rectified voltage used to power the control
circuit D3 and thyristor pulse-forming network management. After a
chain of Rp, VD1, R1, R2, and the first element of the chip D1.1,
receive signals, roughly the shape. (Figure 2.1).
Then these pulses through R3, D5, C1, R4, converted to a saw, a form
of which varies with the R4. (Figure 2.2). Elements chips c D1.2 to
D1.4 equalize signal (attached to a rectangular shape) and prevent
the influence of the transistor VT1. Ready signal passing through
D4, R5 and VT1 comes to managing output thyristor. As a result, the
control signal by changing phase thyristor opens at the beginning of
each half period, in the middle, in the end, and so forth (Figure 2.
3). Regulation of the full range of smooth.
Nutrition and chip and the transistor VT1 receive from KREN05. (it
pyativoltovaya Krenke). For it is necessary to tie a small radiator.
Strongly Krenke no heat, but heat dissipation needs, especially in
hot weather. Instead of transistor KT315 can apply KT815, but may
have to pick up the resistance R5, if not open thyristor.
Fig.2. Charger for car batteries. Diagrams and
design of the radiator
It consists of a thyristor D3 and 4-diodes KD213. Diodes D6-D9 are
chosen from considerations that are suitable for current and voltage
and should not be screwed. They are simply pressed against the
radiator metal or plastic plate. The whole thing (including the
Thyristor) mounted on a radiator, and under the diodes and
thyristors enclose insulating heat-conductive plate. I found a very
convenient material in the old burnt-out monitors. He is and the
power supply from the computer. At the touch it is like a thin
rubber, is used to import equipment. But of course you can use
ordinary mica. (Fig.2. 4). In the worst case can be made for each
diode and thyristor its own radiator. Then no mica is not needed,
but the electrical connection of radiators should not be.
Consists of 3 windings:
1 - 220 V.
2 - 14 V, to supply management
3 - 21 - 25 V to supply the power section.
Fig.3. Charger for car batteries. PCB
They check the work as follows: connect to the battery charger instead
of a light bulb at 12 V, for example on the dimensions of the car. About
the turn R4 brightness light bulbs must be changed from very bright to
fully extinguished condition. If the bulb does not burn completely, then
reduce the resistance of R5 half (to 50 ohms). If the bulb does not go
off completely, then increase the resistance of R5. Add approximately
If the bulb does not burn completely and nothing helps, then peremknite
collector and emitter of transistor VT1 resistance of 50 ohms. If the
bulb is not lit up - incorrectly assembled power part, if on fire, look
for fault in the control circuit.
So, if everything is regulated and lights need to set charge current.
The figure is a resistance 2 ohms (wire resistance of nichrome at 2
ohm). First, take the same, but a 3 ohm. Connect the charger and jumper
wires short-circuited, which went to the lamp and measure the current
(on the ammeter). It should be 8.10 A. If it is more or less, then
adjust the current through the wire resistance Rprov. Sam nichrome can
be 0,5-0,3 mm in diameter. Remember when this procedure, the resistance
of great heats. It runs cooler when charging, but not so much, it's
normal. So Make it cool, such as holes in the hull, etc. But fans
poiskrit crocodiles will not be equal, sparks arbitrarily, charger,
nothing will happen. Strengthen resistance Rprov. better on getinaksovoy
And the last - on ventilation. Among the elements KREN12, C2, C3, VT2,
R6, R7, R8 collected cooling radiator (mounted assembly). By and large
it is not necessary (unless you are doing super mini charger), it's just
rage. If you have a heat sink (for example) of the aluminum plate 120 *
120 mm, then this is sufficient for heat dissipation (the area of the
factory radiator of this size, even large). But if you really want the
fan, put one Krenke at 12 V and connect it to a fan. Otherwise you need
to install the sensor transistor VT2. It must be attached to the
radiator through the same insulating heat-conductive plate. You can use
the CPU fan from the processor 386, or 486. They are almost identical.
All resistance device 0,25 or 0,5 Va. Two trimming by an asterisk. Other
It should be noted that if instead of KD213 diodes will be used D232 or
the like, the voltage winding Trr 21 The need to increase to 26-27 V.
Ed. 02.12.09. V. Gainutdinov