THEME: Charger attachment
A charger attachment 10 ber. 2015 10:27 #1
The attachment to the charger allows you to automate the charging and discharging of batteries of almost any type. This attachment is implemented on the ATmega8 MC. The firmware, schematic and algorithm are in the archive. The program for the MC was written by Soir. I encountered the following difficulties during the operation of the device. First, in the mode of charging the battery in the menu item “Maximum voltage” the initial value of the voltage is 14.8V. After pressing the button “Plus” the initial value of voltage is reset. Further you can use “Plus” or “Minus” buttons to set the maximum voltage only 4,4V. Secondly, during the process of charging the battery, the recharging is carried out at the set time if the set value of the minimum current and the real value of the minimum current coincide exactly. If the values of these currents do not coincide, then the process of recharging lasts infinitely long, it is not possible to predict the value of the minimum current value, it is different for different batteries, some have 0.07A, others 0.04A and so on. I would like to recharge the battery, if the actual current was less than the minimum current value set. Please ask Soir, if you have the desire and time to fix the firmware of the MC.
- . LCD.zip (53KB)
Charger attachment 19 ber. 2015 05:50 #2
And can not be used in such a beautiful device operational amplifier more widespread at least LM358 or any of the domestic?
The attachment to the charger 19 ber. 2015 06:01 #3
Charger attachment 19 ber. 2015 07:24 #4
Charger attachment 19 ber. 2015 07:40 #5
Nothing complicated. The LM358 wiring diagram is even simpler. Domestic ones, like the 140 series, can be tricky: correction, balancing, power.
The charger attachment 22 ber. 2015 11:51 #6
Hello, would it be time consuming to add regulation to the device, maintaining charging current with PWM or phase control?
Charger attachment 22 ber. 2015 16:56 #7
. add regulation to the device, maintaining charging current with PWM or phase control?
You can add PWM, I don’t understand about phase control. There will be changes in the circuit. You don’t need to change the rest of algorithm? If you need it, please write it down at once.
Attachment to the charger 23 ber. 2015 05:53 #8
- . 534.gif (32KB)
Charger attachment 23 ber. 2015 18:24 #9
Soir, so I thought suitable also set the charge time 1-24hours, then turn off the charge
- CHARGE.rar (12KB)
Charger attachment 23 ber. 2015 18:46 #10
So I take it two circuit options are possible? It would be too complicated with thyristors. So I suggest PWM on transistors. And wanted to clarify again the full algorithm of operation. Do you need a thermometer, do you need a relay, discharge mode, etc.. Maybe some parameters in the settings are unnecessary.
Charger attachment 24 ber. 2015 19:06 #11
Hello, thermometer and discharge is not required, -according to the charging voltage, switch the relay – transformer windings
- 6-24.rar (11KB)
Charger attachment 25 ber. 2015 07:23 #12
But what if I hadn’t asked? Now the relays have been added, how to control them. Can you describe the algorithm in detail?
Charger attachment 25 ber. 2015 18:27 #13
such an idea? you can set in the menu: – directional charging current 0,1-10A – charging time 1-24 hours – maximum voltage at reaching which the attachment disconnects the charger from the AB A- for 6V battery 6-8volt B- for 12V battery 12-15volt C- for 24V battery 24-30volt – when you select A – relay switches to winding 9 volts when you select B – relay switches to winding 17volt when you select C – relay switches to winding 27volt – Charger cannot be started, until the battery is connected to the charger terminals
Charging current – battery voltage – battery run time – and if it is possible the voltage and current setting appears on the LCD display Thank you
Charger attachment 25 ber. 2015 18:43 #14
I would add more protection against over-polarization and complete shutdown in case of “forgetfulness”. That would not burst the battery
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The attachment to the charger 26 ber. 2015 05:57 #15
A diode included in series with the battery protects against improper connection. And also pert offers to lock the charger in case the battery is not connected. Essentially, this includes protection against reverse polarity. There is also protection against “forgetfulness” in the algorithm – “- charge time 1-24 hours” — Questions to pert . 1. How should the charger be disconnected from the battery? Will it be another relay or just set the PWM output to 0? 2. I suggest to make an automatic selection of the transformer winding depending on the set charging voltage. For example, if you set 8V – the 9V winding will be on. Set the voltage above 8V but below 24V – 17V winding.
Charger attachment 26 ber. 2015 06:13 #16
pert proposes to convert the set-top box to a battery charger. I use power supply with voltage regulation in the range of 5-30V and with current regulation in the range 0-10A, so switching of transformer windings is not necessary. The device is designed to automate the process of charging and discharging the battery. The discharge mode is necessary to determine the real capacity of the battery and to train the battery “charge-discharge”, which partially eliminates the desulphation of the battery plates. The charge mode sets the parameters of the battery protection during charging. The setting of maximum current, voltage and temperature just protects the battery from overheating. When charging the battery, it is necessary to separate the charging and recharging of the battery. Before you charge the battery, you must set the maximum charging voltage, which is indicated on the battery case. The battery is not connected to the charger. When the battery is fully discharged, during the charge the voltage will be at a minimum of 11-12V, and the current will be maximum, its value is set with the charger within 0.1C (C – capacity of the battery). When charging, the voltage of the battery will increase and tends to the maximum value set in advance, the charging current remains unchanged. As soon as the battery voltage reaches the maximum value, the charging current will decrease and the battery voltage will remain almost constant. The battery is considered to be fully charged when the charging current reaches a minimum. Then the recharge process begins. The minimum charging current and recharge time are set in the front panel. As soon as the recharge time has passed the charger will disconnect the charger from the battery.
The charger attachment 27 ber. 2015 12:30 #17
Didn’t quite stick to your description, but look what came up. I don’t have the opportunity to test the operation of the current regulator. If I have time this weekend, maybe I’ll try to build something on the layout. — I was just working on a battery from a kid’s toy. When charging/discharging it, I thought it would be useful to track the changes in battery voltage over time. Assembled such a device on the layout and indeed, you can easily plot the charge/discharge curves and track the characteristics of the battery. I added the same option to this firmware as well. It records up to 500 points with a selectable time interval of 1-60 minutes.
Automatic attachment for car battery charger
After adding the automatism to your existing car battery charger you will have no worries about the charging mode of the battery. As soon as the voltage on its leads reaches (14,5±0,2)V, the charging will stop. When the voltage drops to 12.8…13V charging will resume.
The set-top box may be made as a separate unit or integrated into the charger. In any case the necessary condition for its operation will be the presence of a pulsating voltage at the output of the charger. Such voltage is obtained, say, when installing a double half-period rectifier without a smoothing capacitor in the device.
Schematic of the auto-transformer
It consists of a trinistor VS1, a trinistor control unit A1, a circuit breaker SA1 and two indication circuits on LEDs HL1 and HL2. The first circuit indicates the charging mode, the second circuit monitors the reliability of connection of the battery to the terminals of the automatic battery charger.
If the charger has an arrow indicator – ammeter, the first indication circuit is not necessary.
The control unit contains a trigger on transistors VT2, VTZ and a current amplifier on transistor VT1. The base of the transistor VTZ is connected to the slider of the trimmer resistor R9, which sets the trigger switching threshold, i.e. the charging current switching voltage. “Hysteresis” of switching (difference between the upper and lower switching thresholds) depends mainly on the resistor R7 and at the resistance shown in the diagram it is about 1,5 V.
The trigger is connected to conductors connected to the battery terminals and switches according to their voltage.
Fig. I. Schematic diagram of a set-top box.
Transistor VT1 is connected by the base circuit to the trigger and operates in the electronic key mode. The collector circuit of the transistor is connected through resistors R2, R3 and the control electrode – cathode of the trinister to the minus output of the charger. Thus, the base and collector circuits of pa VT1 are powered from different sources: the base circuit is from the battery, and the collector circuit is from the charger.
The trinistor VS1 acts as a switching element. Using it instead of electromagnetic relay contacts, which are sometimes used in these cases, provides a large number of on – off charging current, necessary to recharge the battery during long-term storage.
As can be seen from the diagram, the trinistors are connected with the cathode to the minus wire of the charger, and with the anode to the minus terminal of the battery. This makes trinistors easier to control: when the instantaneous value of the pulsating voltage rises on the charger output, a current starts flowing through the trinistors control electrode immediately (if transistor VT1 is open, of course).
And when a positive (relative to the cathode) voltage appears at the anode of the trinistors, the trinistors will be reliably open. Besides,’ such connection is advantageous because the trinistors can be attached directly to the metal case of the automatic set-top box or to the case of the charger (in case the set-top box is placed inside it) as a heat sink.
With the switch SA1 you can disconnect the STB by setting it to “Manual” position. Then the contacts of the switch will be closed and through “resistor R2 the control electrodes of the trinistors will be” connected directly to the pins of the charger. Such a mode is necessary for example to quickly charge the battery before installing it in the car.
Parts and design
Transistor VT1 can be of the series indicated in the schematic with letter indices A – G; VG2 and VT3 – KT603A – KT603G; diode VD1 – any of the series D219, D220 or other silicon ones; reactive diode VD2 – D814A, D814B, D808, D809; trinistors – KU202 series with letter indices G, E, I, L, N, as well as D238G, D238E; LEDs – any from AL 102, AL307 series (using limiting resistors R1 and R11 set the required direct current of used LEDs).
Permanent resistors – MLT-2 (R2), MLT-1 (R6), MLT-0,5 (Rl, R3, R8, R11), MLT-0,25 (others). The trim resistor R9 is SP5-16B, but another resistor of 330 ohms will do. 1,5 kOhm.
If the resistance of the resistor is greater than that indicated in the diagram, a constant resistor of such resistance is connected in parallel to its terminals, so that the total resistance is 330 Ohms.
Parts of the control unit are mounted on a board (Fig. 2) made of one-sided foil-faced glass-tex plastic with thickness of 1.5 mm. The trim resistor is mounted in a hole with a diameter of 5.2 mm, so that its axis protrudes from the print side.
The board is mounted inside an enclosure of suitable size or, as mentioned above, inside the enclosure of the charger, but necessarily as far as possible from the heated parts (rectifier diodes, transformer, trinistors). In any case a hole is drilled in the wall of the case opposite the csi of the tuning resistor. LEDs and the switch SA1 are mounted on the front wall of the housing.
Fig. 2. The printed circuit board of the device.
To install the trinistors you can make a heat sink with a total area of about 200 cm2. For example, a duralumin plate with thickness of 3 mm and dimensions of 100X100 mm is suitable. The heat sink is attached to one of the walls of the case (say, back) at a distance of about 10 mm – to ensure air convection.
It is acceptable to attach the heat sink to the outside of the wall by cutting a hole in the housing for the trinistor.
Before fixing the control unit it must be checked and the position of the trim resistor slider must be determined. To the points 1 and 2 of the board connect the DC rectifier with adjustable output voltage up to 15 V, and the indication circuit (resistor R1 and LED HL1) – to the points 2 and 5. The slider of the trim resistor is set to the lower position according to the diagram and the voltage of about 13 V is supplied to the control unit. The LED should light up. Moving the slider of the trimmer upwards in the circuit achieves extinguishing of the LED. Gradually increasing the supply voltage of the control unit to 15 V and decreasing it to 12 V, are achieved by trimmer, so that the LED was lit at a voltage of 12.8-13 V and extinguished at 14.2. 14,7 В.
Alexander Vasilievich Korobkov, leading specialist of a Moscow company, was born in 1986. He took up radio amateurism in high school, where he assembled a detector receiver as an eighth-grader. Two years later he assembled a superheterodyne. In the 60’s he designed and assembled a transistor tape recorder. The first publications in the “Radio” magazine are related to that period. Somewhat later he began to publish in the collection VRL. The main subject of his publications in the last decade – automotive electronics.
