October 30, 2015 at 16:01Power bank AutostartPRO, teardown
So, a review of the new piece of iron. Today it is an external battery, it is also a powerbank, it is also a jump-starter AutostartPRO. Able to charge USB peripherals, laptops, and start engines with a dead battery.
The device comes in a hard cloth case, where in addition to the bank itself, chargers, adapters for proprietary laptop power connectors, and a bunch of instructions are stocked.
On the power wires for lighting a car already familiar from the previous review, there is a box in which a board dotted with Schottky diodes is hidden - to protect against current flowing into the bank. There is no fuse in this case, therefore, diodes will save from polarity reversal. By self-destruction.
The bank itself is made of soft-touch plastic, and, surprisingly, it can be easily disassembled - just unscrew the two screws and the case is divided into two halves:
So, under the cover is a classic model aircraft battery, a controller board that charges, converts and controls the battery, and board with LED.
Great, you can start testing.
The first test is battery capacity. For these purposes, I used a third-party charger, with functions of discharge and monitoring.
The battery comes pre-charged, but recharging it will not hurt. Then you can start the discharge test, with a log entry.
According to the test results, it was possible to pull out a little less than 4 Ah from the battery. I believe that according to all specifications from the Chinese, this battery runs as 4, but the Chinese have stopped laying “reserve” capacities, and as a result, the user already gets a little less than the declared one.
At the end of the charge, a little more was poured into the battery than it was poured, but this is not surprising, the efficiency is not single. In general, with the capacity, everything is clear.
On the packaging, and in all documents to the bank, the capacity is 13600 mAh, and here marketing tricks begin. According to my guesses, the capacity equivalent to one cell is given. The bank has three cells, each with 4 Ah, but even in total only 12,000 mAh is obtained.
And this reduction was made based on the “information content” - conditionally, a bank with 13,600 mAh can charge a phone with a 2500 mAh battery five times. In practice, the figure will be different, due to non-ideal converters and different actual capacities. In this regard, it’s more correct to write the capacity in Watt * hours, but apparently the figure of 13600 mAh looks more attractive than the miserable ≈50 W * h :) I can recommend writing as much as 50,000 mW * h, the figure looks even more impressive.
Moreover, with an adjustable output of 12/15/19 volts, these numbers are completely confusing. The user puts 19 volts at the bank output to charge the laptop, and what final amount of energy should he expect?
Okay, let’s leave this moment to the conscience of the device’s developers, look at the charge / discharge controller board.
The board functionally consists of five modules:
The bank is turned on by a hardware switch with a very small stroke. When I disassembled the bank, the thought crept in me that the switch commutes the current in the amount of amperes. Later, after studying the circuit, everything fell into place - the switch sends an Enable signal to the controller input, which, in turn, allows the operation of all other converters. However, the switch is very delicate, and after several hundred switching it can fail. In the photo he is visible in the right corner.
There are pluses in the fact that in this case there is a switch. On banks with a power button, the controller monitors the current of consumers, and if it is insignificant, the controller turns off the circuit. There is no such bugoff with the switch, and if the bank is turned on, it gives out power regardless of the load.
Battery charger
It is implemented on the MP26123 chip, which allows you to charge 2 or 3 cell batteries with a charging current up to 2 A. But, the strict requirement is a supply voltage of at least 15 volts, so charging from 12 volts will not allow charging up to 100% of the battery capacity, which is somewhat uncomfortable.
A standard charger, by the way, produces 15 volts. Charging from 5 volts (USB) is impossible in principle - the bank does not have a boost converter in front of the charger, respectively, the bank is chained to its own mains charger.
I was interested in the balancer circuit implemented on a separate board located directly on the battery: The balancer and the protective circuit of the battery cells are made on a compact board, on the S8254A chip and three assemblies of AF4935P transistors. In case of overcharge or overdischarge, it turns off the battery or the consumer.
5-volt DC / DC converter
Designed on a TPS54331 chip, with a conversion frequency of 570 kHz, which reduces the output ripple and uses compact components.
When testing the 5 volt line, a funny moment came out. A limit current of 2.5 A is declared along the line. Such a current can indeed be removed, but if it is slightly exceeded, the converter begins to turn off and on the load with a frequency of one second. It looks like an error in the soft-start scheme, and in fact can provide some problems to the consumer. There is such a thesis - switching on, like any other transient process, exerts a load many times greater than working in a steady state. In this case, the consumer may be raped by repeated switching of the power source, which may result in failure of the consumer. This moment can be registered by monitoring the LED under the USB port of the bank. A uniform glow - all is well. Started blinking - overload, it's time to turn it off!
DC / DC converter in 12/15/19 volts
So, the most interesting part of the bank is the boost converter. Allows you to charge laptops and other banks with voltages 12/15/19 volts. If desired, it can even charge itself;). The choice of voltage at the output of the converter is performed by the button. At the first moment I was confused - what will happen if, in the process of work and with the connected load of 12 volts, the switch button is accidentally pressed. During the tests, the fears disappeared - the current sensor on the line programmatically blocks the voltage switching, and it will not work to ruin anything. There remains the option to select 19 volts manually before connecting the load, and only then connect the consumer, designed for 12 volts. Here protection from the fool is impossible.
By circuitry, everything is quite smooth: the boost controller of the FP5139 boost converter operates at a frequency of 1 MHz, respectively, this provides a low level of ripple, a compact inductor, and a minimum number of smoothing capacities. It controls the transistor NTD4906N, which in pulsed mode can provide current up to 223A. An inconceivable figure, such currents there, of course, do not exist. The removal of high voltage from the inductor is involved in the assembly of Schottky diodes MBRB2060CT. 20A, for this circuit it is just right. Well, in fact, overload protection is implemented on two low-resistance shunt resistors.
When testing for maximum current, an impressive 4A was removed from the converter, moreover, regardless of the voltage (after all, at 19 volts this is 76 watts!)
As for 4 amperes, everything is clear - the current is calculated by the voltage drop across the shunt. But in terms of protection - not quite: in most cases, the controller turned off the converter according to the indications from the shunt, but in some cases the converter with an unpleasant fading squeak went to the defense itself.
On protection against overheating - at a current of 4A, the converter did not work even 5 minutes. At the same time, honest 12/15/19 volts are kept on the line in all cases.
At some point, when switching the load, not only the converter turned off, but also the indication of the charge level, all the voltages disappeared. The bank stopped showing signs of life, and I was already upset. According to the results of the autopsy, it became clear that ... everything is fine - 12 volts are legal at the battery terminals, and after disconnecting and connecting the converter board, it worked as before. But remember this point follows.
LED driver, LED
A LED is installed in the bank, with a reflector lens and a heat sink board. I was pleased with the individual driver for this LED, it looks like a complete solution. It is turned on by a long press of the button, has three operating modes - continuous light, SOS, and long flash. An objective assessment of power is impossible, so all I can say is that it shines brighter than the LED flashes of phones.
Controller
It was not possible to determine the true nature of this Chinese (marking L41628D, housing SO16). By functions - it can display the battery charge on four LEDs, in four gradations (although it was possible in eight), monitors the current along the 12/15/19 volt line, controls the flashlight, and eats power from the battery 24/7. Displays the charge process. At the right moments includes converters. Nothing fantastic.
Engine start test
It can be assumed that the continuous discharge current of this battery is 40C. As previously measured, the battery capacity is 4Ah, respectively, the current will be 160A. Well, you can warm up a car battery in 5 minutes. The weather is still not the harshest, so a dead battery was found, and the engine was actually started from the bank. Here's what happened:
Starting the engine without a regular battery, from my point of view, can be dangerous - diodes protecting the bank from the incoming current are soldered in the bank’s plus wire, so when the engine is started, the generator will start idling, and what voltage is installed in the car’s on-board network is unknown. Better not take the risk.
Conclusion
Compared with the previous version of the auto starter, everything looks more attractive - plugs on the connectors, a robust housing, a good flashlight, sufficient capacity, the ability to power laptops, a case for storing all the accompanying iron.
In general, the bank is a harsh male tool, with the expectation of careless handling with hands in the galley, opening cans of beer with sharp angles, highlighting dark alleys with a powerful flashlight, and using it as a weapon to wave a half-kilo bank will not be difficult. Sharp corners, durable plastic and a ribbed surface will only please them.
GeekTimes readers have the opportunity to purchase the new Autostart PRO with a 10% discount using the GEEKT-AVSTPRO code, which is valid for 14 days from the date of publication of the review.
The device comes in a hard cloth case, where in addition to the bank itself, chargers, adapters for proprietary laptop power connectors, and a bunch of instructions are stocked.
On the power wires for lighting a car already familiar from the previous review, there is a box in which a board dotted with Schottky diodes is hidden - to protect against current flowing into the bank. There is no fuse in this case, therefore, diodes will save from polarity reversal. By self-destruction.
The bank itself is made of soft-touch plastic, and, surprisingly, it can be easily disassembled - just unscrew the two screws and the case is divided into two halves:
So, under the cover is a classic model aircraft battery, a controller board that charges, converts and controls the battery, and board with LED.
Great, you can start testing.
The first test is battery capacity. For these purposes, I used a third-party charger, with functions of discharge and monitoring.
The battery comes pre-charged, but recharging it will not hurt. Then you can start the discharge test, with a log entry.
According to the test results, it was possible to pull out a little less than 4 Ah from the battery. I believe that according to all specifications from the Chinese, this battery runs as 4, but the Chinese have stopped laying “reserve” capacities, and as a result, the user already gets a little less than the declared one.
At the end of the charge, a little more was poured into the battery than it was poured, but this is not surprising, the efficiency is not single. In general, with the capacity, everything is clear.
On the packaging, and in all documents to the bank, the capacity is 13600 mAh, and here marketing tricks begin. According to my guesses, the capacity equivalent to one cell is given. The bank has three cells, each with 4 Ah, but even in total only 12,000 mAh is obtained.
And this reduction was made based on the “information content” - conditionally, a bank with 13,600 mAh can charge a phone with a 2500 mAh battery five times. In practice, the figure will be different, due to non-ideal converters and different actual capacities. In this regard, it’s more correct to write the capacity in Watt * hours, but apparently the figure of 13600 mAh looks more attractive than the miserable ≈50 W * h :) I can recommend writing as much as 50,000 mW * h, the figure looks even more impressive.
Moreover, with an adjustable output of 12/15/19 volts, these numbers are completely confusing. The user puts 19 volts at the bank output to charge the laptop, and what final amount of energy should he expect?
Okay, let’s leave this moment to the conscience of the device’s developers, look at the charge / discharge controller board.
The board functionally consists of five modules:
- Battery Charger, charge current up to 2A (MP26123)
- DC / DC converter, output 5 volts, current up to 3A (TPS54331)
- DC / DC converter, output 12/15/19 volts, current 4A (FP5139)
- LED driver and LED (marking DR4NA, SOT23-6 housing)
- Controller (marking L41628D, SO16 housing)
The bank is turned on by a hardware switch with a very small stroke. When I disassembled the bank, the thought crept in me that the switch commutes the current in the amount of amperes. Later, after studying the circuit, everything fell into place - the switch sends an Enable signal to the controller input, which, in turn, allows the operation of all other converters. However, the switch is very delicate, and after several hundred switching it can fail. In the photo he is visible in the right corner.
There are pluses in the fact that in this case there is a switch. On banks with a power button, the controller monitors the current of consumers, and if it is insignificant, the controller turns off the circuit. There is no such bugoff with the switch, and if the bank is turned on, it gives out power regardless of the load.
Battery charger
It is implemented on the MP26123 chip, which allows you to charge 2 or 3 cell batteries with a charging current up to 2 A. But, the strict requirement is a supply voltage of at least 15 volts, so charging from 12 volts will not allow charging up to 100% of the battery capacity, which is somewhat uncomfortable.
A standard charger, by the way, produces 15 volts. Charging from 5 volts (USB) is impossible in principle - the bank does not have a boost converter in front of the charger, respectively, the bank is chained to its own mains charger.
I was interested in the balancer circuit implemented on a separate board located directly on the battery: The balancer and the protective circuit of the battery cells are made on a compact board, on the S8254A chip and three assemblies of AF4935P transistors. In case of overcharge or overdischarge, it turns off the battery or the consumer.
5-volt DC / DC converter
Designed on a TPS54331 chip, with a conversion frequency of 570 kHz, which reduces the output ripple and uses compact components.
When testing the 5 volt line, a funny moment came out. A limit current of 2.5 A is declared along the line. Such a current can indeed be removed, but if it is slightly exceeded, the converter begins to turn off and on the load with a frequency of one second. It looks like an error in the soft-start scheme, and in fact can provide some problems to the consumer. There is such a thesis - switching on, like any other transient process, exerts a load many times greater than working in a steady state. In this case, the consumer may be raped by repeated switching of the power source, which may result in failure of the consumer. This moment can be registered by monitoring the LED under the USB port of the bank. A uniform glow - all is well. Started blinking - overload, it's time to turn it off!
DC / DC converter in 12/15/19 volts
So, the most interesting part of the bank is the boost converter. Allows you to charge laptops and other banks with voltages 12/15/19 volts. If desired, it can even charge itself;). The choice of voltage at the output of the converter is performed by the button. At the first moment I was confused - what will happen if, in the process of work and with the connected load of 12 volts, the switch button is accidentally pressed. During the tests, the fears disappeared - the current sensor on the line programmatically blocks the voltage switching, and it will not work to ruin anything. There remains the option to select 19 volts manually before connecting the load, and only then connect the consumer, designed for 12 volts. Here protection from the fool is impossible.
By circuitry, everything is quite smooth: the boost controller of the FP5139 boost converter operates at a frequency of 1 MHz, respectively, this provides a low level of ripple, a compact inductor, and a minimum number of smoothing capacities. It controls the transistor NTD4906N, which in pulsed mode can provide current up to 223A. An inconceivable figure, such currents there, of course, do not exist. The removal of high voltage from the inductor is involved in the assembly of Schottky diodes MBRB2060CT. 20A, for this circuit it is just right. Well, in fact, overload protection is implemented on two low-resistance shunt resistors.
When testing for maximum current, an impressive 4A was removed from the converter, moreover, regardless of the voltage (after all, at 19 volts this is 76 watts!)
As for 4 amperes, everything is clear - the current is calculated by the voltage drop across the shunt. But in terms of protection - not quite: in most cases, the controller turned off the converter according to the indications from the shunt, but in some cases the converter with an unpleasant fading squeak went to the defense itself.
On protection against overheating - at a current of 4A, the converter did not work even 5 minutes. At the same time, honest 12/15/19 volts are kept on the line in all cases.
At some point, when switching the load, not only the converter turned off, but also the indication of the charge level, all the voltages disappeared. The bank stopped showing signs of life, and I was already upset. According to the results of the autopsy, it became clear that ... everything is fine - 12 volts are legal at the battery terminals, and after disconnecting and connecting the converter board, it worked as before. But remember this point follows.
LED driver, LED
A LED is installed in the bank, with a reflector lens and a heat sink board. I was pleased with the individual driver for this LED, it looks like a complete solution. It is turned on by a long press of the button, has three operating modes - continuous light, SOS, and long flash. An objective assessment of power is impossible, so all I can say is that it shines brighter than the LED flashes of phones.
Controller
It was not possible to determine the true nature of this Chinese (marking L41628D, housing SO16). By functions - it can display the battery charge on four LEDs, in four gradations (although it was possible in eight), monitors the current along the 12/15/19 volt line, controls the flashlight, and eats power from the battery 24/7. Displays the charge process. At the right moments includes converters. Nothing fantastic.
Engine start test
It can be assumed that the continuous discharge current of this battery is 40C. As previously measured, the battery capacity is 4Ah, respectively, the current will be 160A. Well, you can warm up a car battery in 5 minutes. The weather is still not the harshest, so a dead battery was found, and the engine was actually started from the bank. Here's what happened:
Starting the engine without a regular battery, from my point of view, can be dangerous - diodes protecting the bank from the incoming current are soldered in the bank’s plus wire, so when the engine is started, the generator will start idling, and what voltage is installed in the car’s on-board network is unknown. Better not take the risk.
Conclusion
Compared with the previous version of the auto starter, everything looks more attractive - plugs on the connectors, a robust housing, a good flashlight, sufficient capacity, the ability to power laptops, a case for storing all the accompanying iron.
In general, the bank is a harsh male tool, with the expectation of careless handling with hands in the galley, opening cans of beer with sharp angles, highlighting dark alleys with a powerful flashlight, and using it as a weapon to wave a half-kilo bank will not be difficult. Sharp corners, durable plastic and a ribbed surface will only please them.
GeekTimes readers have the opportunity to purchase the new Autostart PRO with a 10% discount using the GEEKT-AVSTPRO code, which is valid for 14 days from the date of publication of the review.