19.10.2023
Adjustable power supply - charger for electric bicycle. Which electric bike charger is used after the adoption of European environmental standards? Video review during the setup process
Charger for a 24-volt “canister” bicycle battery. At the time of purchase - the cheapest one found on Ali. I wasn't surprised by the quality of workmanship, but it works as advertised. I recommend it if there is nothing else. Dismemberment, phone photos, a couple of measurements.
The idea of buying a spare charger for my bike came to me as soon as the bike itself (Eltreco Marsel of the first release) appeared. A “junior class” bike, folding, with 20-inch wheels. In the description of the bicycle, spare parts and accessories, the assembly company indicates a voltage of 24V.
About tension, chemistry and disclaimer. Be sure to read!
"24 volts"- This is not the exact voltage of the battery used in the bike. This is rather a class of electric vehicles with optimal achievable power and a reasonable price. This classification was established during the popularity of lead batteries, usually produced in the form of 12-volt blocks connected into 36-, 48-, 60-, 72-volt chains. Now there are several different grades of lithium on the market, and many types of batteries with different chemistry and number of cells fall under a specific “norm”.
My "24-volt" vela - the simplest and most common case in the lower class: 7S LiPo. That is, inside the canister there are seven series-connected lithium-polymer packages, each with a maximum voltage of 4.2V. Multiply: 4.2*7= 29.4V. It is at this voltage that the battery is considered fully charged, and the automatic charging is turned off. This point is not always clear, many manufacturers of chargers, batteries, and bicycles label their products simply as “24V,” suggesting the use of standard accessories and without going into details. At the same time, for lithium batteries, a difference of several tenths of a volt is very critical. Inattention to these subtleties can cost you at least an expensive battery, and in the worst case, it will result in a serious fire. Be careful when choosing and operation of a third-party charger, no matter how perfect it may be in itself. I leave all possible risks in this regard to your discretion..
The included charger for my bike was perplexing - the size is slightly smaller than a brick, the charging current is only 2 amperes, the rigid detachable power cord with a large “computer” connector is all against carrying it with you. The power reserve of the device is only about 20 km, exactly one way to the dacha. That is, we needed a device that was more portable and, if possible, faster...
Alas, I had to give up the idea of speed after some time. After two seasons of not very active driving, the battery died. Opening and knee-jerk repairs with replacement of the depressurized can showed that it is really better not to charge this “canister” with a current of more than two amperes - the dense packaging of nameless lipoles, the absence of thermistors inside the package... Well, let it be two amperes.
What finally helped me decide on a purchase was that the standard charger was simply stolen ( as well as another half-centner of material surplus, including photographic equipment - therefore I really, really apologize for the quality of the pictures in this review. Someday I'll definitely fix it). All winter, Ali slowly dug for the cheapest possible analogue, Avita - for stolen goods, and at the same time soldered a booster to charge a canister from a laptop power supply - but in April the subject of the review was discovered, 584 rubles at the time of purchase. The season was approaching, there was no point in thinking further.
The order arrived in less than 20 days with free shipping - an absolute record! The credit goes to the seller, the post office, customs - I don’t know. Most likely - His Majesty Random.
A yellow envelope, inside - a slightly wrinkled white box made of thin cheap cardboard, good for nothing. I immediately threw out the packaging - there are already too many photos of Chinese baby bumps here. On the box, a Chinese calligrapher wrote something in the spirit of graffiti with a bold black marker, which was later difficult to recognize as “29.4V2A”.
Inside is the hero of the review:
An ordinary small brick with a two-color LED on the front side and a not very evenly glued label on the bottom. The plastic looks cheap but is durable.
Here's a comparison with well-known items and the power supply from Asus K43:
Dimensions - 115x47x31. The power cord is removable, with a “tape recorder” connector, low voltage, and is tightly sealed. Both are short, no more than a meter; if this is only beneficial for the low-voltage circuit - there is less voltage drop - then the network network must be extended. In my previous charger I soldered a ready-made high-quality three-meter wire with a plug from , but I didn’t have it at hand, so I decided to extend the one I have... Right now! Complete cord - full guano with conductors made of copper luminium:
Shiny white is not poluda, it is lumin. At the first touch with a soldering iron, the copper coating dissolves in the solder, and the bundle turns into a grayish sour. You can solder it with swear words, but it’s better to throw it straight into the trash: even if it’s soldered, or if it’s whole, such a wire won’t last long. However, the already mentioned Elektromontazh also sinned by selling clad wires for copper a year ago.
The connector for connecting to the battery also needed re-soldering - out of the box the charger has a regular cylindrical plug with a diameter of 5mm, but I need an XLR. There is another not very pleasant surprise: the low-voltage wire looks solid - but the wires are thin, less than half a square by eye, although 18 is written on the cable.
Okay, soldered, connected - as expected, first to the battery, then to the network (otherwise the output voltage immediately rises to the maximum, and charging automatically turns off, considering that it has already charged everything). The process started, the LED lights up red, nothing exploded :) After a couple of hours the green light turns on - the battery was already half charged. The charger got very hot - ok, an excellent reason to see what kind of boiler is inside it. A strong knife and a clamp will help us - we start from the corners, it is not sealed too harshly, the plastic itself is quite soft.
The first thing we feel when we open the case is that it STINKS. GASOLINE. I don’t know what they are doing with it there. Maybe they wash off the flux and save alcohol... I had the same smell from freshly unpacked Chinese gas engines for mowers and mopeds. Here's what's inside:
The board is not secured in the case; there is a piece of foam tape on the cover near the transformer for pressing. Radiators hang mainly on the terminals of the parts; it is very advisable to at least glue them to the board with elastic glue (by the way, colleagues, recommend a silicone-like glue with good adhesion and strength).
The capacitor on the high side is 68 µF * 400V, on the low side - 470 µF * 50V, both 105°C. On the left - a connector for the power cord, a heatsink for a high-voltage transistor, a bridge, a soldered-in 3.15A fuse; on the right is the output diode heatsink. Basic powder - SMD:
Soldering - knee:
Hefty wire shunt:
There is no input RF filter; instead of a starting posistor, a jumper is soldered in. The converter is assembled on something like an 8N60 field machine. There is a distance of at least 10mm between the tracks of the primary and secondary circuits on the board, even in the area of the optocoupler, there is no slot. There is a correct kilovolt capacitor between the primary and secondary common wires. The circuit for stabilizing the charging current and voltage cut-off is based on the classic LM358 based on TL431, the rectifier diode is MBR20200. For some reason, the latter heats up too much for two amperes of current.
Low voltage circuit diagram
Before it cools down, measure the temperature:
The hottest part is the transformer, although it is quite large for 50 watts and looks high quality. On the left is the trans, on the right is the transistor radiator (on bare metal the thermometer lies, but the trans is really very hot).
Finally we got to the main thing: charging current and cut-off voltage.
The ticks are most likely moving a little, because... not verified and, apparently, magnetized - without current they show half an amp, this can be treated by turning on relative measurements. Sorry again for the terrible photo. At the time of shooting, the indicator shows 2.14A. The current does not decrease towards the end of the charge. This is bad - for a more complete charge and proper balancing of the battery, the final current should decrease by a factor of 10. But it is not fatal - especially if in addition to this there is a more advanced charger.
The voltage gauge, which has been reviewed and praised here many times, and has never been altered, can be considered truthful:
Out of ineptitude, I reset the maximum voltmeter reading - it was 29.51V.
As we see - the stated parameters are met in terms of the precision of the components used. :) A slightly higher current is good in itself; it will charge a little faster without the danger of overheating. Increasing the voltage by 0.1V on a 7S battery is not scary, especially considering the thin low-voltage cable. There is, however, some probability that charging is cut off by the BMS built into the battery. At your leisure, you will need to build an adjustable load and check everything again. But for now I’ll do just that.
Summary:
An ordinary Chinese product, without outstanding merits or critical flaws. Can be taken as an additional spare-portable memory, taking into account the possible re-soldering of the connector and replacement of the power cord. The price, in my opinion, is too high: power supplies for laptops with even higher power are one and a half times cheaper. Well, of course - a niche product... But there is simply no ready-made charger specifically for 7S lithium - for less money. In addition, just six months ago, 24V 2A chargers on Ali cost another 100-200 rubles more.
If it were not for the price, it could be recommended as a basis for conversion to other voltages/currents: after all, it was done well for the Chinese industry, the circuit is simple, the output voltage margin follows from the input voltage margin.
In the meantime, the driving season is ahead - we will see how the piece of hardware will withstand it.
PS: Dear colleagues, this is my first review here, so please kick, but please, not strictly. :) What is lengthy - we will shorten, what is short - we will add, what is unclear - we will clarify, what is dark - we will illuminate. And in one of the next reviews we will replace the shutter with a 30D - and then everything will be completely fine! :)
I'm planning to buy +3 Add to favorites I liked the review +30 +46In order for the batteries installed on electric bicycles to last longer, they need to be properly charged, i.e. The service life of this important element depends on how efficient the charging method is chosen.
There are several methods: One is based on the use of a constant voltage of 13.8 W, another, called two-stage, constant current, and the third uses constant current and a charge depending on the capacity of the nominal battery.
The first charging method is considered the most preferable. In this case, the battery is connected to a source that maintains a constant voltage throughout the charging process. As charging increases, the current decreases. Gradually it decreases to zero, becoming insignificant. In this way you can achieve 95% battery charge. It's useful to know that when developing lead acid batteries unattended ones, the low value of the recharging potential was taken into account, based on the need to minimize the volume of gases released during “bringing up” to full charging.
Electric bicycles have some nuances associated with charging batteries. For example, when the voltage during recharging increases to fifteen volts, sulfation noticeably decreases, and due to the design features of these batteries, corrosion of the positive electrodes increases, leading to rapid failure of the battery. Therefore, it is recommended to use an electric bike charger that supports higher charging requirements. The best choice for maintenance free batteries would be pulse type charging, capable of providing constant voltage.
It is even better if they are equipped with a temperature sensor, since its value slowly increases during the charging period, causing an increase in capacity, which leads to overcharging, i.e. the charge level is higher than the required value. This has a negative impact on battery parameters. If it is charged at a low temperature, the situation will be the opposite, i.e. the battery will be undercharged. Temperature sensors can correct these parameters, eliminating such effects and, therefore, extending the “life” of batteries.
In order to charge a lithium-ion battery used in electric bicycles, use a special charger connected to household power supply 220v. Two different cables are supplied with it, one of them is necessary for normal connection to an outlet and is about 1.4 meters, and the other to the battery socket (three-pin socket) and its length is 1.1 m. They are suitable for any bicycle that uses a battery with a capacity of ten to twenty amp/hours. These chargers automatically stop charging once the battery is fully charged.
To determine this, there is a special indicator on the charging case: it lights up red during the entire charging process, and, as soon as it is completed, changes it to green. Charging lasts approximately four to five hours. At the same time, you can charge the battery by removing it from the vehicle or directly on it. To extend its service life, it is not advisable to charge the battery in rooms with negative temperatures, or immediately after bringing it from the cold into a warm room. You can start the process as soon as the battery warms up to room temperature.
In online stores, of which there are many on the Internet, they offer the following types of chargers for lithium batteries installed on a vehicle called an electric bicycle:
- For lithium phosphate batteries with a capacity of 36V 12 A/h and 36V 12 A/h.
- For lithium manganese batteries with a capacity of 36V 16A/h.
You should not use a charger that is not designed for a specific battery type (specific voltage and capacity) to extend the life of the batteries.
For charging types of batteries: lithium magnesium, lithium ion, lithium polymer with values capacities 8-14 ampere hours and rated voltage 48 V in automatic mode, the charger is designed with voltage power supply 220 V, the maximum consumed current is 0.8 A. At the output it gives 0.8 A - the maximum consumed current and voltage - 1.8 – 0.05A, changing automatically. Its dimensions and weight are not at all large. They are equal to 166 x 84 x 60 mm and 0.650 kg, respectively.
A warranty card is issued for the charging device for a period of six months. In automatic TM devices “Volta bikes” the optimal current and voltage are ideally selected. The charging current should not be more than 10% exceed the rated battery capacity to extend the latter's service life. If you use devices with a higher current, the battery charging will speed up slightly, but the battery life will be shortened. TM “Volta bikes” with a nominal voltage of 24 V is capable of efficiently and quickly charging batteries whose capacity 10-14 A/h, producing an output current of 1.8A. It can also be used to charge batteries capacity 7-20 A/h. Among the negative consequences, we can note a slightly increased charging time, and that’s all.
For lead batteries, the following charger can be considered as an option.
Technical characteristics of NBC-01 (RV-24v)
- Maximum current consumption is 0.8A.
- Supply voltage and output voltage respectively: 50Hz, 220-240V and 28-28V.
- Automatically varying charge current – 0.05-1.8 A.
- Dimensions, mm - 160 x 89 x 54.
- Power cord, length for connecting the battery: 90 cm and 65 cm, respectively.
- Weight, g – 344.
Hi all! I am posting my universal power supply with charging functions, which can be a universal solution for radio amateurs, car-moto owners, owners of electric vehicles, etc.
ATX conversion scheme
The principle of alteration is:
- Fitting standard ATX computer blocks on TL494 to an adjustable power supply with voltage and current limitation.
- Raising the output voltage to 90 volts by reworking the output part of the unit and replacing the transformer.
- Integration of a charge circuit with pauses into the block (the simplest transistor multivibrator).
Initially, the unit was planned to charge and resuscitate electric bicycle batteries. The output characteristics of the unit are 0-90 volts constant voltage and adjustable current up to 2.74 amperes. The ATX power supply is used as the basis. The transformer is taken from the power supply unit of the V770/570 monitor. Digital voltammeter - ready-made Chinese 100 V 10 A. Next, see a photo review of a homemade design:
The block contains a battery charging circuit with pauses (to charge the battery). There is also short circuit protection.
Video review during the setup process
