Connecting & Charging 3S2P 18650 Cell Pack with HX-3S-FL25A-A BMS: Balancer, Overload & Discharge

Question

Hello, I have a 3s2P cell package and I have a question if it can be loaded with this module. In the seller's drawing, the 3s1P package is drawn, whether it will load properly when the links are connected in parallel. Is this module enough to charge such a package and protect it against...

Wojtek(KeFir) · Accepted Answer

No. This has two functions. Balancer - spreads the load equally on the links. And the OVP UVP OCP fuse. Nothing more. There is no charging logic, no temperature measurement, no charge time analysis, no current ramp.

krzysiek_krm · Accepted Answer

Hello, sellers call these tiles: a safety system with a balancing function. In my opinion, you can use your plate only as a protection system type hardware secondary protection but even this function is not quite sure. First of all - security. Vendors delightfully give detection voltages OVC = 4.25 - 4.35 V and OVD = 2.3 - 3.0 V. This is some mindless tracing of the first page catalog data of the voltage detection system, actually these voltages are from a certain range, but the end user has no possibility of adjusting them . The systems are manufactured in a number of versions that have different combinations of these voltages pre-set. You should read the markings of the detection systems on your board and check in the catalog data whether by accident the current combination of detection voltages does not match your links like the ox to the carriage. Second - balancing. From the available here and there descriptions of this board, balancing uses hardware 4.2 V detectors, which short-circuit the cells with 100 ? resistors, giving a dizzying 42 mA balancing current, i.e. balancing is formally but it is not there. Such a balancing current is great for low power systems, but the 25 A current limit suggests that this is probably not the case. You should therefore buy some decent charger with reliable balancing. It would also not have been necessary to equip the battery with signaling detectors and possibly disconnecting the load at a cell voltage higher than the final cut-off voltage, notorious disconnection by the protection system will cause rapid deterioration of the cells and shorten their life time. greetings

Wojtek(KeFir) · Accepted Answer

No, only BMS. Here's a bit to read: An example of a scalar that has a stitched Li-ion charging program in it is LTC4007. Linear technologies generally have a whole range of charge drivers for everything. Generally, this company has very interesting and unusual scalaki. Unfortunately - to buy it in Poland is a massacre. Third World.

Wojtek(KeFir) · Accepted Answer

The balancer is only needed when charging. You can connect a BMS that will not have a balancer in it. It will simplify the layout.

krzysiek_krm · Accepted Answer

That's what I meant. Plenty of devices have a processor in which some threshold voltages or currents are set. Some devices are completely hardware, they also have some threshold values. In the case of lithium-ion cells, which are quite sensitive to overcharge and excessive discharge (for explosion and ignition), additional use of hardware secondary protection systems has been adopted, which are quite simple and therefore highly reliable, which in case of what just cut off the link from the rest of the world : charger or load. The processor may hang, the hardware system may be damaged, so the extra protection system is simply a redundant protection. It's a bit like fuses here and there - you can assume that a TV, computer, washing machine or whatever manufacturer did it well - so why fuse.

Dawek1997 · Answer

The electronics have been taking care of the amateur for some time, but somehow I could not get the whole BMS, balansers. So, BMS, as I understand it, I can only use to protect cells from discharging, overloading, and before downloading too much electricity, and the balancer to load each cell evenly. The purpose of this package, welded together links, will be to place it permanently in the middle of the portable speaker. Therefore, a similar BMS circuit with a balancer only for a smaller current because I definitely do not need 25A, can be mounted in the middle of my device, connecting to this charger and lead from it a connector to connect an external 12.6V power supply with a current limit of 8A ? Would that be more correct? ( Added after 2 [minutes]: Is this only BMS and not a charger and I can not charge it? I'm already confused

Dawek1997 · Answer

Hmm ... So I could connect the BMS itself to the links as a protection of these cells against excessive discharging during the operation of the loudspeaker, and connect a charger such as imax for charging? Additional balancer's duplication is unnecessary because the charger has it in itself, and the balancer is only needed for charging? I connect the charger in parallel with the BMS in the loudspeaker? Added after 30 : I apologize in advance for my curiosity

Dawek1997 · Answer

So it will be the correct connection? I do not bother you anymore head as correctly.

Wojtek(KeFir) · Answer

No, definitely not. Here you have BMS without a balancer. He only measures the voltages of individual sections and analyzes them. You use the balancer from the charger.

Dawek1997 · Answer

or from Imaxa 2 wires to BMS input pins from controlling cells?

Wojtek(KeFir) · Answer

No. You just did not have current connections. And BMS must be without a balancer. You will recognize it after the lack of a section with 2-4 transistors and high power resistors. (not to be confused with the shunt to measure the current of the packet).

Dawek1997 · Answer

Mhm ... So everything is like in my schematic but I also have to lead two wires from Output BMS and also connect to Imax and it will be cacy?

Wojtek(KeFir) · Answer

Do not Output only B + and B- with those round sockets on the left on Imax. These are the current terminals - that's how it charges the battery. This small plug only measures if everything goes well and even.

krzysiek_krm · Answer

The two plates HX-3S-01 found by you are only I'm afraid, however, that it may have a slightly too low OVD detection threshold, I think you should use a system (or systems) to signal the state in which the voltage any link is lower than (say) 3 V. Unfortunately, you probably are not right. From available here in the network (although slightly obscure) diagrams show that connecting to B + and B- you will connect the charger to the bare battery, bypassing the cut-off transistors and current resistor, ie the protection will not work, please connect to P + and P - anyway, having a physical tile you can see how connections are going. So from another keg, do not abuse the abbreviation BMS, it is usually a Battery Management System - a fairly extensive and complex system of very advanced dominion over the battery.

Wojtek(KeFir) · Answer

Well, that's right. But take a look at all modeling packages. You are just charging directly, using the built-in security device. In turn, in laptops is how you write, the battery electronics is permanent.

krzysiek_krm · Answer

To be honest, I hardly know these buy chargers, maybe they have such in themselves protections or maybe they do not. It seems to me quite unlikely, these chargers are usually quite universal, for different types of cells, so they would have to have these protection systems configured in some way, which would probably be quite complicated and rather expensive. Certainly they have such protection built into the software, but the use of a hardware security system is advisable. It is such a last line of defense cells in the situation when everything else fails: the processor will hang, the output transistor will break short, etc. It is just a certain redundancy, using a relatively simple hardware layout, for which the probability of failure is quite small, of course, this is not an impossible event, but there are no devices with 100% reliability.

Wojtek(KeFir) · Answer

Well, they have it. They have a processor, a program in the processor, and he controls it. You have a display, a keyboard and you set yourself.

bigdanmura · Answer

There are a number of collaterals called colloquially BMS or PCB, PCM. Most of them are security with or without a balancer. The balancer on the security allows you to control every single cell in the package. I check the control. There are protections with a charging system eg TP4056, using a built-in balancer to properly distribute and control the charging current, discharging on each cell as in powerbank packages where we can connect a typical mains power supply with a specific voltage and current to the charging. What I'm looking for - all modeler and dedicated loaders have built-in hardware and software protection allowing for professional charging with pulse current in 3 modes, setting threshold parameters of the cell, etc. If we want to charge the charger via the BMS, it's only on the B + input, B- (raw link) ) and not on P +, P-. We give all control to the charger and not the security system (mirroring). Of course, in package layouts over 1s there would have to be additional output to the charger balancer. It loads the cells through dedicated chargers while in the cell container I have a built-in PCB protection system to not damage the cells during operation. That's all )))

korejwo · Answer

Hello, I have a bms with a separate input for discharging and charging, but I want to connect it just under the input for discharging bypassing the charging plug. I would do everything with a cable to unload tz (charge and unload) if it is safe and possible? 10s3p package

szeryf3 · Answer

Please tell me what this contact described as F- is for?

tadek125 · Answer

Hello Will heat up the cutlet a little I convert Makita 14v batteries to li-ion As far as I understand the connection of bms and balancer to the package of cells, e.g. 4s1p, I do not know how to connect bms and balancer to the 4s2p package. Should I use a separate balancer and only 1 bms for each package? Or maybe only one bms with a 4s balancer and then connect 2 batteries (1 from each balancer package)? Or maybe there are some balancers for a larger number of cells, in this case for 8 and 1 balancer? Or maybe it is solved differently in the original screwdrivers. I am asking for a hint and clarification

Grendel · Answer

Hello. In such a situation, one BMS with a 4s balancer is used, and the cells are connected by 2 in parallel. Such a circuit, usually only 3s2p, is used, for example, in every older laptop.

Connecting & Charging 3S2P 18650 Cell Pack with HX-3S-FL25A-A BMS: Balancer, Overload & Discharge

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