5

Batteries don't often fail low voltage or short circuit, but if they do, then a 'very parallel' arrangement could be bad as all the good batteries gang up on the bad one to force a high current through it. Protect each battery with a fuse in series. Before connecting them in parallel, make sure one or more of them aren't duds, check each individually into a ...


3

This is a very common occurrence if your load contains a large capacitor bank. The problem is that if the voltage over a capacitor changes fast (as when you connect the load to the power supply), this results in very large currents. This can be seen by the following differential equation for the capacitor current: $$I_c(t) = C \frac{dV(t)}{dt}$$ ...


2

I see two potential problems with your circuit. The first problem is battery protection. Li-Ion batterys need a proper charger and protection circuit or they can be a fire hazard. There are Li-Ion cargers that have a wide DC input range an should be used here. The battery pack should also be protected from overdischarge. There are Battery Management Systems (...


2

The USB C standard has a Power Delivery Protocol. Basically what happens is the device that you want to charge in question will ask the power supply (power bank, wall outlet, car charger, etc) for a certain voltage. The power supply will respond by either giving the device the requested voltage, or give the device the next lowest available voltage since it ...


2

To answer my original question, yes it is possible for an old battery to sink large currents. I believe it is caused by plates disintegrating and pieces falling and accumulating on the bottom, eventually creating a short. But this condtion usually persists past the first few minutes of charging, so it can not be called inrush current. Now that I have thought ...


2

Does that mean the negative pole of the battery is connected to all of the metal in the car, and thus the current flows through the whole car body during the process? Yes. It's cheaper and more convenient than running a copper ground wire everywhere.


2

Yes that is normal, the sleeve connection of the jack most likely touches the tip and ring when plugging and unplugging. Yes, wiring large battery currents via a short-prone audio connector rated for 1A max current does seem like a bad idea. It is a completely wrong tool for the job. There are far more suitable connectors available that are designed for ...


2

If the fan requires 40 Amps, it will draw 40 Amps from somewhere. If the alternator produces more than 40 Amps, 40 Amps will go to the fan, and any excess will go to charge the battery. If the alternator produces less than 40 Amps, the fan will still get 40 Amps, and the battery will provide the "missing" current required to provide the 40 Amps for ...


2

Most lead-acid batteries charge at a constant 14 4 volts, so charging several in parallel is really just a charge-current issue. If the charger cannot supply enough current it will likely lower the charge voltage to protect itself. As the batteries charge up the voltage will rise, but should NOT go over 14.4 volts, or you could "cook" the batteries,...


1

Base on comercial website comercial website it give this data Module will discharge cell which exceed 4.2V Module will cut-off charging when any cell exceed 4.25V So for your question Does this mean if all batteries are full it just starts "burning" power through the resistors for all cells? The answer is no because it cut-off charging current. ...


1

A battery will need a charging regime to match its chemistry. So, this regime will change over time as the battery state changes. The charging circuit is designed to supply some fraction of the current capacity as some batteries are capable of supplying hundreds, or thousands, of amps for short periods of time - usually seconds. Charging the battery at its ...


1

You have solved 'sparking at plug-in' by delaying mosfet 'turn-on'. Likewise you could avoid 'sparking at plug-out' by first turning off the mosfet and then plugging out the load. You would need to wire an additional switch to the controller.


1

Yes, you can. I do not see anything wrong with it except for the extra junk of communication cables and apparent higher cost. In fact, that is what happens in some big energy storage systems. It is easier to replace a single BMS instead of the single BMS for multiple smaller modules. It also helps with the integrity of the individual cell. Basically your ...


1

Parallel connection of lead-acid batteries is done routinely in a lot of cases - including almost all UPS devices, small boats, offroad cars, etc... The more identical batteries are, the better. They ABSOLUTELY must be the same voltage. They MUST be of the same type (flooded/gel/AGM, starter/traction/standby), it is good if they are the same brand and even ...


1

If you have a constant current trickle charger, you can simply connect the 6V battery to the 12V charger and it will be fine. Do make sure to check the short circuit current of the charger so that it is below C/10 of the battery you are charging. You might not want to let the charging proceed to completion (i.e. do not top off). For high current chargers and ...


1

Short answer is no. The same current will pass through both batteries to charge them. What happens when one battery is fully charged and the other isn’t quite done? The charger will keep sending the current and overcharge one battery.


1

If your current out of the LM317 is Iout you are dissipating 3V*IoutA power at the LM317 as heat. Also, check what are your current ratings of your router and your ONU to calculate your power requirements and check if your supply can handle it. Measure the voltage and current at the 5V supply output to see if it is able to support the load.


1

You are confusing/conflating two different things. I read between the lines that you want to charge your batteries "most optimally", and thus want to determine the port power capability. The method to charge the 2S battery geometry is an entirely different question. First, you don't need to "Enumerate the USB port" (more accurately, you ...


1

The negative terminal on a battery connect directly to the body of the car, usually the frame or engine. So when you connect your jumper cables to some arbitrary piece of bare metal, you're in fact hooking it to the negative terminal of the battery. It's so much easier hooking up jumper cables when you can just hook up the negative to any bolt on the engines....


1

Your description isn't clear, but given the basics of the charger and 2 batteries, and usb source, the problem is clear. You aren't using the right setup. Your charger is for a single 3.7V LIPO, A 1S charger. You have 2 batteries in series, 2S, and 5V is not enough to charge a set of batteries that have a 6.4 to 8.4 voltage range. The batteries have a ...


1

There are two possibilities for how balancing is done depending on the pack architecture. If the pack is 4 series, each one composed of 4 parallel cells, then no balancing is required for the cells in parallel. They are directly connected together and cannot get out of balance. simulate this circuit – Schematic created using CircuitLab If you have 4 ...


1

There is a reason OUT+ and B+ are separated. There is a battery protection between OUT+ and B+. If you short it you effectively disable this protection, and that is definitely not a good thing. I wouldn't do it.


1

No, you are following a line of reasoning that doesn't really hold up. The inrush current of any new battery will be enormous unless it is limited somehow by the charging source. But a normal car can easily deal with this. If this was an issue, then every car would have this problem every time it starts. Also, if anything an older battery would likely have ...


1

You're overthinking this - the belt is probably glazed or the tension is not adequate. Once the belt starts slipping it can quickly develop a slippery surface (glazed) that makes future slipping more likely even when correctly tensioned. The alternator has current limiting so the torque required will not go above some level even if there is a heavy load on ...


1

It is a good safety practice that you should always have at least an extra layer of protection when dealing with Li-ion batteries. A proper design shall have: A well designed, robust charging and discharging circuit A battery protection circuit A battery with protection circuit built-in #3 would be the last resort in case both 1 & 2 failed. You can ...


1

This is a common way to integrate a battery protection IC. The protection IC controls the two mosfets in Q1. If the battery is overdischarged, it turns off the right mosfet, preventing current from flowing from ground to the negative battery terminal (i.e. prevents the battery from discharging). If the battery is overcharged, it turns off the left mosfet, ...


1

First: Look at the documentation (datasheet) of the battery. They should have the wires labeled in that. If not, read on: I would first find the power lines (so + and ground) using a multi-meter. From there, take note of that and tape the leads for that up (so it doesn't accidentally short). After doing so, we have 3 wires left. In this image you can see ...


1

My suggestions, MOSFET based inrush current limiter: https://github.com/msglazer/Anti-Spark_Switch (Generally used in octocopter) Anti-Spark XT60, XT90 connectors explanation: https://youtu.be/X71Suakve6A (Video) In Anti-spark connectors, they are using small value high power resistors approx 6 ohms. This Resistor helps in reduce inrush current due to ...


1

You can get a spark hooking up 12V jumper cables between cars because you are making and breaking a circuit in the many-millisecond time it takes to connect. The inductance in the cables or receiving circuit is surprising in its ability to keep current flowing in a collapsing magnetic field when a circuit is broken. It's nothing to worry about. If you want ...


1

Your design has excessive inrush current because it has no protection for a bulk capacitive load. Thus the surge current is I=V/ESR for ESR includes cap and contact resistance. You could consider a PTC rated for the max Joules of charge energy but that adds a minor cost and heat. Even 2.4A USB power to Apple iPad products creates a black carbon strip in the ...


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