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Can batteries be connected in parallel then in series then in parallel again?

My primary concern to address your question: Can I connect two 12S2P modules in parallel making it a 12S4P providing each module has the same voltage and BMS? My concern would be about battery packs ...
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-2 votes

Can batteries be connected in parallel then in series then in parallel again?

You can do anything you want with specs for Delta V, ESR and I max. How you achieve this depends on those specs probably with switching L regulators to equalize V and stay under I max. dI=dV dt / L ...
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Is battery charge efficiency related to its self-discharge?

Charge losses depend on CC and CV rates for overvoltage as leakage is non-linear wrt overvoltage and charge losses are quadratic I^2ESR while power transferred is V*I(t) So efficiency is more complex ...
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1 vote

Is battery charge efficiency related to its self-discharge?

Self discharge good to take into account if charging current and self discharging current are comparable. In most cases with fast charging they are tens times smaller, and most impact to capacity ...
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1 vote
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Is battery charge efficiency related to its self-discharge?

Coulombic efficiency is the ratio of charge extracted to charge inserted. It makes no assumptions about what causes the loss, and therefore incorporates self-discharge. Most battery types have very ...
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4 votes
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Does a battery drain if used in series of a power supply to boost voltage?

Here's the schematic. The rechargeable battery is in 'series addition' with the power supply. It is bound to get discharged. Please note the polarities. There is no possibility of the battery getting ...
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-2 votes

Battery heat emission

the edits in question clearly indicate ESR if tested during 40 A. 200mV / 40 A = 5mohm and 8 Watts of heat The battery is capable of delivering 8kW of external heat if CCA tested with a 5V drop from ...
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0 votes

How is it possible for a 12000 mAh battery pack to power a DC motor that requires 70 amps of current?

The current a motor takes depends upon the load. That motor can take up to 79Amps (the link states 85A) but the amount of effort to drive the skateboard must typically be such that the current is much ...
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3 votes
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How is it possible for a 12000 mAh battery pack to power a DC motor that requires 70 amps of current?

The motor says it requires a continuous ~79 amps of current. The link says that maximum current is 79 amps, which is probably the most it can take without damage. Continuous current almost certainly ...
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1 vote
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Voltaic pile: question on components

Meters were invented two decades later (Oerstead's compass.) So, how did Volta discover that something was going on here? Wet fingers! With hands well soaked in water (or seawater, or vinegar,) ...
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Voltaic pile: question on components

Holding the structure of heavy metal disks was done possibly by wooden poles. The A stood for Ag = Silver, and Z for Zn = Zinc. He focused only on this galvanic electro-potential of bimetals and ...
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1 vote

Lead acid battery: What happens if very low charging current is applied for an extended period?

Please observe that your only charging parameter is the (constant) current set at 750mA. The answers will initially consider just that, then elaborate other situations. Question 1: What would happen ...
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1 vote

Voltaic pile: question on components

Correct, the bars only serve to contain the precarious pile of discs. If they were current-carrying then each disc would be shorted to each other and you'd get a whole lot of nothing and maybe some ...
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10 votes

Why are these capacitors treated as if they are in series? Why must the incoming and outgoing current in a battery always be equal?

Unless this circuit is being operated with a voltage source with frequency in the megahertz or more, there's not much point in analysing what happens to actual charges here. You can rely on Kirchhoff'...
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6 votes

Why are these capacitors treated as if they are in series? Why must the incoming and outgoing current in a battery always be equal?

This is a model, or ideal circuit, that is a useful approximation (in many cases) to a real world circuit. If we wanted to use a circuit model to take account of the charges on the surfaces of the ...
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parallel boost converter for more current

The input configuration to the converters is not as important as the output impedances of the converters. If there is significant difference in the output impedance between the two converters, then ...
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0 votes

parallel boost converter for more current

Your first picture will work, but your second is problematic. If there is a small difference in the output voltage between both converters the load current is not equally split, one may have the main ...
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1 vote

Power camping lantern with 12v AGM battery

I have a lot of LED experience that I can share from the last 20 yrs. Simple version Choose a Battery with adequate Ah capacity that is < 25% above the LED voltage if you would like to have a ...
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2 votes

Power camping lantern with 12v AGM battery

AGM batteries do require venting. No one would recommend using one in a low/no ventilation area/container, even if you are not charging it in that area. May be better off putting it in a box outside ...
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Reverse charge protection for parallel primary lithium cells (CR2450)

Here is a solution for you. Schematics with a comparators. Use it.
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-1 votes

How to control current to charge batteries?

A BMS is not a charger. It is a device that protects the pack from overcurrent, overvoltage/overcharge, undervoltage/overdischarge, overtemperature/undertemperature, and similar conditions. Your phone ...
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4 votes

How to get multiple voltages from a single battery?

The easiest way for a hobbyist to do this is to purchase one or more buck regulator modules that use a switchmode regulator chip to reduce the voltage without much loss. Then use the 12V for the motor ...
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1 vote

How to get multiple voltages from a single battery?

Getting a voltage lower than the battery is simpler than a voltage greater than the battery. A voltage divider will give you a lower voltage, but the voltage will be sensitive to the load. A voltage ...
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2 votes

How to get multiple voltages from a single battery?

You can use relatively cheap components. So-called voltage regulators are quite ubiquitous. They come in two main types. Assuming that your microcontroller does not draw much current you can use a ...
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0 votes

How to get multiple voltages from a single battery?

I would use two DC>DC converters to give each device their own supply, fused of course. Trying to connect them in series will lead to voltage fluctuations if the motor load changes etc
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1 vote

Circuit to charge three lead acid batteries in parallel and discharge them in series

I tried this, but finally I decided it's not worth the effort. This schematic was my draft for the test: There may be errors in the schematic, don't trust it! Danger to come! To your question: I used ...
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0 votes

How to control current to charge batteries?

this BMS does not cause a current limit, the 15A and 13A are just the highest currents it can work with. For charging you should use a buck converter with a current limit.
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How to fix oscillation of an 'over-discharge protection' circuit for a lead acid battery

Connect the cathode of the Z diode to the load side. It cannot turn on again. To restart the circuit, use a button switch between emitter and collector of the transistor. A catch diode across the ...
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MOSFET Power Switching Circuit

The problem might be the internal drain/source capacitance of the P fet. If you connect your battery, the voltage of the P fet source rises very fast and feeds this delta-U forward to it's source. ...
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Substantial voltage drop when connecting battery to DC load

I have seen this effect on other batteries. The reason was, that the BMS logic was either in deep sleep or one of the cells were in undervoltage state. The BMS had disabled the internal load switch ...
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Should I use a DC-DC converter or an LDO?

Consider using a boost converter chip in a SEPIC configuration. This can act as step up and step down in one circuit.
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1 vote

Should I use a DC-DC converter or an LDO?

It looks like LiPo batteries stay above 3.3V in normal charge levels, and drop to 3.0V when they're below ~80% capacity. Image source: https://learn.adafruit.com/li-ion-and-lipoly-batteries/voltages ...
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What did I do wrong - recharging sealed lead-acid battery with recycled computer PSU

You should have used a 1n4007 diode had you put a diode on the positive side power would have only been allowed to flow in one direction. I've never put fluid into an empty battery before so can't ...
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5 votes

Can you use a 12V lead acid battery to switch a contactor?

That resistance you quote is for the auxiliary contacts, not the coil. The coil takes a peak current of 3.8A (ie a 4 ohm load) and features a built in economizer which limits the current draw after ...
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1 vote

Charge a 12V 90Ah led acid battery using 12V 20A SMPS

Your question: If I use the above SMPS will that SMPS reduce the current accordingly or give the total 20A current? Short Answer: Most probably it will not provide an adequate current, triggering ...
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1 vote

Charge a 12V 90Ah led acid battery using 12V 20A SMPS

No, because a switch mode power supply is not a battery charger. Power supply can also be damaged when connected to another voltage source, the battery. You need a battery charger to charge batteries. ...
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3 votes

What are the possible reason for swelling a coin battery?

Any idea what could be the reason? Have you read the data sheet of your specific battery? Here is one from a garden variety Energizer CR2032 and it's operating temperature is -30C to +60C https://...
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3 votes

What are the possible reason for swelling a coin battery?

Swollen batteries are a common cause of failures. It is the sign of gases being created inside the battery, usually because of excessive temperature or deep discharging that catalyse different ...
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1 vote

Off-grid computing

Say you got 2640W peak solar panels... On overcast days, the power you'll get versus all your electrical loads seems... wildly optimistic. For example, over the last few months (jan-may) my 3kW peak ...
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4 votes
Accepted

Charging two 18650 batteries separately but using them in parallel in one circuit

As far as my understanding goes, you're probably better off making a pack out of the two cells and both charging and discharging them together. When you connect two cells of different charge states ...
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2 votes

Charging two 18650 batteries separately but using them in parallel in one circuit

I presume the charger stops at 4.20V +/-x % and then slowly decays to a plateau voltage due to a double layer charge effect. So time delays might cause a voltage difference, but it shouldn't be ...
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0 votes

Circuit to charge three lead acid batteries in parallel and discharge them in series

The problem is, if you mis-sequence your switch/relay connections, you will dead-short the battery and fuse the relay contacts so you'll never get them disconnected. Make/break sequence will be ...
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1 vote
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How to simply balance two parallel connected cordless drill 18v batteries?

For the time being, I've just coupled the batteries through Schottky diodes in series in order to prevent stronger battery starts charging the weaker one. But, I know this is not enough for even out ...
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0 votes
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Charging only the first battery in a series

This will not work as you wish. Instead, you will end up with the other batteries reverse charged and destroyed! The charging current to battery one is being directed positive to positive and negative ...
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3 votes
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CR1220 holder 2D footprint error from manufacturer?

What you have there is a "coin cell retainer" not a "coin cell holder". The difference: coin cell retainer*: contacts only the top if the cell; non-isolated; the PCB contacts the ...
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2 votes

Two power sources and two outputs with one switch

It's possible. Here's the schematic.
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6 votes
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Two power sources and two outputs with one switch

Here's a schematic diagram which includes a double-pole single-throw (DPST) switch that should, as @Eugene commented, do what you need: simulate this circuit – Schematic created using ...
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5 votes

Fully charged battery voltage of devices

Fully depends on designer's choice. This will vary wildly with device models and various li-ion chemistries. Designers will always tailor the cutoff voltage to what is needed for the product: ...
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3 votes
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How many watts total from 1876 Clarendon Dry Pile Battery / Oxford Electric Bell?

Some back of the envelope calculations: Capacitance of the ~2mm radius ball: 200fF Voltage of (probably) Zamboni piles: 1000V Charge transferred per oscillation: 2E-10C Approximate number of rings: ...
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What type of power supply is best for short circuit experiments?

You could use a constant-current power supply. These give constant current at a variable voltage. But the most useful aspect of them is they are inherently current limited - they cannot give more ...
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