Questions tagged [lithium-ion]

Questions regarding Li-ion batteries (Lithium-ion), including proper charging and usage.

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65 views

Can I keep Li-Ion battery 'charging' continuously at 3.7 V?

I have built a Raspberry Pi NAS and it is powered by a lithium-ion battery through a 5 V step-up module - the one used in powerbanks. The battery is a 18650 Li-Ion battery which is kept continuously ...
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46 views

Discharge protection circuit for 2S Li-ion

I'm looking for a overdischarge protection circuit for two 18650 in series. Preferably not a module. Discharge current is max 1mA. Charging is done in a separate charger My situation is a circuit ...
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3answers
133 views

How to deal with D+ and D- on the end of a device that will be charged only?

This is the opposite of the question posted here: What is the ideal way to handle data pins D+ and D- on a USB power adapter to be compatible with fast charging on devices? While that question is ...
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1answer
25 views

Modifying an existing 3-cell BMS circuit to disconnect the pack at high temperature

There are a number of 3-cell protection boards available online for 18650 cells. None of which appear to disconnect the pack at high temperature. A schematic of one such board is shown below, along ...
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40 views

2S 18650 Li-ion battery pack conundrum

I recently bought a remote control toy for my son which included 2 2S battery packs, with a single SM-3P plug, and a corresponding USB charger as shown here. Initially, the car worked fine, though ...
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1answer
43 views

Expert advice needed on electric bike battery setup

I'm currently building an electric bike for a competition. I know I want a 15s lithium ion NCM battery (max 4.2 volts/cell), but don't have a battery management system or a balance charger than can ...
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45 views

li-ion battery protection circuit [closed]

My goal: To operate a cellphone using a bench power supply in place of the cellphone's Li-ion battery. To this end, I removed the battery from the phone and de-soldered the anode and cathode posts ...
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1answer
36 views

Powering two devices with a Li-Ion battery

I have a Li-Ion battery powered device that can be plugged in a computer for charging purposes as well as for data transfer. What I would like to do is have data transferred to the device via a ...
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15 views

power tool battery pack rebuild

I am currently in the process of replacing the cells in several 20v dewalt power tool battery packs with some Samsung 30q high capacity cells. I was also considering LG HG2 cells, yet they are rated ...
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1answer
30 views

18650 battery pack. Current distribution

I'm creating a 20s6p li-ion pack from 18650 cells. Here is the design I am are using 8 by 0.2mm nickel strips rated for 6.5A. With 6 parallel branches that's 6*6.5 = around 40Amps. But since we ...
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35 views

What is a better way to prevent over-discharge in this low current circuit?

I made a nightlight and was very happy with the dim yet usable output and runtime (months), but my assumptions about battery safety were wrong. I expected the LDO 3.3 V regulator to stop output when ...
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1answer
64 views

Charging a Li-ion battery with a Buck Convertor & ATmega8 [closed]

I'm trying to charge a 7.4 V Li-Ion battery following the CC/CV protocol and have a few questions. I want to use an SMPS from my old laptop that can provide 20 V/3.25 A and feed that to a buck ...
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46 views

Lithium ion Battery

What is the difference between lithium ion battery internal resistance and internal impedance? Are both same, if not which is greater ? How these values will be measured and how they help to analyze ...
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3answers
82 views

How to raise voltage output of charge controller IC due to cable loss?

I am using a CN3703 IC to charge a 3 cell li-ion pack (layout as below.) The charge current is programmed using a resistor between its CSP and BAT pins which develops a voltage drop of 200mV. The ...
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1answer
41 views

Is open circuit voltage of the supply important for Lithium battery charging process?

Is open circuit voltage of the supply important for Lithium battery as long as we guarantee that the maximum allowed voltage will not be exceeded when the supply is connected to the battery? Suppose ...
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2answers
47 views

Is it possible to accurately calculate how long a Li-Ion cell takes to charge?

Since Li-Ion cells are charged using both Constant Current and Constant Voltage modes during their charging cycle, and the transition between these points depends on the cell voltage. Is there an ...
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31 views

4S 18650 Custom Charging Circuit

I hope your day goes well. I have a question regarding building a 4+S 18650 charging circuit. I have 4S1P pack with 4 batteries in series and I am trying to build a charging circuit for these ...
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2answers
57 views

How dangerous is soldering lithium ion phone battery, and how easy is messing up

I plan on leading a workshop on how to create led devices(shoes, clothing, etc), and mostly plan on teaching how to do it with old electronics, like phone batteries. The point is trying to do it as ...
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23 views

Asymmetrical load distribution on Li-Ion cells within a battery pack

I am designing a battery pack with 18650 Li-Ion cells. Each cell is installed on a seperate PCB and the PCBs are connected over wires to form a 2s4p configuration. I am aware that this is not an ideal ...
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2answers
90 views

Why aren’t there any “ultra high energy density” batteries on the consumer market?

I have heard of ultra high energy density lithium cells that boast incredible figures from oxis, sion, and solid energy that blow current li-ion cells out of the water. There are probably even more ...
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3answers
63 views

How can I power a circuit while charging its Li-ion battery pack?

I'm creating a portable device that can be powered by a battery pack, or plugged in and used while charging the battery. At 4:18 in this video (shown below), it shows that the circuit can be powered ...
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2answers
296 views

Low-side switch MOSFET cannot deliver full voltage

I have designed a portable lens heater prototype. Using: 18650 Li-ion battery Arduino ProMicro (3.3V , 8MHz) by adafruit (https://www.sparkfun.com/products/12587) Push button switch PMV16XN N-channel ...
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1answer
48 views

Identify chip on 2S BMS / Balance card

I picked up a bunch of Chinese-made 2S BMS / Balance boards. As is the norm with inexpensive Chinese boards, they came with essentially NO documentation aside from how to hook the board to the ...
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24 views

Is it risky to use a non-isolated step-up CV/CC controller as a battery charger in a van?

I want to use my van's 14V alternator output to charge the 24V lithium (LTO) house battery. Commercially available devices come with bells and whistles for all kinds of lead batteries that I don't ...
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2answers
89 views

laptop batteries charging myths - Long life OR short life

I'm very conscious about the life of battery. Some people say that don't keep plugged-in laptop all over the time and remove battery charging at 70% and again charge at 40% so your battery cells ...
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83 views

Lithium battery charger and balancer circuit (or IC)

I am working on a project which sould charge and balance 4 to 6 (maybe 8 in future) serial connected lithium cell batteries (~4000 mAh capacity) with about 4A of charge current. First I looked for IC ...
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1answer
57 views

Homemade LED flashlight [closed]

I want to make my homemade LED flashlight into an old utility light body. My plan is to use XHP70 LED from CREE (12V, 2,8A) and power it using 2S Li-Ion cells (6-8,4 V). My idea is to use boost ...
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15 views

Red LED on TP5100 Li-Ion charger constantly on without charger connected

I have two 18650 batteries connected to a BMS which is wired to the input/trigger of a power drill as well as to the output of a TP5100 charger. Everything seems to be working great. Except: The Red ...
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6answers
3k views

Why are Alkaline, NiMH, and Li-ion AA measured differently (mAh, mWh, etc)?

Looking around Amazon, it seems that different types of batteries are measured differently: Does anyone know why? Li-ion are measured in mWh 1200mWh ALTIZURE (Cheap-Os) 3200mWh Deleepow 3000mWh ...
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65 views

Why are Alkaline, NiMH, and Li-ion AA measured differently (mAh, mWh, etc)? [duplicate]

Looking around Amazon, it seems that different types of batteries are measured differently: Does anyone know why? Li-ion are measured in mWh 1200mWh Cheap-Os 3200mWh Deleepow 3000mWh AmpTorrent ...
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1answer
36 views

Diode for 200v charging of ev battery module

Im attempting to use a DC power supply to charge a 200v battery module. I realise the power supply is not "smart" and I do not plan on fully charging the module. Long story short, I just need to ...
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1answer
52 views

If you have a BMS, will current be limited at some points to a DC motor and affect performance?

I am part of a group in a senior design project. We are designing an electric bicycle. Our professor proposed an issue to us and we are having trouble figuring it out, as we can't really seem to find ...
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105 views

Can you identify the name of this battery discharging plug (photo attached)?

I am trying to source the male/female sides of this connector that fits on a 48V Lithium Ion battery. Can you please identify the name of this type of connector?
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77 views

Issue with TP4054/How not to damage li-po charger ICs

My issue is: The TP4054 I am using started drawing 150 mA after something I did. I know that I have probably fried it and the obvious answer is I should ditch it and take a new one. However I am not ...
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56 views

PTC or One time Fuse or fusible resistor for li-ion protection.any suggestion?

I designing a kind of portable device ,it contains 450mAh Li_ion or Li_Poly Battery (depends on space on PCB). I design this system for mass production (10k-20K). I want to add overcurrent protection ...
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1answer
69 views

High power opamp-based constant current source circuit

I am currently working on a high-power 28S lithium-ion charger for EV. I'm on a constant current stage, so you don't have to worry about all that balancing thing, I just want a constant flow of 15A ...
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1answer
47 views

Charging battery with external charger while powering load

I am building a device which I would like to be able to charge with several different types of external battery chargers (different Icharge within spec of battery, of course). If I understand ...
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0answers
42 views

Why would a battery BMS refuse to function after cutting off the wires and reconnecting them?

I tried to rebuild my laptop (Dell Inspiron 5537) battery pack with new Li-Ion cells so I removed the case, disconnected the cell wires and connected those wires to the new cells. After this point, ...
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1answer
80 views

Why do lead-acid batteries perform better than Li-ion with substantially more ampere hour?

I've been using a 36V motor that draws ~13A current at peak. I initally used a set of three lead-acid (12V 12A) batteries in series to power the motor. They had sufficient power to easily take a ...
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53 views
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88 views

Is it possible to only fill a Li-ion BMS partially?

I'm putting together an 18650 battery pack for an e-bike. The BMS is specified for 10s 36v 40a. Is it possible to use the BMS with only, say, 2 or 3 of the 36v packs of cells I made? The use case ...
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1answer
92 views

Effect of submerging a laptop in isopropyl alcohol without removing batteries

It's common knowledge that water damage on many electronic devices can be mitigated using isopropyl alcohol at a high concentration. Many guides have mentioned disconnecting the battery before using ...
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1answer
47 views

Li-Ion Protection IC Always in Overcurrent Detect Mode

I am seeing an issue with AP9211SA-AF-HAC7 Battery management system. The battery protection circuit, designed as per the schematic attached (the same as the reference design in the data sheet(https:/...
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2answers
114 views

Correct solar panels to pick for drone-mod

After this, I think I will take a course on electrical engineering (fuzzy from school days). I'm trying to add some flexible panels (they were <14g a panel)) to my drone (HS120D), to possibly give ...
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24 views

How to correctly test an ebike battery for wear / capacity?

I am looking at purchasing a used lithium ebike battery. Are there any reasonably quick tests that can be performed prior to exchanging money to test the overall wear of the battery? These are the ...
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2answers
66 views

What is the maximum current which can pass in a Li_ion battery?

I am connecting a load to a Li-ion battery (4.2V), but I don't know how much maximum current can pass through a Li-ion battery. When I know it, I will connect the load accordingly. What is the ...
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2answers
100 views

Is charge batteries in series faster than in parallel?

I would like to know if charging 7 lithium-ion batteries in series with BMS 7S are faster than simply charge them in parallel. Please for your advice, thank you!
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2answers
58 views

How to safely test a Lithium Battery Management System board

I'd like to design a Battery Managements System board (based on TI bq40z50-R2) for my own small (2-4s) lithium battery pack, but I am still unsure how can I test it safely. I am worried that an error ...
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1answer
50 views

Is a special charger required for Li-ION battery packs with a BMS?

I am replacing the lead acid batteries in an electric scooter and a kids electric motorcycle, in addition to building a 48V eBike battery pack. The (3) units require 24v, 36v & 48v respectively ...
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1answer
60 views

Boost converter output still active when boost IC is turned off

Am using the tps61175 boost converter ic in a project. per the datasheet here i noticed when i pull the EN(enable) PIN LOW and the boost converter ic turns OFF , i still read voltage at the output ...

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