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Questions tagged [lithium-ion]

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

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What’s the max instant current draw from a Li-Ion protected pack?

I’ve been looking for this and couldn’t find the answer so far. What’s the max current that those Li-Ion video camera protected battery packs, as the Sony NFP-550, NFP-970 can handle? I know for ...
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1answer
162 views

Battery capacity calculation/method [closed]

While calculating battery power capacity requirement for a circuit consisting of multiple loads having different power consumption, how should one proceed to avoid any error? How it is done in ...
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55 views

Relation between terminal voltage and charging speed in Lithium-Ion/Polymer batteries?

I tested charging a 5200 mAh (20 Wh) battery at 10W. Its charging level at the beginning was 20%. The terminal voltage was 3.68V. Now, I applied 10W of charging rate to the battery. The terminal ...
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76 views

Capacitive discharge excess being used for battery recharging

I am currently designing a circuit similar to a cattle prod that is intended to be attached to a drone. The cattle prod is powered by a lithium-ion battery, charging up a capacitor and then quickly ...
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3answers
154 views

How to connect LED strip to be powered by charger and batteries

I plan on using it mostly plugged in, batteries are there just for extra mobility and won't be used most of the time. Don't know lot about batteries so in first scheme I added a switch (pos. 1 ...
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2answers
145 views

How to measure output voltage of this Li-Ion battery circuit?

I've designed an AtTiny85 based Lithium-Ion battery protection/boost circuit that monitors the battery voltage and cuts the battery power to the external powered circuit when the battery dips below a ...
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2answers
401 views

TP4056 - Li-lon Battery Charger temperature problem

I bought an TP4056 component for develop a Li-lon Battery Charger. While I was designing the circuit that was in the datasheet file I realized that the value of two resistors (R1 and R2) was not ...
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1answer
111 views

Discharging 18650 battery at constant rate

Hello I am planning to do some tests with a 18650. In these tests my goal is to measure required time to discharge them with different discharge current rates (1A, 2A, 5A and so on...) The op amp ...
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42 views

Is it a bad idea to connect two Li-ion batteries in parallel? [duplicate]

Suppose I have two Li-ion batteries for smartphones. One could say that if they are connected in parallel, then the voltage given to the device would be the same, but the capacity would be doubled, ...
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2answers
144 views

Charging 4x 18650 Li-Ion Batteries in series [closed]

Hello StackExchange community. So i have been for a long time wanting to build someything portable and recharchable with the 18650 batteries. the only problem is i cant find any good guide on how to ...
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1answer
77 views

Li-Ion Battery Solar powered circuit

I am currently working on a Solar powered project but I am having a hard time making it work: I have a PCB with an Arduino and a sensor, this circuit consumes 250mA for around 2 seconds every 10 ...
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1answer
72 views

Connecting unbalanced parallel battery strings to a common DC bus

We are currently researching a system in the design phase which will use 2 parallel 48V lithium battery strings. Each string will have a battery management system ensuring the cells are balanced. ...
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711 views

How to charge lithium ion battery in series and parallel?

I want to use TP4056 in my solar power bank project to charge a lithium-ion battery (3.7 V, 2000mAh each one), but I don't know how to use it when I want to charge more than one battery. Is those ...
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1answer
141 views

4s battery pack, how to build?

I have 8 cells (samsung icr18650-26f), and I want to build a battery pack 4s 14.8v (4x3.7v) to power an LCD Controller Board that requires a 12v4amp input I have an idea of the design of this battery ...
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2answers
111 views

How come consumer products aren't powered by power banks? [closed]

I wonder why no commercial battery-powered consumer product is designed to be powered by power banks. All of the ones I know of have either built-in battery holders or internal LiPos with charger ...
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107 views

Can I add an INA219 voltage\current sensor to this USB powerbank?

I have a Raspberry Pi Zero in a small robot that I have been powering off a USB powerbank and it works great. Unfortunately when the USB battery goes flat the power is cut and the Pi crashes. I want ...
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1answer
44 views

How does this circuit works for detection of Logic low, Logic High and Hi-Impedance state?

I was working on a design of Li-ion battery charger using LTC4001. Here a pin is called CHRG, which indicates the different state of charging like charging cycle begins, threshold reach(i.e 4.2V or C/...
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1answer
73 views

Safety of Lipo batteries

I help organize a robotics competition in my home town. For the past 16 years, we provided each team with two 12v battery powered drill. They were cheap, easy to find and provided us with 4 batteries, ...
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1answer
46 views

What are the tradeoffs when building a modular battery pack

I want to build a 120 v / 128 Ah battery for an EV conversion project (small car with short range). I plan to base this on 18650 size lithium-ion batteries (recovered from old laptop battery packs). ...
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1answer
65 views

Is there any problems with driving a single 5mm LEDs off of a single or parallel 18650 batteries? [duplicate]

I want to drive one or two small (5 or 10 mm) white LEDs in parallel using one or multiple 18650 3.7vV Li-ion cells. The main reason I want to use the 18650's is, I already have them, they are ...
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1answer
95 views

Using li-ion battery in place of a lead acid one in a desk lamp [closed]

I have a rechargeable desk led lamp with USB power input. Although it's supposed to hold charge, it only works when plugged. I opened it and found that the problem is about included lead acid ...
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1answer
1k views

Can I safely parallel 2 separate 18650-based Li-Ion battery packs, each with their own BMS? [closed]

I have a couple of 18650-based 10S2P 36V nominal 4.4Ahr Li-Ion battery packs from my electric skateboard which I'd like to permanently put in parallel to double my range and improve my power during ...
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1answer
49 views

Why or when does battery capacity matter in a series circuit?

I have 3 sets of doubled 18650 cells from a laptop battery, and I gather that it can be dangerous to use cells of different capacities in series. This question is more about the theory than practice. ...
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1answer
148 views

3.5v solar panel Li-Ion battery charger

I am planning on recycling some cheap low voltage solar panels that came out of a gardening light. I have two of these modules, that soldered in series provide a voltage of around 3.5v (on direct ...
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2answers
331 views

Adapating a single cell Li-ion battery voltage to 3.3V low power application

I'm planning to use a single cell Li-ion battery to power up a custom made circuit. I'm planning on using a ESP-12E module board as the application will need to connect every once in a while to ...
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2answers
91 views

Smartphone internal charging circuit type and efficiency

USB usually provides 5V (or even more, for example 9V with Qualcomm Quickcharge) and the phones contain a single li-ion cell with 3.5-4.3V, so there must be some dc-dc converter in between. I wonder ...
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1answer
40 views

Wiring Up a Li-Ion Battery (Band 2)

I have a Li-ion battery that I pulled from a MS Band 2. It comes with a protection chip, which I am having trouble with. The chip has 4 accessible pins, labeled "P+, K, T, P-". I've tried every ...
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0answers
36 views

Motorcycle LiFePO 4 / Super capacitor 24v hybrid possibilities?

First please let me apologise, I’m quite frankly a complete newbie to electronics and come from a strictly design background. However, I'm really interested in learning and understanding electronics ...
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1answer
627 views

How to calculate the heat dissipated by a battery pack?

I have a battery pack consisting of 720 cells. I want to calculate the heat generated by it. The current of the pack is 345Ah and the pack voltage is 44.4Volts. Each cell has a voltage of 3.7V and ...
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2answers
291 views

Li-ion battery cell balancing statistically unnecessary when many cells are in parallel?

Lithium ion batteries packs need to be balanced because of a small random voltage difference for each section in series, that may cause the voltage levels in a pack to diverge over time, right? So if ...
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1answer
57 views

Designing a 2S Li-ion charger with 5V 2A input

I'm interested in designing a few similar charging circuits based on the specs of the title which is getting a charging for 2 cells in series(or more) from a 5V input. Now my question is: Assuming I ...
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95 views

How can I size the current ripple of a DC-DC converter for lithium batteries

I am designing a bidirectional DC-DC converter to charge and discharge batteries on a DC bus. The power of this converter is 50 kW and the average current in the inductor (the same as that on the ...
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2answers
66 views

Use regulator when input voltage is above threshold other wise use direct input voltage

I don't have much practical knowledge of electronics. I am trying to operate esp12e with single Li-ion battery with charging circuit. I am planning to use a good LDO regulator because Li-ion battery ...
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1answer
122 views

ESP8266 (esp-07) powered by battary(s) for at least 1 year

Hey all I am trying to see how long I can possibly have a ESP8266 ESP-07 operate with only 1 or 2 of the Lithium Ion Battery 18650 Cell which claims to have 2600mAh. I am making a window alarm sensor ...
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60 views

A lot of questions regarding lithium ion power supplies and power regulation with safeguards

Per a members request I am making a post compressing multiple possible posts into one and providing additional info. I am making a 18650 powered portable electronics workstation that will have many ...
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1answer
307 views

Connecting 18650 batteries in parallel? [closed]

I have encountered a bizarre situation, i bought two 18650 batteries each of 3.7V, 2200mAh, im using a Tp4056 based charger with battery protection which has DW01A and FS8205 to protect the battery ...
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2answers
111 views

Higher current draw from powerbank?

I have a powerbank with a 20,000 mAh capacity, from which I can power different devices. The devices include an LED strip and a Raspberry Pi Zero W (RPI Zero W). The LED strip consists of 60*5 ...
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2answers
148 views

How can I split a 5v power supply into 4 isolated (no shared ground or live) channels?

I need to power a number of tp4056's with the battery outputs in series (using tp4056's because I have a bunch already, and because I want to be able to add more cells in series later). If I do this ...
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2answers
184 views

How to find out the spec of an unmarked li-ion battery [closed]

I have got some li-ion batteries which I don't know anything about and there is nothing written on them. Can you advise some testing methods to find out about their specifications and charging data so ...
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1answer
55 views

Charging Lithium ion battery with a modified charger

I've a defective charger for a small LED torch light, its output is 4.2V / 500mA. I may not find an alternative one, so I'm considering modifying a mobile phone charger as following: The mobile ...
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2answers
99 views

Is fast charging a Lithium-Ion battery from 0% to 30% better or worse for the battery health than fast charging at 30% to 70%?

According to this answer, fast charging is only recommended for the battery from 30% to 70% instead of 0% to 70%, while I thought that the emptier the battery is, the higher of a C rate it can handle. ...
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93 views

Batteries have a constant charging speed from 0%→70% instead of being any faster at 0%?

A mobile phone I tested keeps charging at the same constant speed from 0% to 70%, which is 10 watts. It uses MediaTek PumpExpress (input power: 12V 0.83A, despite the wall charger is capable of 12V 1....
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2answers
749 views

Hiw to build UPS using TP4056 and 18650 Batteries? [duplicate]

I have build this UPS battery supply to power a Raspberry Pi using 18650 batteries,using the TP4056 battery charge controller. The circuit as follows: This is working fine at the moment, but I'm ...
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1answer
55 views

Does charging near maximum C rate have the same effect as high battery levels?

We know: The maximum C-rate decreases with the increasing charging state. Let's assume an 2 Ah Lithium-Ion or Lithium-Polymer mobile phone battery. (2 Ah is considered tiny in 2018, but this is just ...
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3k views

Do I need a BMS for Li-ion batteries connected only in parallel? [closed]

I have a device that runs on a single cell Li-ion / LiPo. The physical case for that device allows me to put in one to three 18650 cells. Unfortunately given the disposition of the cells, I can't buy ...
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1answer
2k views

Using a multimeter, can I tell if a lithium-ion battery pack is brand-new?

A few years ago, I ordered a replacement cell phone battery from Amazon, and while it worked, it didn't last as long as I expected. I wondered if the seller had scammed me by selling me a battery that ...
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1answer
29 views

Can I charge 1 cell Li-ion battery with a charger for 2 cells?

I'm designing a battery charger using monolithic step-down battery charger that operates over a 4.95V to 32V input voltage range. On the datasheet I found a typical schematic for 2 cells but using ...
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198 views

Balance of current through oring diodes

I’m curious about current flow through an oring diode configuration. I’m using oring diodes to “autoselect” between two power sources: a 4.2V (max) battery, and a 5V USB line. The battery has one ...
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1answer
445 views

MPPT charging a li-ion battery

I just designed this MPPT solar charge controller which outputs 4.2 V regulated via MPPT, it uses the SPV1040 IC. This will be used on a satellite with 4 side panels, each with 8 solar cells in ...
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1answer
51 views

Charging and Using a Lithium Battery

I’m using an Adafruit micro-USB Charger connected to a standard 850mAh LiPo battery. I would like to know if it’s safe to charge the battery while also using it. The circuit that the BATT and GND pins ...