Questions tagged [cell]

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1answer
47 views

What could happen to my cells? I overcharged them a bit

I left my 3.7 V Li-ion cells charging for a long time with a low current 5 V charger. Now when I check the voltage, it is at 4.31 V. The cells didn't get hot, not even warm, but I'm afraid of what ...
9
votes
7answers
3k views

A battery is not connected to anything. Is there a voltage between its plus and minus poles?

Here's one mental picture of a battery: The electro-chemical reactions inside the battery happen only when there's a closed circuit. When you place a voltmeter across the poles, then you create a ...
0
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0answers
29 views

Controlling Li-Ion charging through USB

I am trying to design a circuit with power supply for a microcontroller with a li-ion cell depending on whether a charger is connected or not. I tried it first in the Falstad simulator. "USB 5V&...
0
votes
1answer
74 views

MCP73831 charger - how to control low voltage cell

Does the MCP73831 have a way to set a protection to shut down the main output if the supply voltage is too low? I would like to implement (without coding) a protection which disconnects the cell if ...
0
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0answers
29 views

Change just the cell on a LiPo battery

This question is more to understand why it hasn't work for me, this is the case: I have an old Kindle 2nd generation e-reader, the batteries are almost depleted, working just a few minutes. So I have ...
2
votes
2answers
88 views

Debate on wiring risk of positive/negative wires along a path

I came across a design of a battery pack. As you see on the photo, the red wire is positive and black is negative. The red wire lays across the top of the battery pack and comes to the connector. One ...
0
votes
0answers
27 views

Voltage fluctuation on button cell battery

We had this display device which operated on button cell battery. It allow us to do a read back on battery voltage which on display. The voltage was found stable if leave the display device un touch. ...
0
votes
2answers
70 views

Switch individual MOSFETs connected across lithium-ion cell for passive balancing

I am working on a passive cell balancing circuit using N-MOSFET. The cell voltage will be monitored by the micro-controller and it can also generate corresponding logic level signal according to over ...
0
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2answers
73 views

Water's ability to short an L18650 cell?

Personally I no longer use 18650 cells, I use polymer packs with safety circuits. However having once or twice in the past I have briefly shorted a connection between the positive terminal and the ...
0
votes
1answer
44 views

How to calculate battery lifetime from datasheet

I wanted to understand how one can model the lifetime of a cell when it supplies power to a step-up converter. For this question, I want to focus on two products. Tadiran TL-4930 cell and Adafruit ...