Questions tagged [low-battery]

98 questions
44
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4 answers

At what voltage is a NiMH battery empty?

I have a battery pack of NiMH batteries. It is ten cells with 1.2V, 4000mAh each, put together in series. So rated voltage is 12V. After charging, i.e. when the charging device says that it is finished, I measure 14.3V. When I now discharge, at…
Till B
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29
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3 answers

Why do batteries recover after a load is removed?

I carry a small 2-AA flashlight, and a few times, I have accidentally left it on in my holder. Each time it dies completely, so that no light is emitted, but if I turn it back off and wait for a few minutes, the light works weakly again. The…
22
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3 answers

Low Battery Indicator

I'm looking to make a battery life indicator that I can use in conjunction with a micro-controller. I'm hoping that I can then read the current battery life remaining and increasingly put the micro-controller to sleep to preserve battery life.
littlebirdceo
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18
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If Li-Ion battery is deeply discharged, is it harmful for it to remain in this state unused?

It is well known that Li-Ion batteries should not be deep discharged. But sometimes they do discharge deeply. Is it OK for the device to remain in such state for a long time (and recharge again only when the device is needed again after a year) or…
Vi0
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9
votes
10 answers

Would a 7805 5 V regulator drain a 9 V battery?

Doing some DIY as a hobby, I'm making a small humidity-temperature radio sensor. An ATmega328 is reading from a DHT11 sensor and then transmitting data to a Raspberry Pi by an STX882 radio transmitter. It is powered by a 9 V battery using a 7805 5 V…
Dan Chaltiel
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8
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2 answers

What's a good estimate on how low an alkaline battery voltage can be to still make the battery useful?

Here's a YT video by Duracell about how many batteries declared dead and sent to recycling still have some usable energy. In the beginning of the video there's a sequence where they have a row of batteries and a person quickly touches each with a…
sharptooth
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8
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Is it normal for a lithium ion battery to read with a very low voltage on a multimeter?

I have a PS Vita and I suspect the battery is dead and needs replacing, as the Vita won't charge at all. But the issue could also be the charge circuit, as when plugging it in to charge the charging light doesn't even come on. I've disassembled the…
7
votes
3 answers

A separate MCU to cutoff LiPo on low voltage?

I'm designing a project that is going to work on a flying quadcopter. It features an ATmega328P MCU in the main 5V circuit, and is powered by a small (<500 mAh) 1-cell LiPo battery. I want to provide low-voltage cutoff mechanism to protect the…
Goodrone
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6
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how to build a low-voltage disconnect switch for DC 12.4V 70A?

How can I make a device that will make the power connected as long as the voltage of the power-supply keeps over 12.4 V (adjustable) and disconnect it if it falls below? It also must connect the power back, but only if it rises above 13.5 V. This…
ria
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Low Battery Indicator for 2x AA Batteries

How would I create a circuit which turns on an LED when the voltage goes below 2.5V? I am using 2x AA batteries
John
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5
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2 answers

Stabilizing the UVLO feature on a DC/DC converter

Very many DC/DC controller IC's utilize an under voltage lockout feature by way of an external pin monitoring the applied voltage and comparing it with some internal reference, putting the IC into standby if this threshold is breached. Usually…
smoothVTer
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How do you tell if a Li-ion battery has a protection circuit?

I bought a li-ion battery off of ebay. The listing claims that the battery has a protection circuit, but a week later, the battery didn't cut out or anything. With a multimeter, it is reading 10V when the battery is listed at 10.8-12.6V. Does this…
electricviolin
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Does CKDIV8 save battery life when programmed?

On ATmega328P there is a CKDIV8 fuse bit that when programmed divides clock by 8. I'm wondering if the power consumption is equal on these two setups: micro with 8MHz external crystal and CKDIV8 fuse bit programmed micro with 1MHz external crystal…
Darkhan
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Why isn't my battery charging?

I have a YT7B-BS battery in my motorcycle. My motorcycle doesn't start because the battery voltage is only 12.05 Volts. The battery has the following inscriptions: Standard charge: 0.7 A x 5~10 hours Quick charge: 3 A x 1 hours 6.8 Ah (20 HR) / 110…
Victor Lamoine
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Why fully charge Lithium battery powered devices before first use?

I recently bought a Bluetooth headset and it turned out to be faulty. On getting the replacement, when I asked the customer care guy to test it after little charging, he refused to do it citing reasons like 'New batteries are in deep discharge and…
Anshul
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