97 votes
Accepted

Duracell PowerCheck - How Does It Work?

According to the German Duracell website: As you press the points, a current will flow through a metal strip getting warm. The display is a thermochromatic one. So the increased temperature will ...
Arsenal's user avatar
  • 17.6k
26 votes

Is temperature the only battery charging speed limitation?

Can I charge as fast as I want, provided that I cool down sufficiently? No. To charge faster you need higher voltage to overcome internal resistance. If the voltage is too high it may cause damage ...
Bruce Abbott's user avatar
  • 56.2k
22 votes
Accepted

Is temperature the only battery charging speed limitation?

You certainly cannot charge as fast as you want, but you can indeed increase the charging rate if you keep cooling the battery in the process. Though the point is not to make the battery colder than ...
Dmitry Grigoryev's user avatar
18 votes

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

The electro-chemical reactions inside the battery happen only when there's a closed circuit. For an ideal battery, this is true. However, all batteries have some, hopefully very small, leakage ...
Math Keeps Me Busy's user avatar
16 votes
Accepted

What battery chemistry is suitable for a "time capsule" applicaton?

A gravity-battery might be designed to drop a weight, generating energy, when the time-capsule's opened. A gravity battery is a type of electricity storage device that stores gravitational energy, ...
Nat's user avatar
  • 397
15 votes
Accepted

Why does the voltage of vinegar batteries in series not equal the sum of the individual voltages?

As well as demonstrating some basic electricity generation you will be demonstrating why we don't generate commercial electricity using NZ coinage and vinegar! simulate this circuit – Schematic ...
Transistor's user avatar
  • 175k
15 votes

Batteries in Series

If you connect the 39 + 3 batteries to a load and that load is connected for a longish time you might find that the higher ampere-hour batteries are still running OK and trying to push current to the ...
Andy aka's user avatar
  • 452k
14 votes

What battery chemistry is suitable for a "time capsule" applicaton?

The longest operating battery: https://en.wikipedia.org/wiki/Oxford_Electric_Bell No exotic chemistry required, but it's very effectively insulated so as to prevent self-discharge.
pjc50's user avatar
  • 46.7k
12 votes

Is temperature the only battery charging speed limitation?

A lot of the chemical limitations to which speeds you can charge or discharge a battery actually get worse with decreasing temperature. For example: the charge carrier mobility in a cold battery will ...
Marcus Müller's user avatar
12 votes
Accepted

Allowable reverse current into Alkaline battery

Self-discharge of a 9V alkaline with a 20% down shelf life of 5 years and 500mAh capacity is about 2uA, so I don't think that <2uA is any kind of a possible problem. There is no net charging taking ...
Spehro Pefhany's user avatar
12 votes
Accepted

If you mix the anode and cathode in a electrolyte solution you will have a short-circuit?

You'll end up with a soup of tiny voltage cells, that are randomly arranged in polarity with no way to connect to the anode or cathode, because they are swirling around in the soup. When you use two ...
Aaron's user avatar
  • 7,532
11 votes

Why does the voltage of vinegar batteries in series not equal the sum of the individual voltages?

When any battery is connected to a load its output voltage will drop a bit due to the internal resistance of the battery. If you are constructing a battery then there are four simple things you can ...
user4574's user avatar
  • 12.1k
11 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'...
Simon Fitch's user avatar
  • 32.6k
11 votes

What battery chemistry is suitable for a "time capsule" applicaton?

Industrial Zinc-air batteries have a very long shelf life. They need to be activated (pull-tab) and require an oxygen environment which may invalidate this battery for your needs.
qrk's user avatar
  • 9,179
10 votes

What battery chemistry is suitable for a "time capsule" applicaton?

A nuclear-diamond battery is probably the best choice, they could last for 100's of years. In 2018, researchers from the Moscow Institute of Physics and Technology (MIPT), the Technological Institute ...
Voltage Spike's user avatar
  • 81.2k
9 votes

What battery chemistry is suitable for a "time capsule" applicaton?

Thermal batteries (an unfortunate name because they are not hot until activated) are used in military applications such as missiles. They are activated by a built-in pyrotechnic charge and have an ...
MTA's user avatar
  • 591
8 votes

Is it safe to discharge Li-Ion to 0V?

Storing them "discharged" to ~3V with the device they were used in still preserves lots of energy in the battery. At 3V a Li-ion battery has almost no capacity left. In this graph two 800mAh ...
Bruce Abbott's user avatar
  • 56.2k
8 votes

Is temperature the only battery charging speed limitation?

If you charge too fast, then because the heat transfer is not instantaneous the plates buckle due to thermal expansion and create localised « shorts » which can then cause catastrophic failure. And ...
Solar Mike's user avatar
  • 6,529
7 votes

Why are lithium-ion batteries typically used if they’re so flammable?

Li-ion is primarily chosen for higher energy density (by weight and volume), but also for higher power, higher voltage, more flexible form factor, cheaper and easier manufacture, more efficient ...
Bruce Abbott's user avatar
  • 56.2k
7 votes

Why are(n't) rechargeable batteries damaged by partial charging?

The three statements you quote are all about correct. What's good for a battery heavily depends on the type (chemistry) of the battery. In the old days, earlier than 10-15 years ago, the majority of ...
JimmyB's user avatar
  • 3,863
7 votes

Are lithium ion batteries damaged by strong magnets?

It should not have an affect on the battery, the magnetic field my deviate the path of ions and electrons slightly but not have any effects on the battery itself. If the magnets 'slam' into the ...
Voltage Spike's user avatar
  • 81.2k
7 votes
Accepted

Safe continuous discharge rate of a car battery

Your Varta battery is a Sealed Lead Acid, AGM type. I could not find useful information on Varta's website, so I will refer to other manufacturers that provided data. I tried to find from YUASA brand, ...
EJE's user avatar
  • 1,549
7 votes

If you mix the anode and cathode in a electrolyte solution you will have a short-circuit?

Liquid-metal batteries do exist, but these operate at high (molten salt usually) temperatures and are currently still being researched. They are impractical for most roles due to their high heat ...
rdtsc's user avatar
  • 16.2k
7 votes

What battery chemistry is suitable for a "time capsule" applicaton?

Let's assume we're talking an Earth-bound solution. If the location has a consistent ambient thermal gradient available, and your power needs are low, perhaps a thermopile combined with some energy-...
hacktastical's user avatar
  • 52.7k
6 votes
Accepted

Deciding on lithium battery chemistry, lithium ion (protected) or Lithium Iron Phosphate (no protection) Safety is critical

Let's start with a very important point: With Lithium based batteries a thermistor is a nice last line of defence, but you seem to be making it the centre point of your thoughts. If your thermistor ...
Asmyldof's user avatar
  • 18.4k
6 votes
Accepted

Is a battery's internal resistance a function of integrated current over time?

A cell is a bunch of chemicals between two electrodes. A chemical reaction produces an excess of electrons on one terminal, and a lack of electrons on the other. Once the potential difference ...
Simon B's user avatar
  • 19.1k
6 votes
Accepted

Why are lithium-ion batteries stored at 50% voltage and not a lower voltage?

I've always assumed that the lower the voltage, the less material degradation, but that starting a storage cycle with a voltage too low runs the risk of dropping the voltage to a point where the ...
Bruce Abbott's user avatar
  • 56.2k
6 votes

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

The chemical reactions inside the battery cause opposite charges to build up on the terminals. The buildup of opposite charges creates a voltage difference between the terminals, whether the batter is ...
Matt Timmermans's user avatar

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