Tagged Questions

1
vote
0answers
40 views

Does a crude Li-ion 18650 battery have internal thermal (mechanic?) protection?

For clarification: crude means "it does not have any protection circuit attached". Short history long: I extracted 6 18650 (Sanyo) batteries from an Acer battery pack. They had more than 3V each and ...
2
votes
1answer
67 views

When rechargable battery age, what quality decreases?

When a rechargeable (li ion) battery has many cycles and begins to wear down, what quality actually diminishes? I know it can hold less charge, but is this evident in the potential difference it can ...
1
vote
1answer
60 views

Lithium Ion charging problems - power outages

Does any one know if general charge circuits for lithium ion batteries suffer from this problem: -Flat Battery put on to charge. -A power outage of long duration occurs (say 8 hours). -When power ...
0
votes
1answer
182 views

Charging phones via solar battery chargers

For a school project, I want to make a solar iPhone charger (specifically for the iPhone 4) and I've spent about a week looking up stuff all over the Internet, and I'm stuck for the hundredth time. ...
2
votes
1answer
139 views

From Li-Ion to Li-Po battery: design a new battery pack for old mobile phone

I have an old working mobile phone. The battery, a compatible 3.6V 500mAh Li-Ion is almost dead (the original one was 800mAh). Is it possible replace the battery pack with a 1200mAh or so Li-Po ...
6
votes
2answers
129 views

How can a Li-Ion battery maintain decent characteristics for nine years?

Turns out Opportunity Mars rover is already working for nine years. It uses Li-Ion batteries to store energy acquired from the solar panels. In my experience Li-Ion batteries when recharged ...
4
votes
1answer
173 views

Lithium-ion rechargeable battery, shelf life

For Lithium-ion rechargeable batteries, that have never been charged, or been charged like 2-3 times at most, some 2-3 years back, and having since-then been in packaged condition, what should I ...
1
vote
1answer
86 views

Silicon-graphene battery energy density?

A startup called CalBattery is touting that their silicon-graphene anodes for li-ion batteries "will improve the anode specific capacity performance of lithium battery anodes by a factor of 3X." Will ...
5
votes
3answers
2k views

Measure Lithium ion battery voltage (thus remaining capacity)

What I am working with: I am running my self-made Arduino board (in the sense that I use the Arduino bootloader and code editor) at 3.3V, and powered from a Lithium ion battery, which is USB-charged ...
6
votes
3answers
3k views

Regulated 3.3V from a Lithium-ion (or LiPo) battery

Background I wish to power my circuit with a Lithium-ion or LiPo battery (likely a battery with around 1000 mAh capacity). These batteries have a voltage that goes from 4.2V to 2.7V typically during ...
4
votes
1answer
338 views

What would cause a watch battery to leak?

I am using a CR1220 Lithium Manganese Dioxide battery to keep a real-time clock chip running during periods when batteries are removed from a device. The battery is only connected to two pins on the ...
4
votes
3answers
293 views

Is there any sense in this technique for charging Li-Ion batteries?

This is a replication of this question on Android SE. I feel that it is in fact an electrical engineering question, since it covers batteries behavior in details. Basically there's a claim that the ...
4
votes
4answers
2k views

How is fully charging a Li-Ion battery in 35 minutes possible?

I happen to own a power drill/driver that runs on a Li-Ion battery and ships with a charger that charges it fully in 35 minutes and claims to charge it to 70% in 15 minutes. According to answers to ...
4
votes
4answers
349 views

Overclocking my toothbrush

I use these toothbrushes: http://www.amazon.com/Oral-B-Advanced-Toothbrush-Vibrating-Bristles/dp/B00336EUV8 They tend to run out of battery quite quickly. I'm happy to keep buying more because ...
1
vote
0answers
251 views

How many affordable lithium polymer batteries would it take to safely jump-start a car?

I have a couple of these incredibly powerful 12V battery packs and I got thinking about how feasible it would be to MacGyver an engine starter out of them. These things are rated on the package to ...
3
votes
1answer
341 views

How to measure Li-Po battery leakage?

I'm working on a low-low power system, which is powered by a little solar panel and a Li-Po (Lithium-ion Polymer) battery, which can be \$20\$ or \$ 50\:\mathrm{ mAh}\$. The capacity by now is not ...
2
votes
2answers
1k views

Why are Li-Ion battery so much safer than lead-acid?

Recently I asked how to charge a (lead-acid) car battery at home and looks like the answer is very dangerous, don't do it unless you really really have to. Meanwhile people charge Li-Ion batteries of ...
4
votes
2answers
248 views

Properly charging and discharging Lithium cells during battery testing?

I'm working on some software that automates charging and discharging battery cells to generate discharge curves. I have a few concerns about properly charging and discharging of lithium-ion / ...
11
votes
2answers
438 views

How fast can a Li-Ion battery be charged?

So far I've seen many Li-Ion battery chargers that do the full charge in about 1,5 hours or more. There're also NiMH battery chargers that claim they charge a NiMH battery in 15 minutes and then the ...
5
votes
1answer
222 views

How to power a widget, while the li-ion battery is charging?

I am in need of a way to charge a 3.7V li-ion cell (probably an 18650 type) from a 4.5V - 20V input. That's not a problem, there are plenty of (switching) battery chargers around with that kind of ...
2
votes
2answers
627 views

Use a lithium ion battery from a laptop, for a small project?

Now laptop batteries are very expensive, however I have a slightly beefy Dell Inspiron 1525 laptop with a half year old battery that works fine. Other than complete depletion, of which I have heard ...
4
votes
1answer
455 views

How to test internal resistance on small lithium polymer cell?

I'm coming from a computer science background, and will be writing some software to automate battery testing. I have background in math, but little to none in physics or electronics. Please consider ...
0
votes
6answers
2k views

How to charge Laptop Li-ion Battery cells manualy?

I have received some Li-ion batteries which were originally used in Asus A2 Laptop battery original one and I would like to know if it is possible to charge each cells independently with some device ...
8
votes
6answers
8k views

3.6 or 3.7 Volts: Why 18650 Lithium Ion Battery Cells Differ in Voltage?

I'm very happy I found this place! Some questions in my workflow that make them together unique, but separately perhaps valuable to general public as well: 1] VOLTAGE: 3.6V or 3.7V - 18650 Li Ion ...