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Why is there so much fear surrounding LiPo batteries?

Every cell phone (as well as laptop and nearly everything with a rechargeable battery) uses LiIon/LiPo (essentially equivalent for the purposes of this discussion). And you're right: In terms of ...
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82 votes

Why is there so much fear surrounding LiPo batteries?

To use Lipo batteries safely, you must treat them with the same respect you would anything that can store and rapidly release a large amount of chemical and/or electrical energy. The bigger the ...
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55 votes

Why is there so much fear surrounding LiPo batteries?

When a big company wants to make a LiPo charger, they can: A. Have experts on staff and do extensive testing to make sure the charger will work safely across the full range of operating conditions. ...
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41 votes

Why is there so much fear surrounding LiPo batteries?

[Though this late answer may get little exposure now that the question has exited the hot-list, I think it is essential to further emphasize the contrast between the comprehensive safety features in ...
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14 votes
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Unable to understand Drone's LiPo battery capacity loss

I recall NASA discovered that Li-ions above 4.10V/cell tend to decompose due to electrolyte oxidation on the cathode (+), while those charged to lower voltages lose capacity due to the solid ...
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14 votes
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Why do drones use Li-Po instead of Li-Ion?

For this answer I'm going to define LiPo as flat packs, and Li-Ions as 18650s. The reality is more messy than that, but I believe this way of defining the terms will help answer your question as you ...
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14 votes
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How much can I overcharge a 4.35V LiPo?

The charge (termination) voltage level of Li-ion batteries is specified by manufacturer. The specification is based on reasonably accepted number of cycles ("battery service life") a battery can ...
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13 votes
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Is this MOSFET upside down?

It is correct. You normally see PMOS connected like this to act as a reverse-polarity "diode". simulate this circuit – Schematic created using CircuitLab It has much less voltage drop ...
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12 votes

How much can I overcharge a 4.35V LiPo?

Charging Li-Poly and Li-Ion is not as simple as just pumping a voltage across it. It's a two-stage operation involving both constant current and constant voltage. Apply a constant current of (say) 1C ...
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9 votes
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LiFePo4 vs LiPo

Lipos have higher voltage per cell (3.7 vs 3.2). All else being equal this equates to more power. Lipos may also have lower internal resistance and higher maximum discharge rates, which equates to ...
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9 votes

Understanding LiPo charging / protection circuit

Protection circuits are usually distinct from charging circuits. Many battery packs are designed with the intention of being charged by a dedicated unit that will control the charging process. The ...
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8 votes
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Do cell phone batteries contain protection circuits?

Those batteries do have built-in protections, but not the kind of ones you see on sparkfun batteries. They have thermal protection required for charging the battery and sometimes low charge cutout ...
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  • 1,670
8 votes

why do laptops have 10 or 20 volt batteries if most components only use logic level voltages

Because while total power stays the same, voltage droop across a cable due to high currents can be avoided with higher voltages and lower current. Copper is expensive, and it's simpler to deal with 2....
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7 votes
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Is it safe to charge a Li-Po battery at a lesser C rate than its usual routine?

You can always charge a Li-ion or Li-Po battery at less than its specified rate provided that all the normal charging requirements (CC followed by CV, don't overcharge, don't trickle-charge, don't let ...
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7 votes

DC-DC Boost converter in Parallel

In your post you said that you wanted 1A out at 12V, and that you calculated that you needed 3.24A in with no losses. You didn't state what input voltage you were using, but it can be calculated. ...
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7 votes

why do laptops have 10 or 20 volt batteries if most components only use logic level voltages

Ohm's Power Law: $$ P = V*I = I^2 * R $$ Power lost in copper, and needing to be dissipated as heat, goes up with the square of the current. Consumers don't like thick cables or hot laps. So ...
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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 ...
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7 votes
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Block battery if USB is plugged in

With the drain and the source connected as you show, it will do what you want — the body diode is pointed in the correct direction, as shown below. But you do need a diode in the USB path, so that the ...
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6 votes

Do cell phone batteries contain protection circuits?

I would try to get one of these unsold phones and the wall power supply. Than use the phone as charger. So you eliminate any mechanical problems, you have near to perfect contact and you can be sure, ...
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6 votes

Help please! I need to give constant current to an LED from a Lipo battery

Something like this could be very efficient (not much more than the LED draw) with a CMOS op-amp. For fairly constant visual brightness (+/-10% current) you could derive the 100mV with a voltage ...
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6 votes

Why is there so much fear surrounding LiPo batteries?

All great answers. Here is a short one. A 7.4 volt. 5 amp-hour battery has 37 watt-hours of energy, or 133,200 joules. Compare to a .357 Magnum's 873 joules of muzzle energy. The trick is not to ...
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6 votes

Controlling a DC Motor 48v with a 63v power supply

You actually have a few issues when driving a DC motor with more than the boilerplate voltage rating. Max Current: At no time should you exceed the maximum current rating of the motor. It will ...
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6 votes
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Why don't some 2S LiPo packs include a balancing connector?

If a lithium-ion battery with more than one cell has no provision for balancing, it's a blatant safety risk. As a battery ages, one cell will drop in capacity faster than the other, causing the lower ...
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6 votes
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What's inside power bank car jumper

Not sure which "thingy" you refer to. The smaller lump has protection circuits. But the secret sauce to these emergency car starter power packs is in the big lump. The reason they can put out so much ...
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5 votes
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Short-circuit LiPo battery

You should really get rid of the whole pack and don't absolutely try to charge it. These kind of batteries have very large flat metal pads soldered to a big pcb and it seems very unlikely to me that ...
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5 votes

To protect a LiPO cell from undervoltage, how low current is low enough?

Amongst other things I design solar charged lights. I want customers to be able to put a "dead" light in a dark place for a long while without destroying the battery. My approach is to reduce off ...
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5 votes

How come 18650 Li-ion cells aren't meant to be sold loose?

"Not meant" is not completely meaningful as there is not a consistent international regulation to that effect. However, an 18650 cell is potentially rather dangerous and use without an accompanying ...
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How to charge lipo with a laboratory power supply?

A direct way of doing it is to first analyze the battery and find its C rating. Then set the current limit of the power supply to under C/10, to be safe. So for say 2600 mAh battery, the limit should ...
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5 votes

Why is there so much fear surrounding LiPo batteries?

I think your info is outdated. I had a coworker who was into RC airplanes. They were early adopters of LiIon technology because they are light and hold a lot of power. He related how they had two ...
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5 votes
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How does a battery balance and protection circuit work?

I've read a chapter from a very good book which answers it all. I highly recommend reading that chapter or the book but if you want the very short story things are like this. Normally it is assumed ...
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