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Li-Po Battery Questions

I have always followed the instructions in this tutorial about the care and use of Li-Po batteries... but I still have some questions

www.ez-robot.com/Tutorials/Lesson/26?courseId=4

I haved read other several articles that caution about "trickle charging" Li-Po batteries which is why I always disconnect the charger when its done.

My question is why do notebooks, phones and tablets allow you to continue to use them while they are charging?

Is the battery Lithium chemistry different?

Do they use a "Float charger" verses a "Trickle Charger" which I understand charges only to 80% and is supposedly safe for Li-Po batteries

The reason I ask is that I'm working on a self-docking EZB Roli charging station and I'd like to avoid having to add a means to automatically disconnect the power switch when charging and also to disconnect the charger when its done

Thanks,
Frank


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#1  
There is a difference in the battery chemistry in the Lithium Ion batteries used in phones and the Lithium Polymer batteries we use in the robots, but more importantly, the charging circuit in the phones and laptops are very smart and adjust the current based on temperature, current draw, and other factors.

Alan
PRO
Synthiam
#2  
Laptops and phones do not run off the battery when power is applied. Doing so would add additional stress on the battery. So a switching circuit is used.
#3  

Quote:

Laptops and phones do not run off the battery when power is applied. Doing so would add additional stress on the battery. So a switching circuit is used.


Not to argue the point too much, but I have empirical evidence that this is more complex than that. Under certain conditions, I have seen phones lose battery power even when plugged in, just not as fast as running on battery alone (For instance, running Google Maps navigation, playing music through Bluetooth, screen brightness all the way up because it is day, and phone hot because it is summer, power adapter not the highest available for the phone - for instance, using a 2.5 amp instead or wireless instead of QC 2 or 3 on a phone that supports it).

Ampere or another app that shows the current amp draw will show a small negative if plugged in, a large negative if not plugged in, and will shift to a high positive value when apps that use a lot of power are stopped.

Alan
PRO
Synthiam
#4  
Yeah - that’s how the switching system works. If the external power can’t provide enough current, it’ll start drawing what it needs from the battery. It’s a pretty simple circuit. In fact, my new dell xps laptop has a bios warning on boot that my aftermarket power adapter may not provide enough current and the battery will be used in those cases.

No company would ever ever ever pass a CE certification test by powering a device from battery while it’s charging within recommended use parameters. For example, your iPhone or tablet in reference would specify a certain amperage power supply - which would prevent the battery from being used while charging. This is exactly why those specifications are included as minimal. They wouldn’t pass CE otherwise.

A battery is NOT and will never be a source of power while charging. Even automobiles since OBD 2 requirements mean the alternator must provide enough power to run the vehicle without a battery connected with all accessories enabled.

Assuming a battery can be shared as a power source would be a terrible and unsafe design flaw. Think about what that design would mean... you’re sharing power between an AC mains to DC current with a battery. That’s like purchasing a kitchen freezer that plugs in the wall and also requires you add ice to maintain cold temps lol
#5  
Gotcha. Wonder how much that kind of circuit would cost on its own and if we could build them into robots reasonably. This "dockable, but always on" robot is something that a lot of DIYer's are trying to find good solutions for.



Alan
#6  
I would really like to have that feature. Especially for a robot that I could summon

Frank