What have you learned from the Battery University?

TinderBox (UK)

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I have the dumb charger plugged into an mains wattage meter and it is pulling around 6watts at the moment while charging 4xC 5000mah, I don't like leaving anything charging while i am sleeping or when i go out, so hopefully as the battery`s charge the amount of watts used should go down.

I have noticed that the battery`s are warmer when charging than i would expect, for such a low charge rate, would high internal resistance cause more power to be wasted as heat, or does pulse charging reduce heat build-up when using a smart charger, that this dumb charger lacks.

Thanks for the help Tom.

John.

Hello John,

I would charge them at 250 mA for 48 hours and then do a discharge and see if things have improved.

Tom
 

TinderBox (UK)

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Another question, I just bought an 8x18650 empty usb battery box, I have some old 4x 2200mah and 4x 2400mah, but they only test at around 1800mah at 1amp discharge rate, My question is can i use these mixed battery`s in my usb battery box as they are all connected in parallel.

So any chance of an simple battery question sticky, I have loads of questions like this, but creating an new thread every-time is a waste, I try to add my questions to an existing thread but this is not ideal.

Thanks

John.
 

SilverFox

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Bellingham WA
Hello John,

If the output of your battery box is around 4 volts, then all 8 cells are in parallel and you can use cells of differing capacity. If the voltage is higher you have a series/parallel set up and you can't use cells of differing capacities due to charging concerns.

Tom
 

TinderBox (UK)

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Thanks Tom just as i thought, and that saves me some money.

John.

Hello John,

If the output of your battery box is around 4 volts, then all 8 cells are in parallel and you can use cells of differing capacity. If the voltage is higher you have a series/parallel set up and you can't use cells of differing capacities due to charging concerns.

Tom
 

roadwarrior

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Oct 3, 2015
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Ordered, "Batteries in a Portable World", should have it by next week. Looking forward to what I can learn. :)
 

magellan

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Buchmann's was my first book on lithium ions and I have also used the website extensively. From there I went on to more technical articles on Wiki, monographs on the web, and even The Journal of Electrochemistry.
 

roadwarrior

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Oct 3, 2015
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Mostly just interested in NiMH right now.

Don't know how technical I will get with it in the future, but having stumbled upon this (CP forum) site is what got me interested in batteries in the first place.

If you would have told me 6 months ago, I would end up owning a Maha C9000, 5 quads of AA batteries (soon be 7) and keeping an ad hoc log of each cell......I would thought you were crazy! :eek:

But here I am today a registered member of the CP forums with all the above and Buchmann's book on order......:D....so who knows.:thumbsup:
 

TinderBox (UK)

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Any of your guy`s watched this video, it`s quite interesting.

At 35 minutes, they mention how charging to 4.35v can lead to sudden battery failure, a lot of manufactures are doing this now to get that little bit extra energy.

At 45 minutes, by the addition of a few chemicals, 300 cycles, can become 2000 cycles.

I virtually never charge my tablet or phones beyond 80% level, My Samsung Tab S1 i bought last November has been charged to 100% three times to calibrate the battery gauge.

http://powercartel.com/2014/11/notes-from-why-do-li-ion-batteries-die-lecture/

John.
 
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Dr. Tweedbucket

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Ohio
I just went over there because of this thread and holy CRAP!! I learned something! :party:

I typically keep my laptop plugged in all the time, but guess what? It's a freakin LITHIUM-ION battery pack and that's a big no no! :duh2: The Lithium Ion batteries like to relax just a little bit, they get all tense when they are at full charge. So from now on, I'll charge it up and then unplug it.

The other thing is, I noticed one time the battery pack was getting pretty hot and I was wondering what it's big stupid problem was? :mad: Well, little did I know, that could have been MY big stupid problem if I didn't unplug it.

Ok, all is well, so thanks to whoever started this thread, that was a good idea! :)
 

MidnightDistortions

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I typically keep my laptop plugged in all the time, but guess what? It's a freakin LITHIUM-ION battery pack and that's a big no no! The Lithium Ion batteries like to relax just a little bit, they get all tense when they are at full charge. So from now on, I'll charge it up and then unplug it.

Li-ion cells dont like staying in a 81-100% charge state for very long so I usually will charge my phone several hours before I need to use it when I dont have access to a charger.
 
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