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Powering with 4.8V
#1
I encountered a problem from someone: he wants to use li-ion cells to power a small motor that works at 4.8V.
Problem is that a single cell would be too low and 2 in series would be too high.

I'm thinking of recommending him using 2 cells in series and something like this:

http://www.datasheetcafe.com/mp23070n-da...regulator/

The objective is to have as little loss in the conversion as possible. Is that good or are there better solutions ?
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#2
As long as you have plenty of margin with the motor's anticipated current draw (especially when starting & loaded), this should be fine.
Korishan likes this post
Running off solar, DIY & electronics fan :-)
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#3
The buck listed can do 4A peak current. So you will definitely need to make sure of your surge current on the motor. You might be able to parallel two of these together with diodes to keep backflow into the other chip, though (not certain of this though).
You could also build a buck converter with a nano, some FETs, diodes, and inductors. Julian Ilett did this with his MUPPET build. Altho, I'm not sure of it's current capability, been a while since I've watched those vids.
Proceed with caution. Knowledge is Power! Literally! Cool 
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#4
Some 7805 will do the trick?
The 5 amp i mean not the 1 amps, keep it simple.
They even have ready to build schematics, for extra amp and lower volt adjustment.
(not even needed), just use two capacitors at the line plus in(33uf) and one on the plus line out(0.1uf)
gnd is gnd
He will be fine.

or
+ 1 on Korishan

The best i could do for now:
http://www.datasheetcatalog.com/datashee...05CT.shtml
Could not upload the proper pdf, sorry.
This is the quickest link i could find that came in the neighborhood of what your friend must have
And i won't send you one of my data books Angel Angel

With best regards
Korishan likes this post
Still learning English. Learning Li ion and solar technology.

2800 cells in packs Exclamation above 2500mah and 90%soh.
~400 cells between 1800-2500 and above 90%soh(sell?)
600 cells between 2200 - 3000mah, 80-90%soh (sell?)
3000 waiting for testing.
approx: 0 cells not safe for use: dead, heaters, to high ir or sd/vamps

Time is our enemy, must work to, the sun is our friend, must relax to.
With best regards
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#5
(05-17-2019, 05:33 PM)100kwh-hunter Wrote: Some 7805 will do the trick?
The 5 amp i mean not the 1 amps, keep it simple.

The 780x regulators are linear type devices & dissipate some serious heat = less efficient
Most are rated about 1A
Something like a LM2576 would give a fixed 5V @ 3A output & is simple to build with.
thunderheart likes this post
Running off solar, DIY & electronics fan :-)
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#6
Thank you for all the suggestions. I'll pass them along.
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