Anyone know a lot about 18650 batteries?

Forums › Gadgets, robotics, home automation, electronics (including wearables) › Anyone know a lot about 18650 batteries?

LennonNZ

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#272423 24-Jun-2020 11:30

I am waiting a slightly strange need . In Simple Terms a UPS. I need to run a RPi on Batteries but be able to charge the batteries without losing power.

USB Power In-> TP4056 BMS -> 4P (4*18650 in Parallel) -> DCDC Convertor back to 5V -> USB Output -> Raspberry Pi

https://www.trademe.co.nz/electronics-photography/other-electronics/electronic-components/other/listing-2675078822.htm?rsqid=66e5c15bdf64448f8e14eb04436bc668-002
https://www.trademe.co.nz/electronics-photography/other-electronics/electronic-components/other/listing-2666170173.htm?rsqid=9af0747b878f4e00a17ca78d9a70bf36-001

Or would a 4S be better and use a different BMS and DCDC Convertor

https://www.trademe.co.nz/electronics-photography/other-electronics/electronic-components/other/listing-2674136832.htm?rsqid=a09090d874a9432aa5062dca3d839f88-001
https://www.trademe.co.nz/electronics-photography/other-electronics/electronic-components/other/listing-2674189456.htm?rsqid=b3fc14234c7644f8989b46ef352b4f7a-002

There is this which is already made

https://www.aliexpress.com/i/4000337496660.html

But I cannot find it available in NZ.

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#2511543 24-Jun-2020 16:13

Just order that one from Alix. There should not be a problem.

hio77

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#2511631 24-Jun-2020 17:39

Yes that will work. Remeber to add battery protection, 18650s are fun when they get warm ;)

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Gordy7

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#2511666 24-Jun-2020 19:06

I guess you are discussing 18650 Lithium Ion batteries.

I have used a few 18650 LiFePo4 batteries and had no problems. (from Aliexpress)

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Nate001

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#2511685 24-Jun-2020 19:34

Adafruit make something like you want - https://www.adafruit.com/product/2465

But not sure if it would handle 4 18650s?

shanes

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#2511797 24-Jun-2020 21:05

LennonNZ:

I am waiting a slightly strange need . In Simple Terms a UPS. I need to run a RPi on Batteries but be able to charge the batteries without losing power.

Sound idea, I'm looking to do something similar.

LennonNZ:
USB Power In-> TP4056 BMS -> 4P (4*18650 in Parallel) -> DCDC Convertor back to 5V -> USB Output -> Raspberry Pi

https://www.trademe.co.nz/electronics-photography/other-electronics/electronic-components/other/listing-2675078822.htm?rsqid=66e5c15bdf64448f8e14eb04436bc668-002
https://www.trademe.co.nz/electronics-photography/other-electronics/electronic-components/other/listing-2666170173.htm?rsqid=9af0747b878f4e00a17ca78d9a70bf36-001

Pi's can draw quite a bit of current up ~2A, and the modules you've listed probably won't cut it.

You will need to take into account charging current and the Pi current for the BMS, probably ~2.5A, and the Pi current ~2A for the Convertor.

Geektastic

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#2511805 24-Jun-2020 21:31

They are hard to get "simply" - I need one for a torch and have not yet found one I feel comfortable with except Nitecore. I do not like the iffy branding on most of them.

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LennonNZ

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#2511830 24-Jun-2020 22:40

I ordered 2 of the ready made ones from aliexpress from different sellers

Yes I could find high amp BMS and step down transformers but hopefully the ready made ones works better.
I have a rather large (and heavy) Powerbank at the moment and if the devices don't work well a lot of the ravpower powerbanks have passthru charging.

The project is something like an improved version of http://74.69.57.190/

I expect the unit to self charge itself when not in use via wireless charging or magnetic usb interface.

neb

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#2512153 25-Jun-2020 13:41

There are quite a lot of UPS Pi HATs that do this, Google ups pi hat. Here's one from Australia which might be quicker than the Ali one, which will take at least a month to get here.

LennonNZ

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#2512183 25-Jun-2020 14:47

Anything is faster than Aliexpress to get here.

trig42

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#2512187 25-Jun-2020 14:52

LennonNZ:

Anything is faster than Aliexpress to get here.

Except AusPost Economy. Suspended until further notice...

neb

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#2512197 25-Jun-2020 14:59

Aliexpress is hit-and-miss, during the lockdown I got stuff from there in two weeks vs. the more usual one-month wait. At the moment there seems to be a roughly one-month delay between "hand over to airline" in China and "arrived in destination country". Mind you shipping from the US is just as bad, if they'll ship at all.

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Nate001

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#2512249 25-Jun-2020 15:04

LennonNZ:

The project is something like an improved version of http://74.69.57.190/

Clicking on this at work was a bad idea... IT guys rang me asking to detail where I had been in the past 30 mins, website ran a python script and they thought we were compromised.