Have you built a Handmade small 5V UPS ?

Power sources/conversion, Switching power supplies, Renewable energy, PLCs. Discussions relating to the design and implementation of alternative energies.
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MoDu
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Re: Have you built a Handmade small 5V UPS ?

Post by MoDu » Thu Apr 04, 2019 1:28 pm

I've had more success recently with Powerbank pcb modules. It's been mostly luck to find a chip/board combination that's not one note. I absolutely detest the modern chargers (like my BT headphones) where if you plug it in, the device will turn off.

jeffs555
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Re: Have you built a Handmade small 5V UPS ?

Post by jeffs555 » Fri Apr 05, 2019 5:57 am

You are very close with the last diagram you posted. Would just need to add a couple diodes and a lipo protection board. The protection board keeps the lipo from discharging too low and ruining the cells. Also provides redundancy in case the charger breaks and tries to overcharge or short circuits. The diodes would supply power from the wall wart directly to the step-up and isolate the battery when the AC was on. When the AC went out, the battery would supply power through its diode. The diodes would waste a little power. Could use a low voltage Schottky or an ideal diode in the line from the battery to save power when operating from the battery. Not a problem when powered from the mains and a normal power diode would drop the 5V from the wall wart enough that you shouldn't need a step-up/step-down converter.
5v_ups__v2.jpg
5v_ups__v2.jpg (208.73 KiB) Viewed 1203 times
here is one of many protection boards available.
https://www.aliexpress.com/item/1s-3-7V ... 14272.html

Here is an ideal diode board(ie a mosfet with an ideal diode controller)
https://www.aliexpress.com/item/15A-Ide ... 96276.html

jeffs555
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Re: Have you built a Handmade small 5V UPS ?

Post by jeffs555 » Fri Apr 05, 2019 6:34 am

PS: Here are some Schottky power diodes. When drawing an amp or two from the battery they would waste less than 8% of your battery power so probably not worth trying to do an ideal diode board.
https://www.aliexpress.com/item/New-Ele ... 93279.html

stevestrong
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Re: Have you built a Handmade small 5V UPS ?

Post by stevestrong » Fri Apr 05, 2019 11:27 am

The diodes do really make sense.
However, I think the step-up board implicitly has the low-voltage protection as it only works above 3.7 V.
And the charger modules have the high-voltage protection. So the battery cell is well protected.

jeffs555
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Re: Have you built a Handmade small 5V UPS ?

Post by jeffs555 » Fri Apr 05, 2019 1:02 pm

When it comes to lithium batteries, especially unattended ones, you want a lot of protection. Electronics can and do fail so redundant protection is a very good thing especially when the results can be a lithium fire. The protection boards are very inexpensive.

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Re: Have you built a Handmade small 5V UPS ?

Post by mrburnette » Fri Apr 05, 2019 3:00 pm

ag123 wrote:
Wed Mar 20, 2019 2:54 pm
cross post: ray posted this about LiFePO4 batteries
https://www.stm32duino.com/viewtopic.php?t=421
i think they'd cost more than the average common lipo batteries but may be interesting to look at
...
I ran the prototype for over 2 years! Never an issue. Test uC was an ESP8266 with OLED display .... UDP receiver for my remote based GPS UDP transmitter.

I used an old power-brick, an AliExpress buck module, an Amazon purchased LiFePO4.

Ray

madias
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Re: Have you built a Handmade small 5V UPS ?

Post by madias » Thu May 09, 2019 11:42 am

I use this for many projects and small series productions:
https://www.aliexpress.com/item/ESP32-E ... 96675.html
charger, step up, fuse.. everthing on board for lazy people.

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MoDu
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Re: Have you built a Handmade small 5V UPS ?

Post by MoDu » Thu May 09, 2019 1:30 pm

Thank you Mathias, I've already ordered a few to test. What about a version for LiPos (flat cells) ?

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Vassilis
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Re: Have you built a Handmade small 5V UPS ?

Post by Vassilis » Thu May 09, 2019 2:09 pm

Madias, can this device be used as UPS ?
Can that module simultaneously charge the battery and provide 5V output ?
-Vassilis Serasidis

madias
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Re: Have you built a Handmade small 5V UPS ?

Post by madias » Sat May 11, 2019 8:36 am

Vassilis wrote:
Thu May 09, 2019 2:09 pm
Madias, can this device be used as UPS ?
Can that module simultaneously charge the battery and provide 5V output ?
Yes, should not be a problem, charging chip is (TP)4056e.

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