Emergency power supply for router or modem
On my estate, the biggest problem is the frequent lack of electricity. The situation repeats itself almost every week and this occurs for several hours. I don't know the reasons - there is construction going on around here and maybe there is an interruption when connecting new buildings. Fortunately, the laptop battery, despite its age, still provides support, so I could work in peace, but I don't have internet at the time, as the modem is powered from the mains.
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Design of emergency power supply for router or modem .
On behalf of a client, I developed an uninterruptible power supply (UPS) for an alarm system installed in a garage where power interruptions are constant. This UPS contains a charging circuit for two or three Li-Ion cells, a DC-DC converter from 3.7 to 12V. And it can be used as an emergency power source for a modem or router. For this reason, I have decided to share this project.
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This first one is made on a TP4056 IC and FS3401 field effect transistors. The cell temperature sensor is not used in this case. The LEDs LED1-2 show the status: red - charging, green - its end. The specialised DW01A circuit, which controls a pair of FS8205A field-effect transistors, is responsible for overcharging protection. These are connected between the minus of the battery and the ground of the device.
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The DC-DC converter from 3.7-5 to 12V is made on the MT3608B chip. It is powered from a USB port from a regular charger, providing a current of no less than 1A, or from 18650 batteries connected in parallel when there is no voltage from the charger. The output voltage can be adjusted by changing the value of resistors R8-R9.
I had to create this schematic from photos of a ready-made Chinese instrument as part of Reverse Engineering. The circuit board, on the other hand, I developed myself. It is dedicated for a socket for 2 or 3 cells. If a socket for 2 is used, part of the board can easily be cut off. Surface mount, but due to the larger size SMD components used, they can be soldered by hand. Circuits (wires), transmitting high current, should be strengthened with a thick layer of solder.
The board can be made yourself or ordered from Chinese factories using the files I have attached below.
Emergency power supply diagram
Design of emergency power supply for router or modem .
On behalf of a client, I developed an uninterruptible power supply (UPS) for an alarm system installed in a garage where power interruptions are constant. This UPS contains a charging circuit for two or three Li-Ion cells, a DC-DC converter from 3.7 to 12V. And it can be used as an emergency power source for a modem or router. For this reason, I have decided to share this project.
View of plate from top
This first one is made on a TP4056 IC and FS3401 field effect transistors. The cell temperature sensor is not used in this case. The LEDs LED1-2 show the status: red - charging, green - its end. The specialised DW01A circuit, which controls a pair of FS8205A field-effect transistors, is responsible for overcharging protection. These are connected between the minus of the battery and the ground of the device.
View from below
The DC-DC converter from 3.7-5 to 12V is made on the MT3608B chip. It is powered from a USB port from a regular charger, providing a current of no less than 1A, or from 18650 batteries connected in parallel when there is no voltage from the charger. The output voltage can be adjusted by changing the value of resistors R8-R9.
I had to create this schematic from photos of a ready-made Chinese instrument as part of Reverse Engineering. The circuit board, on the other hand, I developed myself. It is dedicated for a socket for 2 or 3 cells. If a socket for 2 is used, part of the board can easily be cut off. Surface mount, but due to the larger size SMD components used, they can be soldered by hand. Circuits (wires), transmitting high current, should be strengthened with a thick layer of solder.
The board can be made yourself or ordered from Chinese factories using the files I have attached below.
andreyatakum wrote 551 posts with
rating 761 .
Live in city Antalya.
Been with us since 2021 year.
Comments
Add a commentI am looking for such a module, but I only see on Aliexpress modules up to 15-20W. And I would need one that would give 2.5A on 12V that is 22-26W. I have to power a Router, OLT, and a small PC that does... [Read more]
. Did you mean something like this: Link or this: Link ? [Read more]
In my opinion, the easiest way to do this is to buy a PD 65W powerbank, plug in a constant charge from the socket, connect a step-up converter to the output for 12V, or simply connect an 'initiator' that... [Read more]
Here 2 more modules without a case: 4A - Link or 3A - Link . However, please note that these are "Chinese amps". Therefore, if you want to get 3A it is better to buy for 4A or more. [Read more]
is it not the same ? https://pl.aliexpress.com/item/1005006860598580.html :) . [Read more]
. Looks like a solution to the problem - would need to verify that it works as the author assumes. [Read more]
. Well, yes! I was drawing from a similar one. [Read more]
I have, tested, for the router perfect, purchase cost under 10zł with shipping to PL. There is no option to make it worthwhile to do it yourself. PS. I came across a circuit for 2 cells, where the cell... [Read more]
For a terminal drawing a maximum of 8W, will this also be suitable? I am currently using a classic UPS. And I wonder whether such an uninterruptible power supply wouldn't be better in terms of the energy... [Read more]
. These from aliexpress can be connected in parallel. The voltage can be raised on the inverter, someone even described here, probably up to 20-odd volts. Only still the whole thing is powered from 5V,... [Read more]
At my place, I used a Techtron ZA-TECH 500 uninterruptible power supply unit with a 65 Ah battery purchased a few years ago. It is used to maintain power supply to the central heating pumps and in addition... [Read more]
Ready https://www.eaton.com/pl/pl-pl/catalog/backup-power-ups-surge-it-power-distribution/eaton-3s-mini-ups---emea.html [Read more]
I have such a ready-made DC1036P MINI DC36W 2A 5V/9V/12V but it heats up a lot https://obrazki.elektroda.pl/5016544900_1739881546_thumb.jpg [Read more]
The nice thing about this project would be that it would be possible to set the charging voltage of the cells. I would prefer that the cells are not sustained at 4.2V all the time. This will be detrimental... [Read more]
And is it a coincidence that buffer operation for lithium cells is already disadvantageous? [Read more]
It's not as you have a reduced stand-by voltage. It's just keeping the voltage high on the cells that will whip them. It's as if you store the cells at 4.2V all the time for years. When the voltage drops... [Read more]
I bought a UPS from greencell a couple of years ago and I can safely recommend it.So far it hasn't let me down [Read more]
. somewhere here was a description of this power supply what I attached, but I can't find anything on the electrode, although I participated in that thread :D as I have now checked, it bravely holds... [Read more]
. What did you check the capacity on? What model of cells? Are you able to give an IR before and after one year in the device? [Read more]