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Need help for diy ups project

Painhtut3

New Member
Hello . I’m novice learner in electronic. Currently I’m assembling diy ups project like this diagram. But I have one problem while switching main power and backup power . That is switching delay . When main power from smps fail , the MOSFET turn the battery output on but during switching Between battery and power supply There’s a switching delay that make my 12V 1.5 A onu router restart. My question here is how to eliminate that ? I don’t want connection loss for a moment during power outage. Any suggestion, help , ideal will be appreciated
8565154B-62D0-40BE-A641-E61266984677.png
 
Last edited:

Ramussons

Active Member
SMPS - which / where?
MOSFET - where?

You will have to describe your setup a little more for us to understand the problem.
And your schematic is too small to read the component values.
 

Painhtut3

New Member
SMPS - which / where?
MOSFET - where?

You will have to describe your setup a little more for us to understand the problem.
And your schematic is too small to read the component values.
SMPS - which / where?
MOSFET - where?

You will have to describe your setup a little more for us to understand the problem.
And your schematic is too small to read the component values.
SMPS = I use 12 v 5A supply to powering the router and charging the battery pack
MOSFET =IRF9540N between the battery output and boost converter input and the gate terminal is connected to adapter positive terminal . Does it clear or need more info?
 

Diver300

Well-Known Member
Most Helpful Member
SMPS = I use 12 v 5A supply to powering the router and charging the battery pack
MOSFET =IRF9540N between the battery output and boost converter input and the gate terminal is connected to adapter positive terminal . Does it clear or need more info?
The circuit diagram in your first post it too small to see clearly, so the more information needed is a readable version of that.
 

rjenkinsgb

Well-Known Member
Most Helpful Member
Why don't you just use a diode in place of the FET? As long as external power is on, no current will be drawn from the battery.

Note that the battery control board you picture is NOT a charge controller, it is purely under/over voltage protection and balance module. (Plus short-circuit protection).

You need an accurately regulated and current limited supply to charge the battery safely.

This is a setup I use with a similar BMS board and 3S2P battery pack, after the 15 - 20V power source:

Schematic_Charger_2022-05-19.png
 

ChrisP58

Well-Known Member
Most Helpful Member
As already said, the circuit drawing in your first post is to small to be usable.

But before you post a larger version of the same. please make the following changes:
  1. All components should have designators. This will make it much easier for members to accurately comment on your circuit. For example, Diodes D1, D2, etc. Modules M1, M2 etc. Fuse F1. Resistor R1. Connectors J1, J2, etc.
  2. The top left module doesn't have a label. It may be the same as the top right module, but guessing leads to errors. All components should have labels.
  3. It would also help if you provide details/links for the modules you are using.
 

Painhtut3

New Member
It is, thanks for that - and as has been pointed out, you don't have a charger in the circuit.
It has . I use 12V 5A adapter to power this entire circuit and charged the battery through the upper left xl4015 buck converter . And the problem here is not the charging . the problem is with the mosfet switch time because of that the router restart when primary power source fail.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
It has . I use 12V 5A adapter to power this entire circuit and charged the battery through the upper left xl4015 buck converter . And the problem here is not the charging . the problem is with the mosfet switch time because of that the router restart when primary power source fail.

That's NOT a charger, it's just a power supply - Li-Ion are critical about charging conditions, and can burst in to flames if not charged correctly. While that can be set to CV and CC, there's no shut off when it's fully charged.

But as for switching, why the FET at all? - just a simple diode is all that's needed - no switching involved.
 

Painhtut3

New Member
That's NOT a charger, it's just a power supply - Li-Ion are critical about charging conditions, and can burst in to flames if not charged correctly. While that can be set to CV and CC, there's no shut off when it's fully charged.

But as for switching, why the FET at all? - just a simple diode is all that's needed - no switching involveD
 

Painhtut3

New Member
Charging process is mainly handle by xl4015 Step down charger and bms , Ive never faced over charged and discharge issue .
You talk about placing diode instead of FET . How and which ? Can u explain a little bit?
 

Painhtut3

New Member
Charging process is mainly handle by xl4015 Step down charger and bms , Ive never faced over charged and discharge issue .
You talk about placing diode instead of FET . How and which ? Can u explain a little bit?
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Charging process is mainly handle by xl4015 Step down charger and bms , Ive never faced over charged and discharge issue .
You talk about placing diode instead of FET . How and which ? Can u explain a little bit?

You've already got a diode there, just remove the FET and replace it with a piece of wire, drain to source.
 

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