Need help with Low voltage protection circuit

[budm]

Re: Need help with Low voltage protection circuit

So how does it perform using noisy load such as Vacuum motor?

[flinx]

Re: Need help with Low voltage protection circuit

So how does it perform using noisy load such as Vacuum motor?

I have not tested that yet.

[flinx]

Re: Need help with Low voltage protection circuit

SO...

I got sidetracked by a project that I have been waiting a month for (stupid Post office).

I finally hooked up the dustbuster to it, reset the shutoff voltage for 13 volts, and... My control head for my power supply couldn't handle the load. My power supply has a maximum current limit of 15 amps.

When I hook everything up to the dustbuster and turn it on my PS resets. I did some poking around and checked the resistance of the motor. it's .59 ohms. Which means that at 16 volts it pulls about 27 amps cold start. Then it settles in at a comfy 11 or 12amps.

So I have to hook it up directly to one of my switching power supplies that can handle that amperage.

[flinx]

Re: Need help with Low voltage protection circuit

Alright!

I hooked the dustbuster and circuit up to a 15v somewhat adjustable switching power supply that can put out 40 amps and set it for 16v.

It started up just fine and ran fine. I dropped the voltage as low as I could but not low enough to hit the cut off I set.

Voltage did not dip too much when it started up (that I could tell). I did not have an amp meter on it, but I know it pulls at least 11 amps.

After about maybe one minute my thermal camera showed the mosfet was 172° f\78° c and I shut it down since I don't have a heat sink on it.

[flinx]

Re: Need help with Low voltage protection circuit

if anyone cares here is a video of the device being tested under load to cut off.
https://youtu.be/tkce2S1gxYA

[greg1985]

Re: Need help with Low voltage protection circuit

Just got my boards back from JLCPCB
IT works perfectly. though see if you can spot the error (on my part).




Yes I forgot to join a copper area to a network.

Hi. Nice project. Thank YOU for making this. Can You send me gerber file or pcb? I want to order from JLCPCB too. Thanks again for this project.

[Dima Abramov]

Hello i want to utilize this circuitry to put in to Power Tool adapter makita batteries -> other brand tools. The power tool draw can be constant 25-30 amps with peaks reaching up to 100 amps. So in this case IRF9540N from schematic is not a good choice because it would generate too much heat. Is there a better drop in replacement option? Something like PSMN1R2-30YLDX with 2.64 mΩ RDS for rough estimate .

[truclacicr]

FWIW, R5 in the original circuit on page #1 provides hysteresis.