M18 to 12v adapter

[Dieselcamino]

Hey everyone. Tinkering with a project that has hit a wall, looking to run a 12v air mattress pump off of a Milwaukee M18 battery, I found a M18 to USB/12v adapter and fixed up a jumper cord quick, it runs the pump for a couple seconds then dies. I'm assuming the adapter has an over load of sorts. Tried fusing it down but it didn't help. I'm no electrician, any help appreciated.

 

[rlitman]

I had one that I used to power a Milwaukee heated jacket using M18 batteries. It worked well until I tried to run a spray pump that drew 3A. The board let the smoke out within a second. It seems that these have a hard limit of about 1A output.

What I did to make the pump work was to match a bigger (5A) 18V to 12V buck converter to a fused battery adapter:

https://www.amazon.com/gp/product/B08TQV5MPV/?tag=atomicindus08-20

https://www.amazon.com/gp/product/B09652RK9C/?tag=atomicindus08-20

 

[Komet]

Seems like an M12 battery would be really great for this.

 

[blenderfender]

I doubt it would get hot enough to trigger a thermal shutdown after a few seconds. There's probably an overvoltage sensor or an RPM limiter that's shutting things down. Assuming that's the case, you'll need to step down the voltage, using a device like rlitman shared.

 

[dogdog]

The buck converter electronic will shut down if it is overloaded... probably not the OP's pump shutting down. Just get something with bigger 10 or 15AMP ones like posted, op should really find out what his pump draws so he can size the converter properly.... most are just 1AMP 2AMP stuff.

 

[Dieselcamino]

I think I'm going to pick up the converter rlitman linked, thanks.

 

[dogdog]

Get the bigger amp version the 10 or 15 amp one.

 

[Dieselcamino]

Good call, Ideally I want to make a box I can plug an M18 battery into and have a 12v car socket and USB. I already mounted a USB socket on my M18 fan and it works well.

 

[rlitman]

Get the bigger amp version the 10 or 15 amp one.

Good idea. In my case, I knew the water pump drew 3A, so a 5A converter saved me some money and weight, but if you don't know the current draw, there's little risk in oversizing and big risk in undersizing. Too small a converter will burn up if overrun.

 

[dogdog]

Good idea. In my case, I knew the water pump drew 3A, so a 5A converter saved me some money and weight, but if you don't know the current draw, there's little risk in oversizing and big risk in undersizing. Too small a converter will burn up if overrun.

Yea OP have to measure his current draw and determine the needs... though most of those 12V battery don't provide more than 5 or so AMP... but with these converter, you have to discount that 90% at most efficiency... I think typical higher 80 something %...

 

[blenderfender]

Sorry, I misread your original post and assumed that you were connecting the M18 terminals directly to an M12 tool. Agree with the other posters that a higher current converter is probably needed.

 

[signcrafter]

I've done similar projects for a trailer light tester.

Link to my trailer wiring tester

Trailer lights and brake tester with M18 power and remote activated

Have been working on trailers here and there and wanted to make a simple tester for plugging the trailer in and checking lights and brakes. My thought was just a car battery with a cord and some switches. Then simple went out the window. Was watching a South Main Auto video on trailer brakes...

www.garagejournal.com

M18 battery adapter.

https://www.amazon.com/gp/product/B09652RK9C/?tag=atomicindus08-20

Step down transformer

https://www.amazon.com/gp/product/B01JAIC7OO/?tag=atomicindus08-20