Electrical Question

[Mike Goetzke]

I want to add an LED bar light to my snow blower. I want to use my Makita 18V battery for power. I bought two lights - one is 10” wide and the other 20” double row. The 10” uses about .9A and the 20” 4A. I’d like to keep the large one but I can get about 45 minutes of light out of the 18V battery. 45 minutes is probably plenty but would like at least an hour in case the battery isn’t fully charged.

I’m running the lights at 18V. I can get a Makita adaptor with a step down to 12V. Will this make the battery last longer?

 

[bobtskutter]

I might be wrong, but would think the system is running to constant power.
I don't think an 18v to 12v step down transformer will make any difference, the current will increase on the 12v side to maintain constant power.  Do the lights have a dimmer setting, that would (should) lower the power demand and increase battery life.

Off topic: How much snow are you trying to clear?

Bob

 

[woodferret]

Standard LED strips typically will operate at lower current as the forward voltage drops.  i.e. less power, less heat, less bright.  Unfortunately, unless you actually have specs on the strip, the only way you're going to know is to test.
https://www.waveformlighting.com/home-residential/can-you-operate-a-12v-led-strip-at-less-than-12v

There are constant current strips out there, but it would have been plastered all over the listing if it was.

 

[Mike Goetzke]

I might be wrong, but would think the system is running to constant power.
I don't think an 18v to 12v step down transformer will make any difference, the current will increase on the 12v side to maintain constant power.  Do the lights have a dimmer setting, that would (should) lower the power demand and increase battery life.

Off topic: How much snow are you trying to clear?

Bob

Bob - thanks for the reply. I’m in the Chicago area and we have been lucky with little snow so far. I’m retired and just looking to “trick” out my new snow blower.

 

[Mike Goetzke]

Standard LED strips typically will operate at lower current as the forward voltage drops.  i.e. less power, less heat, less bright.  Unfortunately, unless you actually have specs on the strip, the only way you're going to know is to test.
https://www.waveformlighting.com/home-residential/can-you-operate-a-12v-led-strip-at-less-than-12v

There are constant current strips out there, but it would have been plastered all over the listing if it was.

Thanks for the link. I have been using a voltmeter to measure volts/amps in my testing. One thing I found out right away is they lie pretty good about the wattage of these lights.

I did order the 12V voltage converter and will run a test but looks from the articles on these lights that I should be able to get an hour or so out on a freshly charged battery on the larger light.

 

[Vtshopdog]

What about just having a second battery handy??

 

[Mike Goetzke]

I might be wrong, but would think the system is running to constant power.
I don't think an 18v to 12v step down transformer will make any difference, the current will increase on the 12v side to maintain constant power.  Do the lights have a dimmer setting, that would (should) lower the power demand and increase battery life.

Off topic: How much snow are you trying to clear?

Bob

OK - Bob was right. I saw some videos of how LED's were dimmer with less voltage but the light I bought does have constant power demand. The light I bought is rated at 9VDC-30VDC so I'm fine at the 18V from my Makita battery. I ran a test with and without a 12V buck converter and the battery drained slightly faster with the converter. Probably due to the losses in the converter. I did find I can get about an hour from a full charged battery which is more than enough for me but will add a voltage display so as to not drain the battery too far. And, as suggested I can carry a spare battery.

On another snowblower note - there are a few uneven sidewalk sections I need to ride over and this can cause a bump and make the blower hop a few times. I found these skids called ArmorSkids. They are at a premium price but they smooth out the ride perfectly!

Thanks for all the help.

 

[Cheese]

On another snowblower note - there are a few uneven sidewalk sections I need to ride over and this can cause a bump and make the blower hop a few times. I found these skids called ArmorSkids. They are at a premium price but they smooth out the ride perfectly!

Thanks for this information Mike... [big grin]  I installed a 450 sq ft Bluestone patio about 20 years ago and the freeze-thaw cycles over the years have lifted a few of the stones which makes blowing the snow a real PITA. I'm going to measure the Toro blower today for a new pair of shoes.  [smile]

FWIW...As far as LED's go, the drivers for them are either Constant Current (CC) or Constant Voltage (CV). It seems the more industrial focused LED applications use CC while the more consumer focused LED applications use CV. I use both. The LED step lights in the front & rear steps are driven with CC. However the LED luminaires & fence lights throughout the yard are driven with CV.

The LED's you purchased, are CC as evidenced by the large voltage swing. As Bob mentioned, because the 12V supply is voltage limited, relative to the original 18V supply, the LED's will just draw more current from the 12V supply and give you shorter battery life rather than longer battery life. 

 

[Mike Goetzke]

On another snowblower note - there are a few uneven sidewalk sections I need to ride over and this can cause a bump and make the blower hop a few times. I found these skids called ArmorSkids. They are at a premium price but they smooth out the ride perfectly!

Thanks for the info!

I retired about two years ago so tricking out my new snow blower is somewhat a hobby/project. I changed out the skids, added single handle interlock, adding the light, and will soon apply an impeller mod kit.

Ha - I’ll probably have people flashing their brights at me when I snowblow at night.

Thanks for this information Mike... [big grin]  I installed a 450 sq ft Bluestone patio about 20 years ago and the freeze-thaw cycles over the years have lifted a few of the stones which makes blowing the snow a real PITA. I'm going to measure the Toro blower today for a new pair of shoes.  [smile]

FWIW...As far as LED's go, the drivers for them are either Constant Current (CC) or Constant Voltage (CV). It seems the more industrial focused LED applications use CC while the more consumer focused LED applications use CV. I use both. The LED step lights in the front & rear steps are driven with CC. However the LED luminaires & fence lights throughout the yard are driven with CV.

The LED's you purchased, are CC as evidenced by the large voltage swing. As Bob mentioned, because the 12V supply is voltage limited, relative to the original 18V supply, the LED's will just draw more current from the 12V supply and give you shorter battery life rather than longer battery life.