Typical current draw on 18V cordless tools?

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SamTexas   100 MW

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Typical current draw on 18V cordless tools?

Post by SamTexas » May 03 2013 7:41am

I don't have any 18V tools thus the question.

What is the typical current draw you have seen/observed on your 18V (NiCd or Lithium) tools? What's the max observed current draw? What tools is it? Thanks.

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dogman dan   100 GW

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Re: Typical current draw on 18V cordless tools?

Post by dogman dan » May 04 2013 6:59am

I've never had a wattmeter on one to tell. Typical drill and saw batteries are generally not over 2 ah, some even less. Sawing tends to be more continuous, and you can easily drain one in 5 min. Drilling, particularly using a screw gun, is more like many small disconnected discharges, so I can only guess what the draw is. Less than a saw for sure, but most holes drill in less than one battery.

Pretty vague data, but all I can give you.

Regular AC stuff draws more power, and you can feel it's more. Small 110v saw draws about 8 amps, a big worm drive framers saw draws about 12 amps. Drills, depending on size draw 4-8 amps. Those are max amps, like long rips, or drilling steel or hard woods.

My best guess, the 18v tools would be equivalent to half the power of the AC tools at most. maybe less. I bet none draw more than 10 amps of 18v for long. My guess is all are going to run on less than 200w. If they used more, they'd never run on such a small battery.

My 24v lawmower, I have had a wattmeter on. It can easily draw 50 amps in thick grass. No controller, just a motor hooked to the battery. It can amp spike it to all hell. No wonder the SLA's didn't even last a month. Rips like hell on 20 ah of lipo though.

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Re: Typical current draw on 18V cordless tools?

Post by major » May 04 2013 7:53am

SamTexas wrote:I don't have any 18V tools thus the question.

What is the typical current draw you have seen/observed on your 18V (NiCd or Lithium) tools? What's the max observed current draw? What tools is it? Thanks.
With most tools like that it is difficult to get an ammeter in there. I have a Huskie 14.4V 6 ton hydraulic crimper where the NiCad packs have failed and they want like $259 for a replacement. So I gutted the dead battery and installed wires. I can now use any battery. But I had an occasion to use it off a power supply and it hit like 25-30 Amps at the end of stroke.

My Craftsman C3 19.2V shopvac is fused at 30A. Never blew it and don't have an actual read on it.

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Re: Typical current draw on 18V cordless tools?

Post by Harold in CR » May 04 2013 9:11am

The sawzall (Dewalt) 18V saw I just converted, has softened the bullet connector covers a little. Yesterday, I cut off 6 sections of a 4-6" diameter log that was dead and dry. Wood cuts fairly easily, but, took about 3-5 minutes of steady sawing per cut. Cellog'ed the battery (HK 5cell), and V was still 3.85 avg. That don't say much, but, the Cellmeters I bought from HK are not calibrated correctly, so I have to see how to do that, so it will tell me capacity of the pack or each cell.

I don't have a clamp ammeter.
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Chalo   100 GW

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Re: Typical current draw on 18V cordless tools?

Post by Chalo » May 04 2013 1:07pm

dogman wrote:My 24v lawmower, I have had a wattmeter on. It can easily draw 50 amps in thick grass.
You have thick grass in Las Cruces? How does that work? When I was a little kid, I lived in Anthony, and as I remember, grass was not a feature of the yard. Hardpan is what I'd call it.

I can't decide whether RC lipo is a good idea or a bad idea for a lawnmower. I reckon only an industrious person would run it as many as 25 times a year, so limited cycle life is clearly OK for that application. But I thought lithium cobalt batteries had a short shelf life whether you use them or not. If that's so, it seems like a poor match for a lawnmower.
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dogman dan   100 GW

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Re: Typical current draw on 18V cordless tools?

Post by dogman dan » May 04 2013 2:49pm

Not a problem if you have a about 6 ebikes around that also can use a 6s pack. But the real reason to lipo the lawnmower is it can handle a 50w spike. It could run on one 6s pack, as opposed to running like crap on two huge sla's. It's too much for a ping, but a 10 ah a123 pack would work ok. I went to 20 ah 6s, lipo on mine since I had a 10ah 12s pack. On that much lipo, a 50 amp spike doesn't even make it sag much. Instead, I pop the overheat breaker in the motor.

Thick grass is something you have to buy here, with a big fat water bill. 5 inches of rainfall last year. Not many in Anthony buy water for grass. But I do in one area of the lawn near the grill and the back door. Back when summer rains existed, all the lawn could get very thick by late August.

Interesting that you are a valley boy, I didn't know that, or forgot about it. My wife is a Gadsden High girl.

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dogman dan   100 GW

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Re: Typical current draw on 18V cordless tools?

Post by dogman dan » May 04 2013 2:58pm

I just did a load test with a wattmeter on my 24v B&D drill. Driving 3"' screws into 2x4, I was pulling about 150w, and 200w was used to screw into a knot. The b&D stuff is easy to hook up to lipo with a
male plug lampcord and a lipo pack compatible plug on the other end. I ran the test on 5 ah of 6s, 22v under load.

So the max load was about 9 amps, and typical load was more like 7 amps. Saws likely draw similar, but it's so continuous you blow the pack fast with a saw.

SamTexas   100 MW

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Re: Typical current draw on 18V cordless tools?

Post by SamTexas » May 04 2013 3:33pm

Thank you dogman for doing the load test. That's exactly the info I'm looking for.

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Re: Typical current draw on 18V cordless tools?

Post by friendly1uk » May 04 2013 4:22pm

Bosch green 750w power drill:
Specifications:
Power input 750 W
Power output 400 W
Max. torque 10,0 Nm
Max. drill diameter in steel 12 mm
Max. drill diameter in wood 30 mm

18v dewalt:
Specifications:
Max. drilling capacity in wood 38mm, steel 13mm. Max. torque 35Nm.
No Load Speed 0-600 / 0-2000rpm

Say that 35nm is in 1st gear, and the power drill is 5 times faster, the cordless is still 7nm. 500w worth of power drill. 18v. It's around 30 amps.

I'm fairly sure that in 1st gear the dewalt is 80nm. My old nicad 12v bosch is 30nm in 1st. The 10.8v lipo bosch is near 30nm.


I can't quite pin this down from nm and rpm. It's 10:30 at night, I'm in no fit state :)
bmsbattery sent me broken and incorrect stuff, and won't even talk to me about it.

Gui   1 µW

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Re: Typical current draw on 18V cordless tools?

Post by Gui » Jun 10 2018 10:07am

Is everyone still on this topic.

Power tool company make their profit not from their tools. But from the battery.

I have a spare 650w computer CPU
Has
+12VDC x 22amp
+12VDC x 22amp
-12VDC x 1amp

I could connect +22VDC x22amp and -12VDC 1 amp for total of 24VDC 11.5amp. Will it be sufficient to run a Bosch 24VDC or 18VDC circular saw?

Also, any one know is it possible to
Combine (2) +12VDC x44amp and (1) -12VDC x1amp will do to my 650watt CPU ?

Anyone has experience in this mod ?

Thank you.

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flippy   1 MW

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Re: Typical current draw on 18V cordless tools?

Post by flippy » Jun 18 2018 3:14am

no.

to all of the above you mentioned.


if you want more power: replace the cells with the higest current ones you can find. tear open the tool and replace all the wires with 2.5mm or bigger wires the bigger you can fit the less losses you have.
Lithium beats liquid dinosaurs.

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dogman dan   100 GW

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Re: Typical current draw on 18V cordless tools?

Post by dogman dan » Jun 18 2018 7:13am

One easy trick to run a cordless tool is to empty the battery case, solder on new wires that exit the case, then strap on any battery. Cheap RC lipo can then run your tools.

Yeah, crude, bulky, but lots of punch for running the higher drain tools like the saws.

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wineboyrider   100 MW

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Re: Typical current draw on 18V cordless tools?

Post by wineboyrider » Jun 18 2018 9:34am

There are replacement batteries for Ryobi and Greenworks tools made by after market companies like enerup.
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