Makita 18v LXT BGA452 vs Dewalt 18v DC410 vs DC411 vs DC415 36v corldess grinder

This is a short comparison test of 3 4-1/2″ / 114 mm cordless grinders / cut-off tools.

Tests were done with a 3/32″ and 1mm abrasive wheels on a 1/2″ steel rebar by repetitive cutting of 1/2″ pieces until the battery was completely dead. There were 3 tests done for each tool.

BGA452
Makita  BGA452 / BGA452Z, 10000 RPM, 18 volt 3 Ah LiIon Manganese Oxide Battery

Milwaukee V28 0725-20 / 0725-21:
[img]http://forum.drc.su/userpix/3_v28grinder1_1.jpg[/img]

[img]http://forum.drc.su/userpix/3_DC4101_1.jpg[/img]
Dewalt DC410 / DC411 6500 RPM, 18 volt 2.2 Ah LiFePO4 nanophosphate battery

[img]http://forum.drc.su/userpix/3_DWak1_1.jpg[/img]
Dewalt DC415 / DC415KL 6500 RPM, 36 volt 2.3 Ah LiFePO4 nanophosphate battery
Video is coming.

Dewalt Dc410 18v test was done 4 times, 2 times with a LiIon batery and 2 times with a NiCd battery.

Test results:

Dewalt Dc410 – 10, 9.5, 10, 11 cuts
Dewalt DC411 – 14.5 cuts (motor is different from DC410)
Makita BGA452 – 14, 15, 17 cuts
Dewalt DC415 – 31, 32, 31 cuts

Makita battery is 54 Watt-hours, dewalt 18v NANO (was actually the same as NiCd despite 0.2 Ah capacity difference, must be voltage drop) is 39.6 and dewalt 36v is 82.8 Wh

So now let’s calculate efficiency*:

Make Volt Model RPM Cuts Energy Efficiency
Dewalt 18 DC410 6500 10.5 39.6 0.2651
Makita 18 BGA452 10000 16 54 0.2963
Dewalt 18 DC411 6500 14.5 39.6 0.3661
Dewalt 28 DC413 6500 24 64.4 0.3726**
Milwaukee 28 0725-20 8000 28.5 81.2 0.3511**
Dewalt 36 DC415 6500 31 82.8 0.3744

*The tests are based on cutting 1/2″ steel rebar with a 3/32″ (2.4 mm) thick wheel. I highly recommend to use 1 mm wheels (0.04″) with all cordless grinders for cutting applications. [b]When used with 1 mm wheels, you get twice as many cuts as in the table above.[/b]

**Calculated values.

As you can see, 36v dewalt is the most efficient tool, Milwaukee V28 is 2nd close to 36v Dewalt, and Makita is the 2nd last and old Dewalt DC410 being a complete toy.
Milwaukee V28 performs better than 28v Dewalt in terms of work due to higher battery capacity (2.9 Ah vs 2.3 Ah) and higher RPM (8k vs 6.5k). If you are looking to buy just a grinder, I’d go with 28v or 38v Dewalt simply because of much higher battery life.

I like Makita’s locking switch and round body. Dewalt has a finger guard and a momentary switch so at first the grinder feels weird, but you get used to it quickly. When I handle Makita it feels that if you drop it, unimaginable will happen. Depending on the guard position, it can roll towards you and cause injury because it will stay on when it falls out of your hands.

I highly recommend to use 1 mm wheels with 18v stuff because Makita just bogs down with anything thicker and with Dewalt you would be wasting precious battery energy due to high amount of material being removed by a thick wheel.

If you use a thin wheel it will wear significantly faster but the overall amount of removed material and contact area will be smaller, giving you higher cutting speed and longer battery life. Thin disks are very fragile and snap easily. If you accidentally crack one and then turn the grinder on with no safety glasses and gloves on, you can have “bye bye left eye” and possibly disc shards in your fingers. Wear safety gear!

Dewalt doesn’t have the “bog down” problem because it doesn’t need to protect the battery from overcurrent, both NiCD and LiFePO4 (aka NANO) can provide insane currents (70-100 A peak) while Makita’s Manganese Oxide cells completely lose bowel control at 30 A.

The conclusion is, for heavy duty portable applications use Dewalt 36v or Milwaukee 28v grinders. Both match the power of a corded tool and with 2+ batteries should keep up with pretty heavy use.

In lighter 18v class Makita is a clear winner, and 18v Dewalt is good for occasional use only.

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