Let's talk cordless impacts

[scottgib]

There seems to be a misconception here -- 18v can be either Li-Ion or NICAD or NMH.

[lcoleman]

^ noted. They must be using some funky Li chemistry, most larger LiFePO4 cells are 3.2v apiece.

The point about batteries is a good. Whatever you get, make sure you end up with the "commercial" packs, not consumer. On porter cable stuff the good ones are red, not sure on other brands.

Keep in mind you don't want to end up with something too big for small jobs either. Even on mine, I have to be careful on smaller bolts; it'll really crank them down well beyond spec if I'm not fastidious.

[TedV]

there's too many Li battery chemistry to count. Most of the packs I've looked at of Li are the 18650 size and not LiFePO. LiFePO can't discharge at the Amps needed for a power tool compared to the other chemistries. So, nominal voltage is 3.7V each with 5 of them = 18.5V so with my older Porter Cable they have both Li and NiCd in the 18V batteries. But, a fully charged Li is 4.1V each, with 5 in series measures 20.5V. WHOA!!! 20 Volts is better than 18 volts !!! lets call them 20 volts so people will buy the more powerful 20 volts cause 20 volts is better than 18 volts!!!!!!!!!

except internally they are the same mo fo king battery with a different connector..... Not like I'm bitter or anything.....

[90civichb]

I've got a 14v Black and Decker drill that I use for small home stuff, and it is complete garbage compared to the 18v stuff I have used in comparison. My assumption was that the extra 4 volts did make a fairly large difference. As a dumb consumer why would the 20v stuff not be more power than the 18v stuff?

[TedV]

Because both the 18v and 20v batteries are identical sets of 5 cells in series. 4.1v each fully charged, 3.7v nominal rated. Do the math and you see where they get the 18v or 20v. NiCd set is also 18v but might not have the ability to discharge as quickly as the lithium. Watts= Volts x Amps = power. Different chemistry of Li batts also have different rates of discharge.

My lithium18volt pack measures 20 volts when fully charged. Its all marketing aimed at the dumb consumer. This is why Im pissed Porter Cable changed their connectors. They may also have changed chemisrty specs of the batteies, I havent dug that deep yet. Marketing is why they all call them 20 volt max. They have a maximum of 20 volts when charged. Battery protection circuitry cuts the output of the pack when voltage drops somewhere between 3 or 3.5 volts per cell depending on the chemistry. (Ballpark numbers) if the amperage discharge is more they will have more power.

If Lithium cell is discharged or overcharged too far or charge or discharge too quickly, internal damage can occur which can result in a spectacular explosion. Keep them in their happy place and will work for a good long time.

Clear as mud yet?

[steverife]

I want to push a button and then I want the fastener to spin.

[TedV]

Steve, why you gotta be so difficult?

[01badz28]

I've got one of the Goodyear / Pep Boys impact guns and have had it for several years. Unlike Steve, I've found it has a pretty impressive battery life. It has enough charge to change tires (at least)twice, and occasionally getting passed around grid on loan to other folks. I've never killed a battery in a normal autocross day.

[CABoegemann]

Snap-On

[steverife]

I've got one of the Goodyear / Pep Boys impact guns and have had it for several years. Unlike Steve, I've found it has a pretty impressive battery life. It has enough charge to change tires (at least)twice, and occasionally getting passed around grid on loan to other folks. I've never killed a battery in a normal autocross day.

I bought it because so many people raved about them. I've encountered other people that bought their's around the same time as me and they agreed that it was junk from day 1. Bad batch, or they changed it at some point.

[integra55]

Snap-On

great tool … but VERY pricy

[90civichb]

Yeah, Snap-on is pretty much out of the question. If I made money with my tools then possibly I would buy something like that.

[90civichb]

So after a few months I just decided that I would purchase a small 8mm style impact gun and drill. I figure I can just bust most things lose first and then use this to back it the rest of the way out. I can also use this for smaller jobs that a larger 1/2" might destroy. I paid $172 for both bodies, 2 batteries with a charger. They are lightly used but in great shape.



Also, I can't believe they are going to a new form factor with the 20v stuff. Not only did TedV talk about it in here but 20v is just marketing crap.