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AC adapter for cordless power tools?
gryhnd:
--- Quote from: ahofle on January 13, 2010, 11:11:56 pm --- I don't want to overpower anything.
--- End quote ---
You can't "overpower". The tool (or any item for that matter) will only use what it needs. The bad thing is to under power it.
For example, your computer only uses a couple hundred to a few hundred watts. Yet your typical 15amp circuit can provide around 1700 watts :)
drventure:
I wonder if the guts of that PS are small enough to fit inside a battery housing? That'd be the ideal solution. A battery housing with an AC cord coming out of it that, when you need to, you can just slap into whatever tool you need and go.
Ed_McCarron:
Key thing here - cordless tools depend on 100's of amps being available for short bursts - which is why the NiCd and MiMH cells have dominated for so long.
The LiPo packs are -just- starting to be able to hold their own.
A drill may cruise at 500ma, but bear down on it and you're talking 30, 40, 50 amps easy. Think about how hot your drill gets when working hard.
ahofle:
Well just an update...I ended up getting this AC adapter: http://www.powerstream.com/AC-A0407.htm
Was a little disappointed in the quality of the adapter (came in one of those cheap Chinese packages and didn't look like the one on the website), but it seems to be fine.
I opened up the old battery, chucked the dead sub-C cells out, and attached the AC adapter wires to the old battery terminals. Had a little issue with the battery terminals staying put once the Cs were out. The cells were basically keeping the terminals in place, so I had to bend the two unused charging terminals to keep it in place. Kinda hard to explain, I'll have to take a picture.
Anyway, once I finally got it in place, I cut a small hole in the battery housing to run the cord out and reassembled the battery pack. Put it on the 19V setting, plugged it into a drill, and I'll be damned if it doesn't seem to run exactly like a fully charged Li-ion battery pack. I tried 6 different tools and they all functioned normally. The only thing I noticed different is that the drills took a fraction of a second longer to spin up to full speed when the trigger was fully pressed. I mean like a 1/4 second. Maybe this is the short burst Ed is talking about? I have yet to test with a high load (the saw for instance), but so far I'm happy. I'll report back with any updates.
Samstag:
A motor needs the most current at the lowest speed, so you're noticing a slower acceleration because the adapter can't produce the same surge current as the batteries. Since you're using the same voltage you'll eventually get up to the same speed with no load but as soon as you try to do some real work with it you're going to probably notice you don't have the torque you used to.
For jobs that let you keep the RPMs up it should work fine.
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