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DC Motors

DC Motors

DC Motors

(OP)
I just had a discussion with a old colleague that has a small fabrication shop that uses a lot self tapping screws and such in his work.
He just picked up about 40 15.4V like new cordless drills with nearly all the batteries bad and no chargers. He has found that he can put some surplus 18V battery stacks in the battery pack for the 15.4V drills.

The usage is intermittent for short periods.

Is this worth the effort or it a waste of time?

How will the drill motors hold up?   

RE: DC Motors

It is mostly a question of what his hours cost and the new batteries. If they cost more than a new drill, then NO. If less, then YES.

These tools come in several quality levels. The B&D drills had a lower quality range where the bearings (according to the bearing manufacturer) were specified to have an L10 life around 30 minutes. Then again, there are drills that seem to live forever.

If they have BLDC motors, and the overall appearance and feel is good, then I would say it is an excellent idea.

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: DC Motors

(OP)
Thanks a lot for the response.

I just called him and he will convert 7 battery packs Monday. He also has the charger angle covered.

The economics are there as both the drills and battery stacks were essentially free other than freight.  The 15.4V drill motors were made surplus by higher voltage drills and the original batteries and chargers were very poor. I have no idea how the battery stacks got here.   

RE: DC Motors

I have done that and found it to be a big waste of time.  The reason is that the tool is usually used-up about the time the batteries are failing. Twice I've gone to great effort to re-battery the packs only to have the drill fail soon after.  Most common is the motor brushes.  The brushes are used up and you cannot change them because the entire motor is swaged together.  They also charge just about what the whole drill costs new for just the replacement batteries if you try to buy new packs from the maker.

Your case of no charger adds even more expense...

Keith Cress
kcress - http://www.flaminsystems.com

RE: DC Motors

We don't know if they have brushes: "If they have BLDC motors, and the overall appearance and feel is good, then I would say it is an excellent idea"

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: DC Motors

My old 12V Makita is on its sixth and seventh battery packs. Sure it ain't pretty any more on the outside, and the guts have been stripped and cleaned a couple of times, but it's still a canny little drill after ten years of moderate to heavy use. And I can replace the brushes. smile

If it's a half-decent brand I'd definitely give it a try.
  

----------------------------------
  
If we learn from our mistakes I'm getting a great education!
 

RE: DC Motors

Another option for shop use may be to construct a 15.4 Volt supply and cord the drills.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: DC Motors

Keith - Did that little experiment gave you the ET  handle ? :)

Muthu
www.edison.co.in

RE: DC Motors

No but it could have.  About a month ofter rebatterying a Hilti hammer drill it would run but white smoke would jet out of the vents every time. That's when I found out the motor looks to be swagged by a 1000 ton press.

And Skogs, I doubt there is s single cordless tool that uses a BLDC.

Keith Cress
kcress - http://www.flaminsystems.com

RE: DC Motors

I am so disappointed. I always thought that my trusted Makita BDF440 was brushless. No sparks visible through the vent openings - no 'electric smell'. And what did I find when I took it apart? Right, Brushes!

Now, where did I put that little what's its name? And what way goes this little thing? Guess I need to buy a new cordless. Perhaps a brushless this time?

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: DC Motors

(OP)
A quick report all motors are up and running on 18 volts. One failure due to bad connection, fix and back on line.
He was clean and reube all the drill motors and did change a few bearings.

Appreciate the help.  

RE: DC Motors

Thanks for the feed back Uncle Syd.
Yours
Bill

Bill
--------------------
"Why not the best?"
Jimmy Carter

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