Battery adapters

Wurkkos

snakebite

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dayton oh
linear regulator=programmable resistor.
bolt that to a heatsink and it will probably be fine.
the advice to verify protection in the pack is spot on.
some rely on the tool to shut down at low voltage.
i know a guy that messed up 2 ego packs by overdischarging.
 

Lynx_Arc

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Lynx_Arc, I'v noticed in several threads (really all of your posts) you go above & beyond on thorough explanations.
Gold Star to you!!(y)(y)
(looking for blush emoticon) Thanks!. I'm just glad to be of use as my current profession makes little use of my limited electronics and flashaholic information I've gleaned over the years and years...... and years.
 

Poppy

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Yes, a voltage regulator can be used that would allow you to use a wider range of input voltages without noticing output voltage drop that a resistor would have. Beware that unless your battery pack has built in voltage protection (I think most do but some may have the protection built into the tools itself I'm not totally sure) you could drain it below safe levels.
You may need to add a heat sink as you will have the regulator essentially burning off the excess voltage at the 0.4A rate or about 8v times 0.4A making 3.2W of power wasted off a 20v (max 18v nominal) battery pack. A buck regulator would be a lot more efficient wasting a small fraction of that. They use buck regulators and linear (voltage regulators) in lights for similar reasons.
@Lynx_Arc,
Thanks again. I hadn't considered over discharge problems. The regulator I got will allow voltage down to 14V which could cause a problem with the battery. Fortunately, people in a couple of different sites mention that the Ryobi 18+ battery packs have over discharge protection built in.

jake says:
June 7, 2021 at 10:55 am
Sorry I misspoke. My brand of choice (Ryobi) does indeed have the over discharge protection in the battery, but other brands, like Dewalt, put that control in the tool.
I also hadn't considered that I may need a heat sink.

Experimentation comes later today, I hope :)

Do you have a recommendation for a buck regulator?
 

bykfixer

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All I have are store bought C/D adapters that hold AA batteries. But they are very handy for incan lights converted to LED. The LED "bulb" replacement gives lots of fuel mileage and ensures a fridge mount light is not plagued by leaking batteries and works when it gets the call of duty.
 

Poppy

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Here is an adapter I made to use an 18650 in a three C cell light.
It is a one inch diameter dowel, that I drilled out to accept a bolt cut to length.
I cut up a plastic water bottle, and wrapped it around an 18650 cell to increase the diameter of the cell.
Not as fancy as 3D printed adapters, but it works. :)

S6efbyljnB3E69NoeUt9_VJI4=w1920-h870-no?authuser=0.jpg
 

orbital

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Poppy, noticed the battery adapter you have in the OP I can get for my 40V lawn mower battery.
..connect two in series for 80V DC

Wonder what kind of airport or military LED I could run at about 300 Watts, or more..
200.gif
 

Poppy

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I bought this eneloop kit at costco a few years ago. It has two AA adapters to C, and two adapters to D sized cells. A charger, 2- AAA cells, and 8 AA cells.

1637832742239.png


The adapters are still brand new, still in the box, never been used.
 

Lynx_Arc

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It is pretty easy to make AA to C adapters using pipe insulation if you find the right size. You may need to cut the gap a little wider to fit if the AA is too loose in it and it is too tight for the light. You can also use another size for D cells but will need to either stretch the spring or use a spacer as D cells are longer than AAs.
 

Lynx_Arc

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Oops a double post. I'm editing it to tell how I made a 3 or 4AA to D parallel adapter out of 2 large washers, a rubber band and a nylon bolt and metal nut on the top end. The only problem is insulating the top washer from shorting out on the sides of the tube of a metal tube light and 4AAs tend to be larger in diameter than a normal D cell.
 
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