Adding Solder Blobs to Flat Tops

I have never done this before myself. What type of solder should I use? Also, besides cleaning the pos end of the cell and lightly rubbing it down with a fine grit sand paper what other precautions should I be aware of? Will the heat from the solder have an adverse effect on the batt cells?

Thanks in advance...

Dave

I can't answer all your questions, but I can say I got mine to work by dropping a drop of solder on the top. I couldn't get it to stick any other way.

Also this should be posted in the battery section of CPF, and you might get more responses that way.

All I can really say is that it can be dangerous.

Heating batteries of unknown construction containing unknown chemicals can lead to disasterous results. I'll leave it to someone else to give details on ways it can be done.

Daniel

just solder like you would any big solder area, heat it up and feed the solder on it. If you are putting the cells in twisty type lights you may consider the silver solder that is something like 95% tin 5% silver or thereabouts, it should be harder and not squish flat. You may have to do it in 2-3 sessions if you don't get a big enough blob on it to not overheat the battery and damage it. I used a file and an emery board (fingernail file) to smooth off the blob, so if you get the blob too big it is probably easier to just grind it down instead of trying to take off some via soldering iron.

Definitely use the 95% tin/5% silver.

Just don't leave the tip on the battery long enough to get the cell hot!

Bill

Or just use small magnets. Works for me.

Mark

For LED lights why not apply the blob to the LE? I do this with all my L4s,PR-Ts and Alephs and it works like a charm. I don't understand the advantage of blobbing the batteries.

Brightnorm

The only advantages:

You can use them like normal batteries if the form factor and voltage match;

It's used in a simple reverse polarity protection scheme.

Without that blob, a CR123 that's backwards in the L4 will not damage the light. With it, you can now run the battery backwards and blow the light.

The positive terminal in the L4 is recessed so the battery post has to make the contact. Put the battery in backwards and the flat bottom touches nothing.

Daniel

two reasons for the blobs... first you can use them in any device without modification, second you can charge them in any charger without modification.

Minjin, where do you find conductive magnets?

Bill

Look for the rare earth magnets at Radio Shack. Although I typically solder blobs on my Pilas, going with the magnets is definitely the safest route.

Also, effective (conductive) mini-magnets are included with the little LED flashing "bodylights" that are widely available. (2-$4.ea)
Ravers use 'em to attach the lights onto their ear lobes and their clothing. /ubbthreads/images/graemlins/wink.gif

[ QUOTE ]
Bullzeyebill said:
Minjin, where do you find conductive magnets?

Bill

[/ QUOTE ]

Rare earth magnets

Chop,
I have a Nuwali ALX-352l 5 watt Led 3 different power levels plus strobe mode. The problem my pilas 168S have a flat top and the plus contact area at the bottom of the head is recessed, so no contact...what are these rare earth magnets? as far as me trying to use solder my hands are in not good working order... arthritis operations...if I tried to solder something I would probably blow myslf up....
any help or suggestions would be great..thanks....william

there is always the quick aluminum foil ball trick until you get another fix use a small ball of aluminum foil in there to make contact. You can use something like poster putty to hold it in place till you get something else working.

Regarding rare earth magnets, thanks guys, for info.

Bill

[ QUOTE ]
gadget_lover said:
..Without that blob, a CR123 that's backwards in the L4 will not damage the light. With it, you can now run the battery backwards and blow the light.

The positive terminal in the L4 is recessed so the battery post has to make the contact. Put the battery in backwards and the flat bottom touches nothing.

Daniel

[/ QUOTE ]

Good point. Do you know if the L4 has reverse polarity protection?

Brightnorm

Hey.. i have a much cleaner solution to this problem (or at least often a solution).

I had a problem with my current project.. the 10430 batteries are like 1.5mm shorter than a 'true' AAA.. and the head doesn't turn on enough to make contact with the battery normally.

I started with some pretty crude solutions, but with enough trial and error came up with a fantastic solution, and it's related to my 'rubber band powered arc aaa' concept (wrapping a rubber band in aluminum foil and dropping it in the bottom.. it makes the engagement so much more clean and reliable and the 'feel' is so much nicer.

In any event, i didn't want to send out final work with as 'crude' of a solution and came up with something muuuch cleaner.

1) the batteries i have for the project come with tabs.. don't want tabs so i have a bunch of these battery tabs...

2)... I take a little rubber self-stick dot.. like you put under something you don't want to scratch your furniture.

3).. I wrap this strip around the dot.. .. which is 'dome' shaped.. so the ends wrap around to the sticky bottom.

4) this leaves enough 'sticky' to stick to the bottom of the flashlight body, and also holds the strip in place.

It works amazingly well. The lights have such an awesome 'touch and feel' now, and i got the extra height i need and don't have to mod the battery.

-awr