Hi Guys,

How hard is it to make my own batteries if I already have a soldering iron? How much can I expect to save realistically from making my own batteries? Other than convenience, is there any other advantage to commercially prepared battery packs? They seem to cost 2x as much all around.

Thanks for your help!
Donovan

I checked into it. It's not worth it. Have to really watch the heat also if I remember right. I think you can get plastic battery cases at radio shack. That might work for you? I'd just get standard batteries..

We have a local warehouse supply place where I get 1.2v 600ma batteries in a case of 18 for less than $10.

Yea, I solder up my own packs.

A 4.8v 600ma pack cost me about $3.50 including the plug.

rechargeable too?

Minn, that sounds pretty decent. Maybe you can right something up for us on how to solder them safely? Perhaps I didn't look hard enough online for inexpensive batteries last time.

Found this site that has some techniques for soldering nicads:

http://www.silentflyer.org/articles/...batteries.html

Well, how about soldering up your own 1800mAh NiMH or LiPo packs?
I think I'll go to LiPo packs once I figure out the dangers of them. But gosh darn, they are expensive!

FYI: from Red Scholefield's web site:

-----------------------------------------
SOLDERING

Soldering to Ni-Cds is not a good idea. Try to use the welded tabs and solder to those if at all possible. Soldering to the positive button will have a very high probability of destroying the nylon seal. You just can't get the button hot enough to get a good solder joint without compromising the integrity of the nylon seal ring. This ring is under compression and raising its temperature will allow it to relax and the sealing properties are history.

If you can hold a penny between two fingers long enough to get a good solder joint with #18 stranded wire or braid, then go ahead and solder to your cells, otherwise get cells with solder tabs. Remember, nylon is a good insulator, electrical and thermal. There is no thermal path for the soldering heat to dissipate when heat is applied to the cover button of a cell.

Nylon characteristics:
Nylon has its glass transition at 460°F - 500°F . The maximum use temperature of nylon 6-6 parts is about 300°F. (Note that this is considerably below the glass transition temperature.)

Soldering temperatures are in the 450°F to 650°F range.

I realize this flies in the face of all the electric flight “experts� that assemble their own packs but it is never the less fact.

You have never seen a pack assembled by a cell manufacturer or any other pack manufacturer (outside of the hobby market) where connections are soldered directly to a cell. There is a reason.

C. L. Scholefield
Manager (retired) Battery Design and Application Engineering
General Electric Battery Business Department
Gates Energy Products
Energizer Power Systems
-------------------------------------------

While Red Scholefield is probably the leading authority on batteries in RC, this is one of the instances where I disagree with him (partially).

Many people solder up their own battery packs, and while I wouldn't recommend it to someone without a lot of soldering experience, it can be done. If the nylon seal were as susceptable to heat as Red says, then the thousands of flyers making their own packs would be losing planes left and right. That isn't happening.

donoman,
I certainly would NOT attempt it with LiPoly cells though. They're extremely dangerous when abused, and I'd hate to see one blow up in your face.
Dennis-

A few things I make sure to do when soldering a battery pack, is:

First - use a Soldering GUN, not an iron.

A gun gets a lot hotter, so you don't need to keep it in contact with the battery for as long.

Second - Lightly sand the area of the battery where you are going to solder, add a dab of Flux, melt some solder on the gun tip, and touch it to the battery. THis will adhere some solder to the battery with minimal "Time under heat". Next, "Tin" the end of the wire.

Now you have solder on the battery and the wire. Put the two together, and add the gun just long enough to melt the two solders (On the battery and on the wire) And they will merge into one lump. The battery never gets a chance to get over heated.

And RichD, yes, they are rechargeable

Plan to bring some GP 3300 mAh tabbed NiMH cells for cheap in China if I can find them.

Are tabbed NiMH cells easier to solder? I mean, can I do it with a plain ole Weller Ungar soldering IRON with a base and a temperature adjuster?

PS Minn, how do you "tin" the wire? like adding a bit of solder to the exposed tip?

PPS DB, how's the rule against bringing Internal Combustion Engines onto airplanes? Does it really exist?

PPPS Is there a rule against rechargeable batteries? Radio systems? (THANKS A LOT)

Use some fine solder also. Personally I'd use an iron but that's what I prefer for fine work.

I've been making packs out of those kick butt Energizer NiMH for a while now. I can make a 4 cell AA 1800 mah with plug for about $11.00. I made a 5 cell C 2100 mah NiMH for my big coroplast gasser (needed nose weight) with plug for about $16.00. I use an iron, and tin the cell, then use battery braid to tie them all together. I build them in a padded vise, and use small strips of foam on the soldered ends before I heat shrink them. I haven't had one fail yet.

David, yes, to "Tin" means add solder to the wire or component prior to actually attaching it to something.

here's a "How To" for basic soldering:

http://www.rcuniverse.com/magazine/a...article_id=172

There is a place on EBay that sell the battery pack and the tabs on them, just no connection wires. This is so anyone can make up their own battery pack according to the receiver they have.

Where can you just buy the connection wires and plug at?

Mike,
Nice basic guide.

David,
I really don't know whether or not there's a ban on transporting internal combustion engines on public flights. It's a rumor that Dave Brown mentioned in an AMA article. Sorry.
Dennis-

I don't like disagreeing with Red either - but I think it's fine to assemble ones own packs as long as a guy takes the time to learn/do it right.

I'm with Deadeye - the Energizer NiMH make very good TX and RX packs. I buy the 2300 mah NiMH AA 8 pack at WalMart for $17.87. High capacity packs for a very good price.

I've heard Radio Shack has braid for putting cells together. [link=http://radicalrc.com]RadicalRC[/link] has connectors, leads, cell tabs, and cell shrink wrap. Your local hobby store probably has a battery lead with connector also.

Here's some very good info on making your own NiMH packs.
[link=http://members.aol.com/davthacker/nimhfaq.htm#Your%20New%20Battery]Your New Battery Pack[/link]

And Dave's [link=http://members.aol.com/davthacker/cellsoldering.htm]Cell Soldering Help Page[/link] - which MinnFlyer pretty well summed up.

I had to make my own tx pack, because my radio is outdated. If I recall right (this was about 2 years ago) There were metal tabs already to connected to the cell, and i just put connecting wires between them. I then bought some big yellow heat shrink from the hobby store, and pulled a plug off an old busted servo (It's outdated equipment, so you can't buy the plugs) soldered it up and put it in. Works fine.

I agree totally with Min. The only thing I do is glue the cells together first. Hot glue or CA works well. I have used a product called Shoe Goo as well. Shrink wrapping the pack after soldering is also a good idea.

Mark Shuman