Post by thread:[EE]: Connectors for NiMH batteries recently obtai

Olin Lathrop wrote: > > > James, if you lightly sand the flat positive end > > to scar the nickel plating a bit it will solder > > well, then just put a solder "tit" on the end > > of the battery to replace the positive bump > > that is not there. > > If you are going to do this, be very careful about heating the battery. The > battery can be destroyed by solder temperatures. That's why most permanent > connections to these batteries are tack welded instead of soldered. When > you take a pack apart (I haven't done this) I bet you see interconnects that > are tack welded metal strips, not soldered. Yep, good point, but I've been doing this for so long now we just do it without thinking. Sanding the end of the battery is the secret, the metal will then "wet" almost instantly and you can solder to the battery in less than a second. In many TVs and VCRs the replacement batteries they send us must be soldered to wires first, it's just a quick and normal procedure for us. But I do agree that you should not heat the battery up, like clumsy soldering attempts onto dirty metal etc. -Roman -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

M. Adam Davis wrote: > > The major problem is that either end of the cell (or perhaps just one > end) may have vents, gaskets, and other materials which are sensitive to > high heat. While you may not destroy the battery, you will almost > always degrade these materials causing the battery to lose much of its > useful life(improper venting, ruined electrolyte, etc). It's also worth > mentioning here that unless you get the terminal up to solder > temperature, you are only forming a cold solder joint, which will also > degrade over time until it too fails. > > Try to save the tab if you can, and solder to that. Alternately, use a > battery holder. They aren't that expensive, nor do they take up that > much extra room. I have to disgree, you don't have to overheat the battery to solder to it. Good clean metal and a good flux solder and they solder almost instantly. :o) We sell copper braid to the local model (electric) aeroplane club, and sometimes NiCds. They ALWAYS solder up their own battery packs, using the thick copper braid as the conductors between the batteries, some of these small model planes can draw 100 amps! This is considered the "correct" way of doing it, no battery holder would handle their currents. These guys are also battery experts, battery maintenance is a huge part of their flying hobby. -Roman -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

> > It's also worth > > mentioning here that unless you get the terminal up to solder > > temperature, you are only forming a cold solder joint, which will also > > degrade over time until it too fails. Yes, you need to get the terminal up to solder temperature, but only the very surface of it. The trick is to heat quickly and with a large/powerful enough iron that the surface reaches solder temp before any damage is done. This does bring up a point tho'.... you have to be careful with the technique of preheating the other piece of metal that is going to be soldered to the battery. If it is two massive/too hot then as the joint cools enough heat and conduct into the battery to cause damage. Bob Ammerman RAm Systems (contract development of high performance, high function, low-level software) -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

> This does bring up a point tho'.... you have to be careful with the > technique of preheating the other piece of metal that is going to be > soldered to the battery. If it is two massive/too hot then as the joint > cools enough heat and conduct into the battery to cause damage. Perhaps dunk the end of the battery into water immediately after soldering? ******************************************************************** Olin Lathrop, embedded systems consultant in Littleton Massachusetts (978) 742-9014, spam_OUTolinTakeThisOuTembedinc.com, http://www.embedinc.com -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics