Soldering Battery Boxes

erco

I'm watching MacGeek117's Swarm thread about building Runt Rovers and thought I'd share a lesson learned on my last project. When soldering wires onto the type of battery holder shown below, ALWAYS remove the batteries. This idiot soldered wires to the battery box tabs with the batteries installed, and instantly had intermittent battery connections. Soldering to the small external tab softens the plastic case where the metal rivet passes through and the contacts move. In my case, the positive terminal got squished/countersunk into the plastic since the negative spring battery terminal applied steady pressure through the soldering/cooling process. Certainly a frustrating DOH moment and a dumb problem to have at 3 am when the otherwise perfect prototype is due the following morning.

Maybe that's why many kits include boxes with the wires soldered on already!

msrobots

Yes, I made exactly the same mistake once. Actually twice before I found out the problem of melting plastic and spring pressure.

Enjoy!

Mike

MikeDYur

I have been leary of the metal-plastic combos for awhile. Heavy current demands a solid connection. Something that isn't effected by heat.

erco

Heavy currents out of alkaline cells is a losing proposition, but that's another discussion about how I hate alkalines.

Another reason to avoid these polyethylene AA battery boxes is that they will eventually crack near the ends, due to the constant negative contact spring pressure.