JerB

Hi guys

i have been out of the RC hobby now for the better part of ten years but after looking at a couple of my rc cars and tanks I kinda have the urge to get back into it.

One of the areas that peaked my curiosity before leaving back in 2011 was building my own battery packs. All my stuff ran NIMH batteries with tamiya connectors and always thought to myself if I knew where to find the right supplies I could probably make my own ( with proper instructions of course ) I knew I would ask here first as you guys would be able to show me in the right direction on this and where I would be able to order the necessary supplies

any help you guys can offer would be awesome

Jeremy

RustyUs

Same principle. Just use some battery bars, solder, and whatever NiMh batteries/connectors you like...

RustyUs

IMHO, it's cheaper to buy a 2S LiPo these days, than to buy NiMh/NiCd cells.
Just shop around and find what you want: https://www.onlybatteries.com/sub-c-...2-356-1665.asp
Gold Battery Bars Sub-C : 10 Gold-plated battery bars for linking Sub-C cells

Hummer Aeroworks

I welded up a transmitter pack of 8 AA Enloop cells (button top) in early October. The pack now fails to hold a charge. I removed the shrink wrap and found most of the cells to be leaking their contents from the + end of the batteries. The same thing happened to a receiver pack of 4 AAA Enloop batteries after only 2 months. I have used both of these cells in the plastic battery holders (spring loaded) without the cells leaking. I also have a 4 AAA cell receiver pack I made that is wrapped with clear shrink wrap and all of the cells look great and the pack holds a charge. I use 100% nickel strips to spot weld the packs together.
I use an FMA Direct Einstein charger (a charger specifically made for NiCd and NiMH battery packs that allows the user to choose the number of cells and the mAh of the cells) to cycle and charge batteries. I have never had this happen to commercial battery packs I purchased.
Can anyone help me figure out what is happening?

init4fun

Hi Hummer Aeroworks ,

I believe your cells failed because you got them too hot , which is pretty hard to do with a spot welder . Adjust your weld duration time down to about 70% of what you've got it set for now and I'll bet the cells won't cook .

Hummer Aeroworks

Thank you for the reply to my predicament. I appreciate you taking time to reply.
The spot weld takes only a few nanoseconds and the surface of the weld/tab/battery end are not warm to the touch (i.e. when I first started making packs I checked out the temperatures of the batteries by practicing on old cells). I make all of my packs the same way and I have other packs (AA and AAA cells) wrapped in clear shrink wrap and they show no signs of leakage and hold a charge.
Hopefully you may have some other thoughts?
Cheers

init4fun

Hi Hummer Aeroworks

If the cells weren't damaged by heat during the spot welds , my only two other ideas are that they were either manufacturer defective or could perhaps your charger could have overcharged them ? I know it's not likely that they were overcharged since you appear to have a full understanding of what's required to get good service from them , so my best guess now is that you got a batch of defective cells .

Hummer Aeroworks

You must be right. I have used my charger for years on NiCd and NiMH packs and have never had cells leak like these 2 packs. Thank you again for your input.
Merry Christmas!