Did a strong spring ruin my lipo?

[justinm11]

Hey all! Recently my guns gearbox stopped working, and while I was at the local shop and waiting on a gun tech, I bought a cheap used gearbox on clearance. The guy who sold it too me said it might have a more powerful spring installed. I like an idiot put it in my G&G CM16, loaded up my 7.4 lipo into it, fired off a bust and noticed the wires got hot, and the battery got warm... After a few bursts the gun stopped firing all together! This was when I noticed the warm parts. I put it too the side, swapped out the spring in it for the default spring that was in my old gearbox and now it runs perfectly. The old battery puffed up is showing two reds on my battery warning thing (don't know the name of that device) and is now sitting in my fire pit outside. The second lipo seems to be working fine, and nothing seems to be heating up. Did the spring ruin my battery by needing too much power? The gun fired fine for the first 2 or three bursts but then slowed down and I stopped firing immediately. After swapping out the spring it seems to work okay now... What does every one think?

(Edit: There is no MOSFET in this gun yet, I just wanted this as a spare gearbox.)

[ThunderCactus]

1) a lipo should never get noticably warm under normal conditions
2) either your motor is really struggling to pull that spring back, resulting in current overdraw from your battery, and/or it's shimmed too tight causing the same.

[RainyEyes]

If your battery puffs up I think that's a good sign it's toast unless you want fireworks at your next game...

[justinm11]

Yeah, theres no way I'm going to be using that battery again. It's going to be staying in my firepit until I'm sure its safe to dispose of. I'm just curious as too what caused it to do that. I'm thinking the spring was the cause since the other battery seems to be working fine on the gun with my old stock spring in the gun. The guns isn't really shimmed all that tightly that I can see and all the parts seemed like they fit together fairly well. I just didn't want to ruin my second lipo by doing the same thing if it wasn't the spring causing it. The connectors for the wire aren't building up an appreciable heat now either, so I'm thinking that the gun was just drawing a ton of power and cooked the battery. Theres a tiny bit of heat in the internal connector of the gun where the wires from the gearbox connect to the fuse and then head to the connectors to the battery but I'm guessing thats normal since the gun is drawing power. The second battery is staying cool to the touch.

[lurkingknight]

youll need to discharge that lipo.. you can use your charger to discharge it and then wire a lightbulb to it and let it die, then you can dispose of it however you like

[ThunderCactus]

What gears and motor is it using? And what does the stronger spring chrono at?

[justinm11]

When the battery blew I had an old classic army High Torque motor in it which I forgot to mention. I've used that motor for a little while on my old gearbox since I got it for free. It looks like just a stock G&G GR16 gearset, the only difference is a slightly better air nozzle and some better seals from what I can see. As for the spring I have no idea what it would have shot on the chrono, I didn't get that far with it. Now, I've got my stock G&G CM16 motor in it, and I went back to a stock G&G CM16 spring.

As for battery disposal, thanks for the tip lurkingknight. This is the first one I've had go bad on me, so I wasn't quite sure what to do with it.