Discharging question-

[high plains drifter]

So I've got a puffed Traxxas lipo that I'm currently discharging ( connected to a #1157 automotive bulb) and I noticed that when I connected it to the battery, the bulb quickly went out ( from bright light to dim to nothing) within just a few minutes. But now the bulb is glowing full again.

Is this because each cell is discharging individually?.. so the bulb will go from lit then to out... then repeat?

Just curious if this is normal since I've never fully discharged a lipo pack with a bulb. Thanks

 

[HumboldtEF]

No it shouldn't be going cell by cell if you have it hooked to the main power leads.

I've never seen this happen with a bulb connected continuously. I have disconnected a bulb and reconnected a day later and the voltage will rise back up and light the bulb again. Since they're 12v bulbs they dont stay lit for too long but I think they still draw the battery down when not lit.

Once i get them down to .05-ish volts or so I'll just solder the wires together which shorts the battery draining it fully. Check the voltage with a multimeter to see where its sitting.

 

[high plains drifter]

Much appreciated. I'll put a volt-meter on it and see where it's at. In the last couple hours the bulb stayed lit then gradually went completely out. The bulb/ light hasn't come back on since. Pack is still puffed ( not sure if that's normal) and just just slightly/ barely warm to the touch. I planned on leaving it hooked up for another few hours then disconnecting, stripping the ends, and soldering them together before disposing. But yep.. I'm curious as to the current voltage so I'll check. Thanks again.

 

[HumboldtEF]

Oh boy I can understand the concern now, that sounds pretty volatile. I'd treat that like it may blow at any minute, I hope that thing is outside or drained low enough to be less of a threat.

I dont think a pack will un-puff but I would hope it would cool down when it has no charge.

 

[high plains drifter]

I've got it in a steel ammo can with a cinder block on top of it b/c the can lid is open. I started discharging it in the garage but then moved it out to the driveway. I think the neighbors thought I was putting out very heavy-duty looking Christmas lights!

Bulb has been out for a few hours now and pack is cool to the touch so I'm hoping it's about done now.

 

[Kingmeow]

Once puffed, it will stay puffed whether fully charged or down to 0 volts ready for disposal.

 

[high plains drifter]

Once puffed, it will stay puffed whether fully charged or down to 0 volts ready for disposal.

Okay Thanks for confirming.

She's a dead pack now. Zero +/- volts. Ends have been cut from the connector and soldered together as well as the balance leads ( ID- Traxxas) so she should be safe for disposal.

 

[Kingmeow]

Excellent! BTW, there's really no need to solder the leads together once the pack is drained. Just cut the leads/connector (may be able to use it elsewhere) and bring the pack to Home Depot or the like for recycling.

 

[high plains drifter]

Excellent! BTW, there's really no need to solder the leads together once the pack is drained. Just cut the leads/connector (may be able to use it elsewhere) and bring the pack to Home Depot or the like for recycling.

Hey, I'll take any opportunity to do some soldering... even if it's a little overkill lol. I did have em twisted together initially but they kept unraveling for whatever reason. I coulda just wrapped a little electrical or duct tape around the ends but yeah... I love to solder whenever I can... even if a little tough to justify lol.

Going to take it down to Lowes or HD tomorrow.

 

[Ots]

Lipo cells expel gas during discharge and absorb it during charging. Over-discharging expels more gas than can be reabsorbed therefor leaving a pack puffed. So best not to over-discharge.

Lipo cells should be balanced by using a balancer which leaves the cell voltages equal to each other or nearly so. When the voltage difference between cells is allowed to get too high an arc can occur between the cells resulting in the pack catching fire.

Once a bad pack has been safely discharged it is recommended to let it sit in a salt bath for a while before disposing it at an approved disposal site.

 

[Voodoobrew]

I don't think they re absorb gas as they charge. You might be thinking of the dendrites inside the cell. They grow and shrink when discharging and charging respectively. They are like electrivly conductive stelagtites that can short out the battery from the inside. Thems r one of the things that make the batteries explode by causing a short, then heat, which ignites teh burny things.

Sent from my SM-N986U using Tapatalk

 

[HumboldtEF]

Once a bad pack has been safely discharged it is recommended to let it sit in a salt bath for a while before disposing it at an approved disposal site.

The bucket of salt water is no longer recommended method. The salt water tends to corrode the connector making it so after a while its no longer shorting.


12V Light bulb method is preferred.

 

[high plains drifter]

Yeah... I had read up on the salt-water method before discharging this pack and saw that it was considered to be a sort of outdated or unnecessary step. I felt that the battery was safe after fully discharging it and soldering the ends together.

 

[HongRC]

The battery is swollen, which means it's damaged. If it is scrapped, brining it is the most convenient and easiest way, especially if you don't have some gadgets. In addition, in my opinion, Traxxas lipo is more expensive. I usually choose cost-effective lipo batteries, and then replace the appropriate plug myself to save costs.

 

[Greatscott]

Reviving this thread...

Anyone use any of these to take a fully charged pack to a storage voltage. I understand they are extremely slow, but do they really need to discharge quickly?

Amazon.com: VIFLY 2pcs StoreSafe Smart LiPo Battery Discharger to Storage Voltage with Heatsink for 2S-6S RC FPV Drone Battery (2pcs) (XT30) : Toys & Games

Amazon.com: VIFLY 2pcs StoreSafe Smart LiPo Battery Discharger to Storage Voltage with Heatsink for 2S-6S RC FPV Drone Battery (2pcs) (XT30) : Toys & Games

www.amazon.com

 

[nightcrawler48]

I've heard of these but this is the first I've seen. There is no information screen on these so how do you know where the battery is actually at unless you check it with a volt meter / multimeter. And, how long would it take to get a 3S 2200mah battery to storage voltage if it takes 6 hours to get a 3S 1300mah battery discharged to storage voltage? I think I would just as soon use my battery charger to get my batteries to storage voltage. I can do 4 batteries at a time and it takes between 1 - 2 hours depending on state of charge.

 

[diezel666]

Reviving this thread...

Anyone use any of these to take a fully charged pack to a storage voltage. I understand they are extremely slow, but do they really need to discharge quickly?

Nope, never bothered with discharging devices. Always bought a smart enough charger that can do Charge, Balance Charge, and Discharge.

 

[Greatscott]

I've heard of these but this is the first I've seen. There is no information screen on these so how do you know where the battery is actually at unless you check it with a volt meter / multimeter. And, how long would it take to get a 3S 2200mah battery to storage voltage if it takes 6 hours to get a 3S 1300mah battery discharged to storage voltage? I think I would just as soon use my battery charger to get my batteries to storage voltage. I can do 4 batteries at a time and it takes between 1 - 2 hours depending on state of charge.

Nope, never bothered with discharging devices. Always bought a smart enough charger that can do Charge, Balance Charge, and Discharge.

My Venom quad charger has all of the modes, including storage charge, this is me being a little lazy, hoping for a device I can plug into the packs and more or less forget about them.