Lipo Question

[BsudRC]

a fully discharged lipo is 3.0V/cell, though most folks try to set their LVC around 3.4V/cell to play it safe, more info here about the dangers of shunts forming on cells that have been over drained:
https://batteryuniversity.com/article/bu-304a-safety-concerns-with-li-ion

Using Watts Law:
Watts = Volts x Amps

Following example for a 2S-5000mAh battery = 8.4V x 5Ah = 42Wh

If you used a 42W bulb it would take 1 hour to drain a fully charged 42Wh battery.

So plug in the variables for your battery and bulb to get the estimated time to drain your battery

Ok now I'm really confused if it's completely drained at 3V then how is it going to drain to 0?? And it's been discharging for about 2.5hrs now and the bulb is still pretty bright.
@bill_delong I'm speaking of to dispose of them. I know not to go below (for me) 3.7 when I'm running. But to dispose of them you have to discharge all way down to 0 not 3v if I'm understanding right

 

[bill_delong]

I was trying to cover both bases, in the context of preparing the battery for disposal, it all depends on the wattage of the bulb you are using and the amount of watt hours that is still in the battery.

My bulb discharger that I linked above will fully drain most batteries in 10-15 minutes

I need to manually disconnect when I get to 3.4V, it takes seconds to go from 3.4V to 0V with my bulb discharger

 

[BsudRC]

I was trying to cover both bases, in the context of preparing the battery for disposal, it all depends on the wattage of the bulb you are using and the amount of watt hours that is still in the battery.

My bulb discharger that I linked above will fully drain most batteries in 10-15 minutes

I need to manually disconnect when I get to 3.4V, it takes seconds to go from 3.4V to 0V with my bulb discharger

But I need to wait till the bulb goes out before disconnecting right that's when I know it's safe to dispose of?

 

[WickedFog]

Unless you are racing, or charging huge batteries, you have zero need for a DC only charger. Get a Hota D6 Pro. Plugs into the wall, reads IR's, has a kickass balance circuit, and is priced right for its capabilities.

 

[bill_delong]

But I need to wait till the bulb goes out before disconnecting right that's when I know it's safe to dispose of?

Technically, yes, the voltage is supposed to be 0V

 

[BsudRC]

@bill_delong I guess the light bulb discharger worked. The light was out and I hooked it up to my little alarm tester and the tester was blank. Thanks for the recommendation of making one of those. It did take several hours though but my bulb is only 24W but I guess it's always safe to discharge a little slow anyway.

Also still thinking about a charger that checks IR. Only thing is I already have 2 good Thunder Chargers so I really don't need to spend money on another one.

 

[bill_delong]

Another option is to buy a separate IR meter similar to this:
https://www.amazon.com/ALLOSUN-Battery-Internal-Resistance-Analyzer/dp/B01FHF1AHO

Only problem is that you need to carefully check each individual cell from the balance port.

IR meter and temp gun are what I consider to be essential tools for the hobby.

 

[BsudRC]

Another option is to buy a separate IR meter similar to this:
https://www.amazon.com/ALLOSUN-Battery-Internal-Resistance-Analyzer/dp/B01FHF1AHO

Only problem is that you need to carefully check each individual cell from the balance port.

IR meter and temp gun are what I consider to be essential tools for the hobby.

But I am plugging the balance plug into my tester and nothing at all is showing up on the tester it's just Blank. When I plug a good battery (Not completely discharged) it shows up all my voltages. So I'd assume if nothing is showing on the tester then the battery should be completely dead?

 

[bill_delong]

When referencing IR, you are always checking a fully charged battery, this is what is used to check the health of the battery.

You need to get IR readings of each cell when brand new and then monitor the IR over time, replace the battery as soon as 1 cell is more than 1-2 mΩ apart from the others.

 

[Greywolf74]

Another question I have is a lot of stuff I've seen says NOT to over discharge because of the danger of it. But discharging a battery one all way down is over discharging. Maybe I'm just looking at it all wrong and worrying too much about one exploding.

Anyway I got me a light bulb fixed up like @bill_delong said and I've got it on one of my puffed batteries and it's outside in a Lipo bag. How long will it take to completely discharge?

The slower you discharge it down the safer it is but there are always risks so make sure you are discharging the LiPo outside in some sort of non flammable container. Some people use an ammo can, some use cinder blocks, and some people will use their grill.

 

[BsudRC]

I have one battery that is a 3s, it's been stored for awhile. Two of the cells are like 3.82v but one of cells is reading 3.753 is this a concern or will it balance back out when I charge it?

 

[DavidB1126]

I have one battery that is a 3s, it's been stored for awhile. Two of the cells are like 3.82v but one of cells is reading 3.753 is this a concern or will it balance back out when I charge it?

Yes, It should balance out when you start using it. Always balance charge too.
I had a few Hoovo 2s batteries that did that on me. With my charger, I couldn't get them to actually balance so one cell is .2v below than the other. And thats why I decided to get rid of it.

 

[BsudRC]

Yes, It should balance out when you start using it. Always balance charge too.
I had a few Hoovo 2s batteries that did that on me. With my charger, I couldn't get them to actually balance so one cell is .2v below than the other. And thats why I decided to get rid of it.

I always plug in my balance cable when charging. But I'm also new to this gensacearespammers d300 charger too. Not sure exactly how to use the balance feature on it? When I'm on reg charge mode it's automatically balancing as long as the balance cable is connected right? Or do I set it to balance to balance charge?

 

[DavidB1126]

I'm pretty sure yes, the balance cable is for reading both / all cells voltages and balancing them out. The current goes through the main + and - wires. If you only plug in the main + and - wires, you would only get total voltage of the battery.

If your battery has the GTec smart system, you can plug it in, and it should automatically start charging with the appropriate settings.

just to be safe, but it on balance charge anyways. Thats what I normally do with my batteries and my SkyRC Charger.

 

[BsudRC]

I'm pretty sure yes, the balance cable is for reading both / all cells voltages and balancing them out. The current goes through the main + and - wires. If you only plug in the main + and - wires, you would only get total voltage of the battery.

If your battery has the GTec smart system, you can plug it in, and it should automatically start charging with the appropriate settings.

just to be safe, but it on balance charge anyways. Thats what I normally do with my batteries and my SkyRC Charger.

Ok one other question what should I set the target cell voltage at? Isn't a full battery like 4.2v a cell? Or will this charger automatically shut off once the battery is fully charged regardless of what I have target set at?

Also it is the g tech series but I don't have gensacearespammers g tech batteries so I have to manually set my own parameters for each battery on each channel

 

[DavidB1126]

Yes set the target or end voltage to 4.2v/cell if a regular LiPo. If its a LiHV, you can set if for 4.35v/cell. I know a couple racers who overcharge their LiPos to 4.44v/cell, idk why, mostly because if the voltage drop or rest after a charge. But just put 4.2 to make it best for the health and longevity.

Once the battery gets to 4.19 / 4.2 volts, the charge rate (Amps) will go down and will keep going until 0.1 until the charge is finished

 

[BsudRC]

Yes set the target or end voltage to 4.2v/cell if a regular LiPo. If its a LiHV, you can set if for 4.35v/cell. I know a couple racers who overcharge their LiPos to 4.44v/cell, idk why, mostly because if the voltage drop or rest after a charge. But just put 4.2 to make it best for the health and longevity.

Once the battery gets to 4.19 / 4.2 volts, the charge rate (Amps) will go down and will keep going until 0.1 until the charge is finished

Thanks!

 

[Greywolf74]

I always plug in my balance cable when charging. But I'm also new to this gensacearespammers d300 charger too. Not sure exactly how to use the balance feature on it? When I'm on reg charge mode it's automatically balancing as long as the balance cable is connected right? Or do I set it to balance to balance charge?

That cell isn't off enough to hurt anything. Like DavidB said, it will balance out. You should set the charger on balance to balance change. If you're on the LiPo setting it should automatically cut off at 4.2V/C (or at least most chargers do) but Id set it to 4.2V just to be on the safe side.

 

[BsudRC]

Should I charge my lipos in a bag? I usually charge them on a concrete column at my walkway. I do have a bag but it's so aggravating getting cables ran through there and such. The cables just really isn't long enough to run from inside the bag out to the charger. Just wondering if it's safe to charge without being in a bag? I store them In my bag though when not using

 

[Greywolf74]

Should I charge my lipos in a bag? I usually charge them on a concrete column at my walkway. I do have a bag but it's so aggravating getting cables ran through there and such. The cables just really isn't long enough to run from inside the bag out to the charger. Just wondering if it's safe to charge without being in a bag? I store them In my bag though when not using

As long as nothing is around that can catch fire, then they don't need to be in a bag. The bag just helps to keep the flames from shooting out 2 feet in any given direction. You may want to invest in an ammo can, paver or some other non-flammable yet sacrificial item so if something does happen, hopefully it will scorch that instead of your walkway.