Question regarding LiPo batteries.

[CertifiedMike]

As far as I know, once a lipo is lit, it is capaple of producing its own oxygen and can not be easily extiguished.
The bag of sand might buy some time but its not going to stop the fire and more than a cup of water would.
I thought it was a smart idea though.

 

[Speed Chaser]

I keep and charge my lipo in a steel ammo can. Harbor Freight has them pretty cheap

 

[paytonimusrex]

I found an ammo can that can fit in my hauler bag so I think I will get one to put them in but get bags to charge them when at the track

I can’t wait for these new battery leads that I ordered though I had a battery come unplugged in the a main last race weekend

 

[Randy Barron]

you should definitely get a lipo bag I may or may not have one and have been raw dogging it with charging

Already have 2!

 

[Greywolf74]

I'm not sure if this is the proper thread for this, if this isn't, I'll apologize in advance.

That being said, I've just got back into the RC PLANE hobby. The last time I was doing this, everything was using fuel for power. This time I'm using batteries. After doing a lot of reading, I have a few (I hope) simple questions regarding them. I'm just really looking for confirmation that what I intend on doing is actually fairly reasonable.

1. I'm using a 3s LiPo pack. From everything I'm reading, the safe discharge voltage would be 9.0 V (3.0 V/cell). I don't intend on running them that low. I'm wondering if setting my telemetry alarm to 9.9 V (3.3 V/cell) would this cause an issue? Is this too low, too high, correct?

You will get various answers to what is too low or the correct voltage to set your LVC as everyone has an opinion on this. LiPo cells start to degrade at 2.6V, so theoretically anything above that should be fine. HOWEVER, you have to account for voltage sag. You could set your LVC to 3V/C on something that doesn't use much power (like a powered glider) and you'd probably be ok. You use that same setting on some sort of EDF jet however, that will pull a lot more current, and you'll end up damaging your lipos.

I recommend something between 3.3 - 3.6V/C depending on the application. Low current draw RC 3.3 or 3.4V/C will get you a little extra run time. High amp draw application, or you just want to be extra safe 3.5 - 3.6V/C. Anything higher than 3.6V/C is a waste.

2. Maximum charge will be 12.6 V (4.2 V/cell). Is this correct?

Correct

3. Storage voltage should be between 11.1 V (3. 7 V/cell) and 11.4 V (3.8 V/cell).

3.8 - 3.85V/C for storage

4. I'm using the Spektrum NX7e+, I set the alarm on it for the low voltage alarm....correct? (yes, I know that was a silly question).

You can do that, but you also, and more importantly, need to set your LVC in the ESC itself. Id set the radio alarm a little higher than the LVC setting in the ESC so you have time to land the plane before the ESC cuts out.

Any help or advice you could give would be INCREDIBLY appreciated.

The Ultimate Guide to Lithium Polymer (LiPo) Batteries for RC Enthusiasts​

LiPo Comparison Thread​

do yall store your lipos all in a bag or only charge them in a bag? I need to get something figured out for mine

I don't store my LiPos in anything. Once a Lipo has been stable at room temp for 15–20 minutes, it's not going to spontaneously catch fire. What I will generally do is throw my recently used lipos (after storage charging them) in an ammo can and let them sit for a while before removing them and placing them on my storage shelves.

how about their own bags all stored in ammo can

It certainly wouldn't hurt, but it's overkill imo

well that’s an idea, lipos won’t really go off though when just sitting

Correct

I'm not super experienced with lipos. I just mentioned it while we were talking about the ammo boxes.
I thought they were charging in the box too but I may have that wrong.

My experience is in a salvage yard with an acetylene torch and very hot mrtals.
Thankfully and hopefully, NEVER fire!

I have no idea I know charging is in a bag but idk anything beyond that

I charge in my ammo cans if I'm going to be in a different part of the house. In reality, I should charge in my ammo cans all the time, but I admit I'm a bit caviler in that regard. If you're going to use ammo cans, there are a couple of very important things to do to the can first.
1) Remove the rubber seal from inside the lid.
2) drill a vent hole in the can that will not face the top of the can and wont point toward any walls etc. That way if a lipo does go up inside the ammo can it wont be venting flames out toward any falmmable surfaces and it wont be venting flames toward you hand either as you're trying to get the can outdoors.
3) Some people will either line the bottom of the can with some sort of of fireproof fabric (like a welders blanket) or set the ammo can on some sort of bricks or paver(s).

As far as I know, once a lipo is lit, it is capaple of producing its own oxygen and can not be easily extiguished.
The bag of sand might buy some time but its not going to stop the fire and more than a cup of water would.
I thought it was a smart idea though.

This is correct. I'm not sure if the sand would help dampen the venting or not, but it definitely will not put it out.

 

[paytonimusrex]

okay okay so what I got from this is either ammo can or a bag and i’ll get good, charging them at my apartment i’m fiddlesticked either way if they go up in flames cause i’m a second story apartment with ever flammable surface known to man

forgot to keep the bad language out but love the auto correct for it

 

[Greywolf74]

okay okay so what I got from this is either ammo can or a bag and i’ll get good, charging them at my apartment i’m fiddlesticked either way if they go up in flames cause i’m a second story apartment with ever flammable surface known to man

forgot to keep the bad language out but love the auto correct for it

Ammo can. You can take one that goes up and throw it over the balcony on to the ground outside.

A lipo bag does not completely contain the flames, and it also melts. Look up videos of them testing lipo bags on YT. Also, you'd have no way to pick up the lipo bag and toss it off your balcony.

 

[paytonimusrex]

Ammo can. You can take one that goes up and throw it over the balcony on to the ground outside.

A lipo bag does not completely contain the flames, and it also melts. Look up videos of them testing lipo bags on YT. Also, you'd have no way to pick up the lipo bag and toss it off your balcony.

that’s fair I charge mine near my slider currently but will be moving my setup once I get my sim rig out to near a window I guess I can get one I never had issue with then getting bad that but I previously had a few puff up on me so then I stopped using, remember soft case 2s2p lipos lol that’s what I had for my slash that puffed

I also charge my batteries at 5amps from googling and some math that was the safe number I could charge

 

[paytonimusrex]

guess i’ll look into an ammo can ill see how long these charger leads i’m getting in the mail are

 

[CertifiedMike]

Ammo can. You can take one that goes up and throw it over the balcony on to the ground outside.

A lipo bag does not completely contain the flames, and it also melts. Look up videos of them testing lipo bags on YT. Also, you'd have no way to pick up the lipo bag and toss it off your balcony.

It would seem a smart invent to get a ROAR approved metal "bag" that actually works. This doesn't seem that hard to me. Am I missing something?
Why require a plastic bag that cost $15 and don't work? I know they SLOW a fire or help control the flames for a min or 2 but as you said, bags melt.

 

[MrBeanCar]

I hook a small battery checker/alarm to the battery, with alarm set at 3.7v. My goal is to end with 3.8v/11.4v for 3s, which I consider a good storage voltage. So, after flying, there's no need afterwards to do anything to the battery until the next time I fly.

When flying, and I apply a larger amount of throttle, (say, 3/4 to 7/8), the alarm may go off. Especially if the battery is a low c (like 30c). When it does, I cut back to a cruise setting, if it stops alarming, I continue flying. The voltage has gone low due to voltage draw, but in particular, low c batteries have large sag. But they can recover, at lower settings, to a voltage that is still flyable.

I once had an alarm which did NOT go off, but I knew approximately how long the flight should last, so I landed. The voltage had gone done to 3.4 or 3.5 or so. That battery started to puff on my. So, even though some sources say you can go lower than 3.7, it's not a good idea from standpoint of battery life.

Charging in a bag is to prevent the fire from spreading to the rest of the house. An alternative would be to be PHYSICALLY present during the entire charging session. I try to do that, my computer is right by my charging station, so I just play on the computer while the battery is charging.

I have not done it, but I have imagined that putting the battery in a bag, then putting that bag inside a cheap roll around barbecue grill would be a possible safe charging method.

 

[majin]

sounds like I gotta hit up an army navy story then lol

just watched some videos on different storing with ammo can looks like ammo can and bags is the way to go then

hit your facebook marketplace, theres always a gun store that has a surplus of them as well, a gun store has to have many different types of ammo in stock, this means they have lots of ammo cases to get rid of, they will usually let em go much cheaper than anyone else if found. js

 

[Greywolf74]

I hook a small battery checker/alarm to the battery, with alarm set at 3.7v. My goal is to end with 3.8v/11.4v for 3s, which I consider a good storage voltage. So, after flying, there's no need afterwards to do anything to the battery until the next time I fly.

When flying, and I apply a larger amount of throttle, (say, 3/4 to 7/8), the alarm may go off. Especially if the battery is a low c (like 30c). When it does, I cut back to a cruise setting, if it stops alarming, I continue flying. The voltage has gone low due to voltage draw, but in particular, low c batteries have large sag. But they can recover, at lower settings, to a voltage that is still flyable.

I once had an alarm which did NOT go off, but I knew approximately how long the flight should last, so I landed. The voltage had gone done to 3.4 or 3.5 or so. That battery started to puff on my. So, even though some sources say you can go lower than 3.7, it's not a good idea from standpoint of battery life.

Charging in a bag is to prevent the fire from spreading to the rest of the house. An alternative would be to be PHYSICALLY present during the entire charging session. I try to do that, my computer is right by my charging station, so I just play on the computer while the battery is charging.

I have not done it, but I have imagined that putting the battery in a bag, then putting that bag inside a cheap roll around barbecue grill would be a possible safe charging method.

Your lipo puffing had nothing to do with the voltage being 3.4v/c. The reason no one sets LVC to 3.7V/c and higher is because the nominal voltage of a lipo pack is 3.7V/c, meaning that the majority of the capacity of the battery is going to be around 3.7V. That's why your alarm is going off and then stopping when you ease up on the throttle.

Buying a BBQ just to charge batteries on seems a bit excessive to me when you can simply buy a paver and an ammo can and achieve the same thing. If you have a BBQ or ammo can, a charging bag would be unnecessarily redundant.

 

[Robert Droner]

I'm not sure if this is the proper thread for this, if this isn't, I'll apologize in advance.

That being said, I've just got back into the RC PLANE hobby. The last time I was doing this, everything was using fuel for power. This time I'm using batteries. After doing a lot of reading, I have a few (I hope) simple questions regarding them. I'm just really looking for confirmation that what I intend on doing is actually fairly reasonable.

1. I'm using a 3s LiPo pack. From everything I'm reading, the safe discharge voltage would be 9.0 V (3.0 V/cell). I don't intend on running them that low. I'm wondering if setting my telemetry alarm to 9.9 V (3.3 V/cell) would this cause an issue? Is this too low, too high, correct?

2. Maximum charge will be 12.6 V (4.2 V/cell). Is this correct?

3. Storage voltage should be between 11.1 V (3. 7 V/cell) and 11.4 V (3.8 V/cell).

4. I'm using the Spektrum NX7e+, I set the alarm on it for the low voltage alarm....correct? (yes, I know that was a silly question).

Any help or advice you could give would be INCREDIBLY appreciated.

1. 3.0 is THE minimum, below that will kill the lipo/shorten it's safe use lifespan. Set your LVC to maybe 3.5 - When I start seeing <3.6 per cell, it's time to land.
Remember, under load voltage is what LVC sees. Once you get to check the battery, it will be higher, not by much, but higher and that's normally a good thing.

2. Maximum charge on ANY lipo is 4.2v per cell.

3. Storage voltage for me, is ~3.85-ish... per cell. Anywhere in the 3.8-3.85 range is good really.

4. Voltage call out on the radio is also a good way to know when it's time to land. I use a timer already knowing where the voltage is going to be after that amount of time. It starts a 20 second voice call out count down, settable ranges.

 

[Ade C]

I'm waiting for one of the really cheap low voltage alarms to arrive and just wondering if once it's triggered under load does the alarm sound continuously, or does it stop again when the voltage increases when not under load?

 

[DavidB1126]

if once it's triggered under load does the alarm sound continuously, or does it stop again when the voltage increases when not under load?

It stops when the voltage increases / goes back to normal.