Don't forget about those batteries!

[Twowingtj]

Be interesting to find out what item/conditions caused the fire.

[Wayne 630]

Lipo fire and $40,000 worth of damage. An experienced IMAC piolet here was charging batteries in his trailer. Ran in the house for a minute and heard a muffled pop. A few minutes later the neighbors were beating on the front door yelling "Fire". The two batteries being charged exploded, burnt the trailer to the ground, burnt the rear end of the F250 and the side of his motorhome. Three IMAC planes ($3 to $5,000) and lots of support equipment. It was all parked on top of artificial turf ($4,000). The fire department was minutes away and it took their efforts to get the fire out. This all got my attention and all of my batteries are now in lipo bags and I'm present for every charge. Hard lesson learned

[fhhuber]

Color of flame says gasoline got involved... but it looks like fuel lines melted/burned through which could have been caused by LiPo burning.

****************

Hitec HV servos can use 2S LiPo direct with no regulator and most Spektrum RXs can handle it too (3.85v to 9.0v operating range. Lower will "brown out", Higher will burn up). Some of the people flying larger models are now powering their radio systems with 2S LiPo.
(I have one such model under construction, doesn't really need the HV, but I got the servos in a used model I bought.)

Some of the gas engine ignitions want 5.0v regulated, some will operate fine from 4.5v to 6.0v (4 cell NiCd) or 6.0v to 7.0v (2S LiFe) and some want 2S LiPo... and there are probably others that I haven't seen yet.

[skippykix]

That wasn't a lipo fire.

. Yes Ron, it was a LIPO fire. I was standing right next to the plane while he was charging his LIPO batteries getting ready for his next flight. The bottom right corner of the second picture shows what's left of the batteries after he pulled them out.

[fhhuber]

Don't those things use LiFe batteries for their RXs? That looked more like a Nitro fire.

Gasoline.
Looks like a fuel leak that met an ignition source.

You'd have a hard time seeing a glow fuel fire. Alcohol fires (and Ntromethane) burn with a flame that is practically invisible in daylight.

[xviper]

That wasn't a lipo fire.

Don't those things use LiFe batteries for their RXs? That looked more like a Nitro fire.

[RRHandy]

That wasn't a lipo fire.

[skippykix]

This is why I never leave my LIPO's alone while charging!

[fhhuber]

Never store full charged packs in a car that will get hot in the summer sun.
One of the fastest ways to puff a pack is to get it really hot while fully charged.

(Gets hot enough here to bake cookies on the dashboard)

[Elbee]

I have my LVCs set to cut off at 3.7 to 3.8 v/cell at full throttle. The packs are rarely below 3.6 when I pull them from the aircraft. Its a reasonable storage level.

If I run them down due to charging more packs than needed, I do it at full throttle. That will trigger the LVC by 3.7 v/cell. (and its faster than the lower throttle method)


************

You need to worry about battery temperature somewhat...

Best current delivery temp for LiPos is 120 to 130 F. You can severely damage the packs if above 140 F. You are reducing the battery life (charge cycles) at 120 F.

When flying in 105 to 110 F ambient air, its hard to keep the packs below 120 F in anything other than a lazy trainer. Get them out and maximize cooling ASAP. (in the shade with good airflow around the packs, you don't really need to use a fan, but it helps)

DO NOT RECHARGE A HOT PACK Let it cool first.

Most modern ESCs have a thermal shutdown where they cut power to the motor if they get too hot. Some of the earlier ones with thermal shutdown also killed the BEC power... There might still be some made today which will do that. There are also still some without any thermal shutdown, so its a good idea to read about your ESC specs.

fhhuber, Thank you, I appreciate the 'good news'. All then seemed normal, running storage charges now. These LIPOs are most certainly a different animal when compared to NiCads. Best to you, LB

[fhhuber]

I have my LVCs set to cut off at 3.7 to 3.8 v/cell at full throttle. The packs are rarely below 3.6 when I pull them from the aircraft. Its a reasonable storage level.

If I run them down due to charging more packs than needed, I do it at full throttle. That will trigger the LVC by 3.7 v/cell. (and its faster than the lower throttle method)


************

You need to worry about battery temperature somewhat...

Best current delivery temp for LiPos is 120 to 130 F. You can severely damage the packs if above 140 F. You are reducing the battery life (charge cycles) at 120 F.

When flying in 105 to 110 F ambient air, its hard to keep the packs below 120 F in anything other than a lazy trainer. Get them out and maximize cooling ASAP. (in the shade with good airflow around the packs, you don't really need to use a fan, but it helps)

DO NOT RECHARGE A HOT PACK Let it cool first.

Most modern ESCs have a thermal shutdown where they cut power to the motor if they get too hot. Some of the earlier ones with thermal shutdown also killed the BEC power... There might still be some made today which will do that. There are also still some without any thermal shutdown, so its a good idea to read about your ESC specs.

[Elbee]

That's a good way to do it. Put the battery checker on it while you do this so you know when to quit. Anything around 3.8 to 3.9v per cell ought to be good for peace of mind. However, having said this, I had a flying buddy who used to charge his batteries as soon as he got home from the field and left them that way till he flew again. He had batteries that were kept like that for a good part of a season and they seemed to perform just as well when he did finally use them, although we don't know what effect this had on the longevity (number of cycles lost) of these batteries. When he passed away and the batteries went to his friends, they all seemed to work OK.

At 1/4 to 1/2 throttle the starboard ESC was running at 129`F and port is running 114`F. I ran the motors 1/4 to 1/2 throttle as per DD with the battery checker as per xviper. Starboard motor flame-out at 8+ minutes with battery temps at 128F +/- each. ESC temps were 107F+/- each. Thanks for the assist, gentlemen. Best, LB

[xviper]

Throw on some ear muffs, put them in your plane, and run 1/2 throttle to get them down. Ive done this on occasion, as it would take a few hours for my charger to get them down to storage. Especially for these larger more expensive packs, I personally would get them to storage instead of waiting it out.

That's a good way to do it. Put the battery checker on it while you do this so you know when to quit. Anything around 3.8 to 3.9v per cell ought to be good for peace of mind. However, having said this, I had a flying buddy who used to charge his batteries as soon as he got home from the field and left them that way till he flew again. He had batteries that were kept like that for a good part of a season and they seemed to perform just as well when he did finally use them, although we don't know what effect this had on the longevity (number of cycles lost) of these batteries. When he passed away and the batteries went to his friends, they all seemed to work OK.

[Dirty Dee]

Throw on some ear muffs, put them in your plane, and run 1/2 throttle to get them down. Ive done this on occasion, as it would take a few hours for my charger to get them down to storage. Especially for these larger more expensive packs, I personally would get them to storage instead of waiting it out.

[Elbee]

Hey Y'all, I have been unable to fly over the past 3 weeks and I made the mistake of charging two RT 6s 22.2 volt 35C 6250 mah batteries and these have not been used since then. I would be more comfortable if these were at storage voltage, but my charger won't discharge these at their current high voltage. My dilemma is this, do I not worry about it, do I charge these again when I go out next to fly, or do I find a way to discharge these and recharge when I go out next? Any assistance here would be greatly appreciated. Best, LB

[rifleman_btx]

Yeah you're good to go

[doctormike]

Thanks, WintrSol. Mine stops at 3.8. I guess that's ok. Doc

[WintrSol]

Some chargers use 3.8V as the storage level, and some as high as 3.9V; my quad charger uses 3.85V. As long as it is in that range, you're probably good.

[doctormike]

It did get colder since I storage charged them. I did check them with two different chargers. The batteries varied in voltage. My chargers, now that I checked this, do put my batteries at a higher voltage for storage than they should. I'll see how to adjust this. Thanks for your input. Doc

[xviper]

There is always some recovery of voltage during the minutes after use, especially if you run it down more than you should. If you've ever run a battery down to say, 3.5v or lower, as measured immediately after landing, then measure again 10 minutes later, you'll see the voltage come back up a bit. However, I've never seen that happen during storage. On the other hand, that's only 0.5 volts across 3 cells. I suppose it could happen if the temperature or humidity changed (or even barometric pressure) during the storage period. In most scientific reporting of chemical data, "STP" is always noted (Standard Temperature and Pressure) or corrected for, so it's important as it can contribute to variations.