TManiaci

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Hey all...

We've been doing electrics for a little over a year now. Have quite a collection of various Lipoly batteries, and 4 different chargers. Today, I was charging all our batteries preparing for a day at the flying feild. Plugged in one of my 3S HD 2100 mAH 12C Dymond Modelsports on the Astroflight Model 109 Delux Li-Poly charger. Brought the current setting up from zero to 5 amps and specifically noted it was on a 3C1 (showing my son how it auto-detects the cell count). Left it to charge.

After maybe 8 minutes, hear a pffffssstttt hissing sound, and looked over at the battery laying on the workbench. The battery was all puffed up and swollen.... Holy Crap! I grabbed the lead, unplugged it an tossed it on the floor. Then I grabbed the little cake pan that I ususally put the batteries into and tossed the battery into it, took it outside to let it calm down.

I saw that it was smoking in the pan, and got out the digital camera to get a shot of it. Still hissing like a mad snake, there was a cool thick smoke collecting in the pan.

TManiaci

My Feedback: (6)

Well, just after getting that shot, I backed away as the hissing became more violent... then WOOOF! It went off like a bomb, blowing a plume of flame up into the air 5-6 feet high... blasting like a blow-torch. My son, my Father-in-law and I were just watching in shock as if blasted like a booster engine on the space shuttle. I caught my wits, and took another shot as it began to die down.

TManiaci

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The flames died down after 30-40 seconds, and it finally quit smoking after 4-5 minutes.

krayzc-RCU

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Reminds me of those restaurant dishes they bring to your table and they are just a sizzling [8D]

I am glad one was hurt in this deal.

Any idea what happened?

TManiaci

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Trying to figure out what happened... still very concerned about this mishap. This charger auto-detects cell counts, as I said before. Looked at the display after it was all over, and noticed it said 4C2 [X(]. Somehow, during the charge, the charger decided to step it up to 4-Cell voltages (15.61 volts according to the display). It didn't show over the mAH that would be expected (1756 mAH), real weird.

Anyway, WARNING to ALL... these things can go off like a bomb. Had we not been sitting there, probably would have burned the garage down. We're buying one of those ceramic lipo charging pots ASAP. This is nothing to mess around with. I can't describe just how violent the flames were at first, like a huge blow-torch.

TManiaci

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The battery was fine before the charge, and has maybe 30 cycles on it, never been crashed. We almost never run them down to LVC, so generally they are only 1/2 to 3/4 discharged after a flight. We've all seen the lipoly burns where they have done it intentionally. Never dreamed it could happen under "normal" conditions.

TManiaci

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A10FLYR

My Feedback: (1)

5 amps into a 2100 pack would scare me anyway! I realise that they are doing 80% charge in 30 min now on some packs but I still wouldn't have set the charger over 2.1 amps. I wouldn't feel safe.

IBrakeForNobody

My Feedback: (16)

I think I should go buy a fire extinguiser; a c02 one or a foam one?

Glad no one was hurt. I usually charge my li-pos on a brick ontop of something flat inside the engine compartment. Maybe I should build a brick fort or something...

TManiaci

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Yea, I rarely charge at over 1 amp... I was pushing it a bit. Maybe that was what caused it to jump to 4-cell and overload. Good point though.

rajul

My Feedback: (58)

Great balls of fire ! Thank your lucky stars no serious damage was done.

punishment

well, look on the bright side, nobody was hurt, and your deans plug is still good!.

mikekomm

My Feedback: (9)

Sorry to hit you with the brutal facts, but you caused this by charging at a rate far beyond what is appropriate for Lithium Polymer cells. The important thing for all that read this is that the warning that you receive with the batteries, chargers and almost every product that deal with lithium polymer are real! Thanks for your honesty about the steps that led up to this unfortunate event. Most of the time, guys just post a picture of their garage after the fire and........"they have no idea what happened. Must be them darned Lipos"

I'm glad no one was hurt and really hope others that see this will avoid overcharging!

Mike
www.CommonSenseRC.com

guver

My Feedback: (325)

I am sorry this happened and thanks for posting the warning. I know it could happen to me. I have a couple of questions though and do not know this charger.

The questions are between post 1 and post 5.

You verified the auto cell count and then did it change? during the charge?

I realise some will blame the 5 amp rate or cell imbalance perhaps but I am wondering how it got from 8 minutes to 22 minutes as 5 amps at 8 minutes is only about 700 mah.?? the display shows 1756 and 22 minutes.

Thanks and glad you still have a garage and such.

jlkonn

My Feedback: (1)

TMan,
I along with everyone else am glad nobody was injured and you didn't suffer any property loss.
Thank you very much for sharing this and like someone else said thankyou for your honesty about the steps that led up to it.
You are helping us all when things like this are shared.
Sincerely,
John L. Konneker

Red Scholefield

My Feedback: (9)

Exactly! The 5 amp charge pushed the voltage high enough so the Astro saw it as a 4 cell pack and you saw the results. The pack may have also had a significant amount of charge when you started the charge. As the cell count goes up detecting the number of cells becomes more critical.

exeter_acres

My Feedback: (2)

yep...totally user error..
no fault of the battery

I stopped using wood too... since it is sooo dangerous

TManiaci

My Feedback: (6)

Yes, it was definitly on a 3-cell charge when it started. My son had never seen this charger before, so I was showing him how cool it was that it auto-detected the cell count. It changed some time during the charge.

~~~~~~~~~~~~~~~~~~~~~
I realized after the first response to this posting that I made a huge mistake dialing up to the 5 amp charge rate. I was in a rush, and thinking I discharge at over 10C WOT... at ~ 23 amps. So, I brain-farted, figuring anything less than 21 amps is safe... DUH!

You are right, I was really thinking something went wrong with the charger. Then, it struck me that I was over-charging this thing... what an idiot. I have always been very careful to charge well below 1C... goes to show you... haste makes waste.

So, maybe the good fortune of avoiding serious injury or burning down my home, and having a camera handy will help others to take reasonable measures to verify thier practices.

Check and double check... it just cost me a perfectly good $45 lipo. [&o]

TManiaci

My Feedback: (6)

Yea, it said 22 minutes... I put up the first posting "... after about 8 minutes..." because that was my estimate. Indeed, I believe it had charged for 22 minutes when the hissing began. You know how you lose track of time.

I take full responisbility for the cause. Just a stupid mistake. However, I will say this charger is inherently dangerous, by virtue of the auto-sensing feature and the dial-based current setting. I rarely use the Astoflight charger, and use my Triton 90% of the time. The Astroflight was purchased to charge our big 5S2P batteries. I was using both chargers so we could hurry to go fly. Keyword... hurry...

I am fairly sure the Triton would never do this, as it clearly has better safety features. I know I have mis-set charge rates on that one before too, but it won't let you do naughty things... it complains and won't start the charge cycle.

DHG

My Feedback: (7)

TMan,

At the risk of redundancy: Thanks for sharing! A couple of thoughts:

1. Charger manufacturers should include a big, dumb, manual toggle switch with a lockout on it so you can select the MAXIMUM number of cells that the auto-detect is allowed to count. I'm glad now that I got a Triton, which only goes up to 3 cells (11.1V) and nothing but 3-cell packs. That combination is "me-proof".

2. But recently I also got a PolyCharge 4, which uses the same sort of dial-a-crash/auto-cell-count setup you described on the Astro 109. (I think it will sense and charge up to a 4-cell voltage, and the current adjustment for each port is a simple rotary knob.) Based on your experience, I will be paying a lot more attention to the number of flashes of the little green lights (indicating the cell count) and put EACH pack in its own fireproof container. That pack of yours could easily have ignited any other 3 packs next to it in the pan -- converting a $45 mistake into a $180 mistake, even if it didn't burn down the garage.

Good data, brave mission, glad you survived. [&:]

guver

My Feedback: (325)

Got it, thanks. I supose that I can see a 5 amp rate (slight over 2C) increasing the voltaged measured at the charger. This charger must do this "on the fly" as well as when the pack is plugged in.

3S at start if it was nearly full would be 12 volts.
Start chargeing at 2C and voltage climbs to 14-15 volts at the charger tricking it into thinking it a 4S. Hmm, interesting.

mikekomm

My Feedback: (9)

I repeat, this guys honesty is to be applauded! Unfortuantely in todays world, most people with this experience would be calling their lawyer to initiate a law suit against the charger manufacturer. Personal responsibility is too rare and this "stand up" guy.

Mike
www.CommonSenseRC.com

ca$hey

Tman very luckey mate did i read on another thread where you flattend a damaged packout with a hammer was this the pack and did you get a good fun flying day in anyway cheers beaggs

guver

My Feedback: (325)

Yes, I agree. "applause" (even after my questions) I had heard some mumbo about auto cell count, but now will be more careful in how I shop. I for one would have at one time of another charged over the "majic" 1C on purpose and after verifiying the cell count would have walked away in confidence.

I have another questiopn (surprise surprise) Would a volt check at the start have showed a nearly full battery that was perhaps forgotten abouit or mistaken from a dead battery? I do it all the time w/ my batts, try to keep in my head which is full and which is empty, I cannot do it.

TManiaci

My Feedback: (6)

That's right beaggs, I did have a TP1320 that was crashed, and the corner was mashed in some. I flattened it out (not with a hammer, just by hand with a hard flat tool) and reshaped it. The lipo material is pretty pliable. I have kept an eye on that battery when I charge... and it has probably had 20+ cycles on it since then with no apparent ill effects and performance seems to be up to par still too. The materials were not ruptured visually, so I thought it was worth a try... seems to have worked.

Yea, we had a great fly-day. Put up 5 airplanes in one outing. Flew the Funtana 90, Funtana 40 (maiden) and Mini Funtana, the GP U-Can-Do EPP and the Hirobo Extra 300 (maiden). It was a ton of fun, had the airfield all to ourselves.

Yea, I'm sure the voltage would tell the tale before charge. However, I have (had) three of these 2100's, and always forget which has been used. I have numbers on them, but never seem to remember anyway. On the Triton, when you connect a full battery, it just charges for a minute or so and then stops saying it's fully charged. Puts in 3-4 mAH, then decides it's done. The Triton does a lot of pre-charge testing, seems to really do a careful cell check and test loads before it goes to work. It frustrated me before that it took so long to get busy charging, now I appreciate that delay.