Jump to content
Mark Harris

Phew, close call!

Recommended Posts

Yes, you came very close to a very serious problem. I don't see a balancing charge connector on it, so that is one thing that could have doomed it. Also, is this a pack that had a prior problem, like a minor indication of puffing?

Share this post


Link to post
Share on other sites

It has a balance lead, but you can't see it on this photo. I wasnt charging with the balancer this time because my balancer was in use charging another cell.

This battery has been over discharged before, but came back up fine. (i use these for bench testing OSD's.. so only getting around 30-100mA draw depending on whats connected to it.) This one is going to be taken to tandy on monday, as well as my other batteries which i've over discharged in the past. This pack has never been even slightly puffy.

At the moment its sitting on a piece of railway section outside.. with a metal bucket upside down on it.. better to be safe than sorry hehe.

It wouldnt have been a problem if it did go, well not a huge one, i charge my batteries in a pit of sand that would be quite difficult for it to escape from even with the rocket like thrust.

Share this post


Link to post
Share on other sites

I think that is the risk of using an over-discharged LiPO. There have been some grand fires reported by others where the pack had seen a cruel prior use.

Don't under-estimate the thrust from a flaming pack. Some videos I have seen show amazing activity when a LiPO pack goes Chernobyl. Plus, there is always the chance of ugly smoke damage.

Just for grins, have you seen these threads?

http://www.rcgroups.com/forums/showthread....348#post7063655

http://www.laureanno.com/RC/fire-pics.htm

http://www.rcgroups.com/forums/showthread.php?t=463115

http://www.rcgroups.com/forums/showthread.php?t=307324

Share this post


Link to post
Share on other sites

I might have the same problem myself. One of my batteries grew really big one year ago. See picture of battery compared to a normal one.

I still use this battery as powersource for my video RX and amplifier. Works well.

Of course I have to charge it outdoors. I don't like indoor fireworks :blink:

post-13-1188066846_thumb.jpg

Share this post


Link to post
Share on other sites

after seeing this:

http://www.laureanno.com/RC/fire-pics.htm

i think i need to amp up my fire safety... Was a very very close call tonight, i think if the battery had have charged for 1minute longer there would be no garage attached to whats left of my house.

I also need an alternate charging location i think, right next to where i charge is a cabinet full of model fuel, ammunition and spray cans, under the bench is turpentine and oil based paint cans (20Litre cans). Next to this is 60-100l of fuel in steel jerry cans. On the shelf above are various flamables.. like methylated spirits, turpentine, paint thinner, rocket motors, MAPP, Butane and a few oxidisers heh. In other words, the whole area would quite litteraly expode (jerry cans go boom.. so do half empty model fuel bottles and paint cans.. mapp cans, and butane cans..). Oh and then there are the two cars in the garage too.

Time to think about some better solutions.

Anyone know what making a bag out of Rayon would do? i'm thinking an envelope with a tounge that folds all the way back. Rayon doesnt burn :D (must get rayon and test! new Intelligent Flight product perhaps?)

Share this post


Link to post
Share on other sites

As much as I love LiPOs, they scare the dickens out of me. I use a fire safe, have a smoke alarm above it, and a chemical fire extinguisher ten feet away. But, I'm only human, and one day I may make a fatal mistake during a routine charge and I have no idea if my setup will prevent damage to my home. Some say the only safe solution is to charge outside in the BBQ grill.

I get very nervous when I hear about folks admit to using compromised packs (over discharged, some evidence of puffing, puncture wounds, crash damage, or whatever else ails their pack). Yes, these crippled batteries may still provide power, but that may come at a serious price. It isn't worth the risk.

I really like the safety aspects of the new A123 polymer cells. I have a couple of 40-size models that use them and they work great. They are a bit bulky, so small models are out of reach for now. But, I suspect that issue will be solved one day.

Share this post


Link to post
Share on other sites

Yeah Lipos scare the life out of me as well! After my last crash, my E flight 11.1 800mA got crushed, deforming two of the three cells. Still works but I decided to chuck it out, no sense taking the risk and they're cheap to replace anyways. ;)

Share this post


Link to post
Share on other sites

The other day when I crashed 2 of my lipos were a bit wrinkled. I handy flatten then and now I´ve used them to do some test and all the cells are balanced ok.

Would I have problems with them? I would charge it in a safety area an keeping an eye on them.

Share this post


Link to post
Share on other sites

If they are wrinkled, the polymer layers may have separate a bit more than they should. After yesterday.. i'd be inclined to throw them out.

Even a $90 battery is a heck of a lot cheaper than a $750k home and contents.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×