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LiPo charging in the real world

C'mon own up!

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Romeo Whisky17/09/2010 08:56:10
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Perhaps surprisingly, although I have been flying electric models for over eight years, I have only just purchased my very first LiPo battery packs.
When I started, NiCd and NiMh were the only battery types available, and since most of my models were designed for them, some even needing the weight to balance them, I had no need to make the switch to LiPos when they first came along.

Then as the first LiPos came on the market one began to hear and read dreadful stories of thermal runaway with homes burning down and cars burning out - events which STILL occur even in these days of 4th generation LiPos.

So as I live in a small bungalow with integral garage (which is really my hobby room), I decided to go a different route as long as I could, and purchased a batch of Hi-Model 3S LiFePO4 packs which have served me well for two years.  But sadly these are no longer available, and that is why I have now at last taken the plunge and bought my first three LiPo packs.

Now, as if the horror stories above aren't enough to make one paranoid about them, the dire warnings on such as the GC website, in the accompanying instruction sheet (Overlander) and printed in a massive label on the packs (where the velcro need to go) all speak of potential disasters and serious risk, not only to property but also to life and limb.

According to these instructions I am supposed to charge these things on a concrete floor (my hobby room is carpeted), preferably outside (in wind and rain?), with no flammable objects within a radius of 3 metres (impossible), and I am supposed to stand in a cold garage and watch them through the entire charging time (which even with three chargers could take nearly 3 hours!).

Now c'mon lads.  Own up.  Do you really do all this?   What are the real-world practices out there?  Do you REALLY stand and watch them through the whole charging process?  Do you really have a concrete bunker to charge them in?  Do you REALLY store them in an ammunition box in your private air-raid shelter at the bottom of the garden?
Biggles' Elder Brother - Moderator17/09/2010 09:11:07
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interesting post RW. I only have 2 LiPo's (I don't really do electric much) and when I got them I was wondering the same. I must be honest I charge them indoors. But I do use an old asbestos mat to put them on and I always do it when I am about in the workshop working on something else. I wouldn't leave them "unsupervised" - too many scary stories!
 
But as I say its not really my field. So like you I'll be interested to hear what the dedicated leccky chaps say they do.
 
BEB
Bruce Richards17/09/2010 09:14:10
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I charge mine on the wooden bench in my attached garage. Never had a problem. But do make sure your charger is set up correctly for your lipo.
ken anderson.17/09/2010 09:15:49
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 hello romeo-mine are kept in a metal box(some of them) i charge them in the kitchen...on the worktop......and up to now have had no prob's......been using them for 3/4 year's.........
 
         ken anderson..ne..1.
kiwi g17/09/2010 09:19:46
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charging lipos can be dangerous but I think the playing with asbestos mats may be alot more of a worry BEB.
Biggles' Elder Brother - Moderator17/09/2010 09:21:48
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No danger Kiwi as its resin sealed - as long as I don't chip it its fine!
 
BEB
Flite0817/09/2010 09:29:08
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   When I had my bungalow built I had the ceiling rafters strengthened and the roof angle altered to make me a modelling room, now despite all the insulation it does get quite warm (hot!) in the summer so my lipos are kept and charged in the brick built, concrete floored, separate garage, in the winter they are kept and charged  in my modelling room in the attic, in all the years I've been using lipos I've never had a problem, also I don't sit and watch them charge but I also do not go out and leave them unattended, If you're careful and use a modern balancing charger, and discard any "blown" batteries problems wont arise.
           Having said all that the manufactures/ traders need to keep reminder us that problems can arise if correct procedures are not followed, especially for people new to the use of lipos.  
 
                                      F08 
Wingman17/09/2010 09:31:22
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Well Rw I've been using LiPos for about 5 years now and have never had one burst into flames or even puff up and I'm still using the 4 that I originally purchased (Hyperion LVX) although admitedly they are down on capacity now. I charge mine using a Hyperion 610i
charger and the charging is done in my loft workshop with the batteries inside a pyrex casserole dish with the lid on and which is sitting on a 300x300mm ceramic tile - I don't stand over them and in fact due to my advancing years I have occasionally forgotten they were on charge and they have been left on all night. At the field I charge them (usually at 2C) using a Propeak charger which is plugged into the car cigar lighter and the batteries are left lying on the grass beside the car door. To my mind all these scarey stories about LiPos are put about by people who don't understand leccy and don't want to convert to it.
Finally any battery will catch or cause fire if short-circuited so minute inspection of batteries after a crash is, to my mind, absolutely essential( and I've had plenty of practice) especially so with LiPos due to their very high energy density.
Stephen Grigg17/09/2010 09:43:46
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I wonder if the quality of charger is as important.When I bought my first Lipo I also bought a £100 Graupner 16 charger.It controls it all for me I just have to set the programme,beeps loudly and ends the charge.I did hear this year of a club member who left his Lipo on charge all night and his house burnt down with no loss of life fortunately.But he has lost everything including 50 years of memories and you cant get them back only in your head
ericrw17/09/2010 09:49:43
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I use a Lipo bag and keep an eye on the Charger;which indicates when a battery is "Full".   Eric.
Tim Mackey17/09/2010 11:30:47
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Scare stories - but all potentially true.
1) Use a proper LiPo style charger with semi idiot proof software. This means the charger will check the battery being attached, ask you for its description ( EG: 3s, 4s etc ) and then tell you what it "thinks" the battery actually is. You then need to confirm that you have selected the correct battery, and charge rate before the charger actually starts its work.
2) Dont leave the building whilst charge is in process - and just check all is OK occasionally.
3) Be tidy and secure with connectors and cables etc
 
I do most of what the other people have stated also, such as charge 'em on the grass at the field, but I dont use LiPo safes, or bags etc. Been using Lipos now for about 6 or 7 years, and the worst thing that has happened to me is a couple have swollen due to me discharging them in use at to high a rate.
 
IMO the main thing is to have a disciplined and careful approach to chargin
   ( which is where almost all incidents have happened due to user error).

Edited By Tim Mackey - Administrator on 17/09/2010 11:31:11

DH 82A17/09/2010 11:41:00
198 forum posts

   LifePO4   3s   packs are available from Puffin and Robotbirds.
Tim Mackey17/09/2010 11:47:57
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And indeed others...including a wider choice of available pack sizes from Electricwingman HERE
 
Note there are LiFePO4 packs and there are genuine A123 systems LiFePO4 packs - and there are definitely differences between them!
Ask me how I know
Ed Darter17/09/2010 13:18:25
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Without wanting to tempt fate.....
I do pretty much what others have stated. Just charge them on the bench. I don't stand over them, but don't go out and leave them charging either.
I am considering looking at a small ammo case or something from an army surplus store to keep them in, but this is because I have recently gone to 5S packs for an electric heli and the potential energy is quite a bit more than with my other LiPo's if something does go wrong.
Keeping them in a container without a secured lid is not much use really as they are likely to blow the lid off if they do go (which is VERY unlikely)
 
Tim hit the nail on the head, be regimented about what you do and all should be fine. They aren't really any more or less likely to go up than other chemistries if abused. I have personally been stood within 6ft of a NiMH pack that went up because of a duff charger brand new out of the box ! VERY scarey ! Like a mini fireworks display !

Ed
Myron Beaumont17/09/2010 13:38:42
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I've had no problems with my TWO lipos 'cos I've followed advice .But I still keep them in a metal box in 'er indoors's conservatory / workshop. My fuel is also outside apart from a half gallon in my flight box.
Vecchio Austriaco17/09/2010 14:36:59
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I suppose you shouldn't leave your charger alone - you need always be around so you can disconnect if something strange happens. And you should avoid charing your batteries in crammed areas where a lot of combustible material is close to the batteries like Balsa, methylated spirit, glow fuel and so on. But this is equal for NiCds or NiMhs - also they burn when overcharged (did so in my garage leaving a nice burn mark on the working surface).
I charge normally leaving the battery on a piece of Brick - to avoid further burn marks if I will make a mistake again. Currently I have approximately 25 Lipo batteries between 2 and 6 cells in use - and none of them caught fire. 
VA
Romeo Whisky17/09/2010 15:31:49
724 forum posts
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Very interesting replies.  Just a few of my thoughts on what's been said so far ...
 
1.  I know LiFePO4 packs are still available and A123s have been around for ages but the A123s are much bigger than the Hi-Model 3S LiFe 2000mAh's I have been using which are  about the same size and just a tad heavier than an equivalent LiPo.  None of my models are big enough to house a 3S A123 of equivalent capacity.  Hacker have now also started doing square section packs, but needless-to-say they cost a lot more than I paid, and twice the cost of equivalent capacity LiPos.
 
2.  Re keeping them in a metal box - good idea provided the interior bare metal is insulated somehow.  I've lined the interior of mine with Fablon.  But also the issue of whether to have a locked lid or loose lid is important.  A loose lid will blow off if the pack goes up (and presumably there could be several packs in such a box !!!), but a locked sealed lid could turn the box into a veritable bomb.  Best I think is to have a locked metal box with air vent holes in it so as to release any rapidly expanding air.
 
3.  For what it's worth I've covered my garage worktop (basically a Formica kitchen top) with cheap floor tiles seated on non-slip matting, and I both charge on this, and keep my metal box (an old Black & Decker drill case) on this too.
Ultymate17/09/2010 15:49:16
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At a couple of our club nights over this summer our chairman who I'm sure is a reincarnation of Guy Fawkes deliberately set out to overcharge some old lipos that were passed their best. They had to be seriously overcharged (around 17 volts for a 3S pack before they went into self immolation mode.
                          When they did go there were no warning noises just an eruption of flame so if you're not present there aren't going to be warning noises. The way I see it you need to be around when charging your lipos, I don't mean you need to be stood over them all through the charge process as they take a long time to reach danger point. I think there's little risk if you're close by in the same room or your workshop whatever and just check charger and pack every now and then and above all check your charge program selection and then check again
Steve Hargreaves - Moderator17/09/2010 16:29:29
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Interesting topic....Ken I'm not sure about keeping LiPos in a metal box...might it short them out??
 
I have heard of people charging LiPos in a pyrex oven dish complete with lid but personally think this is a bit overkill.....as Timbo stated early on you must take a methodical approach & make sure the number of cells/current etc matches up & then everything should be fine.....after all our laptops & mobile phones use LiPos & we charge them overnight in the dining room don't we?
 
I charge mine on a wooden bench in the modelling room/garage & have a smoke alarm over the bench. I'm not saying a fire couldn't happen but as with everything a sense of perspective must prevail.....
Tim Mackey17/09/2010 16:34:42
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The difference with laptops and mobiles etc is that these are more likely to be li-Ion and hard case constructed - also, they all have some pretty sophisticated PCM safety gizmos built in to the packs, so the risks of fire etc are far less than with the Lipos that we use.
Blimeys, Im starting to sound like the opposition party LOL

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