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mr crispy

Lipo probs, need a new charger?

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Put my 4200mah 2S Turnigy shorty lipo on my basic Vapex balance charger tonight as both cells were around 4.06v. I noticed it wasn't showing the usual red charging lights on the cells after apx 30-45mins so I disconnected the balance plug and checked it on the voltage display. 1 cell was showing 4.08 and the 2nd was 4.54!!! Not very balanced after all. Quick test on another batt and it's seems to definitely be the charger that's at fault.

So 1st question, is my battery now shagged? Its a hardcase so can't really tell if it's puffed at all. Can this be saved and how do I go about it?

2nd question. Can anyone recommend a decent lipo charger that can do storage charges/discharges and monitor my growing collection of 2S lipos that isn't going to involve selling a kidney :)

Any help would be appreciated.

Nic

Edit : I've been looking at the IMAX B6, anyone has experience of them? Sounds very good for the price.

http://pages.ebay.com/link/?nav=item.view&alt=web&id=190818527250

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I'd take that battery with a 4.54V cell and get it out of the house immediately. It's likely puffed and you can't feel it/see it in the hard case. Max voltage per cell is supposed to be 4.2V; above 4.3V irreparable damage starts to occur.

Take it outside to the middle of the yard, throw it in a bucket of salt water for at least 24 hours to fully discharge it, and then dispose of it.

I had a 3-year old Venom LiPo puff on me this week. I was using it to test some electronics and noticed the receiver and ESC kept cutting out. Fortunately the hard case around the cells is clear red, and I could clearly see a black leak from one of the cells. I could also see how the case was bowed. There was no point in trying to charge it and risk a fire. It immediately went into a metal bucket about 30 feet away from my house and stayed out there for a few days.

I have a genuine IMAX B6 (not a copy) and it works fine. I appreciate the status screen that shows each cell voltage while charging.

Be sure to put a storage charge (about 3.7-3.8V per cell) if you're storing the battery for a period of time, and be sure to use a balance charge (not fast charge) each time you top off the battery. Max volage on any cell is 4.2V. Don't let the cell voltage drop below 3.2V per cell with a LiPo cutoff built into the ESC, external LiPo cutoff, or external LiPo alarm.

Any signs of physical damage or premature electrical dropout = dispose outside immediately.

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So I should consider my shorty lipo dead then?

Getting peed off with this, I follow all the advice, only ever balance charge my lipos, always use a low voltage cutoff or buzzer, use a reputable charger and I still get screwed :(

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Chris i have the IMAX B6 .Being using without any problems for 2 years now .

Great charger but make sure you get a genuine one as there are a lot of fake ones about . If it has the hologram sticker its the real thing . . As for the maybe dead lipo - play it safe mate and dispose of it . Not worth a potential house fire for the sake of the price of a new one is it ?

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With bunch of 2-3-4S for both helicopter and RC cars I found that the more you take care the worst it will be. Don't wait till the cutoff to stop playing, charge them even if 70-80% remeaning. You can often drop them really low without much problem. I never use storage mode, I prefer littlebit more higher voltage such as 4,0V. Don't give them a high-amp charge when came out storage they will puffed within 3 days. High discharge 40C+ lipo and low-turn brushless will tend to puffed your lipo in race that normal, don't let them in hot spot. Listen to your Lipo checker!

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Thanks for the info guys. The iffy lipo case was definitely bowed out a little so it's been religated to the garden in a plant pot. I like the sound of the IMAX chargers, how do I know if they're genuine? Where is this hologram sticker Bromvw?

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Hobbywing list both gen and non gen. They have gen in stock in their UK warehouse

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Yes thats the real thing Nic - 100% sure as its identical to mine .

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Are lipos worth the hassle, I don't drive my cars loads but would like the additional runtime and power, but it sounds like they are a pain to look after.

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not a pain at all . just treat them with respect , use a lipo charge sack or steel box when charging and their no problem . BTW are you using a laptop or a mobile phone ? Both are lipo and perfectly safe .

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do they make brushed motors perform better?

Absolutely - but please use a lipo alarm if your going to use a brushed ESC

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Are lipos worth the hassle, I don't drive my cars loads but would like the additional runtime and power, but it sounds like they are a pain to look after.

This is what I thought. I want to use the most up to date equipment for my rc's but lipo's do scare me a bit. I've heard people store them in one even 2 ammo boxes and they have to be treated just right. I might have to go to a meet and check out other peoples chargers and batteries etc. I still feel more comfortable with nimh but realise this is older tech now.

BTW are you using a laptop or a mobile phone ? Both are lipo and perfectly safe .

Hadn't thought about this. I'm already using lipos. :blink:

Mr crispy said this "Getting peed off with this, I follow all the advice, only ever balance charge my lipos, always use a low voltage cutoff or buzzer, use a reputable charger and I still get screwed :( "

How come the phones and laptops are basically plug in and forget and the ones in rc's seem so tempremental with needing to be balance charged, low voltage cutoff, ammo box storage etc?

Sorry to ask on your thread crispy. I'll have to do some research on lipos.

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yeah I charge my iphone in the kitchen and leave it, sometimes overnight, always have, I've also let it go flat, no issues.

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what charge bag do you recommend?

Any really - their much the same .

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Phones and laptops have their own battery monitoring built in, so they usually have problems when someone plugs in a non-standard charger that delivers the wrong volts/amps.

An RC car battery literally gets hammered when you run it hard off road so maybe its not surprising they don't last as long. The power demands we put them through are also more extreme in comparison.

Nimh & nicad batteries can also be volatile and explode, you just don't hear as many horror stories.

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I have a genuine Imax b6ac which plugs into the mains power 240v (aust/uk) I have been using for the last 6 months. Cost about $40 plus shipping. Works well using lipo and Nimh.

I have just ordered the new Turnigy Accucel 6 80w 10A. Looking foward to trying it out.

I completely drain my damaged/puffed lipos with a 12v automotive light bulb first and then leave in a bucket of salt water. Then twist the wires together and discard. Salt water alone for me has never completely discharged the battery.

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I personally don't think that NiMh are that safe either..

The ones in this photo were fairly new race packs.. They had been used for racing that day, discharged, put on an equalising tray, and then charged for storage and then placed in their case..

The guy that owned these had just finished packing his 1:1 car after racing, and had opened the drivers door to go home when he noticed smoke inside the car..

This is what he found when he opened his battery case..

%5BIMG%5Dhttp://i267.photobucket.com/albums/ii320/StumpyRC/2007_1209_0069.jpg

%5BIMG%5Dhttp://i267.photobucket.com/albums/ii320/StumpyRC/2007_1209_0069CELL.jpg

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I had a nimh go off on me years ago but it's was totally pilot error :) It was a small 8.4v Airsoft nimh of around 800mah which I was intending to trickle charge, but I forgot and automatically hit the fast charge button by mistake. 10 mins later while tinkering with my gun I was suddenly aware of a hissing noise and found the battery melting and falling apart... I've not made that mistake again!

I got my IMAX B6 and already used it to charge my lipos, it's very reassuring being able to see the charge in the cells being balanced in real time.

I've got a question though. It allows you to set the amp rate you want to charge them at. I use to have a standard formular for working out the highest "safe" rate to charge a battery depending on its MAH but I can't remember it now or find the info again. Does anyone know what I'm on about or have a link to such a thing? I followed it and never had an issue with my nimhs, I still have a couple that are fully usable some 10 years later! I think it was a matter of dividing the battery's mah by the charge rate and multiplying by 1.4 or something like that. I'd worked it all out for the batteries I owned and typed it up as a quick reference guide but lost track of the sheet :(

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