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_oliK

LiPo swelling and MST Wheel breaking

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Hey Guys, I ran into two maintenance issues.

First off, I keep breaking my MST SP1 +3 wheels. I broke 3 wheels in winter, in a parking garage, which was probably due to the cold weather. But then, two more wheels snapped in hot weather. One broke after repeated small impacts while doing wallruns. Due to my own stupidity, basically. But one broke without any reasonable explanation.

All of them snapped were the spoke connect to the hub thingy in the inside, even though they're quite beefy. (For MST wheels at least)

 

Also, last week I started charging ne of my Yuki Brainergy LiPos, left the room, came back after a few minutes, and found the charger (robbe Power Peak Uni7) flashing it's LED. Pulled the Plug, opened the bag, LiPo is swollen. Polarity and and balancer were all connected properly. Then, I charged my other LiPo, and it took several hours longer than usually, Eventually, I just disconnected it, even though the charger wasn't finished with it. It wasn't hot or swollen or anything out of the ordinary, so I chucked it in the car, drove two really long sessions without the battery dying. Took it out, and Surprise! Swollen!

The battery is mounted on a custom aluminum battery tray, which has flat screw heads protruding from it (about one milimeter, maybe 1.5). However, both batteries show no sign of damage were the screws are. The lower edges seem slightly scuffed, though.

 

Seriously, what am I doing wrong? What's the dealß Bad plastic in the wheels? Broken charger? Bad luck? Please stop my descent into insanity, this is wrecking my nerves, as well as my bank balance.

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What a bummer.

 

How old are the lipos and how many cycles have been through them?

My guess is that your charger is at fault. Sounds like one battery was overloaded during charging and the other was overcharged. Seeing it's a Robbe charger, it can't be all that new. From what I recall, Robbe has been gone for some years now. I'd personally look into a new charger at a reasonable price, rather than risking more lipos.

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Bought the LiPoss last year, but only started using them this year. They've been through roughly a dozen cycles combined.

Yeah, I guessed that. Still sucks. New charger plus two new batteries, yay! Poverty! Homelessness!

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8 minutes ago, Kingfisher said:

Is the charger set for the correct Lipo? 2S, 3S?

Well, .... Turns out, it was set for LiFe. Oh boy. The stupidity!

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If those swollen LiPos are still in your apartment or house, I would get them outside and away from buildings ASAP.

When LiPos swell substantially they could suffer internal shorts (electrode failures) at any time.  This leads to a thermal runaway and eventually a fire.  Don't try to fix these batteries.

I had a Venom hard case LiPo swell to the point of breaking the case a few years ago.  It got tossed in a bucket and left outside about 50 feet away from the house overnight.  Then I made sure the battery was fully discharged before disposing of it.

Take a look at:. http://learningrc.com/puffed-lipos/

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Thanks. Yeah, just the look of these things scare me. 

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If you make up a bucket of super salty water cut the plugs off and chuck it in the bucket. If the battery is discharged it’ll be disabled in a week or so, if it’s fully charged could take a month. Either way afterwards the battery is inert and safe to chuck in the bin. 

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28 minutes ago, Juls1 said:

If you make up a bucket of super salty water cut the plugs off and chuck it in the bucket. If the battery is discharged it’ll be disabled in a week or so, if it’s fully charged could take a month. Either way afterwards the battery is inert and safe to chuck in the bin. 

I'm curious. How big of a bucket, how much water, and how much salt?

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6 hours ago, _oliK said:

First off, I keep breaking my MST SP1 +3 wheels. I broke 3 wheels in winter, in a parking garage, which was probably due to the cold weather. But then, two more wheels snapped in hot weather. One broke after repeated small impacts while doing wallruns. Due to my own stupidity, basically. But one broke without any reasonable explanation.

Hi, the second one could be down to damage done in a previous run, a hairline crack or suchlike.

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6 hours ago, _oliK said:

Well, .... Turns out, it was set for LiFe. Oh boy. The stupidity!

Hey, look at the bright side. No new charger. You're not going to be homeless. YaY;)

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6 hours ago, _oliK said:

Well, .... Turns out, it was set for LiFe. Oh boy. The stupidity!

That would under charge them in theory though, LiFe has a lower voltage per cell fully charged. Unless I'm missing something?

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16 minutes ago, nowinaminute said:

That would under charge them in theory though, LiFe has a lower voltage per cell fully charged. Unless I'm missing something?

Indeed. Could there be a situation where the charger would try to charge the 2S lipo as a 3S life? Thinking that it might read a pack with 7.4-7.6 volts like a 9.9 volt life? This could also explain why it never cut off while charging the second pack, as it tired to get the volts up to 3S life spec.

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7 hours ago, Kingfisher said:

I'm curious. How big of a bucket, how much water, and how much salt?

A cup in a gallon would suffice.

4 hours ago, TwistedxSlayer said:

This is why i still run NiHM.

You are missing out. Just need to be responsible with them, the fun far outweighs the 1/millon possibility

4 hours ago, nowinaminute said:

That would under charge them in theory though, LiFe has a lower voltage per cell fully charged. Unless I'm missing something?

Also lower cutoff. Was a cutoff being used? As per Speedy, get rid of them and start again.

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So. The charger was set to LiFe. I had the balancer plugged in at the LiPo/LiFe port, but turns out the actual power cables were still in the NiMh ports from charging other batteries.

How do I detect hairline cracks?

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6 minutes ago, berman said:

You are missing out. Just need to be responsible with them, the fun far outweighs the 1/millon possibility

Absolutely. One charge lasts forevaaaaarrrr. Also, lighter.

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4 hours ago, _oliK said:

Absolutely. One charge lasts forevaaaaarrrr. Also, lighter.

The main drawcard for me would be the current draw/power. Then the reliability for repetitive charging. They don't false peak and aren't temperamental like NiMh. Lighter works for power/weight, but a lot of the old vintage cars are setup for packs nearly twice the weight, and it can sometimes hinder suspension setups, as the car can sometimes become oversprung.

I have one NiMh (disregarding AA cells) and to be honest, I dont care if I never use/see another NiMh pack again. 😊

Is this your charger? I can see why there was a battery chemistry error.

ury1xg3.jpg

The simple two row digital screen with one + and one - power wire that 99% of chargers are using nowadays is nearly fool proof. Plus they give so much vital information.

Get yourself a cheap battery checker too, pretty much mandatory with LiPos and only a fiver-ish.

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18 hours ago, berman said:

ury1xg3.jpg

I'm sure I've seen that thing on NASA TV when they were still flying the space shuttles! Impressive how complicated they managed to make it! Looks like it would fit right in on Ferris Buellers HI-Fi rack too.

Definitely time for an upgrade I would say!

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Haha that's not even our oldest one. Oh, and yeah, mine is indeed signed by Chris Hadfield, from when it used to belong to NASA.

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5 hours ago, _oliK said:

Haha that's not even our oldest one. Oh, and yeah, mine is indeed signed by Chris Hadfield, from when it used to belong to NASA.

Flight proven space hardware, maybe hang on to it even when you get a new one lol

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LiPo tips

1. LiPos need to be placed in storage mode after you are done using them. If you plan on using them the next day, it’s ok to leave them partially discharged. But I’d recommend to place anything beyond 48 hours into storage state.  When I’m racing, after my last year, I start storing the pack I just used before going home.

I know This is a real pain!! and when I have slacked off, my packs have swollen.. my most recent are in good shape, because I have been diligent about it. 

2. Store the LiPos in the charge pack and put the pack in the fridge.  LiPos do not like hot weather. So in the summer time it’s important that they are stored in a cool place, while in storage state. 

These two steps alone will prolong the life of the LiPo and stop them from swelling. 

 

Interesting thing to note about fridge, is that if you place a pack that has swollen in the fridge, once you pull it out the swelling will have gone down substantially.. once the pack reached room temperature however the swelling will return. So unfortunately once the pack had swollen.. there is not much that can be done 

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