Argh! Overcharged to 4.5v

[Sunder]

I'd say just overcharge them to around 10V and whack 'em with a hammer Remember to make sure your insurance is paid up and your video camera is running.

With a name like Texaspyro I believe you'd do it If I mailed them to you would you post the video here (or leave it as an instruction to the executor of your estate? )

 

[liveforphysics]

I don't know how high your charger floats to, but lets say it floats to 55v and you want it to stop at 47v. Lets say it's discharge current is 3amps.

You could throw 11 x of this diode in series with the charger, and it would make it just a whisker past 47v, and cost a whooping $5 for parts.


http://www.westfloridacomponents.com/DI039/T10A60L+10A+10+AMP+600V+Diode+Axial.html

 

[Sunder]

I don't know how high your charger floats to, but lets say it floats to 55v and you want it to stop at 47v. Lets say it's discharge current is 3amps.

You could throw 11 x of this diode in series with the charger, and it would make it just a whisker past 47v, and cost a whooping $5 for parts.


http://www.westfloridacomponents.com/DI039/T10A60L+10A+10+AMP+600V+Diode+Axial.html

Sounds good. I might print that out and bring it to Jaycar, and see if they can sell me something similar. 55V down to 47v sounds about right (Maybe 49 would be better if it's 100% reliable, as that would be just shy of 4.1), and charge rate is supposedly 2.5A - will that alter how many I need. I actually have no idea how diodes work, except that they pass electricity one way...

Might also talk to an electrical engineering friend to see if he has any ideas.

 

[texaspyro]

With a name like Texaspyro I believe you'd do it

It looks something like this (and yes, that's me and no Photoshopping was done)

 

[Sunder]

Hahaha. Do you look like two face now?

 

[Ypedal]

It's better to over-charge than over-discharge !!!.. ( not that either is good.. but i assure you that if you take a cell past 0v and keep pumping energy via other cells inseries you will get gas !! )

I've overcharged way pas 5v, testing runts to destruction,
see some of the vids :
http://www.youtube.com/ypedal

however, no matter what, i never, NEVER leave the house with batteries charging, not even AA and AAA nimh cells... seriously.. i dont. And i have 2 fire extinguishers, one in the kitchen and another in the office..

As said above, get one of these :
http://www.google.ca/imgres?q=timer+15+amp&um=1&hl=en&biw=1024&bih=571&tbm=isch&tbnid=drwCDx01CzZjsM:&imgrefurl=http://www.hydroponicsxl.com/intermatic-15-amp-grounded-timer-case-12.html&docid=bu1w2EsWS3YfVM&itg=1&imgurl=http://www.hydroponicsxl.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/I/N/Intermatic-Timers-600__44943_zoom_1.jpg&w=600&h=600&ei=sL89T4v3FIPg0QGAhpTaBw&zoom=1&iact=rc&dur=125&sig=116898467706041899287&page=1&tbnh=116&tbnw=116&start=0&ndsp=10&ved=0CHEQrQMwDA&tx=67&ty=56

Only use the red pins, so it turns off within X time, and will not turn back on unless you reset it.\

I"m not sure if it matters, but i would feel it be better to moderatly discharge the cells back down to 4.20v or less, but not as quickly as possible via high load.. LFP might comment on this ?

 

[stinkler]

Dont ask LFP he will tell you to put on safety sandals and hit it with a hammer.

 

[Sunder]

Okay, finally got around to doing a full discharge to 3v/cell on my packs. They're meant to be 10A (2 x 5A in parallel), but since I only charge them to 4.1v, they've been getting about 8.5A for a while. So no significant change there.


Looking at cell balancing, it "doesn't look pretty". but in reality, that's been happening any time I get that low - within 30 seconds of recharging, they're back within 0.01v balance with each other.




Not shown here, is the full recharge, which took 9400mah, which again, is what I expected before I overcharged this pack.

So I'd say I got off pretty lightly with this accidental overcharge. It may have wiped significant life off the pack, but I don't think I've actually damaged any cells. Will definitely be more careful in the future though.

 

[parabellum]

Wait for this cells puffing slightly over next few cycles. Are they compressed?

 

[Sunder]

Wait for this cells puffing slightly over next few cycles. Are they compressed?

They've been quite a few cycles with no puffing. From what I read, if they were going to puff, they would have in the first 4 or 5 cycles.

They are held together by heat shrink, so not hard packed, but they're not just free to expand. I've felt puffing cells in this type of heat shrink before, so I know what to look for, but none yet.

 

[parabellum]

They've been quite a few cycles with no puffing

Good for you. I overcharged hardcases (uncompressed) to about 4.5x/cell and they cracked the cases after few cycles, I just compressed them with fiberglass reinforced tape. Every thing fine since then, must be half year now.

 

[liveforphysics]

They've been quite a few cycles with no puffing

Good for you. I overcharged hardcases (uncompressed) to about 4.5x/cell and they cracked the cases after few cycles, I just compressed them with fiberglass reinforced tape. Every thing fine since then, must be half year now.

I'm glad it's working for you paralellum, and able to provide the experience you're looking for, but I really hope you've got a good safe place you charge and store the bike that you wouldn't be willing to see bathed in flame should you end up pushing your luck a bit too far.

It's awesome to use, but you gotta accept the risks that it might just become a fireball randomly, and plan accordingly.

It's pretty amazing how we have so many examples of it showing amazing resilience to damage, and still lasting and performing somehow, and a couple other examples where it seemingly just burst into a fireball unprovoked (but always with the possibility it was a wiring fault etc).

We really need to start running automotive grade stuff for the commuter bikes that don't have places to part that the owner deems acceptable to bathe with flame.

This is the problem with being pioneers with this stuff, the rewards are awesome when it's good to you, but it's down right scary to see some examples of it biting back.

The OP of this thread charging with the wrong voltage charger, so he has to catch it and stop it to keep it from just becoming a fireball is really really reckless and dumb.

Method's HVC/LVC kit really seems like a no-brainer for doing RC lipo setups. Even it can't safeguard against one just going off while sitting though, that takes better cell mfg and QC, which we aren't going to find with the RC hobby cells.

 

[Sunder]

Yeah, I'll admit it's not my smartest move so far, but I got sick of carrying the charger between home and work all the time.

Besides. I'm a desk worker, and I'm at my desk constantly, with the big blue letters staring me in the face all the time ... Except for unusually early and long lunches of course.

Anyway, I've still put a timer on it, which gets it to about 48v. Obviously would be better off forking out $100 for a proper programmable charger, but I don't need the one at work to balance or get to full - just top it off, so I can keep the higher speeds on the way home too.

 

[liveforphysics]

Yeah, I'll admit it's not my smartest move so far, but I got sick of carrying the charger between home and work all the time.

Besides. I'm a desk worker, and I'm at my desk constantly, with the big blue letters staring me in the face all the time ... Except for unusually early and long lunches of course.

Anyway, I've still put a timer on it, which gets it to about 48v. Obviously would be better off forking out $100 for a proper programmable charger, but I don't need the one at work to balance or get to full - just top it off, so I can keep the higher speeds on the way home too.

Spend the $5 for the diodes to drop the float voltage as well.

 

[Sunder]

Spend the $5 for the diodes to drop the float voltage as well.

Will do as soon as I get the equivalent part from a local supplier. Thanks.

 

[neptronix]

Anyway, I've still put a timer on it, which gets it to about 48v. Obviously would be better off forking out $100 for a proper programmable charger, but I don't need the one at work to balance or get to full - just top it off, so I can keep the higher speeds on the way home too.

Sunder, you're making me ( and probably others ) lose hair here.

Because of posts this, i am verging on not ever speaking about RC lipo ever again. Seems that no matter how hard we try to educate on this forum, someone still wants to play russian roulette with the world's most dangerous battery. All it takes is one idiot doing something like blowing up half a kilowatt hour of RC lipo to get the media / lawmakers in a frenzy, demonize what we're doing, and create new laws and regulation as a result.

Your battery is a potential firebomb now because you never bought the right equipment, and i hope you stop charging like that starting now.

 

[Ykick]

I think we all see this for what it is...

 

[999zip999]

Go and buy a king pan and put it on a timer at lease. Or send them in the mail address to yourself. W.T.F

 

[parabellum]

I'm glad it's working for you paralellum, and able to provide the experience you're looking for, but I really hope you've got a good safe place you charge and store the bike that you wouldn't be willing to see bathed in flame should you end up pushing your luck a bit too far.

Yes, I feel very lucky (accidentally) overcharging, over discharging lipos, revers charging nanos and then using them and still using some of them with no real consequences, just capacity loses. Hope my luck will never end.
We are surrounded by LiPos, we trow our phones to the bed, over newspaper, let them in our pockets with no worry. We let our kids playing with LiPo powered devises. My phone exploded in my hands, with no fire but the battery puffed, ripped back cover of the phone, jumped out and vented on the floor.
Maybe we all are lucky?

 

[Sunder]

Maybe we all are lucky?

If everyone won the lotto, perhaps its not that we're all lucky, but there is a problem with the stats...

 

[Kin]

May have been pointed out already, but if LFP says play it safe...worth listening .

I for one speak against the simple outlet chargers. Those can reset and fail, at least mine for some grow lights (orchards! ; not even mine) have before even though they have backup batteries. Best go with the diodes to drop output. Besides, more than the timer being wrong, you're guaranteed to calculate the time wrong sometime.