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Superluminal

Lipo question - dead batteries?

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Hello, when it comes to wires and electricity theres seems to be a part of my brain that blanks out the understanding of basic concepts - I can just about handle the battery / some wires / esc / motor concept and all my kits that i own or am ever likely to own have nimh and brushed motors.

However a couple of years ago I bought an artf RC plane with some lipo batteries and brushless motor etc and had about 18 months of learning to fly it and got reasonably good. Until sadly last september my flying field companions aircrafts propellor cut my tail plane off during a middair collision and left me with a carrier bag of now useless polystyrene.

As the weather this year is just about getting better I bought a new plane and was about to set it up and neither of the two lipos will start to charge - the flysky charger I have says ballance error on them both and the lipo alarm display i have doesnt show anything when plugged in (it normally displays voltage) They are both genuine Spektrum batteries (££££ sadly) but theyve not been touched for six months after using them - does this mean they are both scrap? 

Im thinking i should have storage charged them or something but didnt at the time.

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Ive only used this charger a couple of times but experimenting with the buttons it has a meter function. Both batteries are showing around 0.3v.

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You can try charging them on NiCd/NiMH mode for a few minutes, just to raise the voltage up above 3V per cell.

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I don't use Li-Po batteries , but I know they have to go into storage charge modeif not used for some time of around 3.8V if I remember correctly . Your charger should have a Li-Po storage default on it to discharge the packs to storage level .

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22 minutes ago, sosidge said:

You can try charging them on NiCd/NiMH mode for a few minutes, just to raise the voltage up above 3V per cell.

Ok will giving that ago - are they likely to be permanently damaged after being at such a low voltage?

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21 minutes ago, KEV THE REV said:

I don't use Li-Po batteries , but I know they have to go into storage charge modeif not used for some time of around 3.8V if I remember correctly . Your charger should have a Li-Po storage default on it to discharge the packs to storage level .

Sadly the voltage seems too low for the charger to recognise the battery in any of the lipo charge modes. 

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12 minutes ago, Superluminal said:

Ok will giving that ago - are they likely to be permanently damaged after being at such a low voltage?

They may not have quite the performance they used to but they should be usable again. I've brought plenty of batteries back to life in this way.

Next time you store something away, unplug the batteries (as a minimum), and give them a storage charge if you can. Most RC electronics put a very small drain on batteries if they are left plugged in.

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They were both unplugged from anything but just left for several months on a shelf. Assume they discharge by themselves given long enough?

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1 minute ago, Superluminal said:

They were both unplugged from anything but just left for several months on a shelf. Assume they discharge by themselves given long enough?

Very slow for a LiPo, when you buy a Lipo off the shelf it will have had a storage charge put into it, and for older stock that could have been a few years previously. They are normally still in range for a charger after all that time.

I can only assume your packs were flat already so had nowhere to go except down below the charger's range.

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Be careful when using the other setting, and stop as soon as the voltage gets above the 3v per cell range (shouldn’t take long). Then cycle them a couple times between charged and storage, should come back to life fine.

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I put my brave pants on and tried charging both of them in nimh mode.

Got about 4v into each of them after charging for a minute at 0.1a.

Have tried charging them again in lipo mode and it comes up with "cell error voltage invalid" error message on both batteriers.

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4v per pack or per cell? I don't think you would get a 4v per cell reading after a minute a 0.1A, you've put almost no charge in after that time.

What are the specs of the LiPo packs from the aircraft?

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its easy to get the "." the wrong place when typing. Are your cells 0.3v as you say,not 3.0v?

I only ask because you then say the cells reached 4v ,charging at 0.1v, that would take ages,not a minute.

3v is low for LiPo but savable,so I have read. 0.3v ,I would say is very bad.  Even at 3v I have read some chargers don't like that.

There are load of vids on YT about "kick starting" to do it correct you really need to do the cells individually not the pack,by making up a lead. only do this if confident.

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2 hours ago, sosidge said:

4v per pack or per cell? I don't think you would get a 4v per cell reading after a minute a 0.1A, you've put almost no charge in after that time.

What are the specs of the LiPo packs from the aircraft?

Hmmmm.....Not entirely sure. When charging in the nimh mode it only gives a single figure for voltage. Its weird, when i first plug it its at about 0.3v and within about 30 seconds it jumps straight up to about 6v and stays there. When I then stop charging it and test the voltage by the charger functiob it still only says a couple of volts -  2 or 3v.

Will try charging them for longer in nimh mode. Would about 15 minutes be safe?

The battery specs are Spektrum 2200mah 3S lipo with a max 6A charge rate

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1 hour ago, Gazzalene said:

its easy to get the "." the wrong place when typing. Are your cells 0.3v as you say,not 3.0v?

I only ask because you then say the cells reached 4v ,charging at 0.1v, that would take ages,not a minute.

3v is low for LiPo but savable,so I have read. 0.3v ,I would say is very bad.  Even at 3v I have read some chargers don't like that.

There are load of vids on YT about "kick starting" to do it correct you really need to do the cells individually not the pack,by making up a lead. only do this if confident.

No was definitely 0.3v on the original measurement using the voltage meter function on the charger.

Unfortunately Im definitely not confident when it comes to wires and stuff.

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Daft question but you have changed to 3S charge mode, rather than the usual 2 for car lipos - and connected the balance lead into the correct input on the charger? I sometimes get this when charging my 2S batts - even though everything is connected correctly. I usually just disconnect everything, reconnect and it sorts itself. 🤷‍♂️

As an aside, I've left my plane lipos at 'storage voltage' for months and months and months and they lose very little (maybe 0.01v per cell over many months). I do check on them periodically though just to make sure they're still OK.

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1 hour ago, Superluminal said:

Hmmmm.....Not entirely sure. When charging in the nimh mode it only gives a single figure for voltage. Its weird, when i first plug it its at about 0.3v and within about 30 seconds it jumps straight up to about 6v and stays there. When I then stop charging it and test the voltage by the charger function it still only says a couple of volts -  2 or 3v.

Will try charging them for longer in nimh mode. Would about 15 minutes be safe?

The battery specs are Spektrum 2200mah 3S lipo with a max 6A charge rate

You'll need to charge it as if it is 9 or 10 cells NiMH.  0.1A will take forever to have any impact on a LiPo  of that capacity, I'd go to 1A.

I certainly wouldn't leave it unattended for 15 minutes, I'd be watching the cells and checking the voltage and temperature all the time. A couple of minutes at 1A should be enough to get them up to a more stable voltage, if not,  I'd consider disposing of them safely.

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Maximum success!!!!!!!! And I'm still alive.

I changed the charge setting to nimh 1A and started charging while carefully watching it. After about 15 minutes it started beeping with a message about the ballance input but a different message to the first which was just an error so it seemed like it had at least detected the ballance lead being connected now. I stopped charging it and switched it back to lipo mode, held the start button for three seconds.....Huzzzahhh! It's detected its got three cells showing on the display screen and is now allowing it to charge. Im currently charging it in balance charge mode and its about 40 minutes in and isnt smoking or getting hot or anything so assume its ok.

Thanks everyone for the help! Thought i was going to have to throw them away.

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3 hours ago, Superluminal said:

Thought i was going to have to throw them away.

Or use them as hand grenades ;)  :ph34r:

Looks like a result then

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7 hours ago, Superluminal said:

Maximum success!!!!!!!! And I'm still alive.

I changed the charge setting to nimh 1A and started charging while carefully watching it. After about 15 minutes it started beeping with a message about the ballance input but a different message to the first which was just an error so it seemed like it had at least detected the ballance lead being connected now. I stopped charging it and switched it back to lipo mode, held the start button for three seconds.....Huzzzahhh! It's detected its got three cells showing on the display screen and is now allowing it to charge. Im currently charging it in balance charge mode and its about 40 minutes in and isnt smoking or getting hot or anything so assume its ok.

Thanks everyone for the help! Thought i was going to have to throw them away.

Definitely continue to monitor them for puffiness etc, but sounds like you should be good to go

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