RCCrawler Forums

jebster · 03-13-2011, 06:11 AM

i have a 2s 5400mah pack that never seems to get fully charged. i use a venom pro charger and balance charge all my packs every time. i have two of the same packs and the other pack works fine (charger chimes and shows 'full'). with the other pack i can keep it on the charger for hours and it never completes. the mah meter keeps ticking up but in a 3 hour period it will manage to put in another 100mah. does this sound like a problem with the pack? i don't have a lot of experience with lipos but i have checked the basics. no damage to the pack, isn't ballooning up, doesn't get hot while charging, seems to work fine in my summit.

forbid89 · 03-13-2011, 07:08 AM

Have you measured the voltage in each individual cells? It sounds like your battery is gone. How many times have you charged the pack? It may just be at the end of it's lifespan.

Charlie-III · 03-13-2011, 07:09 AM

Does it time out during charge, or just keep going but never finishing?
What charge rate are you using?

You may have a cell on it's way out but I wouldn't worry too much.

crawlhog · 03-13-2011, 07:44 AM

does your charger show the voltage of each cell as its charging? if one cell is way off from the others than you have a bad cell and the batt. is bad

Charlie-III · 03-13-2011, 07:47 AM

Quote:

Originally Posted by crawlhog

does your charger show the voltage of each cell as its charging? if one cell is way off from the others than you have a bad cell and the batt. is bad

The Venom ProCharger does NOT show individual cell voltages (I also own one, but if it does, I've never seen it.....), but it would NOT start a charge if a cell was too low in voltage while balancing.

jebster · 03-13-2011, 08:29 AM

i need to check and see if the charger shows individual cell voltages. if it is a bad cell that sucks because the pack isn't that old. maybe a dozen or two cycles.

let me take a look at what the charger is showing right now.

jebster · 03-13-2011, 08:35 AM

just checked. on the venom pro while you are charging a lipo if you hit the increment up button it switches to an individual cell voltage display. i just did it on my pack and both are showing 4.2v so it looks like both cells are ok. i charged it for 2hrs yesterday (5A rate) and it was at a near zero amp rate at the end. i stuck it back on today and it have been going for 1.5 hrs, has almost no amps and has only put in 110mah. seems like it just never wants to call it quits. strange. all my other packs get to a full charge and it shuts down.

at this point i'm not sure what to make of this. charges fine, voltage of the cells looks ok, runs like the other packs but the charger just never seems to recognize it is full.

i appreciate the suggestions provided. i hadn't thought of looking at the voltages by cell.

jebster · 03-13-2011, 08:40 AM

it's a miracle!!!! after almost 5 hours the charger finally said it was done! (the same other pack i have charged in less than 2.) not sure what is going on but at least i know it can get done.

Charlie-III · 03-13-2011, 09:40 AM

Quote:

Originally Posted by jebster

it's a miracle!!!! after almost 5 hours the charger finally said it was done! (the same other pack i have charged in less than 2.) not sure what is going on but at least i know it can get done.

Cool deal, both on getting it to finish as well as the tip on individual cell voltages (I gotta go look at mine now

)

.

Now that it is charged & balanced, it may take less time when you charge it again. It does seem odd though.

murky123 · 03-13-2011, 10:06 AM

what if you charge the lipo with just 1 amp or less. it will take a long time, but it may help.. if you try it once.
someting like 0,1 or 0,2 times the C-rate.

my opinion. is that you do not have to balance your lipo's everytime. I dont know about your charger. but my charger does the balancing during the charge.

the older the lipo is. it my take longer to charge. my old lipo's still charge fairly quick. but the last few mah's can take the most of the charge period.

I have been using lipos up to 2,5 years of age. still going ok. not as much punch as before dough. and the original capacity is less. my 2,5 year old 8A lipo is now full at 6,2A

always charge max 1C

Charlie-III · 03-13-2011, 03:08 PM

To add a bit to murky......most battery chemistries get to ~80% full charge quickly, that last 20% can take some time.

jebster · 03-13-2011, 04:30 PM

i have seen that they charge on an exponential basis (majority happens quickly and then it slows towards the end). it was just odd that two of the same batteries had such different charging time. oh well, i'll just keep an eye on them.

on the topic of batteries for my xr10 i've been running my 1250mah 2s 10c lipos that i use in my son's exceed maxstone 16. runs pretty good and i can get about 30-40 minutes run time. i was curious how long my run time would be if i went to a higher c 3s pack (same mah). i don't comp so i'm not looking for extreme performance. i'm more concerned with run time. i'm running 55t, stock pinions, fxr w/ punk dig.

EddieO · 03-13-2011, 05:16 PM

Lipo packs are like a woman....if they puff up, replace them.....if they quit putting out as much as they did, replace them....if they start looking all worn out, replace them.....and of course, if they blow up on you, replace them....

Later EddieO

j-bird · 03-14-2011, 12:09 AM

i have a pack that has swollen up and the case is tight and this happen out of the blue, it still charges and runs fine is it bad? what should i do with it if it is? how do i properly dispose of it

JohnRobHolmes · 03-14-2011, 07:33 AM

Quote:

Originally Posted by EddieO

Lipo packs are like a woman....if they puff up, replace them.....if they quit putting out as much as they did, replace them....if they start looking all worn out, replace them.....and of course, if they blow up on you, replace them....

Later EddieO

I think you win the award for biggest chauvinist on the board

But it is certainly a fair assessment for batteries.

OP- Sounds like your pack may have cells with different IR, or you could have discharged it until totally dead a few times too many. It can make trouble for low current balancers. Does it take so long every single time you recharge, and only on that pack?

jbird- Discharge that pack slowly and throw it out or recycle it. A swollen pack is dangerous, especially during charging.

EddieO · 03-14-2011, 09:34 AM

Maybe we should look up what chauvinist means

Just being funny......

Later EddieO

Quote:

Originally Posted by JohnRobHolmes

I think you win the award for biggest chauvinist on the board

But it is certainly a fair assessment for batteries.

OP- Sounds like your pack may have cells with different IR, or you could have discharged it until totally dead a few times too many. It can make trouble for low current balancers. Does it take so long every single time you recharge, and only on that pack?

jbird- Discharge that pack slowly and throw it out or recycle it. A swollen pack is dangerous, especially during charging.

JohnRobHolmes · 03-14-2011, 09:49 AM

Quote:

Originally Posted by EddieO

Maybe we should look up what chauvinist means

Just being funny......

Later EddieO

By all means look it up if you need to. I'm not referring to patriotism.

I suppose I don't catch the humor in considering women disposable. If you consider yourself not being chauvinist with that remark, then you must have an equal view that men are disposable too

EddieO · 03-14-2011, 10:06 AM

I've looked it up before, no need to again.....it certainly doesn't fit the bill of what I said. Shallow, sure.....but that's the point of the humor....hopefully you never watch Lisa Lampanelli, you may be offended into oblivion....

And I must be doing something right, married for 14 years next month......

Later EddieO

JohnRobHolmes · 03-14-2011, 10:11 AM

I don't watch TV, sorry.

I guess living with a social worker/ rape trauma volunteer and having my best friend going through his Masters in Social work has me particularly sensitized to comments degrading women. I read it again, still no humor to me no matter how shallow it is.

jebster · 03-14-2011, 10:18 AM

Quote:

Originally Posted by JohnRobHolmes

I think you win the award for biggest chauvinist on the board

But it is certainly a fair assessment for batteries.

OP- Sounds like your pack may have cells with different IR, or you could have discharged it until totally dead a few times too many. It can make trouble for low current balancers. Does it take so long every single time you recharge, and only on that pack?

jbird- Discharge that pack slowly and throw it out or recycle it. A swollen pack is dangerous, especially during charging.

it seems to take that long every time on that pack. i do have cutoffs on all the rigs i use it in and never run past the 3.6v/cell recommendation. seems strange to me that the internal resistance would be that different but it is a possibility. i'll run it through a few more cycles to see if this continues. i will say mine isn't showing any signs of damage (swollen) so i'm not concerned about it flaring up.

03-13-2011, 06:11 AM	#1
jebster I wanna be Dave Join Date: May 2010 Location: The east coast Posts: 2,599	what are the signs of a bad lipo pack? i have a 2s 5400mah pack that never seems to get fully charged. i use a venom pro charger and balance charge all my packs every time. i have two of the same packs and the other pack works fine (charger chimes and shows 'full'). with the other pack i can keep it on the charger for hours and it never completes. the mah meter keeps ticking up but in a 3 hour period it will manage to put in another 100mah. does this sound like a problem with the pack? i don't have a lot of experience with lipos but i have checked the basics. no damage to the pack, isn't ballooning up, doesn't get hot while charging, seems to work fine in my summit.

03-13-2011, 10:06 AM	#10
murky123 Quarry Creeper Join Date: Jul 2010 Location: netherlands Posts: 348	what if you charge the lipo with just 1 amp or less. it will take a long time, but it may help.. if you try it once. someting like 0,1 or 0,2 times the C-rate. my opinion. is that you do not have to balance your lipo's everytime. I dont know about your charger. but my charger does the balancing during the charge. the older the lipo is. it my take longer to charge. my old lipo's still charge fairly quick. but the last few mah's can take the most of the charge period. I have been using lipos up to 2,5 years of age. still going ok. not as much punch as before dough. and the original capacity is less. my 2,5 year old 8A lipo is now full at 6,2A always charge max 1C Last edited by murky123; 03-13-2011 at 10:11 AM.

03-13-2011, 07:08 AM	#2
forbid89 Quarry Creeper Join Date: Feb 2011 Location: Vancouver, WA Posts: 423	Have you measured the voltage in each individual cells? It sounds like your battery is gone. How many times have you charged the pack? It may just be at the end of it's lifespan.

03-13-2011, 07:09 AM	#3
Charlie-III I wanna be Dave Join Date: Nov 2010 Location: 07456 N. NJ USofA Posts: 8,314	Does it time out during charge, or just keep going but never finishing? What charge rate are you using? You may have a cell on it's way out but I wouldn't worry too much.

03-13-2011, 07:44 AM	#4
crawlhog RCC Addict Join Date: Feb 2010 Location: a house Posts: 1,986	does your charger show the voltage of each cell as its charging? if one cell is way off from the others than you have a bad cell and the batt. is bad

03-13-2011, 08:29 AM	#6
jebster I wanna be Dave Join Date: May 2010 Location: The east coast Posts: 2,599	i need to check and see if the charger shows individual cell voltages. if it is a bad cell that sucks because the pack isn't that old. maybe a dozen or two cycles. let me take a look at what the charger is showing right now.

03-13-2011, 08:35 AM	#7
jebster I wanna be Dave Join Date: May 2010 Location: The east coast Posts: 2,599	just checked. on the venom pro while you are charging a lipo if you hit the increment up button it switches to an individual cell voltage display. i just did it on my pack and both are showing 4.2v so it looks like both cells are ok. i charged it for 2hrs yesterday (5A rate) and it was at a near zero amp rate at the end. i stuck it back on today and it have been going for 1.5 hrs, has almost no amps and has only put in 110mah. seems like it just never wants to call it quits. strange. all my other packs get to a full charge and it shuts down. at this point i'm not sure what to make of this. charges fine, voltage of the cells looks ok, runs like the other packs but the charger just never seems to recognize it is full. i appreciate the suggestions provided. i hadn't thought of looking at the voltages by cell.

03-13-2011, 08:40 AM	#8
jebster I wanna be Dave Join Date: May 2010 Location: The east coast Posts: 2,599	it's a miracle!!!! after almost 5 hours the charger finally said it was done! (the same other pack i have charged in less than 2.) not sure what is going on but at least i know it can get done.

03-13-2011, 03:08 PM	#11
Charlie-III I wanna be Dave Join Date: Nov 2010 Location: 07456 N. NJ USofA Posts: 8,314	To add a bit to murky......most battery chemistries get to ~80% full charge quickly, that last 20% can take some time.

03-13-2011, 04:30 PM	#12
jebster I wanna be Dave Join Date: May 2010 Location: The east coast Posts: 2,599	i have seen that they charge on an exponential basis (majority happens quickly and then it slows towards the end). it was just odd that two of the same batteries had such different charging time. oh well, i'll just keep an eye on them. on the topic of batteries for my xr10 i've been running my 1250mah 2s 10c lipos that i use in my son's exceed maxstone 16. runs pretty good and i can get about 30-40 minutes run time. i was curious how long my run time would be if i went to a higher c 3s pack (same mah). i don't comp so i'm not looking for extreme performance. i'm more concerned with run time. i'm running 55t, stock pinions, fxr w/ punk dig.

03-13-2011, 05:16 PM	#13
EddieO I wanna be Dave Join Date: Apr 2007 Location: Arlington, Washington Posts: 2,303	Lipo packs are like a woman....if they puff up, replace them.....if they quit putting out as much as they did, replace them....if they start looking all worn out, replace them.....and of course, if they blow up on you, replace them.... Later EddieO

03-14-2011, 12:09 AM	#14
j-bird RCC Addict Join Date: Dec 2010 Location: middle,tn Posts: 1,326	i have a pack that has swollen up and the case is tight and this happen out of the blue, it still charges and runs fine is it bad? what should i do with it if it is? how do i properly dispose of it

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03-14-2011, 10:06 AM	#18
EddieO I wanna be Dave Join Date: Apr 2007 Location: Arlington, Washington Posts: 2,303	I've looked it up before, no need to again.....it certainly doesn't fit the bill of what I said. Shallow, sure.....but that's the point of the humor....hopefully you never watch Lisa Lampanelli, you may be offended into oblivion.... And I must be doing something right, married for 14 years next month...... Later EddieO

03-14-2011, 10:11 AM	#19
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	I don't watch TV, sorry. I guess living with a social worker/ rape trauma volunteer and having my best friend going through his Masters in Social work has me particularly sensitized to comments degrading women. I read it again, still no humor to me no matter how shallow it is.

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