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4S battery issue - one dead cell, twice in a row.

4S battery issue - one dead cell, twice in a row.

Old 04-14-2013, 04:40 PM
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Default 4S battery issue - one dead cell, twice in a row.

Does anybody have any idea what would cause Cell 1 on a 4S pack to strangely go below 3v by itself?

I don't run my cars too often, sometimes I may plug in a battery to test steering out, barely use much as it doesn't get run hard, and then top up the storage charge.

I was previously using a HPI Vorza which got me into RC late last year and I bought some Zippy 30C lipos to use with it and generally they were fine. Especially on 6S, it flew!!

I recently put together a new buggy with a Viper VTX8 ESC and Tekin 1900 motor.

I had ordered some new Nano-tech batteries but they hadn't arrived by the time I was able to take the new buggy to the track for practice/testing.

I ran the batteries and put them in storage mode when I got home. I then grabbed one to try out some stuff and noticed that there was no throttle, only steering.

Everything was new so I was looking at the receiver. Even though I could see the ESC responding to the Tx I swapped it out but no change. I worried the ESC was faulty, then the motor.

Finally I grabbed another battery and it was all fine. I checked the cells with a simple cell checker and Cell 1 was showing as zero and it was beeping away at me.

I put it down to a battery gone bad and wrote it off.

My Nano-tech's arrived and I used my No.1 3300 for two races, tried a 5000, then switched back to the 3300 again. For the last race the No.1 3300 was still not quite ready apparently so I used the No.2 3300 for the last race. Then we packed up and I shut down the No.1 battery noticing that Cell 1 was saying 3.95 and the other cells were all in the 4.18 vicinity, which I thought was strange, but I figured I'd continue at home.

Plugging that battery in again I got a Balance error and my cell checker showed the same zero volts error on Cell 1.

I managed to get the charger to show me the cell voltages and it reports Cell 1 at 2.6v I think it was, and also alarmingly it now shows Cell 3, and possible another over 4.2v, one of them was 4.25.

I have an iCharger 306b, powered by a Turnigy 1200w, 24v, 50A power supply. It's set to stop charge at 4.19 too.

So far the other two batteries used yesterday, which was once each, were fine when I set them to storage charge. I hope that doesn't change and they don't show Cell1 being under next time I want to use them.

Any idea what could be causing this?
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Old 04-15-2013, 04:47 AM
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I've borrowed a multimeter and it shows cell 1 as being zero, not 2.x like the iCharger shows, and the other cells are what I remember the iCharger showing.

Cell 2 = 4.20
Cell 3 = 4.26/4.27
Cell 4 = 4.16

Does this sound like something my charger would have to do? It's been fine up until now, when I started using the new buggy with new electrics, and it's set to stop charging at 4.19, which is what it was doing the last time I saw this battery during it's last charge cycle, all cells were under 4.19 but cell 1 was at 3.95 or something similar, and things were taking a while.

It is just not good to have this happen twice in a row and I'd like for it to not happen again or its going to get expensive and inconvenient.
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Old 04-15-2013, 06:46 AM
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Sounds like a wiring issue, as it could be getting cell 1 voltage from Total Voltage - Cell2+3+4. I'd go looking for a loose balance wire. I had this happen with a Gens Ace 5S softpack before, cell 4's balance wire came loose and the charger was estimating the cell voltage.
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Old 04-15-2013, 07:08 AM
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try balance charging ur batteries..sounds like maybe u have a charger issue..but unclear as dont know how ur charging..
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Old 04-15-2013, 07:22 AM
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Originally Posted by bigdog69 View Post
try balance charging ur batteries..sounds like maybe u have a charger issue..but unclear as dont know how ur charging..
He's already described using a proper balance charger, and has used a multimeter to show us it's the battery in question.
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Old 04-15-2013, 08:10 AM
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It does sound like bad internal wiring in the battery. Make sure you LVC is 3.2 or 3.5. I don't know what the viper's come set up with. With the RX8 it's 3.0 by default.
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Old 04-17-2013, 10:49 AM
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Personel eperience has been, using an onboard balancer is I was having issue with the 3rd cell being balanced correct when I was done charging. I went to a blinky balancer and my old MRC, then charge it overnight at 1amp with the blinky balancer. Once I got the 4 larger batteries balanced, I haven't had much problem. I have 2/5000/6s/45c batt's for my 600 heli and 2/5000/4s/50c for my truggy. I noticed right out of the box the issue and was able to get them back into balance, so next batteries you get, try the blinky and a slow charge to really bring them in and I hope you have good luck as I love my big truggy, Chris
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Old 04-17-2013, 12:30 PM
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LVC was at 3.2 by default, I've bumped it up to 3.4 now.

It has been suggested that Cell 1 has been copping it from this ESC, which is 220A, and the new battery I used was rated at 215A, something I wasn't aware of.
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Old 04-22-2013, 10:52 PM
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I have had to resolder balance wires on several lipos they are usually right at the end of batt under tape. If you took one down to 0v it would of puffed that cell. I cut my way in carefully to find it , soldered it & and use shoe goo to fix all back down. Hard case might not pass roar inspection after that. Be careful not to short any thing out.
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Old 04-23-2013, 07:48 AM
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how old are the cells? I know older packs can have cells that lose their capacity and fall out of balance quicker as they age.

If you run higher capacity packs, then you will be less likely to go out of balance as the pack doesn't go anywhere near LVC before the end of a race.
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Old 04-23-2013, 02:18 PM
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Originally Posted by billdelong View Post
how old are the cells? I know older packs can have cells that lose their capacity and fall out of balance quicker as they age.

If you run higher capacity packs, then you will be less likely to go out of balance as the pack doesn't go anywhere near LVC before the end of a race.
I've once been doing this for six months almost. The lower C pack is from late last year and the higher C, lower mah pack was brand new.

This weekend I race again and I will be monitoring things more closely.
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Old 04-23-2013, 02:58 PM
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I ran into this problem with a New 4 cell pack.. It took me 4 cycles to get my battery up to correct voltage...charge -discharge.. all the way to 3.5 volts a cell..and I have a schulze charger and very good high dollar batteries..
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Old 04-23-2013, 03:59 PM
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Was one of your cells at zero?
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Old 04-28-2013, 05:06 AM
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Ok, today all went well. I brought three of the 3300's and three 5000's, all charged and ready to go.

I started off with the 3300's and stayed with them all day. This time I let the battery I had just raced with cool down before charging it, and I only needed to do that twice when I was there to cover the five races.

Last time I just kept charging mainly the one 3300 for the first three races, then a 5000 to test, and a different 3300 for the last race as the first one was still doing it's strange charging, prior to dying.

Checking the batteries each time they were all coming out of the car pretty much at storage voltage, no practice to speak of, just a lap or two slowly in the mains for the rolling starts we do.

The storage voltage was confirmed when each was put on the charger in Storage mode and they beeped ready right away!

The one reading I remembered to get at the track showed I was using 1500mah for a race with this buggy's setup. I was just trying my best to race in a controlled way, so I'm pretty happy with that.

I hope the battery issues are behind me now.
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