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Old 11-25-2020, 09:11 PM   #1
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Default New lipo help?

Hey yall, need a bit of help. I recently bought a turnigy graphene 4s 1400mah 75c battery from hobbyking. Matter of fact, i ended up buying 2 more before i found the issue with the first one. But the other 2 check out ok.

Heres my issue, n yes ive tryed contacting hobbyking, but cant post a pic for the complaint for some reason. But the first batt i bought wouldnt charge. It kept telling me to check cell count. So i did n they came out as 3.71 3.72 0.00 3.72

My question is, is there a way to get it to take a bit of a charge, without over charging or chancing a fire, enough to get the 3rd cell to show so i can safely balance charge it?

Any and all help is much appreciated! Thanks yall!
Have a safe n HAPPY TURKEY DAY!
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Old 11-26-2020, 12:55 AM   #2
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Default Re: New lipo help?

there is always a risk of fire, with lipos, you can charge that cell through the balance port from the nicad setting, but that cell will alwayse be an issue. file for a return. don't screw with it.
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Old 11-26-2020, 01:04 AM   #3
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Default Re: New lipo help?

I agree with VoodooBrew. Wait until you get a response. Don't mess with it.
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Old 11-26-2020, 01:34 AM   #4
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Default Re: New lipo help?

What's the total pack voltage? I've currently got 1 pack that will show similar, i.e.: 3.70, 3.70, 0.00, but when I check my total voltage it will show 11.1, so the cells are fine, but the problem lies in the balance lead wire. It's not necessarily dangerous, but now my charger won't let me balance it. I'd still be upset if a brand new battery did that and still want a replacement if the hassle of dealing with that process is worth your time.
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Old 11-26-2020, 03:43 AM   #5
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Default Re: New lipo help?

I contacted HK n they told me to file a claim. I can fill it all out, but when it wants me to add a pic, it wont let me. They wanna see the cell voltages, which is understandable. But the mobile site wont let me do it.

My boss said it could be a balance wire not connect properly n that it could be fixed. Or swap the leads for 3 n 4 n just use it as a 3s
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Old 11-26-2020, 05:01 AM   #6
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Default Re: New lipo help?

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Originally Posted by indybama View Post
Or swap the leads for 3 n 4 n just use it as a 3s
Be careful of this. As mentioned above, your issue may not be that the cell is dead, but that balance wire for that cell has lost connection somewhere. Easy way to find out is to check the voltage on the main two lead connector (i.e. , not the balance lead).

Let us know what you find out.
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Old 11-26-2020, 05:20 AM   #7
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Default Re: New lipo help?

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Originally Posted by OnTheTrail View Post
Be careful of this. As mentioned above, your issue may not be that the cell is dead, but that balance wire for that cell has lost connection somewhere. Easy way to find out is to check the voltage on the main two lead connector (i.e. , not the balance lead).

Let us know what you find out.
If the 2 main leads show proper voltage, wat would b the next step? Can it b fixed without returning the battery to HK?
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Old 11-26-2020, 05:44 AM   #8
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Default Re: New lipo help?

Checked it on the main leads n its 13.26v
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Old 11-26-2020, 07:47 AM   #9
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Default Re: New lipo help?

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Originally Posted by indybama View Post
Checked it on the main leads n its 13.26v
So your issues isn't [directly] that cell #3 is low, it's that the balance wire for cell 3 has a loose or break in the connection somewhere between the pack and balance plug.

Doing the math, unless your other cells are lower than what you posted in your first post, cell #3 is at 2.11V. So I'd get to a computer, file your claim with photo showing total pack voltage as well as balance voltages, and get that pack replaced.
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Old 11-26-2020, 07:54 AM   #10
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Default Re: New lipo help?

That’s rough Bams, especially with the holiday weekend.

With a bad balance lead I wouldn’t risk it myself to avoid thanksgiving fireworks.
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Old 11-26-2020, 08:03 AM   #11
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Default Re: New lipo help?

Looks like folks above me have helped you out to determine a bad connection with the balance lead. Unless it's a bad crimp connector on the end, you won't be able to fix the bad connection at the cell side of the connection. You will have to tear the pack apart and solder on that one cell. WAY too much risk.

Let me put it this way...DON'T RISK BURNING DOWN YOUR HOUSE!

File a claim with HK on your PC so you can upload the picture. I've done that with them when I had a whacky voltage with 1 cell. They don't even want the bad pack back (in my case). They will ship you a new one.

If they don't want the pack and you want to be frugal, you can redo the balance connector to skip the bad connection and turn your 4S pack into 3S.

Last edited by Kingmeow; 11-26-2020 at 08:55 AM.
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Old 11-26-2020, 08:14 AM   #12
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Default Re: New lipo help?

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Originally Posted by Kingmeow View Post
If they don't want the pack and you want to be frugal, you can redo the balance connector to skip the bad connection and turn your 4S pack into 3S.
I don't think that would work like that. And may be risky safety wise. The 4th cell is still wired in to the main connector in series with the other three. Just because the skipped balance lead was eliminated from "viewing that cell", it's still there. Most likely your charged wouldn't initiate a charge as the balance lead reads show 3 cells while the voltage from the main connector shows a much higher voltage so the charger safeties would kick in (hopefully ).
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Old 11-26-2020, 08:31 AM   #13
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Default Re: New lipo help?

Thanks fellas! Guess ill have to see if i can file from the ol laptop. Thankfully the other 2 work great.

Hey tb, hows it goin brother! Been a bit. I got these batts wen HK had their halloween sale with 45% off. Got them for bout $24 each.

Thanks again everybody! Yall have a safe n HAPPY THANKSGIVING!
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Old 11-26-2020, 08:59 AM   #14
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Default Re: New lipo help?

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Originally Posted by OnTheTrail View Post
I don't think that would work like that. And may be risky safety wise. The 4th cell is still wired in to the main connector in series with the other three. Just because the skipped balance lead was eliminated from "viewing that cell", it's still there. Most likely your charged wouldn't initiate a charge as the balance lead reads show 3 cells while the voltage from the main connector shows a much higher voltage so the charger safeties would kick in (hopefully ).
OTT, you are 100% correct and thanks for the correction! I haven't eaten turkey yet and I'm already in a tryptophan coma!

I was thinking about some of the airplane guys who would take a pack like this and physically remove a bad cell. We had one guy who was super frugal and he would make good packs by taking the good cells from discarded packs.

You can tell which ones were his due to the "fancy" wrapping of reinforced packing tape around his packs. We laugh but they work perfectly until their demise (worn out of crash). NOTE: DON'T TRY THIS ON YOUR OWN UNLESS YOU KNOW WHAT YOU ARE DOING AND YOU ARE OUTSIDE OF YOUR HOUSE.

(I've seen in person 14S helicopter packs (2x7S) caught on fire from a crash. To say it was spectacular is an understatement! We wouldn't put it out and just let it burn to the end. It generated a HUGE plum of smoke. You would have thought a house was on fire!)

Last edited by Kingmeow; 11-26-2020 at 09:04 AM.
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Old 11-26-2020, 10:16 AM   #15
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Default Re: New lipo help?

My boss is one of those plane guys lol. Hes got a airport behind the concrete plant. He has big fly-ins a couple times a year. But anyway, he told me it could b made into a 3s if need be.

Not somethin im willin to myself though. Not much of a fire bug lol
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Old 11-26-2020, 10:37 AM   #16
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Default Re: New lipo help?

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Originally Posted by indybama View Post
My boss is one of those plane guys lol. Hes got a airport behind the concrete plant. He has big fly-ins a couple times a year. But anyway, he told me it could b made into a 3s if need be.

Not somethin im willin to myself though. Not much of a fire bug lol
I would tell him to give you a hand if he knows how to do it. It's quite easy if you know how. Some airplane guys do this all the time. Might as well get a new 3S pack out of it if an expert can do it (and provided HK doesn't want the pack back).
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Old 11-26-2020, 12:03 PM   #17
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Default Re: New lipo help?

In my experience it's VERY difficult to make or modify your own Lipo. I've flown RC planes for decades and had my share of old packs where one cell went bad. I hate to waste something that can be made useful. The issue is, the tabs on Lipos are usually done with what I recall is called "hammer soldering"....???? You cannot get a safe reliable solder joint on a lipo battery tab with our regular run of the mill workshop soldering tools. Once the heat's hot enough to get a good solder joint, that same heat most likely ruined or reduced the life of that cell. Or worse, started the chemical reaction that could result in a fire.

I tried my darnedest one time to simply solder a balance wire back on a cell. Couldn't get the joint to stay and gave up. Some have had success but never worked for me and not worth the risk of loosing control of a plane where others are around.
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Old 11-28-2020, 01:26 AM   #18
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Default Re: New lipo help?

Quote:
Originally Posted by TheLetterJ View Post
What's the total pack voltage? I've currently got 1 pack that will show similar, i.e.: 3.70, 3.70, 0.00, but when I check my total voltage it will show 11.1, so the cells are fine, but the problem lies in the balance lead wire. It's not necessarily dangerous, but now my charger won't let me balance it. I'd still be upset if a brand new battery did that and still want a replacement if the hassle of dealing with that process is worth your time.

Sounds like it could be a bad BMS reporting a dead cell or more likely a simple bad solder joint to he 3rd cell. Sounds like it's not getting data some how.



Also I find it hard to believe that a 0V cell isn't puffed up like a marshmallow. Either way it's not your problem for a brand new battery. They should take care of you.



If they don't fix it, tell them that everyone in forums said it was good stuff and good service from the shop. And since it wasn't fixed they (the forums) will be very disappointment that things have change and no longer live up to their reputation.
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Old 11-28-2020, 11:11 PM   #19
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Default Re: New lipo help?

if you cant upload the pic to their website then upload it to a separate image host and link to it in the claim.
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