is my LiPo toast already?

SchrodingersCar

SchrodingersCar

Member
So I have a 4s 5500 LiPo that I've only flown with a total of THREE times... It's worked pretty great as far as I can tell. I've balance charged it every time at <1s. I've never even discharged it below 40%!

I went to charge it today and my charger threw a cell balance error - looked at the voltages and it says 3 of the cells are at 3.8v and 1 is at 1.5v. Any idea how this could have happened? Did I just get a lemon of a battery, or is it possible I did something wrong? I'm still pretty new to this...

Also, any chance of saving this one, or time to recycle it already?
 

Benjamin Kenobi

Benjamin Kenobi

Easy? You call that easy?
A cell at 1.5v is bad. Have you checked it with another lipo checker in case the charger is being strange? I would put that lipo somewhere safe, like outside!

What brand lipo is it?
 

PeteDee

PeteDee

Mr take no prisoners!
Batteries do just fail, I had from new that was quite weird, totally dud cell, rewoked the pack to be a 3S rather than a 4S, use it on my ground station now, now other cells have failed since the first one.

Pete
 

SchrodingersCar

SchrodingersCar

Member
It's a storm lipo from helipal. I don't have any other way of checking individual cell voltage, but I just checked the total voltage with my buck converter on the copter (it has led for total voltage in and out), and it reads 15.3v... totally fine! Maybe it is the charger? It works fine on my other batteries (same exact brand and model). Could it be a wiring problem on the balance lead?
 

PeteDee

PeteDee

Mr take no prisoners!
Fully charged pack should be 16.8V though, looks like the charger is right.

Pete
 


G

Gary Mortimer

Member
I am afraid I have to agree with the comments above, its likely toast perhaps you let it discharge too much or it was duff from the start. Don't be tempted to fly with it. As Ben says treat it with caution!
 

SchrodingersCar

SchrodingersCar

Member
Yes see my first post - I've done it all by the book. I don't think there's actually a bad cell. It's either bad wiring on the balance lead (could that even lead to "partial" voltage??), or a bad charger. My balance charger reads 12.9v (3*3.8v and 1*1.5v) but the voltage coming off the main line reads 15.3 (presumably 4*3.8v - can't read individual cells.)

This battery is fresh off of a flawless flight that landed at 14.8v under load. It has not been charged. I guess I'll need a 3rd way of confirming voltage to find the real culprit...
 

SchrodingersCar

SchrodingersCar

Member
I finally figured this one out: It turns out one of the wires on the balance plug somehow detached inside the battery. It's hanging loose from the connector now. Does this mean I've gotta recycle it? Damn thing only lasted 3 flights, but I'm certainly not comfortable enough to attempt to repair...
 

kloner

kloner

Aerial DP
soldering the balance leads is pretty easy and straight forward, just make sure to seal it back up tight.

when you get a pack in the mail, always check it with a cell checker and return any pack with a low cell..... never charge or change the plug till it's looked at. If a pack sits around in the wrong climate they will drop a cell sitting there
 


kloner

kloner

Aerial DP
I use packing tape.... it's a huge metal tab with solder on it in there that's missing a wire,,,,,hard to miss

trim the top along three of the four sides and flip up the flap.....
 

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