First time ever forgot to storage charge my lipo for 1 1/2 days

[Surchaufeur]

First time ever i have fail to do my responsabilities with my lipos. I took 3 lipos 2 days ago used only 2 and i think i got mixed up because the third lipo was half charged at 3.88v per cell and the second lipo was dead on 3.8v per cells and i think its where i god brain fked. Its the warmest day today herr in montreal so i decided to charge my 4s first and.... 3.69v on 4amps charge. Ussualy my 4s stops at 3.50ish v per cells. Im monitoring the lipo now but is my lipo been conpromise at this point? Im pretty responsable of the voltage of my lipos so this freaks me out a bit.
My 4s sat there for 2 days at 3.5v per cell

 

[Mike-NLD]

Stressed out as you are.. Did you made a mistake in charging program?
Puttin it on "balance" in stead of "storage"

My 4s packs also end around 3.5vpc when storage charge

 

[r4nd0m]

uhm 3.8V is still ~40% - doesn't really matter, I have had lipos on 20~30 for 1.5years or so - charged, ran as expected don't be too focussed on this kinda stuff - its more about not to allowing the lipo to reduce too much over time so it may result in damage

 

[Jerry-rigged]

Storage charge is NOT an exact science... yes, 3.85v is "Best" but 3.7v is still good, as is 4.0v. Main thing is, you don't want to store them around 3.0 for very long, or at full/nearly full.

Full disclosure, though. A few of my oldest lipos have been left "full" and forgotten for months at a time. They tend to drop to about 4.15v-4.10v, but other than that, no issue.

 

[jkflow]

Leaving a lipo at a different level for a couple days will not critically damage it. Just don't do it regularly.
You are impacting life time of the pack but it won't 'explode' or anything like that.

Category 'harmless'. Out of a ~ 100 cycle life you probably degraded it by 0.01 cycles
Not worth the rise in blood pressure.

Proper storage charge is 3.75V-3.85V, all my chargers stop at 3.85V. As stated before, not an exact science and it only impacts cycle life of a battery. Damage would be visible by extreme puffing, not the light swelling some people freak out over.

 

[Surchaufeur]

I think i miss explained my 4s lipo has been sitting for 2 days at 3.5ish volts per cell

Storage charge is NOT an exact science... yes, 3.85v is "Best" but 3.7v is still good, as is 4.0v. Main thing is, you don't want to store them around 3.0 for very long, or at full/nearly full.

Full disclosure, though. A few of my oldest lipos have been left "full" and forgotten for months at a time. They tend to drop to about 4.15v-4.10v, but other than that, no issue.

uhm 3.8V is still ~40% - doesn't really matter, I have had lipos on 20~30 for 1.5years or so - charged, ran as expected don't be too focussed on this kinda stuff - its more about not to allowing the lipo to reduce too much over time so it may result in damage

I know 3.8v is storage what im saying i failed for the first time to store my lipo at the right voltage for 2 days bassicly completly drained at 3.5v per cell
SO far my lipo is ice cold on the charger

Stressed out as you are.. Did you made a mistake in charging program?
Puttin it on "balance" in stead of "storage"

My 4s packs also end around 3.5vpc when storage charge

No i just completly forgot to charge my discharged 4s when i got back home and i got confused between my 2 other packs who were already at storage voltage

 

[nino]

WHAT ARE YOU DOING MAN THROW IT AWAY, QUICK!!!

Just kidding. It'll be fine.

 

[Surchaufeur]

WHAT ARE YOU DOING MAN THROW IT AWAY, QUICK!!!

Just kidding. It'll be fine.

Yikes
They are 40$ cheapest lipos i got a few cell defects but seller remplaced them for me but once i removed the bad cells they are always balanced and discharged equaly was thinking to not getting them anymore because of the quality issues i had but if i get the good ones they are really good for what you pay. They are a year old now

 

[r4nd0m]

I know 3.8v is storage what im saying i failed for the first time to store my lipo at the right voltage for 2 days bassicly completly drained at 3.5v per cell
SO far my lipo is ice cold on the charger

I cant even remember how many times I actually flattened a pack down to 0% in my over 13 years of RC - happens - if you got a good pack you may get away with it if not the lipo will actually degrade much faster as it may have caused some damage but again I wouldnt overthink this its like never run out of petrol or even more so diesel where you need to get rid of the air ... it may cause harm but its not the end of the world

 

[Outcastblxnut]

3.5 for 2 days ohhhhh no?

 

[jkflow]

If this happens often, I'd used to use these cheap slide indicators when I had ~ 10 packs for flight. Keeps the guess work out of it but honestly I forgot to set the slider or confused myself with what red or green meant
You have to set them manually.

I believe the Spektrum batteries as well as Dones (DJI) come with a standard 2 day 'return' to storage circuit but will only do it for charged batteries.

https://www.amazon.com/EV-PEAK-Non-...battery+indicator+slide&qid=1587847625&sr=8-2

 

[Surchaufeur]

Charge ended 3811mah(4000mah rated)

 

[r4nd0m]

If this happens often, I'd used to use these cheap slide indicators when I had ~ 10 packs for flight. Keeps the guess work out of it but honestly I forgot to set the slider or confused myself with what red or green meant
You have to set them manually.

I believe the Spektrum batteries as well as Dones (DJI) come with a standard 2 day 'return' to storage circuit but will only do it for charged batteries.

https://www.amazon.com/EV-PEAK-Non-...battery+indicator+slide&qid=1587847625&sr=8-2

I used those indicators but you still get it wrong by not changing the indicator while being distracted or sliding one over while throwing another back int the box etc

The Smart batteries have a mechanism that reduces the voltage but for a 5000mah 6S it will still take roughly 14 days or more to get there as the chip doesn't consume much really

 

[Jerry-rigged]

I know 3.8v is storage what im saying i failed for the first time to store my lipo at the right voltage for 2 days bassicly completly drained at 3.5v per cell

Yeah, 3.5v is technical not "Completely Drained", that would be 3.0v. You could leave a battery at 3.5 for about a year and still only take a few % off the battery life.

 

[olds97_lss]

Leaving them full tends to drive the internal resistance up, which effectively "ages" the pack. As they age, IR goes up, then they have less capacity, get warmer on discharge and output current goes down. Again, over time. Some last years, others seem to last months.

Leaving them closer to 3V on a shelf is more of a problem though because as they sit, they self discharge (IR will speed this up as well). If they go too low, the charger won't charge them, or the cells just die and won't hold a charge.