Battery daily storage and spark question

[Cooper]

Hey guys I have two questions or some general opinions. One, what is everyone's opinion on having lipo stored fully charged? I'm not talking long term storage, just a couple days or even overnight. I have always charged my lipos right after I use them and then put them away till next time. Been doing this for years. Recently a friend said that this will cause them to swell or catch fire, if stored fully charged. To be frank, I never gave it a thought, and never had an issue.

Second question is about anti-spark connection. Some say it will save your esc to have a spark resistor. Some say not. I just want to make sure my opinion gells with others. I have always thought that the esc were basically capable of handling the initial charge, well the caps,. And if use of spark arrestor it would mess up the auto detect of voltage for the esc. I'm using 8s ~30 volts, and cc 240 controller. I haven't had any problems but if I'm going to pop my speedo I will put one on. And I have never been bothered by the spark as in scared it will jump and shock me. It's dc electric and I'm usually not grounded better than the terminal I'm marring it to even if I were standing in waste deep water.? Is it just me being ignorant or have I been reading too many ignorant opinions and not getting the facts? ( and I mean no ill intentions by saying ignorant, as the definition is lack of knowledge). Now granted I'm not placing my fingers in direct contact with terminals. Just want to see if I'm on the right track or if I need some schooling.

[JIM MARCUM]

Just my opinion, but I store my LIPOs fully charged & store them in those silver colored fiberglass LIPO storage bags. Go for the largest size bag.

Only LIPOs I've had swell on me were either cuz they were cheapies, or running too much prop. Haven't heard of LIPOs swelling in storage, yet. Always good to store them in a cool, dry, fireproof place.

Running 8-10 cell LIPOs will arc & destroy 8mm bullets when packs are connected to the ESC. Been there done that. I always use a parallel inline resistor to pre-charge the ESCs caps before completing the LIPO/ESC connections. There is a tiny bit of current loss if you leave the resistor in parallel with the batt wire, but EZ to just unplug the parallel resistor wire. EZ to make, or buy them here on OSE.

Here in way-too-green Southern California, we can't even get our feet wet in our lakes. So, I don't have a clue about handling LIPO wires while in the water. Just guessing, but putting both + & - leads in your mouth would be a very bad idea. I'M JOKING - DON'T DO IT!!![/B]JIM

[Cooper]

Just guessing, but putting both + & - leads in your mouth would be a very bad idea.


So I can't test them like a 9volt? Sticking your toung in-between terminals?

Lol!!!!!

[JIM MARCUM]

Just guessing, but putting both + & - leads in your mouth would be a very bad idea. So I can't test them like a 9volt? Sticking your toung in-between terminals?

Lol!!!!!

Uh, 37 Volts, 500+ amps dead short? In your mouth?

Be sure to record it & post on Utube, or have your survivors post it if........................ JIM

[Old Sloppy]

Wait a minuite guys,

Lipos like to be "Storage Charged" @ about 45 degrees F (in a wine cooler) and 50% charge ( 3.85 volts per cell).

If you leave them fully charged the "C" rating will decay ( a 40c battery will turn into a 18c battery) I have (2) F.P. 5s 7,400 mah packs I run them as a single 10s pack.

I have owned these packs for years they are/were 20c rated and have been left charged even when they shouldn't have been.

So they work O.K. for sport uses, but they will not win any races......

They act like they are 18c rated at this time, in other words 10s runs like 8s of fresh cells.

My cells have rather High levels of voltage sag under a load.

As for the "Anti-spark resistor" ,
the spark alarms some folks, It is actually a good thing. it indicates the health of your caps.
the anti spark resistor may make you feel better, but it dosen't help your ESC at all.
I have 5.5mm bullets that are partly eroded by years of sparking, they do not require replacing yet, only the tip is eroded the deeper main contact area is like new still.

Harry

[Old Sloppy]

Just guessing, but putting both + & - leads in your mouth would be a very bad idea.

it might hurt, might burn your toung.

Harry

[Cooper]

Well that is what I thought about the spark, that it is a good thing. Just wanted to reinforce what I thought to be accurate. But the question still stands about the lipos, over night or for a couple days, not long term storage. So again is a couple hours or even a couple days what u guys keep your lipos fully charged? What do you consider storage? Not the voltage but the length of time!?

And I was very much jokeing about sticking my tongue to the terminals to check charge !

[Cooper]

If you are toping out your 10s batts c rating wouldn't you be getting a brown out? How can you tell they have diminished to a 18 c rating?

[Old Sloppy]

If you are toping out your 10s batts c rating wouldn't you be getting a brown out? How can you tell they have diminished to a 18 c rating?

The voltage sag under a load is higher than when new.

I do not leave my batteries fully charged overnight.

not since I learned from my first lipo pack.....

I will charge them up in the morning, ready for that day's playtime, if I do not get to run them down by bed time, I will then discharge them.

[Cooper]

Ok I haven't experienced that yet, have to look at the data logs. Always trying to learn something, I have a good knowledge base and I know what I'm working with and what I'm working on, but nobody around here does, the local hobby store doesn't even want to sell lipos! And still doesn't believe that I have a boat that will do 75mph let alone 30+volts!! Thanks for the info.

[Remmie81]

If you leave them fully charged the "C" rating will decay ( a 40c battery will turn into a 18c battery) I have (2) F.P. 5s 7,400 mah packs I run them as a single 10s pack.

I have owned these packs for years they are/were 20c rated and have been left charged even when they shouldn't have been.

So they work O.K. for sport uses, but they will not win any races......

They act like they are 18c rated at this time, in other words 10s runs like 8s of fresh cells.


Harry

Harry,

Am I understanding correctly that you are saying that your lipos that are a few years old are not giving the C that they used to give?

[bill34207]

I learned a long time ago not to leave my packs fully charged for storage and had the same experience as old sloppy. They would lose their punch and develop heavy voltage sag under load. My own thought is that a day or so isn't all that harmful since I usually start charging packs a day ahead of use time. (only 2 chargers and many packs to get done for a days worth of running). I do however put them all back to storage voltage (around 3.8v per cell) at the end of the day. Long term storage fully charged is just as damaging as leaving them stored fully depleted.

As for the arcing with HV setups, I have no spark suppression on any of my boats. I suppose it will erode the bullets over a period of time but haven't really ran across that problem yet. I knda like having a curious onlooker watching when I plug them in to see the expression of his face when it makes that distintive "snap".

[drwayne]

Cooper.
You had best make a list of those who do, or do not....

I do not store batts fully charged.. 3.75-3.8 for me.. overnight/24hrs is ok.. but that's rare
I do use a spark arrestor.

[properchopper]

Just curious ( not questioning the 1/2 charge storing concept) - but what is the reason batteries stored at full charge or depleted result in a drop in C rating or punch ?

[Old Sloppy]

Harry,

Am I understanding correctly that you are saying that your lipos that are a few years old are not giving the C that they used to give?

Yes!

Harry