hoverlow44

So I wasn't sure where to post this.. Iv'e been flying for a while now, and im pretty knowledgeable when it comes to RC components such as servos, batteries and such. I have a debate going on with my dad. He says that Lipos must be balanced all the time. On every charge cycle, We're talking about Rx lipos, very low discharge rates. And i tell him that you dont really have to balance a lipo unless its really out of balance. And plus if you are gently discharging the battery like in a Rx application, then unbalancing is rare. So what do you guys think? He also says that lipo cells are very different electrically and thats why they need to be balanced every time.... So i dont know. I think hes being overly cautious.

AMA 74894

My Feedback: (1)

this is just my humble opinion, but it's sort of like saying 'you're being overly cautious with the can of gasoline and that zippo lighter.'

you are making the assumption that the battery is being 'gently discharged' but (unless your checking the individual cell voltage after each flight) you don't KNOW that.
the same goes for how much the cells are out of balance. if you do check the individual cell voltage every flight, then you could assume the cells are staying in balance.
until they don't.
my personal opinion is that lipos SHOULD be balance charged every time, (should be, not necessarily MUST be)

I've been using Lipo's and LiFe's for nearly 10 years, and I ALWAYS balance charge them.

hoverlow44

I usually check the voltage of each cell, and they are always with in .01 V of each other. And this is in my 8S 4400 mah pack that i fly my 70" yak for about 8 minutes of 3d flight. Now, using the same concept, but with a 1900 mah 2S lipo used on a Rx application, i can't imagin that that would be much different. Unless of course, the batteries act completely different than in a high discharge situation. Plus they are good thunder power betteries, not china brand lipos.. So i don't know i guess ill have to test out my theory.

Redback

I always balance my Lipos because my charger will do it and there seems no reason not to.

Terry

opjose

I always balance charge at home, and do a normal charge at the field.

A non-balance charge doesn't take as long to complete, so I reserve that for the field.

jester_s1

That's kind of like asking whether you really have to check the oil in your car every month or be sure the doors are locked when you leave the house. Most of the time, everything is fine. But the consequences are severe when it isn't. Within a pack, one cell in a lipo can have more resistance than the others, which changes both the charge and discharge speed. With time, that can lead to the pack being out of balance and therefore dangerous. How much time? It depends on how different it is. I have watched my packs as they get close to full charge and often see 1/10 of a volt difference in them. I doubt that would destroy the pack if I weren't balancing, but it still proves the point- every cell is different.
Why is this even a conversation worth having anyway? It takes all of 5 seconds to plug in the balance tap when you are charging. I'm no lipo expert by any means, but I do know that since good quality lipo chargers with integrated balancers came out, reports of lipos bursting into flames have dramatically reduced.

AMA 74894

My Feedback: (1)

exactly. hence my 'you're being overly cautious with the gasoline and zippo lighter' comment...

KW_Counter

Even Red has said that balance charging every time is not necessary.
Balance if you can but if in a tight situation an occasional direct charge won't hurt.
I try to always balance charge since I always charge at home.

Just my opinion based on others knowledge that I trust.

Good Luck,
KW_Counter

NEW222

I always balance charge my lipos. If I accidentally forget my balancer I will just charge and fly then balance as soon as I get home and recharge. But I do only use 360 - 1300 mAh 2s batteries.

rt3232

My Feedback: (6)

Ok Hear is another guestion why when checking lipo's with a checker thers no load applied to each cell or the pack ?

Cheers

hoverlow44

Well i got some lipos in planes as Rx power, and it is a pain to remove the battery just to balance it. It's doable, but that would involve like 20 min everytime just to remove and re install the battery.Unless i add extra long balancing leads. But i dont want to modify the pack

hoverlow44

Use a volt checker with load application.

JohnBuckner

My Feedback: (1)

So does this mean you also never remove your Lipo for charging? Oh my, what a brave sole you are, especially so since you never balance charge.

John

rt3232

My Feedback: (6)

hoverlow44

I would except as yet I have not found any mfg that provides one. So do you have a suggestion ? both of my LHS's tell me it is not needed, but i am just questing that.

Cheers

AMA 74894

My Feedback: (1)

no need to modify the pack. I do essentially the same thing, except that I extend the balance plug on my charger, not on the battery...
(but I Do typically pull the pack out of the airplane at least a couple of times per season)

hoverlow44

Most of my planes have accessible areas to balance a lipo. It is a new plane im building where it looks like it will be difficult to balance since battery is in an awkward place due to CG reasons. But i will try to extend the balacne leads of the batt. To this day i havent had a Rx lipo go out of balance more than +-.01 V

raptureboy

I do the same thing as you do. they rarely go that far out of balance in 1 or 2 flights and I practice safe charging when I do. A bal charger is no guarantee that you will not have a battery blow up, I saw one do this at the field once sitting on a guys tailgate after coming off a charge. You could just switch to a LiFe pack and not worry about it.

hoverlow44

Yeah thats true. usually packs that always go out of balance usually have something wrong within the cells, and shouldn't be used anymore.

oliveDrab

Are we talking about removing the Lipo..........from the plane? Well of course yes, remove the Lipo from the plane every time it's to be charged. Unless you want your plane to burn to the ground if the Lipo should decide to go berserk. Oh wait - the Lipo is for Rx power? - didn't see that at first until I re-read your post. I use a NimH for Rx power.

I plug in the balance connector each and every time I charge my battery. Additionally, my Hyperion charger has a separate "Balance Mode" that balances only without actually charging. Takes a long time.

oliveDrab

Do you really mean ".01" or ".1"? I've got a 6-cell Lipo that might read : 3.77 3.78 3.78 3.79 3.75 3.77 . So there's a spread of .04. If it does that I put the charger into "Balance Mode" and take the time to balance the battery. Then I get a spread of .00 or .01.

Is a difference of .04 tragic? I thought .1 was the limit at which you start to worry a lot.

hoverlow44

I really mean .01. But that is in my smaller 2s lipos i use for Rx. In my larger batteries like my 8S which are subject to about 50A or more of discharge when flying my 70" yak, then there is a bigger difference, up to .06. .04 is not bad at all. i wouldnt be concerned.

lopflyers

My Feedback: (12)

My receivers get LiFe and I balance charge em every 3-4 charges. My Lipos are all 4-6 cells so I balance charge em everytime.

dbsonic

My Feedback: (3)

+1 balance everytime. If you got the boards and the balance charger, why not.

speedracerntrixie

My Feedback: (29)

If you never balance charge the battery then it's difficult to tell if it has developed an issue or not.....that is until you are trying to find a way to extinguish the fire that used to be your airplane.

hoverlow44

i always check individual cell voltage under load. .5 A