Lipo taking a looooong time to charge / balance
 

One of my 2s pack has started taking a much longer amount of time to charge and balance than my other packs. It is taking about an hour to put 2500mah or so back in the pack. It normally took about 35 minutes.(the pack has 30 cycles on it and started taking this long to charge after about 20) My other packs also charge in 30-35 minutes. It is balanced and runs fine with no puffing or anything of that nature. It has never been overheated, and never run down anywhere near lvc. Most of the time I still have about 3.7-3.8 volts per cell left it it when I go to charge. Thoughts?

Get a better charger

Stop the charger when the cells get to 95%

Cheers

Getting a better charger would help. But he may have a great charger. He did not say. If one of your cells happens to get out of wack, the balance will take that much longer. It is what it is. Every lipo is different.

I'ld say you've got a cell on the way to lipo heaven.

One of my 4s has this problem, the others charge perfect in about 1 hour but the fourth cell in this one won't go over 4.16v, the other cells read 4.19v - 4.20v. I have a B6 duo 10amp charger, its the same as the protech duo & a 30amp power supply
http://www.amainhobbies.com/product_...S-10A-200W-x-2

I over herd someone at the track say that you can bring a lipo back to life from 5 - 10 minutes on nickel charge, is this true ?

That's only done to bring the voltage up on a pack that's been run too low.

Yep, a 4.16V lipo cell + nickel charge for 5-10 minutes = another stupid youtube video. (While possibly slightly amusing, it also releases toxic and corrosive smoke)

I dischared for an hour & then hit it with some nickel charge at 10amps for 5 minutes & then charged it on lipo balance with good results. I think it just needed a kick in the ass.

There's a reason it is lower in voltage than the others, could be higher resistance in that one cell. It happens and may not even be a problem with non-balance charging but it is telling you "Hey, something isn't right with me and I may not be living for long."

Bottom line is that you should use a cell equalizer (basically a discharger for multi cell lipos that matches the voltage across the cells) and bring all the cells down to the same voltage BEFORE putting on a charger. Then charge as normal and see if it keeps up with its brothers.

That's funny. I'm having the same problem with my venom 2s 5000mah... cell 1 is at 4.2v and cell 2 wont go past 4.0v. Battery only has two cycles on it. I plan on taking it back to the LHS to see if I can exchange it. It seriously tries to charge and balance it for 2+ hours. :flaming:

Guys,
Make sure you are cycling your packs 8-10 times to allow them to fully break in and settle before you start to worry.

Run your pack for about 50% of the charge, and re-charge normally, no balance. Then, after the pack has settled in/broken in, then balance charge it.

I recommend balancing only ever 12 or so cycles. I've seen packs get damaged from balancing every time.

--Paul Susbauer
Product Manager
Venom Group International

No disrespect at all but how can you prove that?

I've never had any lipo have to "break in" to balance charge or balance out correctly. Other aspects might improve but not balancing.

I'm a noob when it comes to lipos, and just recently i had a 2 s 5000mah suddenly take almost double the normal time to balance. Actually i shut it off after 2 hours, normally takes about an hour. Anyway a week later i was going through charging lipos for a trip to the track and this same lipo wouldnt charge at all due to low voltage. I checked the cells and one was at 4.19v and the other was only .86v. I tried the nimh charging trick, then charged that cell alone (took pack apart) and it took a while but eventually hit 4.2v. Voltage on the other cell remains 4.19v, but the bad cell wont hold a charge, and I assume that is why the balance takes so long.

Why is balance charging not a good idea for every charge?

8 - 10 cycles sounds like a load of waffle

Decent pack with cells accurately matched for IR and capacity should be good to go from brand new

Why would you not balance every charge unless you are in a hurry ?

Learn how to charge a cell individually and start them at the same voltage

Get a better charger with a higher bleed current

If that doesnt help get rid of the pack

Cheers

I totally agree and see your point about the load of waffles...... LOL but pray tell what is a "higher bleed current"?
Thanks,
--Shag