What is working good in the ol' cub?

[duck9191]

you can use the balance function on your charger, which would bring the two high cells down to 3.85 then try to recharge it, might work better that way. if it still is reading low i would say the cell is bad. also run the plane on the ground for a few min then recheck the cell voltage to make sure it is still balanced.

you would want to fly to 3.7v per cell, which would equal a pack voltage of 11.1 resting volts.

[flydiver]

Left column is volts/cell, middle column is approx capacity at that voltage, right column is merely column 1 x 3 so I don't have to do the math in my head. If it was a 2S battery it would be 2x column 1.

Are you charging AND balancing? I think those are separate functions on the Turnigy (no personal experience).

That discrepancy is something I would be concerned about. Something like 4.14/4.12/4.11 I'd be fine with but 3.85 is not good. That would throw my Cellpro into [safety charge] mode.

LVC on the stock electronics is 8.8-8.9v....period. Do the math and you will find that less than 3v/cell. I would NOT recommend flying to LVC if you want your lipo to last a long time.

OTOH, if that's the way that cell balances it's not likely to live long anyway. A decently made cell will get closer than that without balancing. I've got a cheap s**t ABF 2200 and a PZ 1800 that have a lousy/lazy cell. The PZ finally got so bad I couldn't fly it. Guess I'll see how long the ABF lasts. They were appearing for awhile as 'Mystery' cells, but then there were a number of 'flavors' of those.

One of the inherent dangers of dealing with HC is bad merchandise. It's too expensive and too much hassle to deal with warranty work generally and I've read that they are not terribly responsive. Why should they be when the stuff is so cheap they can barely keep it in stock.

[gagallagher04401]

I did use the balence function on the Turnigy charger, I let it set for a bit "balence charger but did not seem to change.

Iplug in the 4 pin connector o the charger for balencing, and the battery lead to the charger output leads.

Well I am pissed if this battery is no good. it is brand new! 16.00!!!

How about dischaging the battery, then recharging?

Will leaving it charging on to fill that cell when the other two say they are full, will that hurt?

[gagallagher04401]

Well I guess I am goign to just return that battery to hobbycity, and get another one, that way there is no worries. The other battery seemed to be fine.

Any place in the USA to get Lipo's at a good price? This overseas BS if for the birds.

Thanks
George

[ginginho]

Apr 8, 2009 11:50:40 GMT 1 gagallagher04401 said:

Will leaving it charging on to fill that cell when the other two say they are full, will that hurt?

Very possibility, depending on your charger and what the charge cut off is based on. If it's the highest then as the other two hit 4.2v it'll stop (hopefully!) but if it's based on the lowest and doesn't stop sending charge to the others, you are likely to have an indoor firework display. Did running that pack for a couple of minutes in the SC change the charge being shown on that cell?

[ginginho]

Apr 8, 2009 3:39:52 GMT 1 flydiver said:

OTOH, if that's the way that cell balances it's not likely to live long anyway. A decently made cell will get closer than that without balancing. I've got a cheap s**t ABF 2200 and a PZ 1800 that have a lousy/lazy cell. The PZ finally got so bad I couldn't fly it. Guess I'll see how long the ABF lasts. They were appearing for awhile as 'Mystery' cells, but then there were a number of 'flavors' of those.

One of the inherent dangers of dealing with HC is bad merchandise. It's too expensive and too much hassle to deal with warranty work generally and I've read that they are not terribly responsive. Why should they be when the stuff is so cheap they can barely keep it in stock.

I have read that there are different qualities of "Mystery" batteries from Hong Kong (ebay), some good, some very poor. The reason being that "Mystery" source their cells from multiple factories and there are obviously some who's production and QC are better than others.

[gagallagher04401]

ginginho

I have not had a chance to use it in the cub yet, I planned on trying them flyign tonight, wheatehr permitting, shoud I try flying with the battery for 5 min or so? Then check it?

I would rather not go through the hassel of sending it back and waiting if at all possable.

Thanks
George

[flydiver]

Fly it for 5" and check it. Try recharging. See it it sorts itself out.

Check what it costs to ship it back. You'll probably find it not worth the hassle. If it's not, just mark it, fly it, watch for problems and chalk it up to experience. You will have some like this. Be glad it's not the charger that's hosed.

The reason HC gets the biz is there is just about no where that can match their price for comparable lipos, motors, ESC, etc. It's easy to find them for 2-5x the cost. Use eBay at your own risk. The are occasional deals but a lot of lipos that have been dumped due to problems.

These guys have a good reputation:
fusion-pack.com/

And these guys have very similar cells for a bit more but state side:
www.valuehobby.com/index.php

[patmatgal]

Good advice in posts 56 & 67, hope things work out for the good. At least you saved enough on the other 2 batteries to almost pay for the 3rd , if its a lost cause. Even better would be if after several 50% discharges and balance charges the 3rd battery gets all cells balancing close to each other.

[gagallagher04401]

I will try it hopefully it sorts it self. I'll let you guys know.
(by the way I only got 2 batteries, so I am bummed one is not balancing)

[gagallagher04401]

Ok well I tryed my plane tonight after work. First off WOW, so much more power, and speed, really enjoyable!

I used the rhino battery I got that woudl not balance. I flew with it, I endedup hitting the LVC I think " plane motor just stopped. I brought her in and checked the battery still not balanced.

I also want to note I was i the air for maybe 5 min brouhgt it down checked the battery, no difference, thouhgt I woudl try it again, thinking maybe I did not use it long enough, went back up in the air for maybe 30 secs, and the LVC (I think) kicked in and the motor stopped, and the plane fell, luckly I landed it. Checked the battery again still not balanced.

Thoughts?

Send it back? about 12.00 to send back to hong kong. 6-10 days. Will they send me a new one with the EMS shipping I originally used to et the inital package from them?

Thanks
George

[patmatgal]

Spending $12 more on a $20 battery, a week to get there, a week to be examined and 2 weeks to get back (not EMS and probably on a slow freighter) not worth it IMO. Try flying it for 5 minutes (or howevr long it takes to use no more than half the mah), charging it like a normally discharged battery and repeating the whole process half a dozen times. At the end of all that the cells should be more closely balanced. If not just fly using the battery like normal until it gives up the ghost or you get fed up with it.

[flydiver]

Flying will not balance it. If anything if there is an inherent cell imbalance use will make it worse.
Charge it, see if it will balance decently. Funky cells my charge and balance and then become imbalanced with use again. When they go bad the weak cell deteriorates voltage so quickly the overall performance of the pack is compromised.

If you did pull the lipo jumper, and only flew 5" on a 1550 lipo that is not decent performance. It would indicated to me the voltage sagged. You should easily get 10", likely longer out of it.

You didn't do it any favors by flying it again - that's over discharge, a path to early lipo demise since the LVC on the cub is too low anyway. OTOH, it's likely not a good lipo and doesn't matter.

You need some tools to measure voltage, minimum, and better if you got a wattmeter to really know what you are doing. It's a pretty critical tool once you leave the RTF world.

$12 on a $16 battery. Your call.

Did you try the other lipo? When one is bad I'd sorta suspect the other. They maybe came out of the same 'batch'.

[gagallagher04401]

The other battery balanced 4.2V perfect. I did not fly with it though.

I did also pull the lipo jumper.

I got home and charged the bad battery to see if any difference.
I am getting right around
4.2, 3.90, 4.2 per cell How far should the cells be off and still be ok?

So I know I do not want to fly to, or below LVC, is it guess work to find out what you can fly on a battery with out discharging it to much? Fly some, stop, check, fly some, stop, check.. etc... what a pain in the rump!

[flydiver]

Apr 9, 2009 1:56:22 GMT 1 gagallagher04401 said:

4.2, 3.90, 4.2 per cell How far should the cells be off and still be ok?

So I know I do not want to fly to, or below LVC, is it guess work to find out what you can fly on a battery with out discharging it to much? Fly some, stop, check, fly some, stop, check.. etc... what a pain in the rump!

Balancing is only part of the story. Well chosen and well made packs are pretty self-balancing. This kind of cell matching does not happen in high production cheap manufacturing. Those bad packs I owned would balance. They just wouldn't perform. It sounds like yours doesn't perform nor balance. I suspect one cell has a pinhole in it from manufacturing. It's likely on it's way to dying soon. It's unfortunate but nasty warranty problems is a risk inherent in dealing with HC. The trade off is the cheap price.

Yes, with an ESC that is not adjustable to safe LVC limits (most ESC) then you need to learn to fly by time. Some TX have timers, some folks get timers (cellphone?), some (me) just guestimate.
The only thing I fly to LVC is my A123 since they are so tough.

If that's too obnoxious just fly to LVC and replace lipos every so often. Some guys just do that deliberately. Others wonder why their lipos don't last.

As you get better and used to the new level of power after awhile you can tell when the battery is getting puny and stop.

Some better ESC (Castle) have LVC you can set where you want. Some of the Turnigy are pretty good and are resold under a lot of names. Some are really crappy. Real ALL the instructions before buying.

Wait until you get to the part where you want ailerons and 4 servos or even 5 and there's a new bridge to cross in complexity.