HobbyCity Lipo Warranty - Important Information!

[Bondonutz]

Dude, sorry to hear of your Lipo misfortune. I hope you get it sorted out.
Do you have a seperate balancer like a "Blinky" or something ?
Try cycling it again but when charging use a much lower amp level going back in ?
I doubt very seriously they can tell weither you cycled your pack if you send it back, just drop the voltage back down to what it came with 3.85 per cell prior to returning.

[pinkpanda3310]

Originally Posted by Bondonutz

Dude, sorry to hear of your Lipo misfortune. I hope you get it sorted out.
Do you have a seperate balancer like a "Blinky" or something ?
Try cycling it again but when charging use a much lower amp level going back in ?
I doubt very seriously they can tell weither you cycled your pack if you send it back, just drop the voltage back down to what it came with 3.85 per cell prior to returning.

They only reject cycled packs that are claiming under voltage as I read it. And I do agree, how would they know if it's been cycled?

[simplechamp]

Originally Posted by whitrzac

you do relize that even IF they warrenty it, you have to pay shipping to them, and the shipping back...

Originally Posted by simplechamp

So now I can either send them my pack and have them tell me it's not covered and make me pay shipping both ways

Yes I do understand that, I've been saying from the start I didn't think they'd warranty it

You guys do make a lot of good points. Like I said before the main thing that gets you is you have to agree to all the terms and warranty requirements by default. I could argue all day with them but in the end I agreed to the terms.

EDIT: I wanted to mention that by my own stupidity I told them (in the RMA form) that I had cycled the battery. I didn't look at the lipo warranty info until after sending the form, again my own fault. But it's like how else was I supposed to prove the pack had a bad cell? It's that catch 22 situation again. Gotta charge to prove the need for a return, but charging voids any chance to return. If I told them I didn't cycle the pack they would ask how do I know there is a bad cell.

Oh well, I'm going to do a few cycles later tonight on lower current and see if I can get the one cell to balance up. I can set my iCharger to the most accurate balancing along with enabling trickle balancing, so it will take a long time but hopefully will give some improvements. I would be happy if it even got within 30mA of the other cells.

[hoober]

It looks like the only chance for a warranty is to check and have a cell under 3 v on the day of delivery. Hobbycity might be overwhelmed with "bad" batteries that are returned that are simply out of balance. This is what appears is wrong with your pack. No amount of cycling will bring it into balance, even a "balancing charge" may not do it.

I don't consider myself to have OCD about cell balance, but when I do balance packs they are within 0-5mv tested over a few hrs. Your pack should just be balanced first, and then test it out to see if anythig is wrong with it. It might just be a mismatched pack or have one cell with a higher self-discharge rate than it's siblings.

[simplechamp]

I don't have a separate charger and balancer, so when I say "cycling" the pack, it is being balance charged (on the most accurate mode with trickle balancing at the end), then it discharges down to about 3.4V per cell, then the cycle repeats.

I did this 3 times yesterday and actually got the cell to balance. I still think the one cell is always going to drain lower, but I have yet to test the pack. Any of my other packs balance up perfectly with one balance charge, while this pack took 4 cycles on the slowest, most accurate balancing mode. The weird thing is that both the suspected bad cell and good cell have the same internal resistance (2 milliohms when fully charged).

[Bondonutz]

Glad the pack came around for you Jason,hope it holds ?

I had a cell that was pretty low compared the rest on my recent order, I have a seperate balancer and it took 4 hrs for it to level out and it ran fine today. Need to charge it now and see where their all at ?

My friends and I are having problems with the balance plugs being crap on the Turnigy and Flightmax 4s packs. I had to replace 5 so far this last few weeks for friends and 1 of my own. Anyone else having this problem ?

[BrianG]

I've had one cell on a 5s pack be lower than the rest as well. I just put the leads of 1M ohm resistor (or any really high value) in the balance tap of the suspect cell and clip my charger leads directly to each resistor lead. Then, I set my charger for 1s and charge at 0.5A. Every 100mAh or so, I stop the charge, let sit for a minute or two, and check the balance. If I have a high cell, I do the same, but discharge instead. This is faster than the measly 100mA balance rate of my balancers, but you have to be very careful not to touch the leads together at any time.

As far as connector quality, I haven't had an issue yet. However, I always make myself some balance connector caps so that dirt/debris doesn't foul up the connector when running.

[simplechamp]

It'll will be interesting to see how the cell behaves after being discharged. I hope it stays in balance, but I have a feeling it will have the tendency to drain lower than the other cells. Only time will tell.

[Bondonutz]

Our balance tab problems have ben w/brand new unused packs.

[KaztheMinotaur]

I just looked up the Hobby City battery warranty myself.

I was charging my Zippy 5S, 5000mah, 30C batteries for the first time. I had 2 cells come up to 4.13 and the others were full, balance charges. I have it on the blinky now and then I will charge it at a lower amp rate.

Is that to much of a difference?

[simplechamp]

Originally Posted by KaztheMinotaur

I just looked up the Hobby City battery warranty myself.

I was charging my Zippy 5S, 5000mah, 30C batteries for the first time. I had 2 cells come up to 4.13 and the others were full, balance charges. I have it on the blinky now and then I will charge it at a lower amp rate.

Is that to much of a difference?

Personally I think anything more than 10mV difference is too much out of balance. So that would be having most cells at 4.20V and one or more other cells at 4.19V. Even a cell at 4.19V bugs me, and I want all my cells balanced to within 5mV or less.

Of course HC says it's acceptable for cells to be up to 245mV out of balance, which is ridiculous IMO. It would be nice if we could get some official recommendations from lipo manufacturers on what is acceptable as far as cell balancing.

I got the 4.09V cell to go back into balance by putting my charger into the slowest most accurate balance mode. BrianG also suggest just charging the individual cell as a 1s pack using the main charger leads directly into the balance taps of the low cell using some high-value resistors (see his post for more details). Hopefully you'll be able to get your cells back in balance too!

[KaztheMinotaur]

So the balance will be more accurate when balance charging at .5A instead of 5A?

After being on the blinky for a while (4) cells are 4.07 and the 5th. is 4.08. I'll balance charge it tomorrow.

[BrianG]

Originally Posted by KaztheMinotaur

So the balance will be more accurate when balance charging at .5A instead of 5A?

After being on the blinky for a while (4) cells are 4.07 and the 5th. is 4.08. I'll balance charge it tomorrow.

Not sure about "more accurate", but it will balance easier. If you are charging a 5Ah pack at 1C, that's 5A. Most balancers bleed off excess charge at a rate of 100mA-300mA. Normally this is fine for packs that are slightly imabalance. But a highly imbalanced pack may reach 4.2v/cell before the balancer has a chance to do its job.

Look at it another way: You are charging a 4s pack at 5A with a balancer capable of 100mA discharge rate. Let's say one cell is high, which means the balancer will bleed 100mA off the cell as it is getting the 5A charge, which results in a net charge level of 4.9A (5A-0.1A). Depending on how bad the imbalance is, that high cell could exceed 4.2v before the others catch up.

[KaztheMinotaur]

Yeah.

[lincpimp]

Ok, since you guys are on the lipo topic... heres some "good" info from someone with a "little" lipo experience...

First off, so not expect to have alot of lipo sucess if you are using a stand alone, non charger thru balance (aka blinky). 1st off you have no over charge saftey in place for the individual cells with this balancer, only for the whole pack. So if you have a single cell failure the charger can continue to overcharge the other cells... Puff puff pop. AHHHHHH my house is on fire!!! My beautiful elvis plate collection is gone, why God, why!!!

A charge thru balancer (such as the hyperion lba10) is much safer, as it will interrupt the charge if any 1 cell goes over or under voltage. Still not the best option, but can be had cheap used as it is "old tech", and will work with some of the older lipo chargers. Also, some of the older lipo chargers (astro 109 stands out to me) are a bit weird in how they accomplish the cc/cv charge. A newer charger with all of the bells and whistles is a good investment, IMO. Especially the models that can be updated.

Now an internal balancer charger (suchas the hyperion 6 and 7 series) are the best, as the charge rate will be automatically adjusted if the cells are going well out of balance. I have personally noted this when building mixed cell packs for myself, and then charging them up, if the cells are well out of balance the charger will do .3 amp, regardless of what setting is selected. Plus you get all kinds of nifty info about the cells, and pack, etc.

Also with zippy lipos, you get what you pay for... They are cheap for a reason, so either toss the offending pack, or live with it. I could see complaining if you bought a thunderpower pack, but HC is not making much on these packs, and I can see why their warranty info reads that way.

Heres a little cheap charger that is actually 4 seperate chargers in one box. This charger is good for 2amps max, and charges thru the balance tap. So it will charge the cells individually till they are all full, and thus, balanced. I paid 26 bucks plus shipping and this is a great charger if you have a well out of balance pack, or are putting some cells together that are in various levels of charge.

http://www.hobbycity.com/hobbycity/s...Charge_Capable

Not trying to be a dick, but that is how it is... I have fooled with almost everything out there, and this little charger beats out any stand alone balancer option for up to 4s. You can even run 2 different capacity mah 2s packs on this charger at the same time. Or a 3s and 1s, or 4 1s cells if you like (would have to make a custom adapter to do that).