Zippy Compact 35C cells overrated!

[mvly]

For comparison, I have the nanotech 25C 10s5Ah. IT has around 200 cycles before 2 packs started to die. The rest was ok but sagged a lot more than when new. Replaced the 2 bad packs and everything was good again. The new pack is keeping the old one from sagging too much. Now I am around 300 cycles now on it. I do baby them though, no more than 5C ever and always try to keep them at storage voltage. These are around 2-3 years old now. The newer supporting packs are 1-1.5 years old. They have less than 80% full capacity now for sure. I tested it last time and it was around 90% when it was around 150-200 cycles. However because i only discharge to 3.6V and charge to 4.15V, I get effectively 60% capacity from the pack. This is OK for me because these were relegated to a sparingly used electric scooter. I have since moved to the Nissan Leaf battery which is much safer and better. Close to 200 cycles and I still get pretty much the full capacity if I use it a 1C or less. A bit more saggy now, but not so much. And I got them used in the beginning so they are pretty decent.

I would recommend nissan Leaf pack if you can get it and if it will fit on/in the your bike. Cheaper in terms of $/Wh. And pretty much everything better than the Lipo HK can supply.

 

[Ragonamuffin]

I am about to order a decently large batch of lipo from hobby king. I literally tried to purchase a batch of Zippy batteries only to have HK's payment system fail on me preventing me from checking out. Now seeing this thread it seems that was some divine intervention! Thanks for posting your issues as it saved me much trouble. (my vehicle has individual pack holders to keep the batteries safe (hopefully) The idea of thermal runaway destroying my project or worse my home gives me nightmares!

I have already designed my vehicle around cheap hobby grade lipos due to the high discharge requirement I have. According to this thread it seems Turnigy is the way to go for many reasons. Is this a valid conclusion?

On another note I know very well that lifepo4 is a much better chemistry in the long run. How many cycles approximately would I get out of a Turnigy lipo using it to its C rating and close to a full discharge?

I have built my own lifepo4 packs but I have zero experience with lipo.

Thanks in advance lipo masters! I hope I'm not hijacking the thread.

 

[izeman]

answering your questions can be a vague guess only.
a) you want to buy cheap hobby rc lico
b) use it to it's claimed c rate
c) use all of it's power down until they're dry
that's the worst thing to do if you want to live them long. c-rates are known to be highly exagerated. so if they say 20c i would not to more then 5c (i do 2-3c on my build). don't discharge then below 3.65v or balancing will take ages.
if you don't charge above 4.1v it will prolonge live a lot as well.
how many cylces they can stand in your special case? no one can really tell, because it depends on the point where you say that they are dead for YOU. is it 80% claimed amp hours? is it massive voltages sag? is it swelling of a single cell?
but to give numbers: 100-200 cycle should be doable quite easily.

 

[MAGICPIE3FOCUSPOWER]

Thanks for info all!
I had almost bought these cells :lol:

 

[Ragonamuffin]

Thanks for the reply izeman! So it seems lipos really don't last very long, and C ratings are wildly overrated! I was planning on pulling 12c from a 20c pack. I am glad I consulted the forums before making a purchase. What would you recommend for a 12c discharge? The best discharge rating I can find in a lipo (something like the turnigy nanotech 40c 80c peak)?

 

[TotalConfusion]

Has anyone tried the Polyquest batterys at all, Ive been following this thread for some time now as im looking at getting some Lipo Myself as a spare and i came across these http://hobbyking.com.au/hobbyking/store/__12459__Polyquest_5000mAh_5S_25C_45C_Lipoly.html

They are currently out of stock but for $21 each AU it would only cost me $200 for 10 bricks. I also notice that there other smaller capacity battery in the same model is like $158 ???

Has anyone had any real world experiences with these batterys at all?

 

[miuan]

To avoid confusion, I repeat that all of my Zippy Compact cells have been reliable and kept perfect balance and zero puffing when used at 2-5C. No DOA cells either. They are not high power cells, but quality is reasonable.

 

[izeman]

i didn't say lipo is generally over rated. but imho zippy and similar cheap stuff is a best guess. there are high quality nano tech cells that can stand the claimed c rated w/o problems. but if you look for the best wh/$ rate zippy is the way to go. just use double the cells you want and you get twice the range and half the stress for the cells.

 

[MAGICPIE3FOCUSPOWER]

Yup I agree with you!

I was into RC 1:8 electric cars, Had some cheap HK lipo's well after some runs lipo temparature was very high and pack was growing So I switched to Kokam and Hyperion lipo's and no more issue's, only the price ......

 

[izeman]

not to forget that those 6s packs are mainly made for helicopter or 1:8 rc cars. one battery to take care of. and you take them out of the toy (feel if it is warm/hot) and can inspect it for any problems. then they are charged with a dedicated balance charger that give you a good feeling about the health of the battery.

 

[izeman]

not to forget that those 6s packs are mainly made for helicopter or 1:8 rc cars. one battery to take care of. and you take them out of the toy (feel if it is warm/hot) and can inspect it for any problems. then they are charged with a dedicated balance charger that give you a good feeling about the health of the battery.