grade b lipos from hk

[steveo]

I was wondering if anyone is using them and how there experiences have been?

I really would like to know how there voltage sag is compared to say to a regular 20c-30c turnigy lipo? Also curious to know there ir at 3.85v and fully charged..

The more info the better

Thanks
Steveo

 

[leffex]

Yes they work, about same c rate but i think there is some connection error in them, they should not be charged at over 1c but maybe 0.7c is max anyway, 4.5a charge with 5000mah killed it OR the wires are much easier to get lose than regular branded batteries. Ive bought a few 2s b hardcase lipos and one have shorted so it only reads from one cell. I got about 100 cycles from it. It has happened twice that my ride stops with a connection brake and i suspect the bgrade lipo.. I removed it and connection was working again for the rest of the batteries. When wires move a little connection gets lose or something. I don.t know exacly.

Good luck ... Better performance and safety with the hardcase 4s anyway.

 

[steveo]

Thanks for your input?

Have you ever measured there internal resistance?.. you can use a i charger.. or some other type of charger that will give you reading

thanks
steveo

Yes they work, about same c rate but i think there is some connection error in them, they should not be charged at over 1c but maybe 0.7c is max anyway, 4.5a charge with 5000mah killed it OR the wires are much easier to get lose than regular branded batteries. Ive bought a few 2s b hardcase lipos and one have shorted so it only reads from one cell. I got about 100 cycles from it. It has happened twice that my ride stops with a connection brake and i suspect the bgrade lipo.. I removed it and connection was working again for the rest of the batteries. When wires move a little connection gets lose or something. I don.t know exacly.

Good luck ... Better performance and safety with the hardcase 4s anyway.

 

[Punx0r]

Surely it will vary from batch to match. They are presumably batteries that don't meet the already-pretty-low HK lipo quality standards, ergo expecting any kind of consistancy is probably unrealistic.

Considering how sketch "grade A" HK lipo can be, I just wouldn't risk my money on them.

 

[dogman dan]

I wrote a pretty sarcastic comment saying about the same thing, then deleted it.

One use for them comes to mind. A long tour, where you need a lot more capacity on the cheap, and 10-50 cycles would get you through the tour. With a pack in the size of 30 ah or more, you could be discharging them at such a low c rate that high resistance might not matter.

This might work really good, if you were touring someplace you can't air ship your battery to. But you could ship a cheap new battery there.

 

[leffex]

They are grade b because of or more of the cells have higher resistance. I would assume it could be 10-20 or even more if you are unlucky or lucky maybe less.I have smart6 charger but as i tried, tested my batteryes b grades 2s and. Turnigy 4s they showed irregular resitnaces, sometime one cell was showing, sometimes all but they were not consistent and sometimes cell 3.4 and sometimes only 1 and 2. Do i have to have a load when testing them like a lamp 100w?

 

[Hillhater]

Try this..
http://endless-sphere.com/forums/viewtopic.php?f=14&t=48739

 

[leffex]

I abandoned two of my bgrade 2s hardcase lipos. Usually I dont go WOT (10C on batteries), but this time I had a WOT run for 7km and end voltage was 3.3 from normal 3.7, also I would estimate battery temperature to be 70-80C at the end , they were puffed almost double size. so I guess they are not so safe to use anymore. -- packed in fire protective bag and put into a barbeque for now.

I got about 300-400 cycles on those b-grades.