lipo questions...
 

Hey everyone, I have some questions about lipos…

I am thinking of getting one of these two lipos
http://home.comcast.net/~truerc/custompack.htm (the 5s pack at the very bottom)
and
http://www.tanicpacks.com/catalog/pr...roducts_id=588

which would give me more runtime, the 8000mah or the 5000mah because of its higher discharge rate.

Also, should I stick with 5s with the Quark 125, or try 6s? I know people were having trouble with 6s and I don’t want to make a very expensive mistake….

(BTW I can get the tanic 5s 5000mah for around 210 or so….)

What exactly would these lipos be going in (truck, motor)

And as long as your setup doesnt require more than 80 amps constant the 8000mah packs will give you the most time

The 8000mah packs will give you longer runtimes no matter what. Not many motors can pull 80 amps constant. Most are like 20 or 30 constant but the spikes go through the room (100+). The TrueRC packs are the way to go.

Seeing as how 6s seems to give some people trouble, I'd stick with 5s. Even if you go with 6s, the manual says it's rated for 6s and if it goes, you can warranty it. It would just suck to wait for the repair that's all.

By the way, how big are those Tanic packs? (the 5s)

I would go for 6S. Like Brian said, if it goes, it's under warranty. Besides, the problems were always with a 80 amp version I do believe.

thanks for the replys everyone, the motor is a 9xl and thr truck is a LSP. i am running 16 cells right now, i dont need any more power really, but more would be good, i am mainly looking for longer runtimes and to drop a few pounds....

*edit* brian, the info is at the top of this page http://www.tanicpacks.com/catalog/in...3a45f4f36ca870

c-gates

I'm running a 9xl and the Quark125 on the 8000mah Truerc cells right now. I have (2) 3s packs and (2) 2s packs. I have run it in both the 5s config and the 6s config and can tell you for sure that it runs much better on 5s. With 6s the Quark gets this very pronounced cogging that is much worse when you first start running, but seems to get less as it warms up. I run basically only in 5s anyway, the 6s just heats the motor up way to much. And besides that, the power is to uncontrolable on 6s and I just wound up breaking things in the drivetrain way to quickly.

BTW: I would go for the 3s and 2s pack configuration if you are running the g-maxx chassis. You won't be able to fit the 5s pack in the g-maxx. The 3s pack barely fits... Plus if you go with the 2 pack (3s + 2s) configuration you can get a second set and run in either 5s or 6s if you want. Not to mention you have better weight balance with the packs split.

Last thing... You don't need the 20-30C packs. The TrueRc 8000mah packs never even get warm. Buying the higher end pack will not gain you anything.


Edit: Forget the g-maxx issue I mentioned above. I just read that its a LSP (T?) But 2s+3s will still give you flexibility.

LSP is Lightning Stadium Pro. A truggy by Hot Bodies.

well i am going with the trueRC packs. i am going to get the single 5s 8000 pack or a single 6s 8000 pack. i run 16 cells now, would 5s compare to 16 cells? i would go with 6s but i am afraid that my controller would not handle it. should i risk it with 6s or stay safe with 5s:032: .......

IMO.... 5s

Its never a good idea to plan on running your equipment at its limit every time. The occasional 6s run would not be an issue, but to run it there every run, would just be asking for issues in my mind.

you are right. i really really want to know how 5s compares to 16 cells.

argg... i want 5.5s lipos :005: :005: ...........

IMO, it somewhat depends on what 5s Lipo and what 16 cell NiMH packs you are comparing. Some packs hold a higher voltage under load than others. Generally, lipos with higher capacities and C ratings will hold the voltage higher under load. Of course, the packaging gets bigger because you are paralleling cells to get that capacity. Each parallel cell is taking only part of the full load. However, popular opinion seems to hold that higher capacity NiMH cells don't quite have the deep deep discharge capability. This is probably due to the fact that the manufacturers are squeezing more capacity in the same physical size (or very close to it) sub-C cell. Something has to give when you do that, even counting technological advancements.

Ideally, a 5s pack is at 18.5v assuming a 3.7v nominal voltage per cell. 16 NiMH cells will be at 19.2v assuming a 1.2v nominal voltage. Lets say you draw 100A. If the Lipo packs is an 8Ah pack rated for 20c (160A), it will probably hold a higher voltage than a NiMH pack at that current since the NiMH will be closer to its max ratings. If that lipo pack drops to 3.5v/cell at 100A, the pack voltage will be 17.5v. If each NiMH cell drops to 1v/cell at 100A, the pack will only be at 16v.

yea..... what he said.....


Actually, I do think you are right on the money with that thought.