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View Full Version : 11.1v LiPo for the Half8



mpetrich
01-23-2006, 10:51 AM
Hello,
Anyone know where to get a 11.1v (3 cell) LiPo that will fit the Half8? The United RC pack by Apogee seems to have been discontinued.
Thanks for the help.
Matt

scottb
01-23-2006, 10:36 PM
...attached is a picture. You do have to do some cutting, and it is not for the faint of heart. But it does fit.

I would also recommend looking into the "motor rotate" modification - this allows you to run a stick battery (like a polyquest 2100).

pimpsmurf
01-23-2006, 10:55 PM
Hello,
Anyone know where to get a 11.1v (3 cell) LiPo that will fit the Half8? The United RC pack by Apogee seems to have been discontinued.
Thanks for the help.
Matt

Contact Troy @ www.b-p-p.com

He will tell you exactly what packs will fit with just about anything. Great dude. Really does his "research". ;)

-JNY

morati
01-23-2006, 11:12 PM
I agree with Troy at BPP....he has recently listed his new packs for the H8 consisting of ThunderPower 900 cells wired in parallel.....$60 for the 7.4volt version and $70 for the 11.1volt version.

mpetrich
01-24-2006, 01:44 AM
UGH!
Thanks you guys. I will get in touch with Troy!
I just ordered a Warp 2 from him and that's what I need the batteries for.
Matt

BiGRoB21
01-24-2006, 02:29 AM
i am running a thunder power 1320 3 cell pack and it fits nice with some mods.

bigron
01-24-2006, 05:04 AM
I'm running 2 Thunder Power 900mah 11.1v packs parallel. They fit great.

pimpsmurf
01-25-2006, 01:48 AM
What about for the Pitbull? I believe someone mentioned that 100mm long was cool. I just bought a TP2100 "Lite pack" or something like that.

I hope it will work... then again, I hope I get my chassis from CAW sometime soon.

-JNY

RURC
01-25-2006, 11:02 PM
I will soon have my 1600 20 "C" battery available. This will fit in the factory locations. It will be both 7.4 and 11.1 and for those insane 14.4. Right now I am waiting for my return quote on priceing so I will have to get back with that. Look for my new thread about Lipo saveing. :D

pimpsmurf
01-25-2006, 11:12 PM
Is it 2 800mah packs, or 1 1600? It will fit in the stock holders on the stock chassis? Kind of moot now I guess, but I hope this 2100 thunderpower pack will work with the Pitbull. =)

-JNY

RURC
01-25-2006, 11:25 PM
It is a saddle pack. It fits the factory locations. It is tight but it fits. Total maH is 1600 20"C".

RURC
01-25-2006, 11:27 PM
It is a saddle pack. Total maH is 1600 at 20 "C". It is a tight fit but it dose fit in the factory saddle holes. Except for the 14.4 it is too tall but a little velcro and walla.

dirtdynamics
01-26-2006, 06:46 AM
i moved my rx under one batt holders and the esc under the other.
that left me with space under the shell on the place where stock electronics used to be.
Its a tight fit but it'll hold till i do the mirror mod.
some pics..

RURC
01-26-2006, 05:37 PM
The problem with that is you have severly raised the CG of your car. Thus changeing the handeling dynamics of the car. I know this because I have been doing that for months. The car handles much better with the batteries in the proper place. That is why I was unwilling to build a Lipo pack and put my name on it till I found a proper pack. It is a poor fix (in my opinion) to a real problem. If you are useing a Mamba and a micro receiver (like I am) they do not even come close to off setting the weight of the battery packs.

dirtdynamics
01-27-2006, 02:12 PM
The problem with that is you have severly raised the CG of your car. Thus changeing the handeling dynamics of the car. I know this because I have been doing that for months. The car handles much better with the batteries in the proper place. That is why I was unwilling to build a Lipo pack and put my name on it till I found a proper pack. It is a poor fix (in my opinion) to a real problem. If you are useing a Mamba and a micro receiver (like I am) they do not even come close to off setting the weight of the battery packs.

Yes the CG is now way up there above the whole car.
But i was just thinking that its now is the middle so its balanced?
maybe thats just me and my 2 cents
I'll do the necessary mods once i get the chance and i'll compare the handling myself...

RURC
01-27-2006, 03:48 PM
When you say middle are you refeering to front to back or left to right? If you put the batteries in the factory locations you have a great left to right balance and with the weight to the outside you have decreased the roll over possabilities.

Hawk
01-27-2006, 05:33 PM
Ah, the old roll center v center of gravity discussion. Is it better to place the most mass near the center of rotation of the chassis so it has less affect or have it lower to have less affect?

Kyosho in the 1/8 category seems to be of the mass in the ctr of the roll axis at the slight cost of CG impact.

Instead of a laydown steering servo they went with a standup servo so that it is nearer to the the drive shafts and center line instead of lower the center of gravity.

This is a trade off, too much one way or the other produces bad results. I look at it like a tube around the longitudinal roll axis. The bigger the tube (more mass further from the axis) the less precise the handling. You need to make the springs harder to handle the increased centrifigal force seen in turning. Keep it all in and low. Less roll bar, less spring, less dampening in shocks. More reactive to steer inputs, less force reacting on tires to force slip.

joseph
01-27-2006, 06:02 PM
Hey Guys im new to this lipo batteries things dont understand which lipos to use in my half 8 want to use it for racing thanks. :cool:

RURC
01-27-2006, 07:30 PM
Hawk,

You are right to a point. Rotating mass positively needs to be in the cneter. But dead mass works and detracts in both ways. There comes a point of diminishing returns if the mass is too great. The batteries that I have weigh 98 grams for the 7.4 and 148 for the 11.1. In contrast to the NiMH or NiCd that are almost twice that. If you are going to have dead mass I want the smaller. My receiver is 4 grams and my speed control is 24.5 grams (this includes wireing). So in comparison my rec and speed cont are severly out done. So in raising the mass up from the front to rear cg as original makes for a more top heavy car. Or at least closer to the top. If I split the weight and move it (the batteries) to an equal distance from the torsional split of the car I have induced 2 things. First I have lowered the cg (top to bottom). Second you have spread out the load (remember I am talking less than 150 grams) so in the event of a side induced force you have some mass that can counter the impact that all mass in the center line will have no effect on. I watch and have been known to record the effects to see the point of diminishing returns. Unfortunately these cars are so small I cant make it work. With Poseche we had yaw and position sensors and gyros and we took the weight out (from center line) to the point where we started to see dimminishing returns. We then backed off to a positive point. Givien what I have done and seen I would rather lower the cg and spread out the weight a little over raise the cg. Now in planes you have a whole other ball of wax, but we dont need to go there. :D

RURC
01-27-2006, 07:51 PM
Hey Guys im new to this lipo batteries things dont understand which lipos to use in my half 8 want to use it for racing thanks. :cool:


Do you want 7.4 11.1 or are you sick and want 14.4 volts. Of course I say get mine (I am 2 weeks from delivering out). But, the ones from United are very good and if you can get Thunder Power or Kokam all of these are very good and a little cheaper than mine. However none of these are 20 "C" rated. Mine will sustain 32 amps continously with bursts at 50 amps. None of the others will. Thus why mine cost more. Mine do not come with balance plugs, WHY you ask. Because balanceing is a gimmick. It was invented and perpatrated to the consumer as nessary. This is false. I have spent the last 3 months learning about this and this is not only my conclusion it is also the conclusion of industry insiders that only put on the systems because the public had been duped. I am wrighting a extensive memo on this that when I have the time to finish will be dumped onto the forums. I have also displaced the LIE that overdischarged LiPo's are trash. I have developed a system that has a 80% sucess rate for saveing LiPo's. This is also going to become available to the public after a little more beta testing. Sorry did I go into a rant. Once I start I cant stop. Get a good charger. I am partal to the Hyperion but there are many others that are just as good. Just because thaty say that they can charge LiPo dose not mean that they can fully charge them fully. I just went through this and I learned a lesson. Make sure that your battery can handle at least 25 amps. This car pulls that a lot (and much more for moments). Look at the "C" rateing of the pack. My Packs are 1600 maH with 20 "C" draw. The math on this is 1600 x .020 = 32. This is the continous rateing for my packs. Others only give you the peak draw (not the ones I mentioned they give both peak and continous). Use the above formula to figure if the pack will work for you.