4s 8000 lipo what brand?

[superek4]

Hi, I need 4s 8000 lipo but not blow my wallet, I know truerc has 4s 8000 but 10c only dun think it's enough for 1/8 CRT.

Maxamps is too expensive so any advise?thx

[lincpimp]

Any reason that you "need" 8000mah.... You could buy 2 4000 zippies and run them in parallel for 8000. What is this going it, cause that much lipo will be heavy and dimensionally big.

[superek4]

i m running a 30min main, i was using 6s 5000 zippy most prob cant finish the race, if i swap batt i will lose out( not a very good driver) i noticed maxamps has 4s 8000 at 700g same as my 6s 5000 with that i dun hv to swap batt.

maxamps 4s 8000 is us399, 4s 6500 us279 its alot

i cant run parallel as theres no space, any advise?

4s 8000mah batteries are not going to provide much more runtime then the 6s 5000mah.
(assume 3.7V per cell "nominal" voltage then 4x3.7Vx8A-h= 118.4Watt-hr
and 6x3.7Vx5A-h=111Watt-hr, only a 6.7% increase in storage)
They end up weight about the same because the store about the same amount of power...

what size battery area do you have to work with? could you put the pack(s) on their side to increase size? (aka do you have the height available). Any pics of your setup?

If you can fit it Mike has a 6s 6000mah battery for $309, my rough estimate is it should give you 30% more runtime (due to more stored capacity). It is pretty sizable though.... 168 x 48.5 x 66.5 mm

here is the link http://www.rc-monster.com/proddetail...pq25c6s6000mah

BTW if any of the battery Gurus disagree with my math/reasoning, please correct it. Thanks

i ran the 4s2p 8000 true rc pack, hate to tell you but its the same cells as the maxamps pack, it has excellent punch, but only runs for about 24 mins, thats with a 1y, so you might get another min or so with your 2000, but it wont cut it

[Finnster]

Mike has a 7800mah 30C or 35C batts in his store. Way better and cheaper than maxcraps.

But the above is true, its not going to give you much mroe runtime (assuming you are not hitting the LVC early due to zippy's poorly matched cells)

Plus, if you are using that 1600 kv motor, 4S is a bit slow for it, esp if you are using 6S now. 5S really seems to be the sweet spot IMO. A 5S 7800 batt would get you there, but its quite heavy. Perhaps think about two small batts and a batt swap? What are the rules you are running against? Do you have to "courtesy pit" if you are running against nitros? Maybe the race director will excuse those if you do a batt swap.

[q8-maxx]

spc has 2s 20C 8000mah for $72-75 :)

[superek4]

I m not sure how but I was told 6s 5000 won't run longer than 4s 8000 becoz of the amount of Mah, per cell does not increase run time but speed coz more cells. Correct me if I m wrong.

I can only take up to 750g which is one sided. 6s 6000 is 900g way too heavy. I can't parallel coz my setup is 1 sided batt n they are 150mm long.

I m racing against nitro already no pit stop is a advantage, but with a batt swap abt 40sec I lose 1 lap already.

I will post my setup pics later now using my crappy iPhone. I m chosing between truerc 4s 8000 n maxamps 4s 8000( but wallet empty)

If there's any other batt abt truerc price or abit more I dun mind thx guys

[nitrostarter]

I'd buy TrueRC before Maxamps...

But why not try these in series?
http://www.rc-monster.com/proddetail...00sp302s3p7800

760g for 2 in series.

dont buy the maxamps, the true rc will hold up just fine as maxamps rates the pack at 160 continuous ans true rc is 80, but really the pack is good for about 120 continuos, you just wont make 30 mins with it, it is about the same runtime as your 6s 5000, it has about the same total energy stored.

Originally Posted by nitrostarter

I'd buy TrueRC before Maxamps...

But why not try these in series?
http://www.rc-monster.com/proddetail...00sp302s3p7800

760g for 2 in series.

I have a pair of those coming in the mail for my buggy, hope they are as good as eveyone says (since Mike is selling them I am sure they are).
But it still does not solve the additional runtime issue.

[BrianG]

A truggy requires around 250w average power (typical from most people's runtime vs battery capacity figures). At 250w and 4s, that equates to ~17A average current. With 5Ah cells, that should give you around 17 minutes of runtime. With 8Ah cells, you should get around 28 minutes of runtime - still a bit short of 30 minutes.

But don't forget that with added capacity comes added weight, which adds to the load and will reduce the runtime. Track conditions (high grip vs low grip), drivestyle (lots of heavy throttle starts vs smooth throttle finger), ESC settings, etc all play a role too. Set the punch control high to allow the ESC to more gradually apply power (helps limit burst current and increase runtime).

But, for a solid 30 minutes, 6s paired with the proper motor and gearing is the key IMO. For the same 250w figure, 6s requires only ~11 average current. You still would need a little over 6Ah to get 30-35 minutes.

[superek4]

Hi Brian,

So if I m not wrong u r saying 6s 5000 will last longer than 4s 5000?

I m running a x2 CRT with 50slip diff n 12pinion, medusa 2000kv motor n watever batt that will last 30mins or more

Originally Posted by BrianG

A truggy requires around 250w average power (typical from most people's runtime vs battery capacity figures). At 250w and 4s, that equates to ~17A average current. With 5Ah cells, that should give you around 17 minutes of runtime. With 8Ah cells, you should get around 28 minutes of runtime - still a bit short of 30 minutes.

But don't forget that with added capacity comes added weight, which adds to the load and will reduce the runtime. Track conditions (high grip vs low grip), drivestyle (lots of heavy throttle starts vs smooth throttle finger), ESC settings, etc all play a role too. Set the punch control high to allow the ESC to more gradually apply power (helps limit burst current and increase runtime).

But, for a solid 30 minutes, 6s paired with the proper motor and gearing is the key IMO. For the same 250w figure, 6s requires only ~11 average current. You still would need a little over 6Ah to get 30-35 minutes.

[lincpimp]

Originally Posted by superek4

Hi Brian,

So if I m not wrong u r saying 6s 5000 will last longer than 4s 5000?

I m running a x2 CRT with 50slip diff n 12pinion, medusa 2000kv motor n watever batt that will last 30mins or more

If you have those batts running different kv motors that both end up spinning the same max rpm and the same gearing on each the 6s pack should give you half as much time again, say 30 mins vs 20 mins on the 4s. You have half as much voltage again with the 6s compared to the 4s.

A 1500-1600kv motor would be the best bet, along with a 5-6k mah 6s lipo. That will yield the longest runtime to the lightest weight. Plus you could get away with a 25c rated packs for track speed, that will also help with weigh/size as the higher c rated cells tend to be a little heavier/larger.

[BrianG]

Originally Posted by superek4

Hi Brian,

So if I m not wrong u r saying 6s 5000 will last longer than 4s 5000?

I m running a x2 CRT with 50slip diff n 12pinion, medusa 2000kv motor n watever batt that will last 30mins or more

Yes. Like linc said, 6s 5Ah will have more runtime than 4s 5Ah paired with the right motor geared for the same speed. No matter how you slice it, it takes X amount of power to run your vehicle the way you want, for the length of time you want. Since power is V X A, higher voltage requires less current for the same power output.

Originally Posted by lincpimp

...that will also help with weigh/size as the higher c rated cells tend to be a little heavier/larger.

... and cheaper.