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Old 03-22-2009, 09:16 PM   #1
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Default Need help does more cells means more run time?

Hi, I need help I hv 4s 5000 n 6s 5000 zippy does my 6s gv me more run time on the same setup? Some ppl say yes some say no I M CONFUSED
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Old 03-22-2009, 09:19 PM   #2
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Hi, I need help I hv 4s 5000 n 6s 5000 zippy does my 6s gv me more run time on the same setup? Some ppl say yes some say no I M CONFUSED
of course it does. your carrying 50% more energy in 6s then in 4s and burning that energy with higher efficiency.


what kind of moron would say no.
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Old 03-22-2009, 09:37 PM   #3
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of course it does. your carrying 50% more energy in 6s then in 4s and burning that energy with higher efficiency.


what kind of moron would say no.
they told me it's more voltage not Mah therefore runtime will b d same. I tot I learnt from 1/8 us thread that it's more run time that's y I buy two 6s

Is there a calculation?
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Old 03-22-2009, 09:44 PM   #4
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Call me a moron but your runtimes will only improve slightly if at all. The S after the number of cells means they are in series and this will increase the voltage. If you want longer runtimes you need a pack with some of the cells in parallel or P.
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Old 03-22-2009, 10:00 PM   #5
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You have to understand what's happening with a higher cell pack. With a higher cell number you'll be increasing your voltage, or power output, but maintaining the same capacity as a lower cell pack with the same mAH rating. For example, if you were to hook up two motors, one with a 6S 5000mAH pack and one with a 4S 5000mAH pack and punched them both to the max, the 6S would spin faster than the 4S, but both would theoretically exhaust the battery at the same time.

So according to that, the 6S wouldn't last any longer than the 4S.

Where the difference lies is in the fact that with a 6S you probably wouldn't punch the 6S pack to the max as often as you would the 4S pack. Therefore, since you'll be more likely to punch the 4S harder more often than the 6S, the 6S would end up lasting longer. This is in fact the case and therefore the 6S lasts longer.

Keep in mind: A higher cell pack is in fact more efficient than a lower cell pack but running your motor at full throttle is more efficient than consistantly running it at partial throttle. With this logic, running a 4S pack at full throttle more often is probably better than using a 6S pack and setting the end point adjustment (EPA) lower.

Ideally, run the 6S pack, but gear so that you'll be at full throttle for a better part of the track (or bashing) rather than always running at partial throttle or have to set the EPA to a lower point because the 6S makes your car enter orbit on jumps. Also, depending on your vehicle, consider the extra weight of a 6S over a 4S (usually 200-300 grams) and the (usually negative) impact it may have on handling as well as the clearance a 6S pack requires. There are advantages and disadvantages to both.
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Old 03-23-2009, 12:10 AM   #6
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yeah, zippy only offer up to 5000amp unless I change to other brands(expensive) the only way is up the cells. I agreed I dun need to full throttle as there's more than enough power just I hv to test it at d track n let u guys know how long I can run it for
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Old 03-23-2009, 03:16 AM   #7
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hi, I was thinking to split my two 6s 5000 to 4s 10000 u guys think possible?more run time that way?
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Old 03-23-2009, 07:31 AM   #8
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hi, I was thinking to split my two 6s 5000 to 4s 10000 u guys think possible?more run time that way?
any advise?
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Old 03-23-2009, 08:22 AM   #9
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Its both true and false, If you stick to the same gearing, you will not see any improvement and will probably pose runtime. however if you re-gear for the new voltage, you will get no more stress than before and the energy available is improved.

Here is an example, I have an RC 10 GT converted to electric, I also have an rc10T4, the GT conversion has a 2500 5s(18.5v) 25s flightpower battery, the T4 has a maxamps 8000mah 20c 2s(7.4v) battery. The setups for each are a mamba max 4600 on the 7.4 setup and a lehner 1200basic XL for the 18.5 setup

both can run to 20 minutes easy, however the gt can make 30 minutes, the t4 can do only 25 to 28. why? The lower voltage requires more amps to maintain the speed, both cars are geared to about 40 and are very close. there is an equation to get the potential use of any battery, you take the mah and times it against the voltage, here is what my two come out as.

the 18.5 has 46,250 potential mah (I think that's how it'd say) available, the 7.4 v setup has 59,200 potential mah's, So why does the high voltage go longer at less potential? Voltage is horsepower, amps is torque. If you have a lower voltage setup you can gear it up, if the battery will support it, and match the high V speed, the price is you use more amps and burn (use) the pack down faster.

The higher voltage setup will be more efficient only if you gear it similarly to the lower voltage setup.
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Old 03-23-2009, 09:08 AM   #10
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Originally Posted by crazyjr View Post
Its both true and false, If you stick to the same gearing, you will not see any improvement and will probably pose runtime. however if you re-gear for the new voltage, you will get no more stress than before and the energy available is improved.

Here is an example, I have an RC 10 GT converted to electric, I also have an rc10T4, the GT conversion has a 2500 5s(18.5v) 25s flightpower battery, the T4 has a maxamps 8000mah 20c 2s(7.4v) battery. The setups for each are a mamba max 4600 on the 7.4 setup and a lehner 1200basic XL for the 18.5 setup

both can run to 20 minutes easy, however the gt can make 30 minutes, the t4 can do only 25 to 28. why? The lower voltage requires more amps to maintain the speed, both cars are geared to about 40 and are very close. there is an equation to get the potential use of any battery, you take the mah and times it against the voltage, here is what my two come out as.

the 18.5 has 46,250 potential mah (I think that's how it'd say) available, the 7.4 v setup has 59,200 potential mah's, So why does the high voltage go longer at less potential? Voltage is horsepower, amps is torque. If you have a lower voltage setup you can gear it up, if the battery will support it, and match the high V speed, the price is you use more amps and burn (use) the pack down faster.

The higher voltage setup will be more efficient only if you gear it similarly to the lower voltage setup.
seems that i must really try out the 6s & see how long it can really last.
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Old 03-23-2009, 10:10 AM   #11
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Hello, I'm a moron and I don't think just adding voltage gives more run time.

I must be missing something. Its my understanding that it is amps that determines how quickly a battery is depleted?

If I gear a 6s setup to pull 40 amps continuous than my 5000 mah battery will last 7.5 mins

Formula: 5000mah x 0.06 / 40 amps = 7.5 mins

Now if I have a 4s setup geared to pull 40 amps continous that same battery will last 7.5 mins too

Now if the question really is, can I get my 6s setup to run as fast as my 4s and run longer because I'll be using less amps. Then yes.

But just adding voltage in itself doesn't.
Same examples.

My 6s setup geared to pull 55 amps continuously from my 5000 mah battery. It'll last 5.5 mins

My 4s setup geared to pull 45 amps continuously will last 6.6 mins.

I added voltage but the battery last longer on the smaller 4s? Obviously the 4s set up in the case will run slower than the 6s. Hence its amps not voltage that determines runtime.
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Old 03-23-2009, 10:17 AM   #12
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Now if the question really is, can I get my 6s setup to run as fast as my 4s and run longer because I'll be using less amps. Then yes.
This is the question that really matters.

When designing a brushless conversion you ought to correlate which voltage you're going to be running with the KV of the motor.

If you going to run more volts, use a lower KV motor. This will make the system more efficient and it will draw less amps than the equivalently geared lower voltage system therefore netting more run time.

If you're just taking the same vehicle with the same motor/gearing and increasing the voltage you're NOT going to see a runtime increase, in fact you're probably going to see a lot more heat.
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Old 03-23-2009, 10:28 AM   #13
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This is the question that really matters.

When designing a brushless conversion you ought to correlate which voltage you're going to be running with the KV of the motor.

If you going to run more volts, use a lower KV motor. This will make the system more efficient and it will draw less amps than the equivalently geared lower voltage system therefore netting more run time.

If you're just taking the same vehicle with the same motor/gearing and increasing the voltage you're NOT going to see a runtime increase, in fact you're probably going to see a lot more heat.
Thank you, thats what I was looking for. People will search/google for the answer to this question and they will probably stumble onto this thread. Whether its for racing or bashing, conversions or rtr stuff, I didn't want them to be lead to believe they could just add more cells and get longer runtimes.
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Old 03-23-2009, 10:39 AM   #14
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Theoretically, the higher mAH pack will provide more runtime when having an equal number of cells.

When using packs with different number of cells, which is the original question, the equation is a bit different.

I'd have to agree with Ryandrea's comments.

Where the difference lies is in the fact that with a 6S you probably wouldn't punch the 6S pack to the max as often as you would the 4S pack. Therefore, since you'll be more likely to punch the 4S harder more often than the 6S, the 6S would end up lasting longer. This is in fact the case and therefore the 6S lasts longer.

Aceldama is spot on as well.
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Old 03-23-2009, 12:17 PM   #15
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Quote:
Originally Posted by kahnen View Post
Hello, I'm a moron and I don't think just adding voltage gives more run time.

I must be missing something. Its my understanding that it is amps that determines how quickly a battery is depleted?

If I gear a 6s setup to pull 40 amps continuous than my 5000 mah battery will last 7.5 mins

Formula: 5000mah x 0.06 / 40 amps = 7.5 mins

Now if I have a 4s setup geared to pull 40 amps continous that same battery will last 7.5 mins too

Now if the question really is, can I get my 6s setup to run as fast as my 4s and run longer because I'll be using less amps. Then yes.

But just adding voltage in itself doesn't.
Same examples.

My 6s setup geared to pull 55 amps continuously from my 5000 mah battery. It'll last 5.5 mins

My 4s setup geared to pull 45 amps continuously will last 6.6 mins.

I added voltage but the battery last longer on the smaller 4s? Obviously the 4s set up in the case will run slower than the 6s. Hence its amps not voltage that determines runtime.
That's what i was trying to say, just upping the voltage won't allow more run time. You got to gear it appropriately, if not . you lose runtime and get heat in return. My 4600 is off the shelf 2s setup (3s max) and was bought for rules of the class, the 5s setup was researched and designed around using a small 5s pack and reaching max efficiency. I'd like to try 6s with it and see if it could get better, but right not there isn't a good 6s capable esc small enough to fit where i need it to, Tekin and mamba are bringing some new esc's soon that will change that though
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