Battery 'C' rating
06-25-2012, 09:23 PM
#1
Battery 'C' rating
I'm not sure I undertand the need for such high 'C' rated batteries. From what I've been reading a typical 1:10 short course esc is good for about 100 amps (give or take) a 2s 5000 mAh 20C battery should supply 100 amps continuous and burst to say 150 (30c). Now I realize you won't damage your esc with a higher rated pack but where does it help? A 40c 5000 would be 200 amp continuous right? Seems enough for 1:8 esc.
06-26-2012, 03:43 AM
#2
Those high numbers only help the marketing departments. A real 30C 5000mAh battery can supply 150A continuous, that's more than enough. Now we just need to find a battery with real C ratings...
06-26-2012, 11:03 AM
#3
1/8 scale esc's make up for lost C ratings because you run 4-6s batteries.
I know people here that run 40c 6s 4600mah packs. 1/8th scale esc's draw
way more current than 1/10 stuff. But as long as your in the 40-60c range your fine. 25c-30c 5000mah is all you really need for 1/10th scale.
I know several that have ran 30c packs for years.
I know people here that run 40c 6s 4600mah packs. 1/8th scale esc's draw
way more current than 1/10 stuff. But as long as your in the 40-60c range your fine. 25c-30c 5000mah is all you really need for 1/10th scale.
I know several that have ran 30c packs for years.
06-26-2012, 01:48 PM
#4
1/10 Cant be classed All in one Bundle.
A 1/10 4wd SC will Suck 10X more juice than a 2wd SC or 2wd Buggy will. Also If your trying to run 30-40C 5000 packs in 4wd SC, Your asking for trouble.
BUY as much "C" as you can. Hobbyking is My suggestion for cheap packs That will MORE than do the job.
A 1/10 4wd SC will Suck 10X more juice than a 2wd SC or 2wd Buggy will. Also If your trying to run 30-40C 5000 packs in 4wd SC, Your asking for trouble.
BUY as much "C" as you can. Hobbyking is My suggestion for cheap packs That will MORE than do the job.
06-26-2012, 02:18 PM
#5
I usualy run 25% more anps than I need. In my etruggy my motor and esc are rated at 120amps so I have 150 apm lipos. 5000mah at 30c and they do fine. In my sc10 when I had it the mmp esc was rated around 100 amps so I ran 6000 28c revtech packs and they never got warm. In my 4x4 slash I had the mmp and castle 1410 combo ran 160amp lipo with out a problem. The high c rating gives you a ton of punch but if you can't handle the punch its not worth buying. Its a marketing gimik. You don't need them. Just check your motor esc rating and buy lipos a little higher than what you need.
06-26-2012, 03:54 PM
#6
Tech Fanatic
iTrader: (13)
The whole problem with C rating is that it's going to vary over the discharge plot of the battery, amongst other problems.
The 1/8 vehicles run higher cell counts, as was mentioned above, to get around the C ratings of batteries.
Higher voltage means better efficiency. This is due to IČR losses. (AmpsČ)*Resistance in Ohms gives you your wasted power as heat (Watts).
Wattage, being the good ole Volts*Amps=Watts, tells us 150 Amps at say, 4S Mid-Pack levels (3.9v * 4) is 15.6v, so ~2300 Watts of Power.
But wait, what's 2300 Watts at full pack voltage (4.2v)? 137 Amps.
And now at nearing the bottom third (3.4v)? 170 Amps.
If your IČR losses in the ESC and wiring are, say, 65w on that 4S pack, it means you've got running resistance around 0.0029 Ohms. Super low, but still 65w of power blasting off as heat, at 3.9v/cell. That dissipated power raises to a whopping 84w at 3.4v/cell, 29% more!
What's this got to do with C Rating? Higher C Rating batteries will hold up higher voltages as you put larger loads on them. Which means your whole system stays running cooler, longer. And this translates directly into equipment life.
This is why a lot of people push for 5S and 6S packs in the 1/8 Vehicles. Yes, it's faster, but if you dial down the top speed (RPM Limiter or the like), the whole setup runs much, much cooler. 150A at 3.9v/cell on 6S translates into 3510w of power, while pushing the same 65w of dissipated heat.
On the topic of ESC's, remember, a 120a ESC can burst into the 300's. Make sure you select batteries that match your burst, as well as your continual running.
The 1/8 vehicles run higher cell counts, as was mentioned above, to get around the C ratings of batteries.
Higher voltage means better efficiency. This is due to IČR losses. (AmpsČ)*Resistance in Ohms gives you your wasted power as heat (Watts).
Wattage, being the good ole Volts*Amps=Watts, tells us 150 Amps at say, 4S Mid-Pack levels (3.9v * 4) is 15.6v, so ~2300 Watts of Power.
But wait, what's 2300 Watts at full pack voltage (4.2v)? 137 Amps.
And now at nearing the bottom third (3.4v)? 170 Amps.
If your IČR losses in the ESC and wiring are, say, 65w on that 4S pack, it means you've got running resistance around 0.0029 Ohms. Super low, but still 65w of power blasting off as heat, at 3.9v/cell. That dissipated power raises to a whopping 84w at 3.4v/cell, 29% more!
What's this got to do with C Rating? Higher C Rating batteries will hold up higher voltages as you put larger loads on them. Which means your whole system stays running cooler, longer. And this translates directly into equipment life.
This is why a lot of people push for 5S and 6S packs in the 1/8 Vehicles. Yes, it's faster, but if you dial down the top speed (RPM Limiter or the like), the whole setup runs much, much cooler. 150A at 3.9v/cell on 6S translates into 3510w of power, while pushing the same 65w of dissipated heat.
On the topic of ESC's, remember, a 120a ESC can burst into the 300's. Make sure you select batteries that match your burst, as well as your continual running.
06-26-2012, 04:48 PM
#8
The whole problem with C rating is that it's going to vary over the discharge plot of the battery, amongst other problems.
The 1/8 vehicles run higher cell counts, as was mentioned above, to get around the C ratings of batteries.
Higher voltage means better efficiency. This is due to IČR losses. (AmpsČ)*Resistance in Ohms gives you your wasted power as heat (Watts).
Wattage, being the good ole Volts*Amps=Watts, tells us 150 Amps at say, 4S Mid-Pack levels (3.9v * 4) is 15.6v, so ~2300 Watts of Power.
But wait, what's 2300 Watts at full pack voltage (4.2v)? 137 Amps.
And now at nearing the bottom third (3.4v)? 170 Amps.
If your IČR losses in the ESC and wiring are, say, 65w on that 4S pack, it means you've got running resistance around 0.0029 Ohms. Super low, but still 65w of power blasting off as heat, at 3.9v/cell. That dissipated power raises to a whopping 84w at 3.4v/cell, 29% more!
What's this got to do with C Rating? Higher C Rating batteries will hold up higher voltages as you put larger loads on them. Which means your whole system stays running cooler, longer. And this translates directly into equipment life.
This is why a lot of people push for 5S and 6S packs in the 1/8 Vehicles. Yes, it's faster, but if you dial down the top speed (RPM Limiter or the like), the whole setup runs much, much cooler. 150A at 3.9v/cell on 6S translates into 3510w of power, while pushing the same 65w of dissipated heat.
On the topic of ESC's, remember, a 120a ESC can burst into the 300's. Make sure you select batteries that match your burst, as well as your continual running.
The 1/8 vehicles run higher cell counts, as was mentioned above, to get around the C ratings of batteries.
Higher voltage means better efficiency. This is due to IČR losses. (AmpsČ)*Resistance in Ohms gives you your wasted power as heat (Watts).
Wattage, being the good ole Volts*Amps=Watts, tells us 150 Amps at say, 4S Mid-Pack levels (3.9v * 4) is 15.6v, so ~2300 Watts of Power.
But wait, what's 2300 Watts at full pack voltage (4.2v)? 137 Amps.
And now at nearing the bottom third (3.4v)? 170 Amps.
If your IČR losses in the ESC and wiring are, say, 65w on that 4S pack, it means you've got running resistance around 0.0029 Ohms. Super low, but still 65w of power blasting off as heat, at 3.9v/cell. That dissipated power raises to a whopping 84w at 3.4v/cell, 29% more!
What's this got to do with C Rating? Higher C Rating batteries will hold up higher voltages as you put larger loads on them. Which means your whole system stays running cooler, longer. And this translates directly into equipment life.
This is why a lot of people push for 5S and 6S packs in the 1/8 Vehicles. Yes, it's faster, but if you dial down the top speed (RPM Limiter or the like), the whole setup runs much, much cooler. 150A at 3.9v/cell on 6S translates into 3510w of power, while pushing the same 65w of dissipated heat.
On the topic of ESC's, remember, a 120a ESC can burst into the 300's. Make sure you select batteries that match your burst, as well as your continual running.
THANKYOU! This makes sense. This is the best description I've read to date. Extremely helpful!
06-28-2012, 12:46 AM
#10
Hi, Im running 4000mah 20c on a 2WD short course truck and an FF03
equiped with GTB2 and Edge. Novak says to use 25c Lipos or higher.
Question is what will be the long term effects of running lower c-rating
Lipos on my electronics? Will it damage them? Cause RX brownout?
From their Lipo warning addendum it says that using low c-rating will
damage the ESC but Ive used mine in racing/bashing conditions with
this setup with no negative effect.
Well I have this instance when I still have my old Havok spec on my FF03
that smoked the next day after whole day of racing at a hot track with
the 4000mah 20c. It was running great before we head home but the
next day I turned it on, it smoked.
So should I stop using this battery and upgrade to a higher c-rating?
Or can I still safely use this set up JUST for bashing? And me a higher
c-rating Lipo for racing.
Thanks
equiped with GTB2 and Edge. Novak says to use 25c Lipos or higher.
Question is what will be the long term effects of running lower c-rating
Lipos on my electronics? Will it damage them? Cause RX brownout?
From their Lipo warning addendum it says that using low c-rating will
damage the ESC but Ive used mine in racing/bashing conditions with
this setup with no negative effect.
Well I have this instance when I still have my old Havok spec on my FF03
that smoked the next day after whole day of racing at a hot track with
the 4000mah 20c. It was running great before we head home but the
next day I turned it on, it smoked.
So should I stop using this battery and upgrade to a higher c-rating?
Or can I still safely use this set up JUST for bashing? And me a higher
c-rating Lipo for racing.
Thanks
06-28-2012, 09:57 AM
#11
1/10 Cant be classed All in one Bundle.
A 1/10 4wd SC will Suck 10X more juice than a 2wd SC or 2wd Buggy will. Also If your trying to run 30-40C 5000 packs in 4wd SC, Your asking for trouble.
BUY as much "C" as you can. Hobbyking is My suggestion for cheap packs That will MORE than do the job.
A 1/10 4wd SC will Suck 10X more juice than a 2wd SC or 2wd Buggy will. Also If your trying to run 30-40C 5000 packs in 4wd SC, Your asking for trouble.
BUY as much "C" as you can. Hobbyking is My suggestion for cheap packs That will MORE than do the job.
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