does voltage affect power in a battrey?
05-07-2010, 04:03 PM
#26
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RE: does voltage affect power in a battrey?
It is a pleasure to read about some real knowledge, normally people talk so much without going to the point, congratulations for you guys for this information that hopefully will help many people to really understand the concepts of electric cars.
I have a Slash 4x4 VXL, I am using a 15T pinion with a 54 spur on 3S (6400), I am having a temperature issue, my motor is getting to hot.
Traxxas say that the VXL system could handle 19T pinion to reach 60 MPH, but if I am overheating with a 15T pinion there is no way that it would take
the 19 teeth load.
Does anybody know what motor would accept more load to avoid such high temps and still go up to 60 mph?
My Esc and battery are cool to the touch.
I lowered my suspension by moving the shocks to the outer holes and the truck is very controllable, now I am just waiting for my 1/8 wheel adapters to arrive so I can use my buggy on and off road tires.
Thanks.
I have a Slash 4x4 VXL, I am using a 15T pinion with a 54 spur on 3S (6400), I am having a temperature issue, my motor is getting to hot.
Traxxas say that the VXL system could handle 19T pinion to reach 60 MPH, but if I am overheating with a 15T pinion there is no way that it would take
the 19 teeth load.
Does anybody know what motor would accept more load to avoid such high temps and still go up to 60 mph?
My Esc and battery are cool to the touch.
I lowered my suspension by moving the shocks to the outer holes and the truck is very controllable, now I am just waiting for my 1/8 wheel adapters to arrive so I can use my buggy on and off road tires.
Thanks.
ORIGINAL: Slo-V Flyer
Yup I was talking about if you were using the same motor/gearing. But yes, stepping down to a lower kv motor or gearing down will both help as you suggested.
Something my geeky post doesn't mention also is that not only are you getting 50% more raw rpm, but 50% more torque due to the (potential) more amp draw, so in essence you're more than doubling the effective power output. Here's an example:
Say on 2s your motor only draws 50 amps upon normal acceleration (as a rough guestimate of the average amp draw)...
2s lipo - 7.4v x 50 amps = 370 watts
Moving up to 3s or 11.1v and keeping the same motor and gearing (for simplicity's sake) your motor may draw 75 amps:
3s lipo - 11.1v x 75 amps = 832.5 watts
You're potentially able to get over 2.25 x the power just by going up 50% in battery voltage.
Double the original voltage by using 4s lipo 14.8v:
14.8v x 100 amps = 1480 watts. Just going from 2s to 4s lipo (double voltage) the motor is making not double, but 4 times the power!
This is assuming your motor can actually handle the amp draw and is geared to be able to run correctly without overheating.
Cool eh?
ORIGINAL: rpg711
a higher voltage with the same kv will result in more current draw, yes. But the max power of a 3s is 50%higher, so you can run less kv and get the same results w more battery life
a higher voltage with the same kv will result in more current draw, yes. But the max power of a 3s is 50%higher, so you can run less kv and get the same results w more battery life
Yup I was talking about if you were using the same motor/gearing. But yes, stepping down to a lower kv motor or gearing down will both help as you suggested.
Something my geeky post doesn't mention also is that not only are you getting 50% more raw rpm, but 50% more torque due to the (potential) more amp draw, so in essence you're more than doubling the effective power output. Here's an example:
Say on 2s your motor only draws 50 amps upon normal acceleration (as a rough guestimate of the average amp draw)...
2s lipo - 7.4v x 50 amps = 370 watts
Moving up to 3s or 11.1v and keeping the same motor and gearing (for simplicity's sake) your motor may draw 75 amps:
3s lipo - 11.1v x 75 amps = 832.5 watts
You're potentially able to get over 2.25 x the power just by going up 50% in battery voltage.
Double the original voltage by using 4s lipo 14.8v:
14.8v x 100 amps = 1480 watts. Just going from 2s to 4s lipo (double voltage) the motor is making not double, but 4 times the power!
This is assuming your motor can actually handle the amp draw and is geared to be able to run correctly without overheating.
Cool eh?
05-07-2010, 04:23 PM
#27
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RE: does voltage affect power in a battrey?
ORIGINAL: Lico Miami
I have a Slash 4x4 VXL, I am using a 15T pinion with a 54 spur on 3S (6400), I am having a temperature issue, my motor is getting to hot.
Traxxas say that the VXL system could handle 19T pinion to reach 60 MPH, but if I am overheating with a 15T pinion there is no way that it would take
the 19 teeth load.
Does anybody know what motor would accept more load to avoid such high temps and still go up to 60 mph?
My Esc and battery are cool to the touch.
I lowered my suspension by moving the shocks to the outer holes and the truck is very controllable, now I am just waiting for my 1/8 wheel adapters to arrive so I can use my buggy on and off road tires.
Thanks.
I have a Slash 4x4 VXL, I am using a 15T pinion with a 54 spur on 3S (6400), I am having a temperature issue, my motor is getting to hot.
Traxxas say that the VXL system could handle 19T pinion to reach 60 MPH, but if I am overheating with a 15T pinion there is no way that it would take
the 19 teeth load.
Does anybody know what motor would accept more load to avoid such high temps and still go up to 60 mph?
My Esc and battery are cool to the touch.
I lowered my suspension by moving the shocks to the outer holes and the truck is very controllable, now I am just waiting for my 1/8 wheel adapters to arrive so I can use my buggy on and off road tires.
Thanks.
And do you know how hot your motor is actually getting? Higher than 180F?
Gear mesh, slipper, etc. check the obvious things.
05-07-2010, 04:36 PM
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RE: does voltage affect power in a battrey?
ORIGINAL: Access
What are you running on? Terrain-wise. On perfectly flat pavement 60mph without overheating the motor is possible, but if you are on rough ground or grass, that's another story.
And do you know how hot your motor is actually getting? Higher than 180F?
Gear mesh, slipper, etc. check the obvious things.
ORIGINAL: Lico Miami
I have a Slash 4x4 VXL, I am using a 15T pinion with a 54 spur on 3S (6400), I am having a temperature issue, my motor is getting to hot.
Traxxas say that the VXL system could handle 19T pinion to reach 60 MPH, but if I am overheating with a 15T pinion there is no way that it would take
the 19 teeth load.
Does anybody know what motor would accept more load to avoid such high temps and still go up to 60 mph?
My Esc and battery are cool to the touch.
I lowered my suspension by moving the shocks to the outer holes and the truck is very controllable, now I am just waiting for my 1/8 wheel adapters to arrive so I can use my buggy on and off road tires.
Thanks.
I have a Slash 4x4 VXL, I am using a 15T pinion with a 54 spur on 3S (6400), I am having a temperature issue, my motor is getting to hot.
Traxxas say that the VXL system could handle 19T pinion to reach 60 MPH, but if I am overheating with a 15T pinion there is no way that it would take
the 19 teeth load.
Does anybody know what motor would accept more load to avoid such high temps and still go up to 60 mph?
My Esc and battery are cool to the touch.
I lowered my suspension by moving the shocks to the outer holes and the truck is very controllable, now I am just waiting for my 1/8 wheel adapters to arrive so I can use my buggy on and off road tires.
Thanks.
And do you know how hot your motor is actually getting? Higher than 180F?
Gear mesh, slipper, etc. check the obvious things.
Now what motor COULD go faster up to 60 mph without heating up? As posted above, what terrain, tires, gearing you run will affect the existing VXL motor, and anything else you run.
BUT, that said, assuming its for a smooth on-road run, I would look to a more capable motor (not that the VXL motor is bad) that can handle the excess amp draw and tall gearing for longer than a couple of minutes, perhaps a longer can motor, "L" sized Feigao perhaps in the 3000 kv range (the 7L I think), or a more pricier Hacker B50-L in similar Kv rating, Medusa, or hell, go all out with the higher Kv Neu-Castle MMM motors.
05-07-2010, 04:58 PM
#29
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RE: does voltage affect power in a battrey?
ya physics i will be takin next year as a senior in highschool im tryin to stay away from it as much as possible ha but thanks for the articles.
05-07-2010, 05:00 PM
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RE: does voltage affect power in a battrey?
Hehe physics was my fav subject.... at least the first half haha, before I became ADD.. as much as I love it. Let us know how your setup works out.
Let us know how your setup works out.
05-07-2010, 06:07 PM
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RE: does voltage affect power in a battrey?
Wow. Very very informative... to the point my head hurts.
So i'm going to be a pain in the ass now i'm affraid.
I'm new to the world of LiPo so don't really know much about them. ok so here goes.
I have a Tamiya TT01-D with a locked rear diff. I have just recently installed an EZrun 13T brushless system in it (ESC and Motor). Would i be able to safely run a 3s LiPo on this system or will it just fry my car? Also, i have seen a liquid cooling system somewhere for motors but not sure where... Would this help at all or am i just best not bothering?
So i'm going to be a pain in the ass now i'm affraid.
I'm new to the world of LiPo so don't really know much about them. ok so here goes.
I have a Tamiya TT01-D with a locked rear diff. I have just recently installed an EZrun 13T brushless system in it (ESC and Motor). Would i be able to safely run a 3s LiPo on this system or will it just fry my car? Also, i have seen a liquid cooling system somewhere for motors but not sure where... Would this help at all or am i just best not bothering?
05-07-2010, 09:27 PM
#32
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RE: does voltage affect power in a battrey?
Slo-V Flyer and Access,
Thank you for the motor suggestions.
Slo-V flyer, combining my previous experience with what you wrote before, it was clear that by adding voltage you also add torque, many people get confused with RPM and torque, but you again clearly demonstrated the recipe for a powerful and fast setup.
I would say that torque is the capability that a motor has to break through the torsion between the pinion and the tire surface (load). High KV motors can also have torque but if they don’t reach certain RPM they will be below the torque curve and that will cause overheating.
Answering your questions: I have a Rc thermometer installed in my truck but my battery just died on me…
My motor’s temperature got so high that it activated the Esc thermal protection.
I was bashing on pavement for about 4 to 5 minutes of some abuse.
My gear mash is good, and all other mechanical parts are the way they should be.
I would like to take the opportunity to say that the original VXL 3350 motor that comes with the Slash 4X4 is a very strong motor, the speed and take off with 3s 6400 lipo battery and15/54 gear ratio is incredible.
I checked with a radar the above setup but with a 13/54 gear ratio and I was already reaching 47 mph.
I will check now with 15/54 and will let you know my final speed, what is amazing is that I still have lots of torque.
I do not race at the track so I like this tall gearing ratio.
Once again thank you for sharing some priceless information.
Thank you for the motor suggestions.
Slo-V flyer, combining my previous experience with what you wrote before, it was clear that by adding voltage you also add torque, many people get confused with RPM and torque, but you again clearly demonstrated the recipe for a powerful and fast setup.
I would say that torque is the capability that a motor has to break through the torsion between the pinion and the tire surface (load). High KV motors can also have torque but if they don’t reach certain RPM they will be below the torque curve and that will cause overheating.
Answering your questions: I have a Rc thermometer installed in my truck but my battery just died on me…
My motor’s temperature got so high that it activated the Esc thermal protection.
I was bashing on pavement for about 4 to 5 minutes of some abuse.
My gear mash is good, and all other mechanical parts are the way they should be.
I would like to take the opportunity to say that the original VXL 3350 motor that comes with the Slash 4X4 is a very strong motor, the speed and take off with 3s 6400 lipo battery and15/54 gear ratio is incredible.
I checked with a radar the above setup but with a 13/54 gear ratio and I was already reaching 47 mph.
I will check now with 15/54 and will let you know my final speed, what is amazing is that I still have lots of torque.
I do not race at the track so I like this tall gearing ratio.
Once again thank you for sharing some priceless information.
05-08-2010, 12:12 AM
#33
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RE: does voltage affect power in a battrey?
well actually i was just doing some before hand research. i am actually going to do it this summer when i get some money workin with my dad but ya i will definately post up the results
05-08-2010, 09:28 AM
#34
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RE: does voltage affect power in a battrey?
ORIGINAL: Lico Miami
Slo-V Flyer and Access,
Thank you for the motor suggestions.
Slo-V flyer, combining my previous experience with what you wrote before, it was clear that by adding voltage you also add torque, many people get confused with RPM and torque, but you again clearly demonstrated the recipe for a powerful and fast setup.
I would say that torque is the capability that a motor has to break through the torsion between the pinion and the tire surface (load). High KV motors can also have torque but if they don’t reach certain RPM they will be below the torque curve and that will cause overheating.
Answering your questions: I have a Rc thermometer installed in my truck but my battery just died on me…
My motor’s temperature got so high that it activated the Esc thermal protection.
I was bashing on pavement for about 4 to 5 minutes of some abuse.
My gear mash is good, and all other mechanical parts are the way they should be.
I would like to take the opportunity to say that the original VXL 3350 motor that comes with the Slash 4X4 is a very strong motor, the speed and take off with 3s 6400 lipo battery and15/54 gear ratio is incredible.
I checked with a radar the above setup but with a 13/54 gear ratio and I was already reaching 47 mph.
I will check now with 15/54 and will let you know my final speed, what is amazing is that I still have lots of torque.
I do not race at the track so I like this tall gearing ratio.
Once again thank you for sharing some priceless information.
Slo-V Flyer and Access,
Thank you for the motor suggestions.
Slo-V flyer, combining my previous experience with what you wrote before, it was clear that by adding voltage you also add torque, many people get confused with RPM and torque, but you again clearly demonstrated the recipe for a powerful and fast setup.
I would say that torque is the capability that a motor has to break through the torsion between the pinion and the tire surface (load). High KV motors can also have torque but if they don’t reach certain RPM they will be below the torque curve and that will cause overheating.
Answering your questions: I have a Rc thermometer installed in my truck but my battery just died on me…
My motor’s temperature got so high that it activated the Esc thermal protection.
I was bashing on pavement for about 4 to 5 minutes of some abuse.
My gear mash is good, and all other mechanical parts are the way they should be.
I would like to take the opportunity to say that the original VXL 3350 motor that comes with the Slash 4X4 is a very strong motor, the speed and take off with 3s 6400 lipo battery and15/54 gear ratio is incredible.
I checked with a radar the above setup but with a 13/54 gear ratio and I was already reaching 47 mph.
I will check now with 15/54 and will let you know my final speed, what is amazing is that I still have lots of torque.
I do not race at the track so I like this tall gearing ratio.
Once again thank you for sharing some priceless information.
05-08-2010, 09:19 PM
#35
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RE: does voltage affect power in a battrey?
ORIGINAL: Lico Miami
Answering your questions: I have a Rc thermometer installed in my truck but my battery just died on me…
My motor’s temperature got so high that it activated the Esc thermal protection.
I was bashing on pavement for about 4 to 5 minutes of some abuse.
Answering your questions: I have a Rc thermometer installed in my truck but my battery just died on me…
My motor’s temperature got so high that it activated the Esc thermal protection.
I was bashing on pavement for about 4 to 5 minutes of some abuse.
One thing I've done in the past is to freewheel the vehicle up to speed (slowly). Turn off the drag brake or any kind of artificial braking (typically done inside the ESC). Lift all the wheels off the ground, and slowly walk the throttle up to about halfway. And release. Look for excessive vibration, excessive friction, etc. Don't take it up to full throttle and watch your tires, etc. as you do this.
With my high-speed setups, I've typically had to belt and balance tires, replace driveshafts (if they get bent even slightly, they start to vibrate like crazy) and so on. Don't be afraid to run your gear mesh a little on the loose side, check for any little rocks on any of the gears, and so on. I've never been much into speed, it's hard to compete with the 'big boys' when it comes to speed (ie. ISC), only one of my vehicles is set up to go past 40mph and even that wont hit 50. The irony is that 50-60 feels uncontrollable to me, while to the rest of the rc world, 60 is quite slow by modern standards (last ISC multiple nitros were hitting 100mph, and electrics, even a 2s, were exceeding 100mph. Traxxas' claimed speed numbers are all over the place, you honestly need to just keep your speed at levels that are sustainable over a complete run (heat-wise) and that you are comfortable with.
05-09-2010, 08:15 AM
#36
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RE: does voltage affect power in a battrey?
I have a question on C rating which I couldn't find mentioned here. I purchased a 3950mah 12C 4s battery which in theory should supply up to 47.4A. Turns out it wasn't good enough to lift a 4lb model off the ground. Whereas a 3s 2750mah 25C will do the job however I was looking for longer flight times and a little more punch which I thought the 12C 4s would give me.
My question: is the 4s 12C battery a dud or does the C rating come into play here in my attempt to gain more time and punch?
Fairly new to lipos but I think I heard buy the highest C rating you can afford. I was trying to suceed on need! I now may have a battery I cannot use.
My question: is the 4s 12C battery a dud or does the C rating come into play here in my attempt to gain more time and punch?
Fairly new to lipos but I think I heard buy the highest C rating you can afford. I was trying to suceed on need! I now may have a battery I cannot use.
05-09-2010, 09:16 AM
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RE: does voltage affect power in a battrey?
ORIGINAL: abbydawn
I have a question on C rating which I couldn't find mentioned here. I purchased a 3950mah 12C 4s battery which in theory should supply up to 47.4A. Turns out it wasn't good enough to lift a 4lb model off the ground. Whereas a 3s 2750mah 25C will do the job however I was looking for longer flight times and a little more punch which I thought the 12C 4s would give me.
My question: is the 4s 12C battery a dud or does the C rating come into play here in my attempt to gain more time and punch?
Fairly new to lipos but I think I heard buy the highest C rating you can afford. I was trying to suceed on need! I now may have a battery I cannot use.
I have a question on C rating which I couldn't find mentioned here. I purchased a 3950mah 12C 4s battery which in theory should supply up to 47.4A. Turns out it wasn't good enough to lift a 4lb model off the ground. Whereas a 3s 2750mah 25C will do the job however I was looking for longer flight times and a little more punch which I thought the 12C 4s would give me.
My question: is the 4s 12C battery a dud or does the C rating come into play here in my attempt to gain more time and punch?
Fairly new to lipos but I think I heard buy the highest C rating you can afford. I was trying to suceed on need! I now may have a battery I cannot use.
05-09-2010, 09:59 AM
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RE: does voltage affect power in a battrey?
ORIGINAL: rpg711
''Punch'' is dictated by your voltage. Runtime is determined by how much total capacity your battery has. Motor speed is determined by how much your battery can supply(mah * c rating) which your 3s battery supplied more. That 4s battery is, i would say, a dud, either that or it's just junk. The lowest 4s batteries are 30c...
ORIGINAL: abbydawn
I have a question on C rating which I couldn't find mentioned here. I purchased a 3950mah 12C 4s battery which in theory should supply up to 47.4A. Turns out it wasn't good enough to lift a 4lb model off the ground. Whereas a 3s 2750mah 25C will do the job however I was looking for longer flight times and a little more punch which I thought the 12C 4s would give me.
My question: is the 4s 12C battery a dud or does the C rating come into play here in my attempt to gain more time and punch?
Fairly new to lipos but I think I heard buy the highest C rating you can afford. I was trying to suceed on need! I now may have a battery I cannot use.
I have a question on C rating which I couldn't find mentioned here. I purchased a 3950mah 12C 4s battery which in theory should supply up to 47.4A. Turns out it wasn't good enough to lift a 4lb model off the ground. Whereas a 3s 2750mah 25C will do the job however I was looking for longer flight times and a little more punch which I thought the 12C 4s would give me.
My question: is the 4s 12C battery a dud or does the C rating come into play here in my attempt to gain more time and punch?
Fairly new to lipos but I think I heard buy the highest C rating you can afford. I was trying to suceed on need! I now may have a battery I cannot use.
05-09-2010, 10:49 AM
#39
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RE: does voltage affect power in a battrey?
ORIGINAL: abbydawn
I have a question on C rating which I couldn't find mentioned here. I purchased a 3950mah 12C 4s battery which in theory should supply up to 47.4A. Turns out it wasn't good enough to lift a 4lb model off the ground. Whereas a 3s 2750mah 25C will do the job
I have a question on C rating which I couldn't find mentioned here. I purchased a 3950mah 12C 4s battery which in theory should supply up to 47.4A. Turns out it wasn't good enough to lift a 4lb model off the ground. Whereas a 3s 2750mah 25C will do the job
05-09-2010, 09:40 PM
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RE: does voltage affect power in a battrey?
so would i be ok running this battery??http://www.horizonhobby.com/Products...#quickOverview
05-09-2010, 09:47 PM
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RE: does voltage affect power in a battrey?
Assuming you are using this for your VXL esc, then yes it is good enough to run pretty much whatever motor you could use with your VXL, since it's rated to handle over 100 amps, and will give you the 11.1v you want to use.
05-09-2010, 09:48 PM
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RE: does voltage affect power in a battrey?
yup i plan on using the complete vxl system. any clue what speeds i would be getting assuming thr tranny holds up. if you cant tell im kinda a speed freak
05-09-2010, 09:51 PM
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RE: does voltage affect power in a battrey?
It depends on the truck, and I don't remember if you mentioned it already, but you can expect about good 40+ mph if you are geared conservatively. You could use the larger optional pinion Traxxas gives for top speed runs, but I would not run that more than 2-3 minutes, to minimize excess load and heat on the ESC/motor and even battery.
I frankly have a hard time controlling my Slash with a 3s lipo even on tarmac, since it is a little tipsy with stock tires and suspension height. A Rustler and more so a Bandit is pretty well suited for some speed runs if you lower/stiffen up the suspension with the right springs and shock oil.
I frankly have a hard time controlling my Slash with a 3s lipo even on tarmac, since it is a little tipsy with stock tires and suspension height. A Rustler and more so a Bandit is pretty well suited for some speed runs if you lower/stiffen up the suspension with the right springs and shock oil.
