batteries
04-29-2006, 10:20 PM
#1
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batteries
i have a pede and the battery life is **** so i don't know what is better buying one expensive battery with like 1900-2000 mah or 2 cheaper batteries with 1500 mah. and approx how much more time per battery do you get for the expensiver ones
04-30-2006, 12:54 PM
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RE: batteries
ok 1500mah batteries are your source for the crappy run time. While IB4200's are great if you're calling 1900mah batteries expensive these batteries will be fall off your chair expensive. These batteries will cost maybe 3 times as much as some 1500mah batteries but they also come with 2 and they have twice the runtime: http://www2.towerhobbies.com/cgi-bin...&I=LXCUH3&P=ML
Trust me I own 2 sets and just bought a 3rd! they're great batteries for bashing and not spending tons!
Trust me I own 2 sets and just bought a 3rd! they're great batteries for bashing and not spending tons!
05-01-2006, 09:59 PM
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RE: batteries
I am running a Fusion speed control and a 19x1 Fantom. If you get a 6 cell pack you will get a longer runtime. The more voltage of the pack the shorter the run time.
05-01-2006, 10:37 PM
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RE: batteries
ORIGINAL: piranha661
I am running a Fusion speed control and a 19x1 Fantom. If you get a 6 cell pack you will get a longer runtime. The more voltage of the pack the shorter the run time.
I am running a Fusion speed control and a 19x1 Fantom. If you get a 6 cell pack you will get a longer runtime. The more voltage of the pack the shorter the run time.
flow rate =amps
volume = volts
flow rate +volume =pressure
amps +volts = watts
watts and pressure are the same . and watts turn motors more watts more power but just about the same amount of run time .that is about the best way i can describ it . to you i may be a little off but not much and the idea behind what i say is right even if i worded it wrong .
05-01-2006, 11:26 PM
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RE: batteries
actually piranha I think it's the opposite. Look while I was buying a power supply for my ICE I said I needed at least a so and so many watt power supply because voltage x amperage = wattage needed. the Higher the voltae the less amerage needed to achieve the same wattage. They could run everything in the world off 12v DC but then you'd have huge think cables lying around since to have a high amperage you need thick cables. So why not just have high voltage and lower amperage? [sm=idea.gif]
05-01-2006, 11:28 PM
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RE: batteries
but batteries discharge at a max rate any more and you hurt the battery it gets to hot .and buy getting the extra 1.2 volt you are letting the motor have those extra watts safely
example mind you that 3000 mah is 30 amps roughly
7.2x 30 =216 watts total
8.4x30= 252 watts total
more volts same amps more watts more power same run time .
example mind you that 3000 mah is 30 amps roughly
7.2x 30 =216 watts total
8.4x30= 252 watts total
more volts same amps more watts more power same run time .
05-11-2006, 05:11 AM
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RE: batteries
ORIGINAL: kingrustler
no way dude you will have same run time out of a 6 cell 3000mah battery pack as you will a 7 cell 3000mah battery pack just with more punch because you have more volts which means more rpms out of the motor not less run time .look at it this way fill two glasses up one with 7.2 oz and one with 8.4 oz drain them both at the same flow rate the 8.4 will take a bit longer to drain but will drain faster at first due to the extra 1.2 oz of volume . . get it
flow rate =amps
volume = volts
flow rate +volume =pressure
amps +volts = watts
watts and pressure are the same . and watts turn motors more watts more power but just about the same amount of run time .that is about the best way i can describ it . to you i may be a little off but not much and the idea behind what i say is right even if i worded it wrong .
ORIGINAL: piranha661
I am running a Fusion speed control and a 19x1 Fantom. If you get a 6 cell pack you will get a longer runtime. The more voltage of the pack the shorter the run time.
I am running a Fusion speed control and a 19x1 Fantom. If you get a 6 cell pack you will get a longer runtime. The more voltage of the pack the shorter the run time.
flow rate =amps
volume = volts
flow rate +volume =pressure
amps +volts = watts
watts and pressure are the same . and watts turn motors more watts more power but just about the same amount of run time .that is about the best way i can describ it . to you i may be a little off but not much and the idea behind what i say is right even if i worded it wrong .
flow_rate*time = amp hour (this is like volume, or the amount of water in your analogy)
flow_rate = amps
pressure = volts (this is like the ability to 'force' current)
flow_rate*pressure = watts (this is like instantaneous power)
flow_rate*pressure*duration = joules (energy, or the amount of power you can apply in some duration of time)
so yes, more watts seen at the motor is more power, but i'm unsure about how that relates to a 6-cell to 7-cell runtime (I asked the same question in another thread). the explaination that was posted was because the voltage has increased, it has increased the current flow (assuming the same load). i'm unsure about that because while the added cell does increase the potential, it also brings added capacitance. now if the increase in voltage increases the current, and the draw (over the full discharge of the battery) outpaces any capacitance the extra cell added, then i could see that as being true.
05-11-2006, 05:21 AM
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RE: batteries
ORIGINAL: kingrustler
but batteries discharge at a max rate any more and you hurt the battery it gets to hot .and buy getting the extra 1.2 volt you are letting the motor have those extra watts safely
example mind you that 3000 mah is 30 amps roughly
7.2x 30 =216 watts total
8.4x30= 252 watts total
more volts same amps more watts more power same run time .
but batteries discharge at a max rate any more and you hurt the battery it gets to hot .and buy getting the extra 1.2 volt you are letting the motor have those extra watts safely
example mind you that 3000 mah is 30 amps roughly
7.2x 30 =216 watts total
8.4x30= 252 watts total
more volts same amps more watts more power same run time .
3000 mah is 3 amps over one hour, or 1 amp over 3 hours, or however else you can split them up. it's kind of like the amount of juice you can store in the battery, not the rate at which you can deliver it.
hope it doesn't sound like i'm correcting you overtly, i just like to make clear any confusion that could lead to more confusion.
05-11-2006, 08:16 PM
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RE: batteries
Yeah there are some cheap 3300 mah nimh packs on ebay too, they make such a huge difference, in my TC4 with a 27t motor I can drift for almost an hour.
05-11-2006, 08:23 PM
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RE: batteries
ORIGINAL: anci3nt
i don't think that is entirely correct. i think this may be a better analogy:
flow_rate*time = amp hour (this is like volume, or the amount of water in your analogy)
flow_rate = amps
pressure = volts (this is like the ability to 'force' current)
flow_rate*pressure = watts (this is like instantaneous power)
flow_rate*pressure*duration = joules (energy, or the amount of power you can apply in some duration of time)
so yes, more watts seen at the motor is more power, but i'm unsure about how that relates to a 6-cell to 7-cell runtime (I asked the same question in another thread). the explaination that was posted was because the voltage has increased, it has increased the current flow (assuming the same load). i'm unsure about that because while the added cell does increase the potential, it also brings added capacitance. now if the increase in voltage increases the current, and the draw (over the full discharge of the battery) outpaces any capacitance the extra cell added, then i could see that as being true.
ORIGINAL: kingrustler
no way dude you will have same run time out of a 6 cell 3000mah battery pack as you will a 7 cell 3000mah battery pack just with more punch because you have more volts which means more rpms out of the motor not less run time .look at it this way fill two glasses up one with 7.2 oz and one with 8.4 oz drain them both at the same flow rate the 8.4 will take a bit longer to drain but will drain faster at first due to the extra 1.2 oz of volume . . get it
flow rate =amps
volume = volts
flow rate +volume =pressure
amps +volts = watts
watts and pressure are the same . and watts turn motors more watts more power but just about the same amount of run time .that is about the best way i can describ it . to you i may be a little off but not much and the idea behind what i say is right even if i worded it wrong .
ORIGINAL: piranha661
I am running a Fusion speed control and a 19x1 Fantom. If you get a 6 cell pack you will get a longer runtime. The more voltage of the pack the shorter the run time.
I am running a Fusion speed control and a 19x1 Fantom. If you get a 6 cell pack you will get a longer runtime. The more voltage of the pack the shorter the run time.
flow rate =amps
volume = volts
flow rate +volume =pressure
amps +volts = watts
watts and pressure are the same . and watts turn motors more watts more power but just about the same amount of run time .that is about the best way i can describ it . to you i may be a little off but not much and the idea behind what i say is right even if i worded it wrong .
flow_rate*time = amp hour (this is like volume, or the amount of water in your analogy)
flow_rate = amps
pressure = volts (this is like the ability to 'force' current)
flow_rate*pressure = watts (this is like instantaneous power)
flow_rate*pressure*duration = joules (energy, or the amount of power you can apply in some duration of time)
so yes, more watts seen at the motor is more power, but i'm unsure about how that relates to a 6-cell to 7-cell runtime (I asked the same question in another thread). the explaination that was posted was because the voltage has increased, it has increased the current flow (assuming the same load). i'm unsure about that because while the added cell does increase the potential, it also brings added capacitance. now if the increase in voltage increases the current, and the draw (over the full discharge of the battery) outpaces any capacitance the extra cell added, then i could see that as being true.
the problem with your statement is that since the added cell is wired in series it does not add capacity but rather voltage.
05-12-2006, 01:02 AM
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RE: batteries
ORIGINAL: R/C fan-addict
the problem with your statement is that since the added cell is wired in series it does not add capacity but rather voltage.
ORIGINAL: anci3nt
i don't think that is entirely correct. i think this may be a better analogy:
flow_rate*time = amp hour (this is like volume, or the amount of water in your analogy)
flow_rate = amps
pressure = volts (this is like the ability to 'force' current)
flow_rate*pressure = watts (this is like instantaneous power)
flow_rate*pressure*duration = joules (energy, or the amount of power you can apply in some duration of time)
so yes, more watts seen at the motor is more power, but i'm unsure about how that relates to a 6-cell to 7-cell runtime (I asked the same question in another thread). the explaination that was posted was because the voltage has increased, it has increased the current flow (assuming the same load). i'm unsure about that because while the added cell does increase the potential, it also brings added capacitance. now if the increase in voltage increases the current, and the draw (over the full discharge of the battery) outpaces any capacitance the extra cell added, then i could see that as being true.
ORIGINAL: kingrustler
no way dude you will have same run time out of a 6 cell 3000mah battery pack as you will a 7 cell 3000mah battery pack just with more punch because you have more volts which means more rpms out of the motor not less run time .look at it this way fill two glasses up one with 7.2 oz and one with 8.4 oz drain them both at the same flow rate the 8.4 will take a bit longer to drain but will drain faster at first due to the extra 1.2 oz of volume . . get it
flow rate =amps
volume = volts
flow rate +volume =pressure
amps +volts = watts
watts and pressure are the same . and watts turn motors more watts more power but just about the same amount of run time .that is about the best way i can describ it . to you i may be a little off but not much and the idea behind what i say is right even if i worded it wrong .
ORIGINAL: piranha661
I am running a Fusion speed control and a 19x1 Fantom. If you get a 6 cell pack you will get a longer runtime. The more voltage of the pack the shorter the run time.
I am running a Fusion speed control and a 19x1 Fantom. If you get a 6 cell pack you will get a longer runtime. The more voltage of the pack the shorter the run time.
flow rate =amps
volume = volts
flow rate +volume =pressure
amps +volts = watts
watts and pressure are the same . and watts turn motors more watts more power but just about the same amount of run time .that is about the best way i can describ it . to you i may be a little off but not much and the idea behind what i say is right even if i worded it wrong .
flow_rate*time = amp hour (this is like volume, or the amount of water in your analogy)
flow_rate = amps
pressure = volts (this is like the ability to 'force' current)
flow_rate*pressure = watts (this is like instantaneous power)
flow_rate*pressure*duration = joules (energy, or the amount of power you can apply in some duration of time)
so yes, more watts seen at the motor is more power, but i'm unsure about how that relates to a 6-cell to 7-cell runtime (I asked the same question in another thread). the explaination that was posted was because the voltage has increased, it has increased the current flow (assuming the same load). i'm unsure about that because while the added cell does increase the potential, it also brings added capacitance. now if the increase in voltage increases the current, and the draw (over the full discharge of the battery) outpaces any capacitance the extra cell added, then i could see that as being true.
the problem with your statement is that since the added cell is wired in series it does not add capacity but rather voltage.
05-12-2006, 02:21 AM
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RE: batteries
In series the cells add up and doesn't change the amount of current, the current is the average that all the batteries produce. In parallel the voltage stays constant but the current is all added from each cell
05-12-2006, 08:54 AM
#22
RE: batteries
Higher the voltage (8.4V vs. 7.2V), higher the current, hence shorter run time, for the same capacity rating..
V = I * R
Resistence in the system (your motor, let's forget about the wire, ESC, etc.) is constant.
So when you up the voltage (V), your current (I) will go up.
With higher current, you are going to drain your battery quicker (say you have a 3300mAh battery, instead of draining at 3A, now you are draining at 3.5A, so it would take less time to drain the battery..)
Hope that's clear!
05-12-2006, 05:19 PM
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RE: batteries
ORIGINAL: anci3nt
yes, true in the macro sense. i was thinking more in terms of the battery physics (the voltage potential and electron production ability). a cell has a finite ability to produce current, and that's why two identical cells in parallel 'double' the capacity (twice the ability to produce electrons at the same potential voltage). put them in series and you increase the electron 'pressure' trying to be forced them out, but there is no doubt more ability to produce current than one cell. that's where i don't know what the behavior of current is in series-cells.
ORIGINAL: R/C fan-addict
the problem with your statement is that since the added cell is wired in series it does not add capacity but rather voltage.
ORIGINAL: anci3nt
i don't think that is entirely correct. i think this may be a better analogy:
flow_rate*time = amp hour (this is like volume, or the amount of water in your analogy)
flow_rate = amps
pressure = volts (this is like the ability to 'force' current)
flow_rate*pressure = watts (this is like instantaneous power)
flow_rate*pressure*duration = joules (energy, or the amount of power you can apply in some duration of time)
so yes, more watts seen at the motor is more power, but i'm unsure about how that relates to a 6-cell to 7-cell runtime (I asked the same question in another thread). the explaination that was posted was because the voltage has increased, it has increased the current flow (assuming the same load). i'm unsure about that because while the added cell does increase the potential, it also brings added capacitance. now if the increase in voltage increases the current, and the draw (over the full discharge of the battery) outpaces any capacitance the extra cell added, then i could see that as being true.
ORIGINAL: kingrustler
no way dude you will have same run time out of a 6 cell 3000mah battery pack as you will a 7 cell 3000mah battery pack just with more punch because you have more volts which means more rpms out of the motor not less run time .look at it this way fill two glasses up one with 7.2 oz and one with 8.4 oz drain them both at the same flow rate the 8.4 will take a bit longer to drain but will drain faster at first due to the extra 1.2 oz of volume . . get it
flow rate =amps
volume = volts
flow rate +volume =pressure
amps +volts = watts
watts and pressure are the same . and watts turn motors more watts more power but just about the same amount of run time .that is about the best way i can describ it . to you i may be a little off but not much and the idea behind what i say is right even if i worded it wrong .
ORIGINAL: piranha661
I am running a Fusion speed control and a 19x1 Fantom. If you get a 6 cell pack you will get a longer runtime. The more voltage of the pack the shorter the run time.
I am running a Fusion speed control and a 19x1 Fantom. If you get a 6 cell pack you will get a longer runtime. The more voltage of the pack the shorter the run time.
flow rate =amps
volume = volts
flow rate +volume =pressure
amps +volts = watts
watts and pressure are the same . and watts turn motors more watts more power but just about the same amount of run time .that is about the best way i can describ it . to you i may be a little off but not much and the idea behind what i say is right even if i worded it wrong .
flow_rate*time = amp hour (this is like volume, or the amount of water in your analogy)
flow_rate = amps
pressure = volts (this is like the ability to 'force' current)
flow_rate*pressure = watts (this is like instantaneous power)
flow_rate*pressure*duration = joules (energy, or the amount of power you can apply in some duration of time)
so yes, more watts seen at the motor is more power, but i'm unsure about how that relates to a 6-cell to 7-cell runtime (I asked the same question in another thread). the explaination that was posted was because the voltage has increased, it has increased the current flow (assuming the same load). i'm unsure about that because while the added cell does increase the potential, it also brings added capacitance. now if the increase in voltage increases the current, and the draw (over the full discharge of the battery) outpaces any capacitance the extra cell added, then i could see that as being true.
the problem with your statement is that since the added cell is wired in series it does not add capacity but rather voltage.
ahhhh you're just confusing me now! But I'll take your word for it cause you know a heck of a lot more about that stuff than me! lol
05-12-2006, 05:40 PM
#24
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RE: batteries
ORIGINAL: Lunchboxer
Higher the voltage (8.4V vs. 7.2V), higher the current, hence shorter run time, for the same capacity rating..
V = I * R
Resistence in the system (your motor, let's forget about the wire, ESC, etc.) is constant.
So when you up the voltage (V), your current (I) will go up.
With higher current, you are going to drain your battery quicker (say you have a 3300mAh battery, instead of draining at 3A, now you are draining at 3.5A, so it would take less time to drain the battery..)
Hope that's clear!
Higher the voltage (8.4V vs. 7.2V), higher the current, hence shorter run time, for the same capacity rating..
V = I * R
Resistence in the system (your motor, let's forget about the wire, ESC, etc.) is constant.
So when you up the voltage (V), your current (I) will go up.
With higher current, you are going to drain your battery quicker (say you have a 3300mAh battery, instead of draining at 3A, now you are draining at 3.5A, so it would take less time to drain the battery..)
Hope that's clear!
05-12-2006, 05:46 PM
#25
RE: batteries
ORIGINAL: anci3nt
what are typical maximum (and safe) discharge rates for 'good' NiMH batteries today?
what are typical maximum (and safe) discharge rates for 'good' NiMH batteries today?