CritterBuddy
February 25th, 2006, 08:49 AM
I'm working with an electrical engineer to help build a dual powered (gas and electric) barstool racer as a Shriner parade vehicle. Original thoughts were the batteries may not last long enough for some of our longer parades including the "play time" before and after. Hence our thoughts moved to the dual power concept where a quick change could be done so we would use gas power outside and electic power inside. However, more research is still needed as we don't know how big (wattage) motor we need or the gear ratio needed to do the things we want to do like wheelies, donuts, 20 mph, etc.
The basic formula for determining how long your vehicle will run is:
P = V x I power (watts) = voltage x current (amps)
However, bear in mind we are not taking into account any power loss for the motor, battery, or other electical components which they all have. This is just basics.
To use this formula let's start with batteries. You can hookup as many 12 volt batteries in "series" as you need to get 24 volts, 36 volts, etc. So if your motor is a 24 volt motor you'll need two 12 volt batteries hooked up in series. If they were hooked up in parallel you would still only have 12 volts but you would increase you drive time if you are using a 12 volt motor. However, we believe we'll need at least a 24 volt moter to make this vehicle work the way we want and we're trying to keep the battery count down to 2 hence why we're dealing with 24 volts. Though there are many types of batteries available, let's assume we will be using a standard automotive battery for reference only which has a 70 amp hour rating. Yes, a deep cycle or gel battery would last longer but remember we're just dealing with basics here.
Motors are also available in a variety of watts/voltages and is where we're still having our problems determining exactly what will work. For this example, let's assume we will be using a 300 watt motor as a reference.
Using basic algebra, we'll convert the formula to:
P / V = I power (watts) / voltage = current (amps)
So this motor/battery combination is 300 watts / 24 volts = 12.5 amps.
Now we can estimate how long this motor/battery combination will last:
70 amp hour battery / 12.5 amps = 5.6 hours continuous usage
The reason I put in continuous usage is that batteries have the capability of somewhat recharging themselves during rest periods. So if you run continuously this motor/battery setup could last 5.6 hours. If you drove say 30 minutes and then stopped 30 minutes you could possibly extend this drive time somewhat.
Another example using a 600 watt 24 volt motor:
600 watts / 24 volts = 25 amps
70 amp hour battery / 25 amps = 2.8 hours
If anyone has any thoughts or experiences using different wattage motors I'd be interested. I'll post more if anyone is interested as my research develops.
The basic formula for determining how long your vehicle will run is:
P = V x I power (watts) = voltage x current (amps)
However, bear in mind we are not taking into account any power loss for the motor, battery, or other electical components which they all have. This is just basics.
To use this formula let's start with batteries. You can hookup as many 12 volt batteries in "series" as you need to get 24 volts, 36 volts, etc. So if your motor is a 24 volt motor you'll need two 12 volt batteries hooked up in series. If they were hooked up in parallel you would still only have 12 volts but you would increase you drive time if you are using a 12 volt motor. However, we believe we'll need at least a 24 volt moter to make this vehicle work the way we want and we're trying to keep the battery count down to 2 hence why we're dealing with 24 volts. Though there are many types of batteries available, let's assume we will be using a standard automotive battery for reference only which has a 70 amp hour rating. Yes, a deep cycle or gel battery would last longer but remember we're just dealing with basics here.
Motors are also available in a variety of watts/voltages and is where we're still having our problems determining exactly what will work. For this example, let's assume we will be using a 300 watt motor as a reference.
Using basic algebra, we'll convert the formula to:
P / V = I power (watts) / voltage = current (amps)
So this motor/battery combination is 300 watts / 24 volts = 12.5 amps.
Now we can estimate how long this motor/battery combination will last:
70 amp hour battery / 12.5 amps = 5.6 hours continuous usage
The reason I put in continuous usage is that batteries have the capability of somewhat recharging themselves during rest periods. So if you run continuously this motor/battery setup could last 5.6 hours. If you drove say 30 minutes and then stopped 30 minutes you could possibly extend this drive time somewhat.
Another example using a 600 watt 24 volt motor:
600 watts / 24 volts = 25 amps
70 amp hour battery / 25 amps = 2.8 hours
If anyone has any thoughts or experiences using different wattage motors I'd be interested. I'll post more if anyone is interested as my research develops.