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Old 09-23-2010, 08:34 PM   #1
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Default Calculating Runtime

What is the best way to calculate runtime? If I am using a Mamba Max Pro w/4600 motor and Venom 2s 4000mah 7.4v battery. I can't remember and would appreciate someone breaking it down with the details. Thanks.
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Old 09-23-2010, 08:38 PM   #2
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Old 09-23-2010, 08:44 PM   #3
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You could try asking around, stating your exact setup, to see what kind of runtime other drivers are getting.

If you're going to figure it out on your own though, you need a charger that tells you how much capacity it puts back into the pack upon recharging. Take that number and divide it by the number of minutes for which you ran the truck, and you'll get the discharge rate in the form of milliamps-used/minute.
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Old 09-24-2010, 05:12 AM   #4
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Do you have the motor and ESC already? Take a lipo and charge it full. Set a timer for 5mins and drive your car. Stop it after 5mins and charge your lipo. Check how much mA's that went into the battery and divide the number by 5. That's how mA's your using per minute.
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Old 09-24-2010, 07:37 AM   #5
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^^^ Then base your run time on 80% of your lipos capacity (4000 x .8 = 3200mah). You shouldn't be draining your lipos of more than 80% of their capacity if you want them to last.
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Old 09-24-2010, 08:00 AM   #6
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Quote:
Originally Posted by DirtRacer68 View Post
What is the best way to calculate runtime? If I am using a Mamba Max Pro w/4600 motor and Venom 2s 4000mah 7.4v battery. I can't remember and would appreciate someone breaking it down with the details. Thanks.

#1 fill your lipo's or battery to 100% charge (peaked)
#2 run your vehicle for a set time doing what you do bash/race but be hard on it. If you race, race for the time as hard as you would in a real race. Mark how long you ran (say 5 minutes to keep it easy)
#3 recharge your lipo - note how much mAH it took to fill it.
#4 Take your mAH used and divide it by how long you ran and you will know how much mAH per minute you burn with YOUR setup, driving style, and track/bash area

2000mAH/5min = 400mAH/min

#5 now you can take this and figure out what most any pack will give you provided it doesn't LVC early (ie too low of a c rating)

5000mah/400 = 12.5 minutes of run time
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Old 09-24-2010, 09:13 AM   #7
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^^^ That assumes you can use 100% of your lipo's capacity, It should be 4000/400 = 10min run time unless you want to overdischarge your lipo. 80% of the lipo's capacity is useable without poss damage to the lipo.
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Old 09-24-2010, 10:33 AM   #8
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There is no way to determine your actual run time based upon the equipment you are using. You can get a decent idea but many other variable factors are involved that will change your run time drastically.
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