BotBitz 85A Manual

Brushed ESC

November 19, 2012

The BotBitz 85A ESC is a customised version of the the Turnigy 85A BESC, (orTz85a for short), flashed with BotBitz firmware enabling it to provide features designedfor Combat Robots. It is designed as a low cost entry level device for featherweight(30lb/13.6kg robots).

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1 SpecificationThis ESC has been flashed replaced with custom BotBitz firmware in order to allow itto be used for brushed motors. (Brushless motors will no longer work)ESC do not have current or temperature limiting and overcurrent and situationswill result in damage to the ESC.

1.1 Current Capacity• 200A burst <1s

• 85A for 1min

• 60A for 2min

• 40A for 3min

For more information see the graphs in testing section.

1.2 Voltage LimitMax Voltage 25VLipo: 2 - 6SNiMh/NiCd: 5-18S

1.3 Size

Length: 65.5mmWidth: 34mm

Height: 17.5mm

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1.4 RC InputThe ESCs have been calibrated to suit the Hobbyking T6A v2 radio. This means thatthe upper and lower limits or the RC pulse-in signal are approximately 2ms and 1msrespectively. If the input signal is outside of these ranges this may cause the ESC tofailsafe. If your robot stops moving at full throttle you are likely exceeding these limits.This can be overcome by adjusting the rates and limits of your radio.

2 WiringConnecting battery to motor wires or reverse polarity will damage the ESC.

The power wires are coloured black (-ve) and red (+ve) and are indicated on theimage below. Ensure that these are correctly hooked up as reverse polarity will damagethe ESC.

The RC input should be plugged into you radio receiver.

The output wires are on the opposite side of the ESC these should be connectedto the two terminals of the motor. Do not allow these wires to short circuit or applybattery voltage to these wires this will damage the ESC.

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3 Testing DataThe 85A ESC was tested under a variety of current loads, for different periods of time.These tests were undertaken at approximately 12V. The temperature of the heatsinkwas measured using a logging device. The temperature at the start of each test wasapproximately the ambient temperature. No fan or active cooling was used.

Two scenarios were examined, 100% duty cycle (full power, constantly on) and50% duty cycle (half on, half off). It was expected that 50% duty cycle is approximatelythe worst case scenario which will have the most ripple and most time spent in resistiveregion.

Figure 1: 25A @ 50% duty cycle for 3min

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Figure 2: 50A @ 50% duty cycle for 1min

Figure 3: 50A @ 100% duty cycle for 3min

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Figure 4: 85A @ 100% duty cycle for 1min

4 WarrantyAll ESCs are tested before shipment and we do our best to ensure they are packagedand shipped correctly to minimise potential damage. If for any reason ESCs do notfunction as expected on arrival please contact us and we will do our best to solve yourissues. If we cannot resolve these issues we may ask you ship your ESCs back to us totest. If ESCs are deemed faulty you will be refunded or replaced at our expense. If theyhave been damaged through incorrect usage or misuse we can replace or repair them atbuyers cost.

Due to the nature of Combat Robotics we can not offer warranty on ESCs whichhave been used in combat.

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