Electric conversion esc issues
06-28-2008, 02:00 AM
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Electric conversion esc issues
Hello all
I have just converted a Hong Nor CRT.5 12th Truggy from nitro to electric. I am using Mamba Max and 4600 motor and at first ran it on 2s (no bec). It ran fine but not quick enough!!
I have now gone to 3s but during first run have come across issues. Firstly I kept losing radio (even from only 10-15feet away) for a few seconds before coming back. I thought the ESC may have been doing a thermo shutdown but I lost all radio ie steering as well. I am using a DX3 spektrum radio.
Then the motor did start cutting out but when checking temps everything seemed fine (hot, but not overly so).
I am wondering if I need a bec as I have gone up to 3s but don't know how to work out when I need one.
Help anyone please
I have just converted a Hong Nor CRT.5 12th Truggy from nitro to electric. I am using Mamba Max and 4600 motor and at first ran it on 2s (no bec). It ran fine but not quick enough!!
I have now gone to 3s but during first run have come across issues. Firstly I kept losing radio (even from only 10-15feet away) for a few seconds before coming back. I thought the ESC may have been doing a thermo shutdown but I lost all radio ie steering as well. I am using a DX3 spektrum radio.
Then the motor did start cutting out but when checking temps everything seemed fine (hot, but not overly so).
I am wondering if I need a bec as I have gone up to 3s but don't know how to work out when I need one.
Help anyone please
06-28-2008, 02:30 AM
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RE: Electric conversion esc issues
There are a couple things it could be..
1. battery cant handle the amps the motor is asking for, voltage sags, and the already overworked BEC cant supply the voltage to keep the RX powered up, when the RX cuts out the esc shuts down, battery voltage recovers, and the reciver comes back online. using 3 cells stresses the BEC more than 2... the built in BEC can supply more current with a 2 cell than a 3, since its basically taking the battery voltage, and burning off everything above 5-6 volts as heat... higher voltage batteries mean more heat, which means less current capacity... A seperate BEC like castles 10 amp unit works differently, it actualy switches on and off to get the right voltage, just like an ESC... Think of it this way, the built in linear BEC thats in most speed controls is like a mechanical ESC, while a seperate switching BEC is like an ESC.... with the linear type, the greater the voltage difference between the battery and the output, the harder it has to work... I dont know how many of you ever used mechanical speed controls, but when you drive around at low speed with one, the resistor gets REALLY hot, while when you drive at full speed, it stays cool..... But I digress...
2. motor is asking for more amps than the ESC can handle... not as likely as number 1, since most BEC's when they cut out will leave you steering control..
3. combination of the above two...
You didnt say what battery, esc, and motor you are using, that would help... The stock losi battery that came with my MMB (2 cell lipo) I have has something built in so when the voltage gets low, the battery clamps down and the truck goes dead till I charge it or it sits for 20 min or so and the voltage recovers...
1. battery cant handle the amps the motor is asking for, voltage sags, and the already overworked BEC cant supply the voltage to keep the RX powered up, when the RX cuts out the esc shuts down, battery voltage recovers, and the reciver comes back online. using 3 cells stresses the BEC more than 2... the built in BEC can supply more current with a 2 cell than a 3, since its basically taking the battery voltage, and burning off everything above 5-6 volts as heat... higher voltage batteries mean more heat, which means less current capacity... A seperate BEC like castles 10 amp unit works differently, it actualy switches on and off to get the right voltage, just like an ESC... Think of it this way, the built in linear BEC thats in most speed controls is like a mechanical ESC, while a seperate switching BEC is like an ESC.... with the linear type, the greater the voltage difference between the battery and the output, the harder it has to work... I dont know how many of you ever used mechanical speed controls, but when you drive around at low speed with one, the resistor gets REALLY hot, while when you drive at full speed, it stays cool..... But I digress...
2. motor is asking for more amps than the ESC can handle... not as likely as number 1, since most BEC's when they cut out will leave you steering control..
3. combination of the above two...
You didnt say what battery, esc, and motor you are using, that would help... The stock losi battery that came with my MMB (2 cell lipo) I have has something built in so when the voltage gets low, the battery clamps down and the truck goes dead till I charge it or it sits for 20 min or so and the voltage recovers...
06-28-2008, 02:58 AM
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RE: Electric conversion esc issues
Thanks Dacaur, that is really useful.
I am running Mamba Max with 4600 motor and 3s Thunder Power 3300mah pack (25c). I think the most lilkely thing is the bec as you say. I have read about other people using seperate bec on 3s. I happen to have a cc bec from a helictopter so I'll use that!!
I am running Mamba Max with 4600 motor and 3s Thunder Power 3300mah pack (25c). I think the most lilkely thing is the bec as you say. I have read about other people using seperate bec on 3s. I happen to have a cc bec from a helictopter so I'll use that!!
