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BrianG · 08.18.2010, 10:26 AM

Are you using 2s? I'll assume you are. No matter what BEC you use, you still need a battery with 1v-1.5v higher than the BEC rating. 2s being at 7.4v doesn't leave much leeway for voltage drop. The only real solutions for 2s usage are:

- Use a better battery that doesn't dip as much under load (higher C rate)
- Use 3s. Of course, that would require gearing and maybe even a motor change to keep speed/rpm in range.
- Lower the BEC to 4.8v or 5v to allow more leeway. Even then, if your battery voltage is sagging a lot, this won't help much.

For 2s applications where battery sag is going to happen no matter what you do, I would actually suggest using a linear LDO (low voltage-dropout) regulator. You may be able to find one capable of 3A+ and less than 1v dropout (BGMicro.com used to have some), but would be easier to use a lower current LDO regulator (like 100mA) and add a pass transistor to get 3A+.

	(#11)
BrianG RC-Monster Admin Offline Posts: 14,609 Join Date: Nov 2005 Location: Des Moines, IA	08.18.2010, 10:26 AM Are you using 2s? I'll assume you are. No matter what BEC you use, you still need a battery with 1v-1.5v higher than the BEC rating. 2s being at 7.4v doesn't leave much leeway for voltage drop. The only real solutions for 2s usage are: - Use a better battery that doesn't dip as much under load (higher C rate) - Use 3s. Of course, that would require gearing and maybe even a motor change to keep speed/rpm in range. - Lower the BEC to 4.8v or 5v to allow more leeway. Even then, if your battery voltage is sagging a lot, this won't help much. For 2s applications where battery sag is going to happen no matter what you do, I would actually suggest using a linear LDO (low voltage-dropout) regulator. You may be able to find one capable of 3A+ and less than 1v dropout (BGMicro.com used to have some), but would be easier to use a lower current LDO regulator (like 100mA) and add a pass transistor to get 3A+.