RC India

RC Equipments => Electric Power => Topic started by: Dreamliner on January 03, 2010, 02:54:43 PM

Title: NiMH plus LiPo
Post by: Dreamliner on January 03, 2010, 02:54:43 PM
Hi everyone,


I am just curious to know whether it is safe to use Lipo and NiMH battery for reciver at the same time.  Currently, I am using BEC on channel 3 on Futaba reciever and B channel is unused.  However, my Sailplane which has removable powerpod can go in thermal for longer duration of flight which I think LiPo may not last longer as most of the power might have been used by the motor.  I intend to use full capacity of Lipo to run the motor and NiMH battery power simultaniously for servos to get continuous power supply once the LiPo is empty.  NiMH pack will be connected to B socket on receiver.

Pls suggest
Title: Re: NiMH plus LiPo
Post by: anwar on January 03, 2010, 03:15:11 PM
Should be fine as long you connect the signal line only coming from the ESC to the throttle channel on the receiver. Just remove/cut the positive wire going from the ESC to the throttle channel.
Title: Re: NiMH plus LiPo
Post by: ankur on January 04, 2010, 01:49:26 PM
+1 anwar bhaiya
but the lipo will not be fully discharged as the esc will cut off the motor[if it has a inbuild bec] so that it could power the reciever
for that purpose u need a esc without a inbuilt bec

[seniors correct me if i m wrong]
Title: Re: NiMH plus LiPo
Post by: sushil_anand on January 04, 2010, 03:51:53 PM
QuoteHowever, my Sailplane which has removable powerpod can go in thermal for longer duration of flight which I think LiPo may not last longer as most of the power might have been used by the motor

When you are in a thermal, the motor would be off. It is not very clear from your posts as to what you are looking for. If you mean you would like to use the motor uptil the battery end point then a separate battery option would be the way to go.
Title: Re: NiMH plus LiPo
Post by: Dreamliner on January 04, 2010, 04:44:48 PM
Hi Sushil,

yes, I would like to use LiPo till end point and then switch to NiMH pack as I am not sure that after endpoint, how long the LiPo will power the servo after the end point for motor?
Title: Re: NiMH plus LiPo
Post by: anwar on January 04, 2010, 04:53:41 PM
Usually you never need this though. The "low voltage cut-off" (which can usually be programmed in many ESCs to low/mid/high) allows only the motor power to be cut off when the lipo charge goes low, but the power to the receiver (and thus to the servos) are maintained for a few more minutes.

By setting the ESC to cut off earlier, you can preserve lots of power for the servos, to ensure a safe landing.