RC_Plane_Guy1

I have recently changed radio systems from Spektrum to Futaba. I am looking for battery redundancy options. And understanding of what works best.

I am not an electronics/ battery expert so have limited understanding. But from reading various other discussions there seems to be conflicting opinions on whether using 1x Rx powered by x2 switches/ x2 batteries is a good idea or not?

Some people suggest it might be a bad idea due to risks that if one pack fails it could drag the other down and the need to use diodes etc. However many people on forums seem to suggest this option is fine and use it regularly. See the parallel batteries article on hangtimes website in support of using this setup (unable to attach link due to being a new member).

I have only ever used either single batteries for small models or a proper dual battery system such as powerbox for high end. So I am curious about the option to use the above mentioned system for my “mid level” models. I want redundancy but not at the high price they can cost. I am nervous of plugging 2 batteries straight into my receiver and dont want to “blow it”!

Any thoughts/ advice always welcome - look forward to reading your replies 😊

Thanks!

FUTABA-RC

I have always run 2 batteries + 2 switches into a single receiver.
The idea that one pack will draw down the other simply does not happen.

I currently use 2 packs into the BoomaRC dual switch (pin operated). There are other similars one. I prefer non-mechanical switches.

I have never used a power box, etc. and personally see no need for them.

If you share what planes you will be flying I can help with more specific suggestions.

RC_Plane_Guy1

I have small stuff on single bats, an Acrowot XL on a DLE30, which is a general sport plane and currently one 5 cell 3300mah Nimh and an emcotec magnetic switch. Seperate Rcexl ignition and 4 cell nimh.

A Boomerang Nano jet with Wren44 which I fly via a powerbox sensor switch and x2 lipo’s.

And now I am just in the process of getting into larger warbirds. I am in the early stages of building a Topflite GS 86” P-47 which I need to decide a setup for later down the line.

Then my current project for setting up is a 2nd hand Blackhorse B/F109 86”. My current stock of bits and proposed setup will be a Futaba 7014 rx, with 2 heavy duty mechanical switches (already in the plane), powered by 2 five cell Nimh’s (3300mah & 5000mah). Rcexl ignition on a seperate 4 cell Nimh. I will then charge the batts seperately not plugged in to avoid any issues there.

FUTABA-RC

The only thing I would change is to swap the NiMH packs in favor of LiFe, basically the same voltage and safe for non-HV servos. LiFe is a far better choice, and lighter, than NiMH. If you have HV servos go with 2xlipo packs.

The P-47 I would do one 7014 (or 7114 when available) with 2xLiFe or LiPo depending on your servos. 2 packs, 2 switches, single RX has been my goto for decades, and I am not alone.

On my 70cc Mamaba I run 2x2550 lipos into a single 7014. Rock soild.
On larger planes I use 3,000 to 5,000 mAh packs.

RC_Plane_Guy1

Thanks for the advice! Why would you decide between LiFe or LiPo dependant on servo choice?

I was thinking of going for LiFe’s on the P47 or when I come to need to buy a new battery. For now though I am making use of what I have (NimH’s) without paying out more money. 😊

And if your normal go too would be 2 switches, why in your first post did you say you now currently use a single dual switch? Is the single specialised dual switch more reliable or any different to using two individual switches?

FUTABA-RC

If using non-high voltage (HV) servos then LiFe with a nominal 6.6 volts is great. Non-HV servos cannot take the full 8.4 volts of fully charged lipos.
If your servos can hendle the higher voltage then do that so you get faster speed, more torque and better performance under load that a lipo gives you.

Just make sure they are performing properly. Do a charge/discharge test to see if you are getting expected capacity.

The BoomaRC Dual hidden switch is two separate electronic switches in the same device. They operate independently despite being in the same device. It is electrically equivalent of two separate switches. I prefer non-mechanical switches as well.