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-   -   Receiver batteries (http://www.rcuniverse.com/forum/rc-jets-120/11384929-receiver-batteries.html)

StephenUK 01-26-2013 09:06 AM

Receiver batteries
 
Hi Guys

I’ve recently bought my first jet - a Boomerang Nano fitted with Wren 44 Gold. The model was second hand from a very reputable local model shop. The only component missing is the receiver. The model appears to be in very good condition, the turbine has a total running time of 110 minutes.

One question I have is regarding radio. I currently use a JR XG11 DMSS radio. I plan to use the 11 channel JR RG1131B receiver. I have noticed that the model is fitted with 2x 2000mah 6v NIMH receiver batteries (plus a 2s lipo for the ECU). The receiver previously installed in the model was a Spektrum with two battery terminals. Is this common practice to use two receiver batteries, presumably one as a backup if the other fails? I have been looking through the JR DMSS range of receivers but they do not offer a similar receiver with the two battery terminals. In my F3A models, my preferred method is to use a 2s lipo and a Power Box Digi Switch, is this suitable in a jet?

Another option is to continue with the two NIMH receiver batteries (obviously replace with new ones) and use a Power Box 12 switch which allows the use of 2 receiver batteries.

Any help would be much appreciated.

Regards

Stephen

JohnMac 01-26-2013 09:45 AM

RE: Receiver batteries
 
Hi Stephen,
Yes it is common practice to use dual batteries in a jet. The main aim is redundancy, as at jet speeds even a momentary loss of control through a brown out event, can be catastrophic. This has the added benefit that twin batteries working in parallel offer twice the current capability of a single battery. Again, jets tend to use high power digital servos, and these are current hungry.
If you intend to replace the NiMh batteries, then my advice would be to go for A123 batteries if you can. I think these are now accepted as the best battery technology currently available. Personally, I use no NiMh batteries in my models.
John

Xairflyer 01-26-2013 10:06 AM

RE: Receiver batteries
 
I agree the Life may be better but see no reason why not to stick with the sub C Nimh batteries which I use in all my models, properly charged they are very robust.

CraigG 01-26-2013 10:11 AM

RE: Receiver batteries
 

Quote:

ORIGINAL: StephenUK

I have been looking through the JR DMSS range of receivers but they do not offer a similar receiver with the two battery terminals.Regards

Stephen

Welcome to jets!

You can plug a second battery into any unused servo terminal. It will operate in parallel with the one plugged into the "battery" terminal.

Concur with JohnMac on the A-123 battery suggestion. I use them in all my jets.

Craig

mick15 01-26-2013 10:18 AM

RE: Receiver batteries
 
I'm not disagreeing with what has been written just giving another view.

I have been flying a Boomerang XL for the last four years with one LiFe 2300 two cell. KISS

m

ash 26 01-26-2013 10:26 AM

RE: Receiver batteries
 
I am with you John been using back -up system in all my models from Gliders to Jets and have been using A123 for the last 4 years now :)

cheers

Andy

StephenUK 01-26-2013 10:33 AM

RE: Receiver batteries
 
Hi guys,

Thank you very much for the information. If I use 2s A123 batteries, Will i be ok to plug these straight into the receiver through a normal switch, without the use of a regulator? the receiver instructions specify an input voltage range of 4.8v - 8.5v and a 'normal rated voltage' of 4.8v? I guess it would depend on the voltage rating of the servos?

Once again many thanks

Stephen

ash 26 01-26-2013 10:45 AM

RE: Receiver batteries
 
I would always go through a regulator like Power Box sensor switch or emcotech

cheers

Andy

bcovish 01-26-2013 11:24 AM

RE: Receiver batteries
 

Quote:

ORIGINAL: CraigG


Quote:

ORIGINAL: StephenUK

I have been looking through the JR DMSS range of receivers but they do not offer a similar receiver with the two battery terminals.Regards

Stephen

Welcome to jets!

You can plug a second battery into any unused servo terminal. It will operate in parallel with the one plugged into the ''battery'' terminal.

Concur with JohnMac on the A-123 battery suggestion. I use them in all my jets.

Craig

If all the channels are being used in the receiver, you can "Y" the second battery into any of the channels on the RX

CraigG 01-26-2013 12:03 PM

RE: Receiver batteries
 

Quote:

ORIGINAL: ash 26

I would always go through a regulator like Power Box sensor switch or emcotech

cheers

Andy
Not everybody agrees but many of us have been running A123 batteries without regulators and without problems of any sort. Goes along with the aforementioned KISS principle. It's an individual choice.

Boomerang1 01-26-2013 01:15 PM

RE: Receiver batteries
 
If the model has been flying fine I'd just replace the batteries with new of the same specification NIMH.

No CG problems, no packaging or access problems, just fit your reciever, set up & fly.

NIMH batteries are fine as long as you realise their good & bad points & use them appropriately.

The set up you have is exactly what I use in my jets, plug the extra battery into any spare socket on
the reciever via a switch or your choice.

Some servos get angry if you feed them too much voltage hence the need for a regulator.

Quote:

In my F3A models, my preferred method is to use a 2s lipo and a Power Box Digi Switch, is this suitable in a jet?
I used that setup at the last jet fly I attended, I forgot my usual batteries so had to make do with what a vendor at the meet had
available, used 2 LIFE batteries & 2 x PB Digi Switches which worked fine. The only thing that concerned me was the current rating
of the Digi switches, jets use lots of servos & the current rating of the switches I bought was quite low. - John.

BarracudaHockey 01-26-2013 02:29 PM

RE: Receiver batteries
 
The reciever you refer to is called a Power Safe reciever and yes, its got dual battery inputs for redundancy and a "soft switch" which means the switch when closed holds the reciever in an OFF state, so if the switch fails they normally fail open, and you just cant turn off your reciever, vice the other way around where if a normal switch opens you loose power.

As for the DMSS recievers, they do not, as of yet, offer Power Safe recievers in DMSS yet and your radio isn't compatable with any of the DSMX power safe receivers.

I was told, end of January for DMSS power safe, but....its the end of January and they aren't here yet so.....soon maybe?

George 01-26-2013 02:54 PM

RE: Receiver batteries
 

Quote:

ORIGINAL: StephenUK

Another option is to continue with the two NIMH receiver batteries (obviously replace with new ones) and use a Power Box 12 switch which allows the use of 2 receiver batteries.

I have been using the dual Power Box switch with 2 2S Fromeco Li-Ions for years and is my preferred set-up. You can do the same and use 2 2S Li-Pos if you were already using the Li-Po. The A123s are a good option as well and many are switching to that set-up. It comes down to personal preference and what you're comfortable with in regards to power, safety and needs.

Welcome to jets, you'll love it!!

sirrom 01-26-2013 07:41 PM

RE: Receiver batteries
 
Yes it is common to use two packs for back up purposes and yes you can just plug the second battery into an unused receiver channel. I for the longest time did not usually do this but started flying giant scale planes with my son so started using dual RX batteries. I set up my 37% ultimate with a smart fly power expander with 2 LiFe batteries plugged in. In my son's plane which is a 30% extra I used two LiFe batteries directly into the receiver. Today that practice saved his plane. He did a very hard snap roll today while flying, when we landed something was a little off so we took off the canopy and one of the batteries had come loose from it's mount and disconnected itself. If the second battery had not been there, we would have lost the plane. So yes use both batteries, with power expander or a just plugged into the rx.

Patrick

sirrom 01-26-2013 07:42 PM

RE: Receiver batteries
 
Yes it is common to use two packs for back up purposes and yes you can just plug the second battery into an unused receiver channel. I for the longest time did not usually do this but started flying giant scale planes with my son so started using dual RX batteries. I set up my 37% ultimate with a smart fly power expander with 2 LiFe batteries plugged in. In my son's plane which is a 30% extra I used two LiFe batteries directly into the receiver. Today that practice saved his plane. He did a very hard snap roll today while flying, when we landed something was a little off so we took off the canopy and one of the batteries had come loose from it's mount and disconnected itself. If the second battery had not been there, we would have lost the plane. So yes use both batteries, with power expander or a just plugged into the rx.

Patrick

Su26flyer 01-27-2013 12:57 AM

RE: Receiver batteries
 


The guy is talking about a Boomer Nano which was designed to be a simple jet and not need all the fancy stuff. If the batteries you got with the jet are ok just carry on using them. Again keep it simple</p>

mick15 01-27-2013 02:01 AM

RE: Receiver batteries
 
at last, some sense.

m

3dean 01-27-2013 02:22 AM

RE: Receiver batteries
 
i wouldnt change the batterys but i would put them through a powerbox sensor switch ,if the switch fails it will do so in a closed position,the lights will also give you an indication of battery condition. a nano may be the budget end of the market but actually its still a sh1t load of £ to stick in the deck

Su26flyer 01-27-2013 03:15 AM

RE: Receiver batteries
 

Quote:

ORIGINAL: 3dean

i wouldnt change the batterys but i would put them through a powerbox sensor switch ,if the switch fails it will do so in a closed position,the lights will also give you an indication of battery condition. a nano may be the budget end of the market but actually its still a sh1t load of &pound; to stick in the deck

You sold yours. Now that was a Bargain http://www.rcuniverse.com/forum/js/f...wink_smile.gif

Dave Wilshere 01-27-2013 03:29 AM

RE: Receiver batteries
 
First...there is no such thing as 4.8v operation...I have argued with JR over this for 10 years plus and have only had a straight answer in the last year. 4.8v is a poor description of battery voltage, it means 4 cell. 6v (common Futaba talk) means 5 cell...Ni or MiMH. These are flat voltages and NOT what we fly at. Good 4 cell packs operate between 5.5 and 5.7v, Good 5 cell packs around 7.2v. JR do all their testing on servos and radios at 5.7v....
Most Rx's now are good over a range of voltages right up to 8.4v (2s Li-Po called 7.4v!!) 2s Li-po when charged. So its down the the servos and sometimes valves as to what they will take.
Powerbox realised a long time ago that an optimum voltage for servos and Rx's is between 5.5 and 5.9v

I fly my Nano with a single Digi switch rated at 3A and 5.5v, it has a 2s Li-Po charged to 8.4v and I have digital servos on everything except nose steering and I can say I fly it hard...for landing I have 90 degree flap, Ailerons raised 12mm and rudders spread 15mm to all act as air brake. I have 100+ flights and the Digi switch heat sink gets slightly warm after flight. (how many of you check the temp of your Sensor switch or even Powerbox unit alu heat sinks...this tells you everything about how hard the unit is working.

In this case if they are good NimH (Eneloop) or quality D cells running 5 cells (so 7v plus), I'd stick in a Sensor Switch (overkill) and fly all weekend.
I have Sensor switches in all my CARF Flashes including the 2006 Instruction manual aeroplane, with the same two 2s Li-Pos with hundreds and hundreds of flights...thats rated at 5A

Dave W

Su26flyer 01-27-2013 03:33 AM

RE: Receiver batteries
 

Quote:

ORIGINAL: Dave Wilshere

First...there is no such thing as 4.8v operation...I have argued with JR over this for 10 years plus and have only had a straight answer in the last year. 4.8v is a poor description of battery voltage, it means 4 cell. 6v (common Futaba talk) means 5 cell...Ni or MiMH. These are flat voltages and NOT what we fly at. Good 4 cell packs operate between 5.5 and 5.7v, Good 5 cell packs around 7.2v. JR do all their testing on servos and radios at 5.7v....
Most Rx's now are good over a range of voltages right up to 8.4v (2s Li-Po called 7.4v!!) 2s Li-po when charged. So its down the the servos and sometimes valves as to what they will take.
Powerbox realised a long time ago that an optimum voltage for servos and Rx's is between 5.5 and 5.9v

I fly my Nano with a single Digi switch rated at 3A and 5.5v, it has a 2s Li-Po charged to 8.4v and I have digital servos on everything except nose steering and I can say I fly it hard...for landing I have 90 degree flap, Ailerons raised 12mm and rudders spread 15mm to all act as air brake. I have 100+ flights and the Digi switch heat sink gets slightly warm after flight. (how many of you check the temp of your Sensor switch or even Powerbox unit alu heat sinks...this tells you everything about how hard the unit is working.

In this case if they are good NimH (Eneloop) or quality D cells running 5 cells (so 7v plus), I'd stick in a Sensor Switch (overkill) and fly all weekend.
I have Sensor switches in all my CARF Flashes including the 2006 Instruction manual aeroplane, with the same two 2s Li-Pos with hundreds and hundreds of flights...thats rated at 5A

Dave W
Dave Your points about voltages etc are very well made and I would agree that a sensor switch (duel) is a good device. I wonder however if a switch that costs about &pound;70 fits into the bracket of keeping it simple on what was designed to be possibly the most simple RC jet.

BaldEagel 01-27-2013 03:43 AM

RE: Receiver batteries
 

Quote:

ORIGINAL: StephenUK

Hi guys,

Thank you very much for the information. If I use 2s A123 batteries, Will i be ok to plug these straight into the receiver through a normal switch, without the use of a regulator? the receiver instructions specify an input voltage range of 4.8v - 8.5v and a 'normal rated voltage' of 4.8v? I guess it would depend on the voltage rating of the servos?

Once again many thanks

Stephen
I have been using A123's since they first appeared in the market, this was before they where available to the RC market, I just use them the same as a Nimh battery (except for charging) their off the charger voltage is less than a fresh charged 5 cell Nimh, they do not need a regulator.

Mike

Su26flyer 01-27-2013 04:35 AM

RE: Receiver batteries
 

Quote:

ORIGINAL: BaldEagel


Quote:

ORIGINAL: StephenUK

Hi guys,

Thank you very much for the information. If I use 2s A123 batteries, Will i be ok to plug these straight into the receiver through a normal switch, without the use of a regulator? the receiver instructions specify an input voltage range of 4.8v - 8.5v and a 'normal rated voltage' of 4.8v? I guess it would depend on the voltage rating of the servos?

Once again many thanks

Stephen
I have been using A123's since they first appeared in the market, this was before they where available to the RC market, I just use them the same as a Nimh battery (except for charging) their off the charger voltage is less than a fresh charged 5 cell Nimh, they do not need a regulator.

Mike
Where does one buy these miracle 123's from. I never seem to see them in normal shops

JohnMac 01-27-2013 05:08 AM

RE: Receiver batteries
 

Quote:

ORIGINAL: Su26flyer



The guy is talking about a Boomer Nano which was designed to be a simple jet and not need all the fancy stuff. If the batteries you got with the jet are ok just carry on using them. Again keep it simple</p>
Yes a simple jet with a £2000 turbine in it. Not to mention the potential safety issues if one battery system fails in flight. NiMh are a poor technology for reliability in my personal experience and that of others. I have had a lot of them fail or just fade away inside a season. They also are poor at delivering high currents. I concede that in this particular jet they may well be sufficient, but with the expressed intent to replace these batteries, then my advice stands. Go for the better technology.
With regard to needing a regulator or not, I have both situations. I one model equiped with older JR servos I have a regulator (Emcotec BIC) fitted to ensure the voltage is always kept below 6 volts. I another jet fitted with Hitec servos there is no regulator and also no problems.
My 2 peneth.
John

Wayne22 01-27-2013 05:16 AM

RE: Receiver batteries
 
it depends on the max voltage that your servos will take. Many JR and some Futaba servos are rated at 6 volts max. I've seen one such servo get cooked running an unregulated 123 pack. NiMH have a bad tendancy to drop in voltage under load....I wont use them except in pairs of 5 cells with a regulator.
Since the Nano only weighs 12 lbs fully fuelled, there is no need to get overly complicated with it.


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