Receiver Batteries
05-02-2018, 05:16 AM
#1
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Receiver Batteries
Hi All,
I am looking to purchase a couple of spare receiver batteries. I have an older Spektrum DX7 which I purchased around 2010.
I am currently flying an Avistar ARF with an OS MAX .46FX engine.
Any recommendation on which receiver batteries to purchase?
Any help on what all the numbers mean on the batteries would also be beneficial.
Thanks in advance for any help.
Brad
I am looking to purchase a couple of spare receiver batteries. I have an older Spektrum DX7 which I purchased around 2010.
I am currently flying an Avistar ARF with an OS MAX .46FX engine.
Any recommendation on which receiver batteries to purchase?
Any help on what all the numbers mean on the batteries would also be beneficial.
Thanks in advance for any help.
Brad
05-02-2018, 06:44 AM
#3
typical Rx battery pack will be 4.8 Volts and around 400 Mah Current, a typical Tx pack will be 9.6 Volts at around 600 Mah . the volts are obvious,...that is what is needed to run the receiver and servos. the differences lie in the second set of numbers. simply put,.... the larger the number,...the longer the battery pack will last before needing to be recharged and of course the longer it will take to be fully charged by a typical charger. the Mah ( milli-amp-hours) is just the unit of measurement for DC current at the given voltage (1000 Mah = 1Amp-hour). ie. 600 Mah = .006 Amps at the given voltage. the choice of what size batteries you use is based on a compromise of what will fit in the space you have and how many flights you'd like to get out of a charge. increasing the capacity of your Rx pack is usually easy to do,....there is usually plenty of room for a bigger battery in the plane, but you have to make sure an larger TX battery will fit in you transmitter.
05-02-2018, 08:27 AM
#4
If you are into saving weight and money, the best battery I have used for Rx is a 700 mAh LiFe battery. The LiFe battery does not self-discharge and a 700 mAh will last me several flights and charge fairly quick. Only thing is you need a charger that can charge LiFe batteries.
Battery: https://hobbyking.com/en_us/zippy-fl...iver-pack.html
Charger: https://www.towerhobbies.com/cgi-bin...&I=LXZWP0&P=ML (You can take it to the field with you and use it with a 12V battery to recharge your Rx battery if you need to, but I have never needed to do that)
Just make sure that your servos are not so old that they can't take the 6.6 Volts of the LiFe batteries. All my servos can handle it and they go back over 10 years.
Stay away from Lipo and NiCD batteries. Lipos have to be removed from the plane to recharge them (and they are still hazardous) and NiCD's are bad for the environment.
Battery: https://hobbyking.com/en_us/zippy-fl...iver-pack.html
Charger: https://www.towerhobbies.com/cgi-bin...&I=LXZWP0&P=ML (You can take it to the field with you and use it with a 12V battery to recharge your Rx battery if you need to, but I have never needed to do that)
Just make sure that your servos are not so old that they can't take the 6.6 Volts of the LiFe batteries. All my servos can handle it and they go back over 10 years.
Stay away from Lipo and NiCD batteries. Lipos have to be removed from the plane to recharge them (and they are still hazardous) and NiCD's are bad for the environment.
05-02-2018, 08:35 AM
#5
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Personally, I shy away from inexpensive batteries. You don't know what brand of cells they use or what quality the soldering and wiring is. If you go with NiMH, look for packs built with Sanyo or Panasonic cells. NoBS sells quality packs. Can't help you with LiFe batteries. I like to be able to check the battery pack voltage with a meter and know how much charge is left and don't want the added hassle of a balance port. LiFe batteries look good until the voltage suddenly drops off a cliff.
05-02-2018, 10:10 AM
#6
I never had a failure with these LiFe batteries and I have been using them for about 5 years now. Only time they failed or wore out is when I accidentally left the receiver switch ON for a long period of time and they discharged to a too low a voltage. My fault, not battery's. The balancing plug is a pain to deal with in some planes that are not easy to get to battery. But they do sell extensions for the balance plug. The benefit of low weight and fast charging makes them very attractive for small planes. For bigger planes, I use Nimh batteries. But I have not experienced problems with either type. I check battery voltage before every flight, regardless of battery type.
You don't need to access the balance plug to check the battery voltage, just the regular jst plug. You do need to access the balance plug for charging though.
You don't need to access the balance plug to check the battery voltage, just the regular jst plug. You do need to access the balance plug for charging though.
05-02-2018, 07:06 PM
#7
I am a very big fan of —-Nicad 1000ma 6.0v packs —in 40 and 60 size aircraft for great performance and battery charge holding power in flight
Most servos are rated for 6.0v and are rated to produce more torque and move faster 6.0v
6.0v packs do not drain as fast as 4.8 ma packs
NiMH do not hold up for the long haul
I do not care for them
I started with Nicads back in the day and never had a failure in over 20 years
keep them fully charged - use trickle and slow charging —is best
cycle them before you fly if you have not used the plane in a while
check them before every flight
you need a100 ma charger( and trickle ) and a Nicad battery cycling tool to service them correctly
i built and sold Nicad packs at one point in the past and know them well so I speak from hands on experience regarding this subject
Enjoy
Most servos are rated for 6.0v and are rated to produce more torque and move faster 6.0v
6.0v packs do not drain as fast as 4.8 ma packs
NiMH do not hold up for the long haul
I do not care for them
I started with Nicads back in the day and never had a failure in over 20 years
keep them fully charged - use trickle and slow charging —is best
cycle them before you fly if you have not used the plane in a while
check them before every flight
you need a100 ma charger( and trickle ) and a Nicad battery cycling tool to service them correctly
i built and sold Nicad packs at one point in the past and know them well so I speak from hands on experience regarding this subject
Enjoy
05-03-2018, 12:53 PM
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NICADS are not that common nowadays. NiMH are just about as reliable, as long as you stick with reputable brands. At least that was my experience over many years.
They do have a higher self discharge than NICADS though. Here is how to deal with that.
Get a 24 hr plug in timer from Walmart. Set it to switch on for an hour every day. leave your charger plugged in and the TX and RX on charge.
When you come in from flying plug in your tx and rx and do a manual set for as many hours that you think. you need. Full days flying 14 hrs just a couple of flights 6 hrs. The autotimer will then run the charger for an hour every day and you can go flying with confidence.
They do have a higher self discharge than NICADS though. Here is how to deal with that.
Get a 24 hr plug in timer from Walmart. Set it to switch on for an hour every day. leave your charger plugged in and the TX and RX on charge.
When you come in from flying plug in your tx and rx and do a manual set for as many hours that you think. you need. Full days flying 14 hrs just a couple of flights 6 hrs. The autotimer will then run the charger for an hour every day and you can go flying with confidence.
05-06-2018, 04:51 PM
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I like to use 5-cell 6v 1200Mah to 1600Mah NiMH receiver packs like this Onyx pack: https://www.towerhobbies.com/cgi-bin...?&I=LXGXMC&P=0
They are compact, easy to charge without having to remove them from the aircraft, relatively inexpensive, and a full charge will allow you to fly a 40-size sport plane or trainer all day without having to recharge.
If you accidentally leave your plane switched on and zero the battery voltage, you can usually recover NiMH packs easily simply by cycling them a few times. LiFe or LiPo receiver packs are ruined if they get fully discharged.
NiCd receiver batteries are also terrific for receiver use, but they are more difficult to find and usually aren't available in higher capacities. I believe that NiCd packs are also a bit heavier than similar NiMH packs of similar capacity.
LiPo and LiFe receiver packs are fine as long as you can manage removing the packs for recharging and you make sure your receivers and servos can accept higher voltages.
There typically aren't any "wrong" or bad choices, but each battery chemistry offers advantages and disadvantages.
They are compact, easy to charge without having to remove them from the aircraft, relatively inexpensive, and a full charge will allow you to fly a 40-size sport plane or trainer all day without having to recharge.
If you accidentally leave your plane switched on and zero the battery voltage, you can usually recover NiMH packs easily simply by cycling them a few times. LiFe or LiPo receiver packs are ruined if they get fully discharged.
NiCd receiver batteries are also terrific for receiver use, but they are more difficult to find and usually aren't available in higher capacities. I believe that NiCd packs are also a bit heavier than similar NiMH packs of similar capacity.
LiPo and LiFe receiver packs are fine as long as you can manage removing the packs for recharging and you make sure your receivers and servos can accept higher voltages.
There typically aren't any "wrong" or bad choices, but each battery chemistry offers advantages and disadvantages.
05-07-2018, 06:52 AM
#12
do receivers handle the 6 volts OK ?. I just bought a 4.8 volt NiCad pack that was 1000Mah from Radio Shack. I think it was $8.50. only had one on the shelf or I would have bought a few !.
Last edited by r ward; 05-07-2018 at 06:56 AM.
05-07-2018, 12:52 PM
#13
No never use a 4.8v Nimh or Nicd with any 2.4 system especially so on the early systems. If you do you are inviting the infamous early 2.4 system brownout's and resultant total losses.
Yes Spectrum was the first to experience this and later Futaba. Truth is on all 2.4 systems early or new the four cell packs have never cut it and corporate was never able to openly admit this with most of the brands.
J.duncker in post #2 and Bigedmustafa post #11 Have given you great and thorough information. Put that Radio Shack pack in the toy car it was intended for please do not put it in your airplane.
I buy my packs in bulk for all my glow airplanes and they are always 6v 2000mah 5c Nimh.
John
Yes Spectrum was the first to experience this and later Futaba. Truth is on all 2.4 systems early or new the four cell packs have never cut it and corporate was never able to openly admit this with most of the brands.
J.duncker in post #2 and Bigedmustafa post #11 Have given you great and thorough information. Put that Radio Shack pack in the toy car it was intended for please do not put it in your airplane.
I buy my packs in bulk for all my glow airplanes and they are always 6v 2000mah 5c Nimh.
John
06-27-2019, 07:39 PM
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A few points on Rx batts
Life batts are the SURE way to go, but not all are created equal. The A123 round life cells in 1100mah and 2300mah flavors are able to handle 30-50amp current under load due to its nano chemistry in each cell. The square plastic baggy Life cells cant handle such a high current under load and are actually a little better then a nimh cell under load conditions. Those Chinese square prism bagged life cells will sag but they do have their place in the market. Life CAN be drained down to 0% with no worries unlike a lipo cell, but they cant be load tested in the normal sense like a nimh cell. Life cells can be charged and balanced while inside the plane Molex connectors make good flush mount solutions for plane walls
Molex balance and charge connectors on Sig LT40
Life cells must ALWAYS be balanced charged each cycle.
NIMH cells have a weight, self drain, and volt sag under load penalty and once they self drain down to 0% the cells could become damaged. Dont use Nimh AA cell packs in high current load or many servo load installations. NIMH sub C cells or larger is a much better choice, and I would prefer a second parallel nimh pack in addition. ALWAYS use a trickle wall wart charger hooked to a simple 1 hour a day timer if you want your your NIMH packs to last indefinitely.
Lipo cells MUST be removed from the plane and the 8.4v 2 cell voltage is too much for most setups if unregulated.They MUST be visually monitored for each charge cycle and can be volatile.
Life A123 cells are the best choice for my high current helis and trainer plane
Life batts are the SURE way to go, but not all are created equal. The A123 round life cells in 1100mah and 2300mah flavors are able to handle 30-50amp current under load due to its nano chemistry in each cell. The square plastic baggy Life cells cant handle such a high current under load and are actually a little better then a nimh cell under load conditions. Those Chinese square prism bagged life cells will sag but they do have their place in the market. Life CAN be drained down to 0% with no worries unlike a lipo cell, but they cant be load tested in the normal sense like a nimh cell. Life cells can be charged and balanced while inside the plane Molex connectors make good flush mount solutions for plane walls
Molex balance and charge connectors on Sig LT40
Life cells must ALWAYS be balanced charged each cycle.
NIMH cells have a weight, self drain, and volt sag under load penalty and once they self drain down to 0% the cells could become damaged. Dont use Nimh AA cell packs in high current load or many servo load installations. NIMH sub C cells or larger is a much better choice, and I would prefer a second parallel nimh pack in addition. ALWAYS use a trickle wall wart charger hooked to a simple 1 hour a day timer if you want your your NIMH packs to last indefinitely.
Lipo cells MUST be removed from the plane and the 8.4v 2 cell voltage is too much for most setups if unregulated.They MUST be visually monitored for each charge cycle and can be volatile.
Life A123 cells are the best choice for my high current helis and trainer plane
Last edited by Ghia; 06-27-2019 at 07:44 PM.
06-28-2019, 05:20 AM
#15
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LiFe packs are just as easy to charge as NiCd or Nimh. NoBs batteies sells a charge lead that lets you charge directly through the balance plug. Many of the newer chargers can do this without a special lead, but mine couldn't. I made my lead myself after looking at their pictures. If you want to make things really easy on yourself, switch the balance plug for a servo lead and use a standard charge port in the side of your fuselage.
