Xantos

Hi Guys,
I've been using redundant/dual power supply for most of my installs in all my jets.
The standard practice was to run two batteries directly thru a switch or thru independent voltage regulators directly to two available ports on the receiver.
Ofcourse most of my installs have been either JR 9ch or 12ch or Spektrum12ch receivers , however recently I was installing a new 12ch AR12020 Spektrum receiver in my Ultra Flash and noticed that the earlier receivers had a Batt1 and Batt2 port whereas the new receiver has only one batt port and the second batt port has been replaced by a SRXL port.
So I sent a email to Horizon Hobby asking if I wanted to use a dual power supply what ports to be used ?
Heres the answer I got :
"SRXL should not be used. The powerbus in this receiver is common and we do not recommend using 2 electronic regulators/bec‚s to power a common power bus.
The Powerbox Gemini is best suited to powersafe receivers which have independent power supply circuitry."

• In the past it was a fairly common practice to power a Common Bus with 2 batteries and i don't think receiver design has changed that significantly
• So what is the best practice to follow now ?

Dave Wilshere

if you are using a Sensor switch as designed for the UF, just pick any spare channel for the second supply, like you say they are all connected.

Dave

Xantos

Dave
I'm using the PowerBox Gemini which is similar to the Sensor except it has a slightly higher rating
Nandan

chuckk2

The real question has to do with a bad battery and it's impact on the system.
Obviously a battery that fails open is not really a major problem, in that the other battery should be able (as long as it works) to operate the system.
What if a battery shorts? Obviously, with no means to disconnect it, the system goes down.
Now we get into a need for Diodes to prevent the "bad battery" from shutting down the system.
The unfortunate part is that the diodes can be a failure point by themselves. In general, any increase in complexity has baggage, including
a higher theoretical failure rate. From simple diodes, things start getting more complex. It's even possible to use FETs to switch from one battery to another.
Perhaps an intent to equalize the drain consistent with the batteries capability might be a goal.
Or, to isolate a bad battery.

When you use two regulators, and they do not have a diode in series with the output circuit, there is no decoupling. It's then possible for them to fight with each other.
When diode decoupling is used, the regulator usually requires a minimum load on the regulator side, in order to provide stable operation.

Cost, weight, and complexity can completely offset any real benefits from redundant power sources.

Dave Wilshere

Gemini works the same.

Dave

olnico

Another solution is to use the EMCOTEC BIC v2 battery backer. Two inputs, two voltage regulators, one output. Isolation of a shorted battery is taken care of by the system.

http://www.ultimate-jets.net/collect...ts/dpsi-bic-v2

ticketec

My Feedback: (2)

I use a smartfly power reg with great succes.

https://www.smart-fly.com/Products/Regulator/3.htm

Two packs in, two regs, and two supply lines out. if a pack fails open or close circuit it immediately cut it out of the circuit. It also fail safes to on should its switch fail. Output voltage is also user selectable

thanks

dave

Xantos

Guys I know there are other options out there for dual power management but I'm just wondering what Horizon/Spektrum mean when they say "The powerbus in this receiver is common and we do not recommend using 2 electronic regulators/bec‚s to power a common power bus." Does it mean they JR/Spekky receivers we use are not compatible for dual power supply ?

mikes68charger

My Feedback: (34)

I just use 2 smaller life 6.6 batterys 3000mah, 2 good swichesh with charge ports and led (MPI), and plug one into the battery port the other into a open port in the reciver.

If no open port, then I soder in (like a Y) the 2nd power supply to a servo I feel has the biggest draw (single elevator servo) or one that is the has the most distance from the battery port on the reciver.

So if the batter is is in the first port to the left, I will tie it into the port as far right as I can go.

chuckk2

When you use two regulators, and they do not have a diode in series with the output circuit, there is no decoupling. It's then possible for them to fight with each other when connected to a "common buss".

kiwi4

My Feedback: (2)

Just because there are two batteries pluged into one reciever doesnt make the system redundent,If one battery shorts it will kill the good battery becaues their connected to the same buss,not a good idea.check out products like the Batt share or the Battery Buffer.These products will manage your power in a shorting incident.Plug two batteries or bec's into them and then the regulator and then the reciever. and not a bad price for both.kiwi4

kiwi4

My Feedback: (2)

Xantos
Thier capatible just not recomended.not a good idea.kiwi4

Zeeb

My Feedback: (41)

Regulators and common power buss setups are just asking for trouble, one reason as already noted but the other is that you rarely find two regulators running exactly the same voltage and so one battery will draw most of the load.

AFAIK, the big PowerSafe rx's from JR an Spektrum do not recommend using regulators. All of those 9 channel and above (I think even some of the smaller ones now) will take up to 10 volts input or to be precise I think they say 9.6 volts so you can use them with two cell LiPO's unregulated with HV servos.

Either run HV servos with the LiPO's or I like A123's on my PowerSafe rx's.

Jeti USA

This might help you. Very simple and elegant solution. I have one on my 7m ASH 31 15kg Full Composite Sailplane.
I know it's not as complicated as Power Box but I prefer sticking to KISS rule. The magnetic switch is just cherry on the top of if.

Either way good luck and many happy flights.

Zb/Jeti USA

The DSM 10 from Jeti is dual input redundant electronic switch designed to operate with included magnetic key. The advantage of an electronic switch is that it offers a virtual unlimited ON/OFF cycles, unlike mechanically operated switches. The redundant DSM 10 switch automatically monitors and switches between two power supplies (Rx Batteries) keeping your system operational.

Final solution in redundancy and reliability from Jeti is here. The DSM 10 is designed for two independent 5-13V inputs and supports up to 10A continuous current or 20A burst current for your connected devices. This unit is most suitable for today's high-voltage servos, which you might be operating directly from a two-cell LiFe battery or similar Li-Poly battery pack. Please note that DSM 10 does not include a regulator, output voltage is equal to input voltage.

http://www.espritmodel.com/jeti-elec...ey-dsm-10.aspx

raron455

My Feedback: (38)

The spektrum 12120 is the powersafe redundant reciever,, Just sayin

Boomerang1

Every battery failure scenario was covered in an article in the 90's in RCJ International.

Included was the situation where a cell in one battery pack was shorted out (the chances of MORE THAN ONE or EVERY cell
failing by shorting or open circuiting at the same time in a pack are less than winning the lottery).

What happened was the good battery tried to charge the bad battery, the current involved was small & the voltage on the both
batteries (feeding the common bus on the receiver) was barely affected. The discharge rate of the good battery was so slow
it would have lasted several flights & the fault would have been picked up during pre flight checks before the next flight.

I believe we over think battery supply requirements. A lot of the hype is from manufacturers selling the latest 'save your plane'
gadget & modellers who don't want to admit they wasted their money on the same gadgets.

John.

Boomerang1

Would this apply to the Powerbox Digiswitch regulating electronic switch? It's not mentioned in the instructions.

I bought two of these from a vendor at a jet fly when I left my flight packs at home & no one was selling replacement
Ni-Cd or Ni-Mh packs, only Li-Fe or Lipo batteries & regulators.

John.

PaulD

My Feedback: (39)

+1 - I'm with you on this one. Love simple dual A123 setups and switch of preference is Fromeco Wolverine.

PaulD