Scorpion Backup Guard

[dkalwishky]

Do you use any kind of backup battery for the receiver & servos? My new Freewing A-10 has a BEC that is tapped off of one of the batteries. If that were to fail all I could do is watch $600 head for the ground and explode into a shower of foam.

I was looking at the Scorpion Backup Guard to have a backup battery in case something happens to the BEC or the battery, at $24 it seems like cheap insurance.

https://www.youtube.com/watch?v=6Vwq6xpRFD0

[dkalwishky]

I did a search and found a few guys like this unit and plan on putting them in their A-10's. AMAIN is out of stack but I found a seller on eBay that has them so I'll be placing my order today.

https://www.hobbysquawk.com/forum/rc-airplanes/jets-and-edfs/52741-official-freewing-twin-80mm-90mm-a-10-thunderbolt-ii-thread/page66

[RCjetdude]

I have been told that there is a newer version which has the power switch mounted on a short harness making it perhaps more convenient to secure and still be able to turn it on or off.

[OV10]

DK....I got one in my Warty.
Avail directly from Scorpion ;)

http://www.scorpionsystem.com/catalog/accessories/backup_guard/S_Backup_Guard/

[dkalwishky]

I have been told that there is a newer version which has the power switch mounted on a short harness making it perhaps more convenient to secure and still be able to turn it on or off.

I couldn't find anything online about that. I do see that many of the people who carry it are out of stock.

[RCjetdude]

I talked with Lucien Miller from Inov8tive Designs at NEFI about it. He was there selling Scorpion products and said the newer version has a remote switch. I have not seen one or been able to find out anything about them either.

[dkalwishky]

I sent an e-mail to the company, I'll let you know what they say.

[xviper]

While you're at it, you should also get the charging adapter so you don't scratch your head wondering how to hook this up to your charger >>>>>>>

https://www.amainhobbies.com/scorpion-backup-guard-charge-cable-scp-backupchrgc/p260701

Not sure, but if you buy direct from Scopion, they may ship it from Hong Kong. Shipping?
Any failure can happen in a plane, even a double failure. My biggest problem with the Scorpion is forgetting to flip the switch just before the canopy goes on. Not sure a remote switch on one of the wires would help in that regard since the current switch position is on the end of the Scorpion and it's not hard to mount it so the end is handy. For me, the A-10 is a "nearly" one thousand dollar airplane, literally the most expensive one I've ever purchased. My Mig 29 comes close but that was purchased when our dollar didn't suck stones. Maybe one should hook up 2 Backups?

[dkalwishky]

There is an eBay seller that has these (and the charging cable in stock), $30 for both delivered to my door.

http://www.ebay.com/itm/Scorpion-Backup-Guard-RC-Charge-Cable-RC-Heli-Airplane-Power-System-LiPo-UPS-/162579475067?refid=store&ssPageName=STORE:HTMLBUILDER:SIMPLEITEM

[dkalwishky]

Lets discuss costs of the A-10, $600 for the plane, two batteries at $220 (for the pair) and a $30 receiver. That's $850 in the air at one time. I figure the $25 for the Scorpion is cheap insurance to protect against a battery or BEC failure.

[RCjetdude]

What freaks me out about it is I keep forgetting to turn it off before unplugging the batteries and everything except for the motors still work. :Silly:

[T-CAT]

There are some good reads over on RCg, helifreak, and other forums comparing various types of back-up systems like this Scorpion BUG (backup guard), the Optipower, Perfect Regulators Proguard Plus, etc.

Some aspects that have come up that may have potential for worry is feedback voltage to the BEC, which could damage or destroy the switching BEC. Some companies have come up with a solution to this (I believe Optipower has with a specific cable that's attached that prevents potential feedback voltage from occurring), while other back up solutions have not.

Another thing that worries me a bit is that the Scorpion Back Up Guard is supposed to activate when it detects the receiver voltage dropping below 5V. However, if we look at this from a PNP Jet standpoint and many other PNP airplanes these days, the BEC voltage is set to 4.8V or 5V. I usually see 4.8V though, and if the BUG is supposed to turn on at 5V, it would turn on right away since the BEC voltage is lower than the activation voltage of the BUG. The electronics in these PNP jets like the servos, retracts, lights, etc., are best used at no more than 5V. If we used a different BEC and set the voltage to 5.5V or something similar just so the BUG doesn't detect low voltage and activate, we are risking the life of the stock electronics.

Food for thought/discussion...

[dkalwishky]

Interesting thoughts T-CAT. I wonder what the BEC output is on the A-10, I don;t have a multi-meter so I cannot test it too see.

[dkalwishky]

Just did a chat with Martin @ MRC, he said the BEC is 5 volts.

[OV10]

There are some good reads over on RCg, helifreak, and other forums comparing various types of back-up systems like this Scorpion BUG (backup guard), the Optipower, Perfect Regulators Proguard Plus, etc.

Some aspects that have come up that may have potential for worry is feedback voltage to the BEC, which could damage or destroy the switching BEC. Some companies have come up with a solution to this (I believe Optipower has with a specific cable that's attached that prevents potential feedback voltage from occurring), while other back up solutions have not.

Another thing that worries me a bit is that the Scorpion Back Up Guard is supposed to activate when it detects the receiver voltage dropping below 5V. However, if we look at this from a PNP Jet standpoint and many other PNP airplanes these days, the BEC voltage is set to 4.8V or 5V. I usually see 4.8V though, and if the BUG is supposed to turn on at 5V, it would turn on right away since the BEC voltage is lower than the activation voltage of the BUG. The electronics in these PNP jets like the servos, retracts, lights, etc., are best used at no more than 5V. If we used a different BEC and set the voltage to 5.5V or something similar just so the BUG doesn't detect low voltage and activate, we are risking the life of the stock electronics.

Food for thought/discussion...

T-cat......... got to say putting that type of info(in bold) out there is really a dis-service to the industry. I would really like to know where you got your information from.:Thinking:
As a trained electrical engineer(microwave) in my early years, I still stay up on the latest tech in this hobby and have not seen anything close to being representative of that statement.:Confused:

[T-CAT]

OV10, I should have clarified better, I meant "these" PNP jets as in Freewing PNP jets. That doesn't mean the servos and other electronics meant to work at the same or similar voltage won't survive at anything above 5V, but we don't know the longevity of doing so. I believe Alpha had a post on a thread where he mentioned not recommending 6V to be used on stock PNP Freewing jets (I'll have to look back in some threads to find it). Which jets, which exact servos though, etc., we don't know. I would rather be on the safe side and use 5V instead of anything more if I don't see the manufacturer specify using voltage higher than that (especially when I don't see any decals on the servos and other electronics recommending a voltage range). If the stock external BEC that comes with particular airplanes is set to operate at 5V, that's what I keeping things at, even if I use a different brand external BEC with the stock electronics. That's just a personal safety measure for what I feel comfortable with. What I wrote isn't meant to be anything as "industry standard" or anything of the sort. There are so many different brands of servos (as we know that we all could easily purchase high voltage servos, retracts that work on 7.4V, etc.), retracts units, lighting systems, etc., some that come with plug and play aircract, while others are aftermarket as you already know, and have so many different operating specifications. With a lot of the "stock" electronics coming with these aircraft, there is a lot of unknown, so venturing further outside the scope of what the manufacturer configured the plane to work with may cause more trouble than it's worth.

No disservice was meant (which I tried to convey as I enjoy this hobby and don't want to see anyone risk their stock electronics and loose a plane like the A-10 that the original poster was speaking of, which is why I provided some input to have us discuss things together), and I mentioned it being food for thought, so people like yourself (an electrical engineer) could shed more light on a subject that may provide clarification on various electrical component operation that we may not know about. :Cool:

[OV10]

T-cat..........Thanx for the clarification. I too remember Alpha's post about the 6V threshold.
With that being said, a BEC will not surge upward a half volt but it can and certainly does sag lower under stressing system demands.
So going back to your statement of going to a programmable ESC that you set the BEC to 5.5v, there is plenty of margin to the top end suggested limit.
If folks are looking for a electronic insurance device the BUG is a very viable solution when used in addition with the likes of the ZTW 6A/10max UBEC.

https://www.motionrc.com/collections/battery-eliminator-circuits/products/ztw-10a-bec-ubec

This also has a better amp output than the stock UBEC provided on the FW 1700 A-10;)
For those with the A-10 a really killer deal for $7 more than the above is the 15A dual input.

https://www.motionrc.com/collections/battery-eliminator-circuits/products/ztw-15a-double-input-singal-output-ubec-ztw300700010

No worry now for supplying all the amps the system needs and this is an ideal solution to having both LiPo sources(like on the A-10) powering the UBEC.
The stock method has only one of the two batteries powering the system.
What happens if that particular battery goes flat before the other?:Scared: With the dual input UBEC you only loose one motor and have half a chance to getting back safely.
If both batteries go flat(cause ya pushed the time or whatever) this is where the BUG does it's job for a dead stick.
More tech food for thought but put in a practical application perspective:Cool:
Best regards,

[Porkster]

Similar is the optipower backup guard.
you dont have to remember to switch it on, you can leave it in the plane, if you dont fly for a while it sets itself to discharge to storage voltage.
i have the version with the warning LED in my A-10

http://www.fast-lad.co.uk/store/prod...ducts_id=27906

[T-CAT]

I have the OptiPower unit as well, but have yet to test it out significantly, and need to try it on my A-10. It's a nice unit, a little heavier and larger than something like the BUG, but overall nice. It had some other features I like too, so hopefully they are worth the cost difference over the BUG.

[dkalwishky]

I could not find the Optipower unit in the U.S. from anyone that has it in stock.