New 7.5g S-BEC good for 8 - 10 cell packs too!

[GregoryJ]

Please note that this thread consists of 2 threads that have been merged (chronological order has been lost). Below is the first thread, the second is a bit further down showing the assembled device. The second thread was posted on the 'electric heli' forum (and then moved here) which is why it only references heli's, but similar priciples apply to all types of aircraft.

First thread...

FirmTronics is lauching a new switch-mode BEC (S-BEC) in a tiny 19mm x 15mm package. The image attached shows the relative size of this small but power device which has just come from the PCB manufacturers and is now on its way to the assembly plant (having a quick stop at the office for a photo shoot). Switch mode BECs are essential for high servo count (> 3) setups and high cell count power packs (>10) where traditional BEC linear regulators may overheat and shut down. If you're serious about protecting your investment, add S-BEC to your shopping list!

It features:
Input voltage: 5.5 to 50 Volts (highest on the market)
Output voltage: 5V
Continuous current: 2.5 Amps
High current tollerance: 3.0 Amps (2 minutes)
Current surge: 10 Amps (10ms)
Size: 19 x 15 x 9mm = 0.75 x 0.59 x 0.36 in (smallest on the market)
Weight: 10g
Other features: Short circuit protection
Low electronic noise signature (EMR)
Pricing: Not yet available.


Available soon. Watch this space. Contact info@firmtronics.com for more info.

[Tres Wright]

Moving to "Product Announcements" forum...

[twguns]

Looks like a really neat piece of equipment... I have a couple of concerns and/or questions...

From your web site it seems that you are not in the US... Where are you and how will shipping & warranty be handeled... I will say that KFS (makers of the U-BEC) have been great in taking care of the very few warranty problems they have had... How will you address this???

I fly big E-helis with all digital servos and I don't think from experience that 2.5A with a surge of 3.0A is enough... I feel you will need to at least equal the U-BEC to compete in that market... I didn't check but the input voltage will need to be in the 45 - 50V range...

Thanks in advance for addressing these questions...

bigTim Wilson

[GregoryJ]

Hi bigTim,

To answer your first question. We are in South Africa which may seem an unlikely country to do business with but we have been manufacturing RC products for nearly 3 years, all of which are exported to the Far East, USA and Australasia and most of them are OEM'd (re-badged as someone else's which is probably why you haven't heard of us before). RC is not our core business but we have many years experience in commercial and industrial embedded software development for multi-national companies. The postal service to the USA is slowish (7 days average) but reliable and competetively priced (about $5 to $7) compared to other countries (eg. the UK). We will honour our warantee on this product exactly like we have on the thousands we have sold over the past years. We have an advanced post-production test facility which should and does significantly reduce come-backs.

On your second question: I don't know why the general consensus is that servos draw large currents. They draw large instantaneous currents but their average (continuous) current is much lower than you may think. For example, I have DS368 digital servos and they draw 650mA when they are forced off alignment. With a significant load, they only draw 450mA which will NEVER be sustained during flight unless the servos are binding. They consume 70mA when idle. This means that you can easily and safely drive 5 of these digital serovs (even if all 5 were continuously under near-maximum load, which lets face it, is highly unlikely). The instantaneous current may be in the order of 1A to 1.5A per servo which S-BEC is completely capable of delivering.

Third question: It can handle up to 50V and we can even go higher with a slight mod which we may do if the market dictates that.

I hope this answers your questions.

Regards
Greg

[GregoryJ]

Second thread starts here...

Hi All,
My company has produced an ultra-compact switch-mode BEC (called S-BEC) which will be launched as soon as distribution rights (currently being negotiated) have been agreed upon. It weighs 7.5g (0.26 oz) and can handle up to 50V input and outputs constant 5V up to 2.5A cont. and 10A current spikes. When I first designed S-BEC, I didn't know about the competition, which I suppose is good. Competition is healthy. I was using a 16 cell pack on my ECO16 helicopter and 4 digital servos and wanted something small, light and efficient. I also didn't want to rely on any linear regulator because not only do they waste power, but they are at risk of "thermal shutdown". The switch-mode BECs have always been for "high cell count" packs but I would like to illustrate why they are good for low cell count packs too (8 cells and up).

Being a manufacturer of ESCs, where linear regulators (standard BEC) were used, we were always concerned about the regulator going into 'thermal shutdown' and it has always been a challenge to dissipate the heat generated from this device - not to mention the MOSFETs. Linear regulators are used in all ESCs that have built-in BEC. The reason that thermal shutdown is a risk is because linear regulators take the input voltage (say, 12V on a 10 cell pack) and provide 5V for the Rx and servos (which lets say consume 1A). The problem is that this 1A is drawn from the 12V supply even though it's only providing it at 5V! The regulator outputs 5V * 1A = 5W, but takes in 12V * 1A = 12W. This means it has to dissipate 7W in the form of heat (and is lost). Its efficiency is therefore Po/Pi = 5/12 = 41.7% efficient. This is actually best case - I haven't even taken into account the 50mA or so required by the regulator to operate!

To compare this scenario (10 cell pack, servos and Rx drawing 1A) with an S-BEC as the 5V supply... S-BEC is 80 to 92% efficient. Lets take the worst case (80%) for this example. 1A is being supplied at 5V (= 5W) but because of the inefficiency, the device is using 6.25W from the supply of 12V. This means that 1.25W is being "lost" (compared to 7W with a linear regulator). The difference is 5.75W (power saving!). Now of course S-BEC weighs something so you'd have to work out whether this power saving warrants carrying the extra weight. Lets work it out...

S-BEC weighs 7.5g. In helicopters it's generally considered that it requires 100W per kg to hover (as also stated in the heli FAQ). This means that you'd need 0.75W to carry the S-BEC. If you subtract this from the power saving using S-BEC instead of a linear regulator, you get 5.75 - 0.75 = 5W of saving.

On a 1kg heli, 5W accounts for 5% of the power required to hover. Pretty cool, heh? If you are using the BEC that is built into your ESC (the linear regulator), change the values I have provided above (with your particular heli) and work out how much power saving you will have using an S-BEC. I'm sure you'll be surprised.

I have announced S-BEC on http://www.rcgroups.com/forums/showthread.php?s=&threadid=143710 for availability.

Greg

[misskimo]

cool . I want one

[GKurt]

Originally posted by GregoryJ


Being a manufacturer of ESCs, where linear regulators (standard BEC) were used, we were always concerned about the regulator going into 'thermal shutdown' and it has always been a challenge to dissipate the heat generated from this device - not to mention the MOSFETs. Linear regulators are used in all ESCs that have built-in BEC.

Greg

You product sounds attractive.

Since you mentioned you're a manufacturer of ESC's, may I ask why you (and all the other manufacturers) continue to use linear regulators, as opposed to switching regulators, in ESC BEC's? Is RFI a concern?

Have you tested your S-BEC for RFI emissions? If so, can you give us specifics? Any real world tests with commonly used ESC's? As you may know, the UBEC needed revising after the manufacturer found an incompatability with certain Kontronik ESC's stiffening caps.

What brand ESC's do you manufacture?

What's the MSRP?

Sorry for all the questions, good luck with your new product.

Greg (question asker, not the manufacturer)

[GregoryJ]

Greg (question asker), no, its not financially viable to use SMPS (switch-mode power supplies) in ESCs. It would probably tripple the price of the ESC in most cases.

RFI is not a concern for the frequencies tested (27, 35, 53/54, 60 and 72 MHz). Obviously we can't test on every single combination of Tx an Rx and ESC, but those that we have tested on, had exceptionally good results. This can attributed to the very short distances between power components (which radiate) and the integrated circuit (less than 5mm!), and the fact that the main power component istelf is shielded. This is all thanks to one of our engineers who holds a PhD on this subject.

All our ESCs are OEM'd - we manufacture them and other companies "badge" them as their own.

S-BEC will retail for $42.95.

Greg (question answerer)

[TMorita]

Have you tested this in electric helicopter applications, or has it only been tested in airplanes and you're assuming it will work for electric helicopters as well?

Toshi

[Ben Diss]

Greg- I agree that 3A is not enough. Heli guys will tell you that 2700mAh receiver packs only last 5 or 6 flights when they're driving big digital servos. A wattmeter attached to a heli will show 1.5A draw while simply hovering.

Also, it does not inspire confidence when your location is hidden in your profile (e.g. "A mouse click away").

-Ben

[RC Man]

I don’t think you sell any at that price when you can get the UBEC for $30 that is good with up to 35v input. That’s what most of us use, it is a proven and very reliable device.

http://koolflightsystems.com/ultimatebec.htm


Your price goal should be in the $20 to $25 area. A little less profit and a much higher volume is always a good marketing strategy.

[ScotY]

Hey, how about a compromise...for us here in the helicopter forum, how about $35? :D Just kidding...pricing should be your choice. If it weighs about 1/3-1/4 the weight of the UBEC and has similar performance, the price does not sound unreasonable. My humble opinion....

[misskimo]

hey , the price is RIGHT in my book ! the weight makes all worth it + the less ma draw

[TMorita]

This should be moved to the Vendor Announcements forum, like the previous two threads...

Toshi

[misskimo]

huh? well I dont mine a hint of ( a new product ) on this board , I dont go to the vender announcements , and if its a good lite product to make our helis lighter ( which we like ) makes it worth wild for this forum , all it is is a ( look over here in the vender side would you )

[gstew]

First, it looks like a really nicely designed and packaged device... nice work.

OTOH, maybe I'm cheap (although I doubt that after outfitting my RappE and converting to LiPos), but I know I'd go buy a UBEC at $30 before I'd buy yours at $43. Its a case of perceived value... At that price, I'd only consider it for a larger and heavier helis... most of them would not notice the 20 or so gram weight difference from the UBEC.

OTOH, if this cost $25-$30, I'd go and buy 4 of them to replace the homemade linear auxilary BEC's on my 10-cell helis... and the next time I outfitted a larger heli, I'd get yours there too.

My opinion.

Greg in Minneapolis

[Fred Bronk]

Sounds nice and may fill a nitch if the price is right. Most ESC manufacturers are coming out with HV BEC's in the ESC with the trend towards Lipos though.

I am moving this to Vendors where it should be. I will leave a link though.

It is also a double post, which is not allowed.

1 post per week please and that includes all forums.

[GregoryJ]

Toshi, I fly with one in my ECO16 with 4 DS368's.

BEN, what on Earth are you talking about? Why don't you just ask me where I am. I'm in Cape Town, South Africa, and we distribute worldwide and have been for the past 2½ years - hence the "mouse click away" bit (tough luck if that bothers you). In fact, our biggest customers are in the US and Far East, both of whom re-badge our products - one or two of our products are on advertising banners right here on rcgroups.

Please go to http://www.rcgroups.com/forums/showthread.php?s=&threadid=143992 to follow the latest thread.

[GregoryJ]

Thanks for all the comments (both for and against - we DO like constructive criticism). The biggest concern seems to be pricing. Let me try to defend it. Firstly, our manufacturing cost is probably higher than UBEC (since I've had a lot of comparison with them) because we're using the absolute latest integrated circuit technology - allowing for the ultra-compact size. Secondly, there are distribution tiers in place which we cannot avoid. We need the bigger players (wholesalers) to be a part of this as we are an engineering company - not a marketing company - and we don't have the required infrastructure within the RC market to "go it alone". These middle-men all have their markup (sad but true). I would love to sell this product at a cheaper price than UBEC, but I believe it’s a superior product (yes, I'm biased) and its pricing should be (and is) pitched accordingly.

Right, I have work to do.

Regards
Greg

[Ben Diss]

Greg- I see you changed your location. That looks great!

-Ben

[Steve McBride]

Your swich mode BEC looks good for high count lipoly setups for sure. I would love to give one a try on a micro heli with 4+ lipoly cells in series. 3A would certainly be enough for that application. I would think there certainly a market for it.

Good luck with it!

Steve

[GregoryJ]

S-BEC has generated a lot of interest of late. Please have a look at the following link to discover why...
http://www.rcgroups.com/forums/showthread.php?s=&threadid=147574&perpage=15&pagenumber=2

Regards
Greg