New series Smart-Fly Power Expanders

[Kiwi]

WHOOOO!, Looks like I was away for a day or two and missed all this so I will do my best to answer. Robert is at the Joe Nall (I am not jealous much) so he wont be in here to help me if I get it wrong until next week.

Hybris, Your question is easy to answer first. The ignition cut off is fiber optic. The battery pack and receiver from the Optical transmitter(thats built into the board) are mounted up near the engine some place. The transmitter on the PEX board on lt sends a light signal up a plastic tube and triggers the switch. There is no hard wiring at all back to the PEX. Its all done with smoke and mirrors. The regulator you see on the board is not the ignition regulator. It is the main power regulator for two battery packs. That regulator is feed from a Battshare system as well to keep both packs evenly discharged.

DAN, GREMLIN I 'm sure FROMECO can make a hybrid pack but I dont see any real advantages in doing that as the battshare is really only a battery balancer. It drags current off the highest voltage pack until they are level pegging then it draws them down evenly. If Kurt and the guys made you a pack with two power leads it would basically be doing the same thing I think.

Caurimare Please dont misunderstand my comments regarding the turbo reg. For a 100cc application a super reg is plenty. That is what is built into the new PEX as well. Both these new boards are designed for a maximum sized model of 100cc. That assumes a plane with about seven to eight medium duty servos. 5955 and the likes. The super reg can handle something like 15 amps continuous if it is cooled properly. Robert has been extremely conservative with the ratings on his regulators so they wont fall over on you at 7 amps. I have tested them and have some new ones in transit to do some testing and show you all what sort of punishment these regs can take. Hang in until they arrive and I will see what sort of smoke we can produce with them.

Guys I'm writing this with a coke in one hand and a sandwich in the other. If I messed up here with any information blame it on the sandwich please. Its too good to put down.

[GremlinX]

Kiwi.. thanks for the replies. So, really, it is only operating off of 1 2600 pack, which is only good for 4 amps... It would be 8 amps IF you could discharge both packs at the same time, equally. I am a little nervous about only 4 amps with 8 5955's on 3D throws! The 5200 series Fromeco's will discharge at 8 amps if I am correct. I think that was my question. For a 100cc bird you would only still go with 2600's? Thanks for the questions... not interrogations! LOL

[Kiwi]

Gremlin.

It draws off both packs and it will drag way more than 4 amps I promise you. The battshare only really works when there is no load or very limited load but as soon as you apply load the voltage will drop on the high pack (we are talking zillionths of a volt here) and the other pack comes in the work in parallel. If you have two 2400 Mah Fromeco packs you will have continuous access to about 5C on each pack. Thats a short circuit capacity of around 20 amps.

However if you have a 5C load on each pack for any length of time mate, you have more problems than I care to mention. Like locked, ganged servos or such.

The sports series are specifically designed for 50cc to 100cc models. Good packs with 20g battery cables gives you an assured current capacity of 6 amps continuous to the PEX. A properly setup servo system even with ganged servos should only draw 100 to 150 Mah at idle. The JR style plugs while rated at 3 amps continuous (3000 Mah) will surely tolerate a spike of as much as 7 or 8 amps. (8000 Mah) But just for a spike, not continuous.

In these sized expanders there is ample protection as they are rated at a fraction of their real capacity.

[caurimare]

kiwi one more thing that has me thinking is that with the new Power System Sport Plus (with the regulator) you guys don't use deans conectors as oppose of the old styles and whats on smart-fly web site
"The Power Expander will provide benefits for 33% planes and up. The unit provides power where it is needed when it is needed. One might ask why you would want to put a Power Expander in a 33% plane when you can support all the servos needed on your receiver ports alone. The answer to this question lies in how the receiver is connected to the battery pack. The normal connection from receiver to battery pack is through a single connector with 22 gauge wire. The normal RC connector is rated at about 3.5A. Digital servos in full stall can draw between 1.5A and 2.5A. With six of these digitals on the plane’s aerodynamic surfaces you can see that the power capability of the battery connector is quickly exceeded. What does this mean? What happens is that you start losing voltage? When you loose voltage to the servos you loose torque, and when you loose torque you loose holding power. You think you don’t have big enough servos on the plane so you go to bigger servos when in reality if you had supplied the full voltage to the servos when needed you probably would not have had to go to larger servos. The Power Expander allows you to provide full voltage to the servos resulting in stronger servos holding power"
so with new power expanders is there something improve so you don't need the deans conectors or do you need them or not?
Thanks again for so many questions.

[hybris]

	Quote: Originally Posted by Kiwi
	WHOOOO!, Hybris, Your question is easy to answer first. The ignition cut off is fiber optic. The battery pack and receiver from the Optical transmitter(thats built into the board) are mounted up near the engine some place. The transmitter on the PEX board on lt sends a light signal up a plastic tube and triggers the switch. There is no hard wiring at all back to the PEX. Its all done with smoke and mirrors. The regulator you see on the board is not the ignition regulator. It is the main power regulator for two battery packs. That regulator is feed from a Battshare system as well to keep both packs evenly discharged.

Your right, I miss read one of the previous posts. I saw "ignition" and "regulator" in one sentence and made my own conclusion. This system makes complete sense now. Thanks for clarifying. When can we get one? I just wish I didn't just buy a smartfly ignition kill and MPI regulators last week.

[Kiwi]

Bob has the new boards due for delivery in the very near future. They were late arriving as it was his intention to have some at the Nall. Of course the supplier missed the deadline. I would need Bob to give you a date but I expect the next couple of weeks will see them up and available.

[GremlinX]

Kiwi, I was just asking this... and I'm sorry if I am not asking it in a good way.
2600=NO more than 4 amps..
Batshare built in switched back/forth between high volt pack to equally drain. This tells me it only drains 1 pack at a time. 2600 is only good for 4 amps... Or.... does the built in batshare equally drain the packs at the same time giving a safe 8+amp draw? I agree, 8amps is high, but it is a 3D plane with a lot of digi's in her. Thanks for your patience answering my questions!

[Rolling Thunder]

Here is a response from Bob about how the Batshare works.

"The BatShare will draw from both batteries when they equalize. Each diode may have a slight different forward voltage drop (i.e. one may be .41V and the other may be .42V) so the battery packs may not seem to be at exactly the same voltage but when you add the battery voltage with the diode voltage on each side that will be equal. The BatShare will switch to the higher voltage battery when there is a difference. For example, when you charge you may not get exactly the same voltage on both batteries, the BatShare will run off the higher voltage battery until things equalize and then the BatShare will draw from both batteries. If one pack has a different capacity than the other pack the BatShare will draw less from the lower capacity pack and more from the higher capacity pack to keep the the battery voltages equal. I hope this makes things clearer."

The next is in reference to the batshare built into the Power Expander.

"If the inputs are both at the same voltage the PowerExpander will draw from both sides. You can get both lights on using regulators and still not draw evenly, or close to evenly, from both sides because of the way regulators work. It is almost impossible to get regulators to share current. The regulator that is set to regulate the higher voltage will always supply more current. This is made worse when the path from the regulator to where they are plugged together is a very low resistance, as with our RegulatorHDs that have 18ga wire and Deans plugs on the output. You can help balance regulators by putting resistors on their outputs and tying them together after the resistors. Since voltage drop is proportional to current, the regulator with the higher current will have a bigger voltage drop across the resistor. This is why you may see better current sharing when you have 22ga wire and standard plugs going into a receiver rather than when you have 18ga wire and Deans plugs going into a PowerExpander. So, even though you have both LEDs lit up that does not mean you will get equal current draw using two regulators. I hope this explained this well enough."

[GremlinX]

Ah.... Good to know... Thanks for the write! I was under the impression that it just switched back and forth ... like take a little here, take a little there... thanks a ton. Keith

[mic783]

This might be a really silly question but does having two 6v nicd batts pluged into both sides of the smart fly power expander create 12v while drawing from both batteries thus killing a 6v digi servo?

[rrritchey]

Hi,
The batteries end up wired in parallel, not series. When you use two 6V NiCds you end up with 6V at the servos.

[JPrc]

How many amps is the battery share rated.