Nogyro

My Feedback: (10)

In a previous thread, I had mentioned that I was going to swap out my old electrical system for a new one that included a Smart Fly Power Expander Pro. Below is a copy and paste of my previous set-up, and below that will be the results of the new installation.....



I've always been rather "thrifty" I guess in my RC purchases. Never buying into the power expander scheme or such. My latest plane, 36% Edge/DA100 started out with a single A123 2300 mAh pack with two leads/two switches going to a Spektrum AR7000 receiver. I also had a third line coming off the battery and powering the ignition as well. How's that for pushing it. The plane flew great, no reboots...... I flew it like this for 100 flights or so. I started getting nervous so I added a second 2300 battery. It has one lead going to the receiver, and one going to the ignition. So let me summarize that. I now have one 2300 with two leads going to the receiver, and the other 2300 has one to receiver and one to ignition. So that's three std plugs powering the receiver. I'm charging with a Cellpro 4S, so I know my total current usage per 15 minute flight. I use the timer on my transmitter as well. I've got 280 flights combined with this system. The plane has always felt sluggish on the rudder with 2-5955 pull-pull on it, and snaps seem kind of weak as well compared to some other 35% planes I fly with. Ailerons,elevators, and rudder servos are all on HD Y's. Leads coming out of A123's are 20 GA. I know enough about electricity to know, that if you limit current anywhere, you can't get the amps out of your servos. Yes the plane will fly, but at a reduced capacity. This I think is one of the most important things that Hammbone has pointed out in several of his threads.

So........... Winter is here, I've got a little extra cash, and my curiosity is killing me! I'm pulling my batteries, and installing a Smart Fly Power Expander Pro. I'll be using the ONE failsafe switch instead of the current three that I have. I've ordered new 2300- A123's from Radical that will come with 16 Ga leads/Deans Ultra plugs. The two batteries will plug directly into the power expander. One 2300 will also power my ignition, so that will all stay the same. The extensions will be redone, and NO Y's will be used. Each servo will have it's own lead plugged directly into the power expander. The way I see it is if my old system was delivering all the power that my servos needed, then my mAh's use per flight will stay the same. If the old system was falling short, then with the power expander the plane should fly more crisp, and the mAh's used per flight should increase. The results will be interesting.........

Forgot to add that it has eight 5955's and one std. analog 545 (I think) on throttle.


Ok, now for the results.....

On my old system, I used 1057 mAh out of one A123 battery, and 744 mAh out of the other for 4-15 minute flights. Notice how one battery had an extra 313 mAh's taken out of it. That is the battery that has a lead going to my receiver and also my ignition. So for a 15 minute flight, I averaged 450 mAh's per flight.

Now for the new system with the SFPE, one failsafe switch, 2-2300 A123's with 16 GA. wire w/ Deans connectors going to the PE. I stayed with the Spectrum AR7000 receiver, and re-did all my extensions so no wye's were in the system. One of the two batteries still has an extra lead coming off it to power my ignition. After 6-15 minute flights, my battery consumption was 1616 mAh, and 1414 mAh, for a total of 3030 mAh's. The one battery only had an increase of 202 mAh's over a 6 flight period. That's 500 mAh's per flight. An increase of 50 mAh's/flight. I had guessed before I installed the PE, that if my old system was short on delivering current, that with the PE, the current drain would increase. It did. In all the 280+ flights on this plane, I had never used 500 mAh's per flight before. My flights are a combination of IMAC and 3D.

Could I tell the difference in how the plane flew? On the ailerons & elevators not much difference, but it made a huge difference on the rudder. My rudder authority really increased in all knife edge maneuvers, especially high alfa ones. Snaps seemed a bit cleaner as well. But no difference in Walls, rolling harriers, point rolls, or flat spins.

Benefits of the PE......... The PE really simplifies installation. I had a wiring nightmare with the old system. Did it work? Sure.... But when you look at the trade offs for a 35% plane or larger, you need to really consider the PE. Not only does it reduce switches, but in my case with running the ignition off one of the batteries, the battery balancing circuit really helped to balance out my battery packs. I was still able to use my AR7000 receiver, only using 5 channels. It also gives me battery isolation if one battery shorts out.

Here's a few pics of my installation:

Hammbone

My Feedback: (309)

Congrats on improving your system, and actually seeing and feeling the difference. Your results are very interesting, and verify what I keep trying to tell people on these forums.

Jim

Nogyro

My Feedback: (10)

Thanks Jim,

I was hoping to see a difference one way or the other, and I did. [sm=thumbup.gif]

yarom

My Feedback: (82)

I have the exact same setting on 2 or 3 planes I fly. Same 8 Hitec 5955 servos. I use 5645s on the throttle.

I use A123 2300mah batteries from Fromeco and/or SinCity Jets. Ignition is always separate battery and circuit.

I also use two small LED modules (99 cents from china) that are installed in the plane's instrument panel and continuously monitor the voltage from both charge connectors on the power expander (or the balance plug on the batteries). That shows me the voltage and I can see when I reach 6.6, or below.

My power consumption, which I always record, has never exceeded 100 to 120 mah per battery per 10 minutes flight. Extrapolating that, about 150mah per battery or 300mah for radio and servos per 15 minute flight. Ignition is very similar - 100mah per ten minutes.

I am wondering about the difference in consumption...

Jake Ruddy

My Feedback: (40)

I really don't want to open a can of worms here. I am a supporter for PE's in larger models or a 9100.. whatever suits your needs but I also agree with KISS and think some go way overkill.

However in my opinion you changed way too much to make an accurate test.


As for power consumption, I have been amazed at the people who state 100-150 usage in a battery because I have yet to see this across multiple planes and multiple people setting them up. I really don't think you can compare the battery usage with other people and get any value from it. The reason is because everyone flies differently. For example I love KE and I love Snaps.. so my mix of IMAC and 3D is going to be a lot different from some one else's. To some lots of 3D is hovering, waterfalls, elevators, blah blah and others that is HAKE, Blenders, rolling harriers, rolling harrier loops, etc. I mean everyone has different skill levels and some can do everything but don't continually hammer on the plane the entire flight. I just think there are way too many variables for those numbers to mean anything.

Nogyro

My Feedback: (10)

yarom,

Our figures are really pretty close. You are using a total of 450 mAh's for a 15 minute flight. That's what I was using before I switched over to the PE. I'm using 500 mAh's now, and I'm sure the extra 50 could be attributed to flying styles.

Jake Ruddy,

Yes, I made several changes at once, but all of them were made in order to use the PE. I made no changes to servo arms, programming, linkage adj. etc. that would change the mechanical advantage on the control surfaces. Anyone that is installing a PE would run all their servos to the PE without wye's, that's the whole reason for the PE. Bottom line is my plane had much more rudder authority with the PE installed than without it. If some of the performance increase is from the removal of wye's, then so be it. But you either have to run a PE or a 9100 receiver with a 10 or 12 channel transmitter to do it. I kept my AR7000 receiver and opted for the PE. Lots of different ways to do it, it's just a matter of choice. That's what's great about this hobby.

catfish2

My Feedback: (43)

I also use a PE with one of my AR7000 mostly to cleanup the installation and also freeup a channel or two. I like the results and will probably use it more in future setups. I think the alternate to your rudder power problem would have been to wye in one of the battery leads beween the rudder and reciever. The reciever wouldn't care and the rudder servo would see very close to full battery voltage. Bet the final power consumption would be very close to the PE results.

Nogyro

My Feedback: (10)

Yes, that may have worked, but where do you draw the line at how many wye's you're going to put into the system? I already had the two rudder servos wye'd together. Now put in another Y for the battery/switch. After a while you have 5 or 6 junctions in 18" of wire. [&o] All those junction points build up resistance and increase the odds of failure.......

JoeAirPort

My Feedback: (41)

Ditto that. I was too lazy to type all that. [8D]

Jake Ruddy

My Feedback: (40)

Another option would have been to use a powered matchbox. or program your hitec servos and create a mix.

I am not trying to knock it, just it makes sense if you remove the "y" on the rudder why you would have more authority. Either way you are happy and in the end that's all that matters.

I was just sharing my initial thoughts on all the changes. You even changed batteries and the wires connected to the batteries. My statement was more that it would have been nice to see phases in the "test" rather than major changes. Although quite honestly I am sure you would rather be flying than doing a bunch of tests! Me too

Josey Wales

My Feedback: (61)

Good info Frank! Glad you like the setup.

Nogyro

My Feedback: (10)

Yes, I could have pieced it out to try to find the weakest link in the system, but I really wasn't interested in doing that. I stayed with the same battery capacity and type, tho the gauge wire coming out of them did get changed. The old ones had 20 Ga. on them, with 3 leads/switches going to the receiver.

I enjoy running tests, but I try not to get too anal about this stuff. It's a hobby, and I enjoy all the facets of it. I'm sure all the fanatics on RCU do!