Eganwp

My Feedback: (1)

Time for some input guys! In the last 6 months I've done a rediculous amount of reading on a123's as I am planning my setup for my new 30% Edge 540. (DLE 55, 5x Power HD9150's, 1x Power HD DS90 throttle, 1485sq.in, 16-16.5lbs, 88.5" ws, 82" length).

This is my first gasser so since I've bought it all new, I wanted to go with the best theoretical setup without going overboard, plus I love researching/reading forums. I've now built 7x 2s1p a123 1100mah packs with custom wire output/balance tabs as I see fit for about $12 fully wrapped and rtf each which is really cheap IMHO. I love these packs so far as far as bench charger testing goes. Now all I have left is yet again my waivering decision on the best setup to use. I already own almost everything for each setup other than the Zeus & 2300's, so cost isn't too big a factor. Here are the options I can't decide between and would appreciate your input (keep in mind I'm gaining redundancy with separate batteries, switches, extensions, etc. all the way up the RX):

My goal is KISS, least weight, redundancy, and enough capacity (65% used max) to fly 4-5 10-12min flights before charging. Any more is simply wasted weight and capactity to my flying schedule.

Option 1:
16g MPI switch 1 batt1>RX
16g MPI switch 2 batt2>RX
90g 1100mah a123 batt1>RX
90g 1100mah a123 batt2>RX
14g Opti-kill
16g MPI switch 3 batt3>IGN (or pin/flag depending on preference)
90g 1100mah a123 batt3>IGN
1g 2x diodes>IGN
-
333g
+ Completely separate systems
- 1x extra battery to charge/maintain
- More complex setup


Option 2:
16g MPI switch 1 batt1>RX
16g MPI switch 2 batt2>RX
90g 1100mah a123 batt1>RX
90g 1100mah a123 batt2>RX
40g 42% Zeus (includes filtering, voltage reduction for ign, opti-kill, ign switch, power, etc)
-
252g
+ Allows removal of these components: IGN switch, opti-kill, 2x diodes, IGN battery - saving weight
+ KISS
- Loose 1100mah IGN capacity (though only ~200mah of that would be used in 4 flights before recharge anyway)


Option 3:
16g MPI switch 1 batt1>RX
16g MPI switch 2 batt2>RX
150g 2300mah a123 batt1>RX
150g 2300mah a123 batt2>RX
40g 42% Zeus (includes filtering, voltage reduction for ign, opti-kill, ign switch, power, etc)
-
372g
+ Allows removal of these components: IGN switch, opti-kill, 2x diodes, IGN battery - saving weight
+ 4600mah total capacity will provide 8-10 flights without charging (however, if I only fly 4 or 5 flights per outing the extra weight carried is useless)
+ KISS
- Heaviest setup of them all
- Overkill capacity for 30%


I'm aware of all issues like common bus bar, IGN voltage reqs, diodes, balancing, max charging amps, etc.

The questions I have that I can't find answers for in my research include:

1. Typical mah usage per 12-15min flight on 30% 3D plane at 16lbs? I've read everything from 150mah - 450mah used for servos only in a 12-15min flight... 40mah - 100mah used per flight on DLE/DL/DA ignition per 12-15min flight... Now I understand it all depends on how hard you 3D, speed, plane weight, altitude, throttle usage, servos used, number of servos, etc so I do understand these numbers seem to very a lot. I just wonder if some of the extremes are wrong or miscalculated as I've only read the extremes once.Can anyone give me personal results for their mah usage per flight and setup (on 30%) so I can get a better idea? I will most likely just have to go fly the thing and a couple flights and see what my setup is actually using. Just would be nice to know a closer figure as this varies my a123 size decisions CONSIDERABLY.

2. The new 42% Zeus... Every report I've read on these things has been positive. I especially like that they went the extra mile on these to include full ignition filtering to 2.4 RX's via transformer switching, while incorporating opti-kill, reduced and selectable IGN voltage, IGN power, built in switch, external power light, etc. This enables me to toss the IGN battery, opti-kill, IGN switch, and diodes for IGN voltage reduction. They seem to be a greatly improved version of the TBM battery elimiation circuit. My question is, is there anything I'm not considering with the Zeus that would cause failure? Someone mentioned if the IGN shorted out, it would kill the Zeus and the RX, though I'm not entirely sure that's true. I may have to talk to 42% designers to get that answer I guess.

3. I'm using a Spektrum AR7000 w/ satellite RX. The last question I have is with regards to bus power on these AR7000's when running dual batteries. I've read several conflicting reports on how the power is drawn from the batts. One side of reports being that it switches to the highest voltage battery and the other reports saying that it draws equally from both packs... This makes a HUGE difference in my mind, because if it truely does only draw from one pack, you loose all amperage availability through the 2nd input to the RX, thus halfing your available power to the entire plane... Both say that this is using 1 connection to battery port and the other connection to a spare channel. I guess I should just do my own testing and tear down my AR7000 to see if it's a common bus bar or not. Otherwise I guess I'll call Spektrum unless anyone can give some input to this.

Thanks for you help guys. Sorry this post is so long...

Eganwp

JoeAirPort

My Feedback: (41)

I like #1 the most but I don't like the MPI switches. Go with the JR/Cermark HD switches. They have a great track record. The MPI has a bad record of failure from my time in the forums.

Just fly once with the new setup like you normally do. Then land and recharge. Keep track of what you put into it. Do this a few times and you will get a feel of what you consume per flight. I bet you will be around 200-250mah per flight. Then make sure to not consume more than 50% of the total battery capacity you have....which is 2200 total divided by 2 = 1100 mah. So if you determine that you burn 200mah per flight I wouldn't fly more than 5 times between charges.

I never recommnd using one battery to supply rx and ig. It's just bad practice even with 2.4G. That's my advice....keep the circuits separate for better noise immunity. That way if your ignition takes a crap it won't take the receiver with it....even with the 42% gizmo I wouldn't do it.

Eganwp

My Feedback: (1)

Hmm.. Thanks for the input Joe. I'm a bit suprised actually as I debated switches for a long time a few months back and nearly everyone told me to go with MPI HD charge jack switches as they were the most reliable next to Fromeco and SmartFly. I am considering swapping them for a Fromeco Wolverine dual switch or something similar that's failsafe. Charge jacks integrated are a must as well. I'll consider this, thanks.

Anyone else?

JoeAirPort

My Feedback: (41)

You'll need to cut the signal wires from your switches to the receiver. This is the balance center tap for charging the batt's. You don't want that wired to the receiver.

The Wolverine would be ideal but they are not making them right now unless you can get a used one. That's why I didn't mention it.

Eganwp

My Feedback: (1)

Yea I'm aware of the signal wire needing to be removed from switch>RX as it'll short the entire battery loop if you try and bind the spektrum RX.

I didn't realize they're not making the wolverines anymore... Hmm, I'll have to look around a bit. I see ValleyView is now bringing in TLT Aviation dual switches built into one with integrated charge jacks and a nice aluminum casing. Trouble is they're on back-order until April or something. I'll keep my eyes peeled.

Edit: I just thought of my 3rd question that I forgot in my original post. Added.

JoeAirPort

My Feedback: (41)

I remember that question (#3) from you months ago. To tell you the truth I don't know for a fact that all the servo ports and batt are connected together as a common bus bar like most receivers. I flew that same receiver in my EF yak and Extra all year with zero problems. I didn't have two batt's but did have two JR connectors from my Smart Fly Super switch. I never knew if they were drawing power from both connectors but they did fly awesome with not a single hickup in many many flights. I was using the Spektrum DSM2 Futaba module in my 9C.

JoeAirPort

My Feedback: (41)

Ok I just ohm'd out a AR7000 receiver power bus with my Fluke 77 multi meter (nothing connected to it). All servo ports and battery port share the same + and -. So this means it's just like any other receiver and all ports will draw power if you have batteries connected to them...equally.

Eganwp

My Feedback: (1)

Awesome!!! Thank you very very much for testing that for me Joe. Greatly appreciated. That is what I figured the answer to be as the other design method just doesn't make sense for cost effectiveness or simplicity on Spektrum's end.

I think I have found a wolverine switch to buy as well that's in stock... I'll let you know. Great to hear that RX setup worked fine for you.

Gillotti

hey boys, to the above reference about using one batt for ign and rx, what do you think of the ignition battery eliminator filter. i was considering a setup for a dle 55 with a big a123 for everything

JoeAirPort

My Feedback: (41)

My above reference clearly stated NOT to do it.

nonstoprc

My Feedback: (90)

A123 batteries can be charged very fast (less than 10 min). The 1100 mah version of A123 is good enough (assume they can be charged at the field) and saves weight.

I personally use option 1 on my 30% Edge (except using Nicads for ign. module and a choke servo). MPI switches are fine, in my opinion.

JoeAirPort

My Feedback: (41)

I thought I read at least a few threads about MPI switches having wires break off. Those JR/Cermark switches are pretty hard to beat. Have you ever seen a report of them failing? I haven't. Anything can fail but the likeliness of some brands is high. I thought MPI was one of them. I'd do a search before I use them.

nonstoprc

My Feedback: (90)

I have used more than 10 MPI switches (HD type) in total. Not experienced wire break off.

Eganwp

My Feedback: (1)

Just wanted to let everyone know that after even more research again (I think I'm easily over 100 hours on giant electrical setups now :P) and a lot of testing of 8x a123 packs I built myself, I'm going with a revised Option 2. Thanks for all your input.

1x Fomeco Wolverine Dual Failsafe Switch (2 Deans In, 1 Deans out)
2x 1100mah a123 packs
1x 42% Zeus


I now have full redundancy, full battery failover safety, dual switch failsafe, battery sharing, any size/type battery input allowed!, 8amp spikes to RX with dual inputs for safety, optikill, voltage fluctuation elimination, RFI interference stopped to RX, variable jumper'd ignition voltage selection, active ignition light, battery active/working lights on switch, charge jacks allowing full battery charging and balancing while in plane (4amp through switch, 10amps if I simply unplug switche's deans connector instead, no excess switches, KISS and EXTREMELY light. I now have everything in hand but still waiting on the Wolverine. Man this 42% Zeus is sweet in hand!

This setup is EXACTLY what I wanted in the beginning, but man it took me a lot of decision making, planning, mapping and electrical knowledge to get there! haha

Best of all, if I find 2x 1100's arent enough, I simply swap one out for a 2300 or even both for 2300s and let the switches battery share do the work!

I can't wait to fly this beast now! Hope my setup can help someone out in the future.

Egan

Magne

In my opinion, you don't have full redundancy, or any kind of redundancy, if you plan on using more power/energy than can be supplied with only one of your batteries, the smallest one to boot.

Two battery packs does not give your battery system any added capacity, it just adds redundancy. The smallest pack still has to do the full job if the biggest pack fails without you knowing it.

Magne

Eganwp

My Feedback: (1)

Yes, obviously I realize this. But please remember this: 200mah / flight * 4 flights = 800mah used total. 1000mah in the worst case scenario. I'm still not using up 1 batterie's full capacity. And yes I would never push a single setup this far, but I'm just speaking for redundancie's sake here. Also, since I know both packs/setups are working when I first put them in the plane fully charged, I'm already getting BatteryX + Y% capacity over Z timeframe, and thus will never max out a single battery's capacity in 4 flights if one did fail.

I also mentioned the versatility of the Wolverine which allows me to use a 2300 setup if I desire to have more capacity. I see no issues with the setup.

nonstoprc

My Feedback: (90)

Yes, as long as the capacity of the two packs are monitored during charging, you should be fine. Somebody in similar dual battery setup even turns on each battery before the flight to make assure there is no dead battery.

200mA/flight is what I got in my setup: 4 5945's and 1 7955, plus the standard throttle servo.