Steve

My Feedback: (54)

Is it safer to run a 6 volt or 4.8 volt system on large models? Does the 4.8 volt systems draw more current than the 6 volt on digital servos, or do the 6 volt systems alow more current draw ( heat ) to the servos? How dependable are the 6 volt regulators? I want to stay as simple and safe as possilbe, even if I need to use a match box or two.


Steve

famousdave

My Feedback: (61)

It depends what you type of model you are putting it in.

Anything that you are doing aerobatics with 6V will put more torque at your fingertips and usually a higher actuation speed.

6V theoretically will fall back to 4.8V if a cell fails, but that is pretty much a pipe dream. If a pack fails, it opens or shorts, it rarely loses one cell. I use 6V on everything I fly.

Here is what I use :

Light plane (under 12 pounds or under $1000):
RX > One 1800mAh 6V NiMh or 2200 mAh 7.4V Li-Ion pack, one switch, one 6V regulator
Ignition (if you run gas w/electronic ign) > One 6V NiMh or 7.4V Li-Ion pack, one switch, one 6V or 4.8V regulator depending on ign
I use all HD leads and extensions

I use NiMh only if I need the weight to balance. Smaller planes with heavy gas engines usually require more weight rearward. Instead of using expensive Li-Ions and adding weight - I use NiMh's

Example : H9 Ultra Stick Lite (G26 Zenoah power)


Larger plane (over 12 pounds or over $1000)
RX > Two 2200 mAh 7.4V Li-Ion packs, two switches, two 6V regulators into batt + aux rx channel (or y-harn if no aux avail)
Ignition > One 2200 mAh 7.4V Li-Ion pack, one switch, one 6V or 4.8V regulator depending on ign
Opto-Isolator for ignition cut-off
I use all HD leads and extensions

CA 31% (3W-75i) , Kangke CAP 232 120 (3W-24i) Kangke Monocoupe (Zenoah G-26)


Very large or expensive plane (20 pounds + or over $3000)
Modelbrau Powerbox Pro
RX - Two 4400 mAh 7.4V Li-Ion batteries
IGN - One 4400 mAh 7.4V Li-Ion battery with reg, switch, and opto - isolator
Airwild HD twisted leads or custom 18gauge leads / Y's on ganged servos

Carden 35% CAP (DA-150), AW 40% Katana (DA-150)


Since I use only Hitecs, I don't ever use or need matchboxes.


DP

AeroDave

DP,
I just purchased a bunch of Hitec 5645 digitals for my 28% Wild Hare Extra Special. Should I run the elevators on a y harness and program them, or just use 2 channels on my 9C?

famousdave

My Feedback: (61)

AeroDave - I had my eyes on that plane - it looks awsome on the website .. how is it in the flesh ??? As far as wiring - you can do either, it really is up to preference. If you have a programmer, I would use it and reverse one and just use a Y-harness. That is what I always do. If you didn't have the programmer and had to buy one ($150) just for that, I would say run two extensions. With that size plane you really can't go wrong either way..

My rule is the less wire you have, generally the better so I'd use the Y..

DP

Steve

My Feedback: (54)

Thanks DP. I am setting up the CA 31% with the 3W 75I. Im using all Hitec 5645s, two per aileron, one per elevator, and a 5735 on rudder.

Steve

ptgarcia

My Feedback: (36)

Steve,

I recommend going with 6.0v on the radio. With the length of extensions needed and the power requirements of the servos I believe it is warranted. You could go either way on the ignition but 6.0v is not needed. I bought a Wild Hare 28% Extra 300 also, although I bought the LX. Here's what I will be using for power:

(3 ea.) Fromeco Relion 2200mAh 7.4v Li-Ion

(3 ea.) Fromeco Super Regulated (to 6.0v) Reliaswitches

This system will set you back about $240 but it will keep you flying all weekend without charging.

Here's what I have on my 28% Laser 200 with (5 ea.) Hitec 5945's and (1 ea.) Hitec 5475 digital servos and Brison 3.2 gas engine:

(1 ea.) Radical R/C 2700mAh 6.0v NiMH receiver battery (no regulator)

(1 ea.) Radical R/C 1650mAh 4.8v NiMH ignition battery

This is more of a budget type system but it does the job very well. Note I do not use a regulator on my 6.0v systems.

In regards to your elevator servo question, I prefer to run each servo on its own channel and use the radio programming to synchronize them. If I had a programmer, I would still use seperate channels but would match servo attributes using the programmer.

By the way, I recommend both battery vendors I mentioned above. Great prices, great products, and great to deal with. Good luck!

GoeKeli

My Feedback: (18)

Steve, good topic! I have been running an 1100 mah JR nicad 5 cell with no regulator running 4 hitec 625s and 1 645. It works very good. I charge at the end of the day and write down how much the battery took. I've never put back in more than 800 mah after flying a lot. I had a regulator on this plane and through advise from some very good pilots I fly with I took it off and noticed no difference. Just one less thing to fail. Ignition on my DA and BME get 4 cells. I'd like to keep things really really simple, in the near future I may be putting together a 35%.
Pauly, fromeco told me their regulators were 5.5 volts. They seem like a really nice company to deal with and have very good prices. My flying buddy had a bad time with radical but I would like to order from them. They have those 1500 mah nicad AA packs that are supposed to really be good. I like lipoly and fly them in my electric planes but the nicads can be fast charged and discharged. Well, seems like they are all getting better and thaks good for everyone.

Joe

famousdave

My Feedback: (61)

I also use Fromco batteries, but MPI 6V regulators.

DP

famousdave

My Feedback: (61)

Steve -you and are building the same plane, same setup! I have the exact same combo... had to really beef up the engine box - pinned and glassed and also ended up tossing the original side plates and firewall and used stronger hard ply.

What are you going to use for low, high and 3D rates ??

DP

Steve

My Feedback: (54)

I've seen a lot of advertizements on Li-poly batteries that you can by. Batteries America sells these for a reasonable price, but I've heard of these exploding. They also sell the chargers and regulators for about twenty bucks each. I have only used Nicads and am not sure about getting setup for other batteries. They also sell the Lithium Ion batteries for a reasonable price as well as fast chargers. I do need to get a better charging system, I just don't know what that should be. I think I will try a 6 volt reciever pack with a regulator. Maybe even two. I'll stay with 4.8 on the ignition. Are the Lithium Ions much lighter than Nicads?

Steve

Steve

My Feedback: (54)

DP. I will probably start out with one inch on low, elevator and aileron, and all I can get on high rate. The rudder I will have to play with to get the best ground handling on low rate. How far have you got on yours? I still have to finish the wings and rudder, then cover it and set it up. I am center hinging all the surfaces and I did not put in any counter balance on the elevators. I may do the same with the engine box.

Steve

ptgarcia

My Feedback: (36)

Thanks for the clarification, Joe. I really couldn't remember what the regulated voltage was and just guessed/assumed 6.0v. And everyone knows what assuming does...

famousdave

My Feedback: (61)

Hey Steve, Li-Polys are OK for electric flyers but too fragile for giants. Li-Ion is rock solid, as good as any NiCad or NiMh. Li-Ions weigh 1/3 as much as NiCads and can save up to 8 oz per plane (including regulators), they have 2x the capacity and do not ever need cycling.

I wrestled with the decision for about 6 mos, but ended up totally converting my entire fleet to Li-Ion. I am amazed at the ease of charging and the longevity of the packs. I will fly all of my planes all day (15 or more 10 minute flights).

The reason for going all one voltage (7.4) is to standardize on the charger needed. I have one Duralite charger that will charge everything I own. Even my large planes with 3 batteries I only need to hook up once and all three batteries are charged at the same time - same rate...

Obviously there is a cost associated with this, but if you have the cash and are leary of doing this only because of the technology and not because of the funds - go for it. The technology is here to stay and I will not be surprised at all if Li-ion totally replaces NiCad technology within a few years. Li-Ion packs are almost getting as cheap as NiCads these days (Fromeco / TBM)..

DP

famousdave

My Feedback: (61)

Steve - as far as the CA31% - I'll open another thread shortly on the giant scale forum and post a bunch of pics, we can move that conversation over there... I am sure most people here don't care about our CA's!!

DP

Steve

My Feedback: (54)

Thanks DP. I'll look into getting set up with Li-Ion batteries. I think they come up for sale in the marketplace on ocation too. I'll look forward to you posts, let me know when you have it started.

Steve

sfaust

My Feedback: (11)

Very shot answer. On larger airplanes, use 6v, or a higher voltage pack (eg, 7.2v) and a regulator (5.5v to 6v). The reason is all the loss in the electrical system due to resistance in the wiring, connectors, etc. A 4.8v pack with never end up being at 4.8v at the servo end, and it will be much worse with the larger airplanes due to the additional wiring, multiple connectors, etc. Starting with 6v, means you could even loose 1.2v along the way, and still be providing your servos with more current that you would with a 4.8v pack and minimal resistance in a smaller airplane. Furthermore, use all heavy duty wiring, gold plated connectors, minimize the length of excess wiring, eliminate connectors by soldering where practical, and use a heavy duty charge switch.

Steve

My Feedback: (54)

Thanks Stephen. I'll so that. I've decided to use two switches, batteries, and regulators. All HD wires. I just need to decide on which type of battery to use.

Steve

deputydog

I've used 6v Nimh batts with no reg for awhile. Current is pushed better on larger models. On my gassers I went to Duralites. Great battery system!

sfaust

My Feedback: (11)

I have pretty much gone to NiMh for all my larger airplanes, and run 6v with no regulators. Its better in my opinion than the NiCds, and I don't have the issues with Lithium, so I settled on them for the time being. But frankly, any of the three would work well, and its just a matter of trade-offs (cost, weight, batt maint proc, chargers, etc) based on personal preference.

Steve

My Feedback: (54)

deputydog, don't you have to use a regulator on the Duralites? I priced Li-Ion batteries with regulators and charger and the new switch with led lights from MPI and getting set up with two will cost about $180.00. I can save about $60.00 using Ni-Mh. When I asked about charging NiMh batteries they said I could use my NiCad chargers. Is this true?

Steve