ON-OFF switch reliability, for onbord elecs.

[freefall]

Thinking about using lipo`s rather than nicad`s for onboard power so this will require my getting a regulator.
Whilst doing a search on regulator info i noticed some do not require the use of a ON-OFF switch and the mention that these often fail.
I have seen that some regs have ON-OFF,one use`s a pinflag(no idea on that fully)and some you just plug lipo`s straight into system(thought that might be bad).
What do you guys do or recommend.

[stevehonn]

My choice would be the Align 2 in 1 regulator which works with a 2S lipo pack and also provides a supply to the glow plug.

[ev0l]

the Arizona from Fomeco is the best I have seen. It has the pin switch you decribe that defaults to "on" if there is a malfunction.

I purchased the Align, read a couple of horror stories and decided my nice new nitro bird was too nice to risk with the cheap reg. The Arizona is pricey, but worth every penny for the peace of mind.

[fsusmithc2]

I use an Align 1900mAh 2s lipo with a Duralight 6v regulator. I just used the switch that came with my DX7 radio. Even the wire tie is still in place. Only thing I had to do was change the JST connecter on the battery to a JR connector. After tidying up the wires the switch sticks out in the front for easy access (no real good place to hard mount it). See attached pic. I chose the 1900 over the 1100 mostly due to the fact that it has a balance tap so I can plug it right up to my Cellpro. That and the higher capacity of course. 44 flights so far and no problems.

[lakespinner2]

I'm trying the Align 2 in 1 switch/glow on a new nRex, so far so good. If it holds together over time I'm going to love it. The onboard glow start might spoil you. :p

I've got over 150 flights on an old raptor titan with the pin switch and Arizona regulator. The regulator is fantastic, rock solid, never a minutes trouble from it. The pin switch, not so much.

The first pin switch, after some time, started turning on when I was hauling it to the field, with the pin installed in the switch. I'd hit bumps in the road and I could see the blue lights flickering on the Arizona regulator in the rear view mirror. I replaced that pin switch with another and it lasted a year or so. Then it started coming on just sitting on the table, again with the pin installed. If I wiggled the pin I could get it to settle either in the on or off state.

I mentioned it at IRCHA to some folks there and they surmised that it was the pin, not the switch, that might be at fault. Apparently the pin has to make an electrical connection between contacts inside the switch to turn OFF the electronics. They said If that pin tarnishes or corrodes, rusts, etc. , then the switch could turn ON. Since it's almost always humid here that may be what happened. I'm still not really sure if it's the switch or the pin, but anyway I got a third switch and pin. I'm told the pin is now made of a different material to help prevent that sort of issue.

It works very well and I like the novelty of 'pulling the pin,' but just keep an eye on that pin switch for any unusual behavior.

[wcc963]

im not gonna be running a regulator, 7.2V straight to the rx and to my 8717's, and just a step down for the tail. :D

[rcmarty]

I assume your using the spectrum system as i've read it's setup for 8 volt system.

Are the 8717's rated for 8 volts ?

Keep in mind with the step down only drops a small amount of voltage (.7 volts if i recall correct) so dropping .7 volts off 8 volts is still going to be a bad thing for your gyro/and or servo.

I'm also waiting for the 8v servo's to come out ,should be interesting to say the least.

The next logical evolution will be to have a gyro/servo combo that is rated 8 volts but no word there.

Should also be good for us spectrum users as the rx's don't like voltage dips. There's going to be some serius issues for a 8v system to dip into the 3.7v or less range !!

Martin :)

[Mercuriell]

I like the ALign 2 in 1 too and as long as you secure the wires with Hot Glue or Silastic there aren't any other major issues. FWIW I keep my battery connected all the time to the Regulator and haven't noted appreciable drain - I think I read 2mA somewhere or ~ 250 days !

[Mike3DPro]

im not gonna be running a regulator, 7.2V straight to the rx and to my 8717's, and just a step down for the tail. :D

I assume your using the spectrum system as i've read it's setup for 8 volt system.

Are the 8717's rated for 8 volts ?

Keep in mind with the step down only drops a small amount of voltage (.7 volts if i recall correct) so dropping .7 volts off 8 volts is still going to be a bad thing for your gyro/and or servo.
Martin :)

Yes, thats still too much voltage on the gyro/servo !
I have heard from others that the 8717s can take 8.0

I have the 8717s, just got them, and they seem very good. Holding is excellent, but they really excel in stopping and changing direction instantly. So if you were making extremely quick (using entire hand on 1 stick - faster than any thumb) collective inputs - not full pitch to full neg - but about from +5 to -5, it will always be dead on.

On another note: after doing some hard servo testing for about 2-3 minutes you can feel the aluminum heatsink get warm. (about 100-110F) Regular servo use, they just stay room temp. When I plug it into 8.0v, they seem fine, but they get warm much quicker. I would not suggest it just because it seems like it would have an impact on the gears over time. (I think the motor would last though) The stopping and starting at 8.0v seems to me that it would just hurt the gears (even if metal) over time, it simply sounds like there's too much inertia on the drivetrain, motor is TOO strong.

If you hold the chopper by the swashplate - the servo's will do "pull-ups"! So they should have enough torque, I would think!

These do however seem to draw a lot of current when reversing, full stall doesn't seem to take quite as much. If I could find my meter I could test it.

[freefall]

ev01, You say you are using the Arizona reg.I might go with that also.I do not fancy using the "pinflag" do know if it can be used with a conventional ON-OFF.I have looked and can not find any mention on the subject.

[MrMel]

im using arizona with a regular switch, you have to solder the output on the switch together (short it) on th "on" side since a short = off and open circut = on.

[Mike3DPro]

UPDATE: I got my meter and tested the servos. With only (3) 8717 servos plugged into the reciever and voltage at 5.78 - 5.8 VDC, I got .08 A of current draw for idle servos.

No load, moving stick fast: peaks of 3.5A and about 2.5A continuous.

Full stall: 9.8-10.5 AMPS!!!

Remember all this is for THREE 8717 servos

The full stall amperage will change depending how far the servos are from their target point. 10.5 is the highest I could make the servo's draw. For full stall I put some rubber handeled 8" sidecutteres under swash and lowered the stick to full neg pitch. Of course I never held the servos in stall for more than about 3 seconds, just enough to get a good reading. I don't know what the bec of the 2n1 is rated for, but I was suprised to see 10.5 amps coming from it. That was just a surge though - I wouldn't expect it to stay at that amount of power for more than a few seconds. The heatsink was warm when I got done.

PS: the align stepdown only takes off some voltage - so like I said 8.0 is too much for a gyro/servo. On a 7.9v lipo, It only lowered the voltage to 7.5v.

[freefall]

MeMel, Can you explain that about the switch again please.Electrics is not a good subject for me.
Are you saying that a standard ON-OFF switch will be no good on the Arizona reg?

[MrMel]

The arizona is default on, if you dont hook up anything it will stay on.
To turn it off you need to short-circut + and - on the switch lead.

So on your normal ON/OFF switch you have input -> switch -> output.
You need to short-circut the output, so when you turn it off you actually shortcircut the cables.

(Its a failsafe thing, if the switch breaks down it will stay on)

So, yep, it works with a normal switch, with modification.

[freefall]

But will it work with a standard switch with no mods.

[MrMel]

But will it work with a standard switch with no mods.


No, well, regulator needs no modification, the switch does (or at least the cable out of the switch)

[freefall]

The more i ask the more confused i get.
So basically i can not use a standard ON-OFF switch.I have to mod it first.
What would happen if i did use a standard ON-OFF switch with no mod.

[MrMel]

The regulator wouldnt turn off, it would stay on all the time.

Here is a simplified drawing of how it should look like.