switch for AXE CP

switch for AXE CP
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switch for AXE CP - 8/22/2007 7:28:36 PM

john339

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Joined: 7/26/2007
From: Clyde, CA, USA
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I have gotten tired of removing the canopy when I crash to disconnect the battery so I installed a small switch.
It is rated at 10 amps 125v so I figure about 40 amps max at our voltages.
Works just fine and now I will have to figure out how to charge the battery without removing the canopy.

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RE: switch for AXE CP - 8/22/2007 8:02:35 PM

MMatheny

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From: Dickinson, TX, USA
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Both of my leads hang out of the canopy - I can plug together or recharge without removing the canopy.

_____________________________

Mike
"Never use your shins as a blade tracking device" - Mike

(in reply to john339)

Post #: 2

RE: switch for AXE CP - 8/22/2007 8:20:22 PM

HalH

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Joined: 11/25/2002
From: Madison, WI,
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It is highly recommended that one NOT charge the battery with it installed in the heli.

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Post #: 3

RE: switch for AXE CP - 8/22/2007 8:32:54 PM

john339

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From: Clyde, CA, USA
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HalH I have read that too but only for the LiPo type batteries. Do you think that our type battery and the small, 400ma, charger pose a problem?

< Message edited by john339 -- 8/22/2007 8:41:53 PM >

(in reply to HalH)

Post #: 4

RE: switch for AXE CP - 8/22/2007 8:43:42 PM

123Splat

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Joined: 4/27/2007
From: Austin, TX, USA
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Dude, I read your post about plugging the charger into the 3-in-1 board by mistake. Maybe letting both leads hang outside the canopy isn't so great? Or, you, maybe, should label one or both?

John339,
Love the switch idea! I always wonder if i'm screwing up the gyro initialization when I shake or move the bird, while plugging in the flight batt.
On the R/C Tanks forum, some of the guys have gotten another battery plug, connected the black leads from the battery and the reciever board and the new plug together, red from the recvr board goes to the center pole of a S.P.D.T. (Single Pole, Double Throw. Three pins: one in center is common, ones on each end connect to the center upon throwing the switch lever in the opposite direction.) One of the outside pins connects to the batter connector, the other connects to the new connector (where you plug in the charger. One throw of the switch is the 'ON' position, the other is the 'OFF/CHARGE' position. You never have to remove the battery, until it gives up the ghost! (or you want to swap with an already charged batt to 'keep on going'. kinda negates the switch/charge idea....)

Ever notice that the battery lead is some dinky guage and the motor leads are huge?? What's up with this? I'm a E.E., by education, (play with computers by practice) and this does not make any sense to me......

anyway,

Splat

P.S. HalH, That's Lithium Poly's No big deal with Nickle Metal Hydrides. They get warm, but they don't go woosh, boom.

_____________________________

It's not the takeoff or the flying, it's the landing and repairing, so I can takeoff and fly again...

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Post #: 5

RE: switch for AXE CP - 8/22/2007 8:50:43 PM

MMatheny

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From: Dickinson, TX, USA
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Well, like you said - leads on the battery smaller than to the 3in1 - so, I check carefully now before hooking the charger up!

_____________________________

Mike
"Never use your shins as a blade tracking device" - Mike

(in reply to 123Splat)

Post #: 6

RE: switch for AXE CP - 8/22/2007 9:03:24 PM

123Splat

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From: Austin, TX, USA
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No, No, You miss the point! The leads (the wires, not the plugs) on the original batt and the 3-in-1 board are the same size ( hence, your almost unfortunate experience). My point is the difference in the size of the battery leads ( the power source) and the Main Motor (the largest power consumer). Everything I learned in school (20 or more years ago, ugh!) says the bat leads should be at least as large as the motor leads!

< Message edited by 123Splat -- 8/22/2007 9:04:37 PM >

_____________________________

It's not the takeoff or the flying, it's the landing and repairing, so I can takeoff and fly again...

(in reply to MMatheny)

Post #: 7

RE: switch for AXE CP - 8/22/2007 9:17:08 PM

Prontow

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Joined: 1/5/2007
From: Dyersburg, TN, USA
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I put a switch on my bird a couple months back, I mounted mine just under the tail boom. To turn it on i have to push the switch up toward the boom, I did this so the possability of the switch getting bumped into the off position is unlikely. Plus it is out of the way and easy to get to. I just glued it in place, works great!

(in reply to 123Splat)

Post #: 8

RE: switch for AXE CP - 8/22/2007 9:26:31 PM

john339

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From: Clyde, CA, USA
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123Splat What a great idea about the switch and charging. I will set it up that way next.
You are right, amps and volts usually need the same gauge of wire to carry the same load.

(in reply to Prontow)

Post #: 9

RE: switch for AXE CP - 8/22/2007 9:32:10 PM

MMatheny

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From: Dickinson, TX, USA
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"The leads (the wires, not the plugs) on the original batt and the 3-in-1 board are the same size "

Splat - OK, so you are saying the wires on the battery and the wires to the 3in1 are the same gauge. So, now what are you talking about being a smaller gauge??

_____________________________

Mike
"Never use your shins as a blade tracking device" - Mike

(in reply to john339)

Post #: 10

RE: switch for AXE CP - 8/22/2007 11:29:55 PM

Heliko

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Joined: 1/16/2007
From: Long Island, NY, USA
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quote:

ORIGINAL: john339

I have gotten tired of removing the canopy when I crash to disconnect the battery so I installed a small switch.
It is rated at 10 amps 125v so I figure about 40 amps max at our voltages.
Works just fine and now I will have to figure out how to charge the battery without removing the canopy.

I think your rating the switch on watts. The 125v rating on the switch is the switch's insulating capablility. Regardless of voltage I don't think that switch can take more than 10 amps. It should still be OK though at least for hovering. The Axe only pulls about 6 amps in a hover. At full throttle though the main motor can pull as much as 11 amps and the tail can pull as much as 2.4 amps at full right rudder.

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Post #: 11

RE: switch for AXE CP - 8/23/2007 3:40:34 PM

123Splat

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From: Austin, TX, USA
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tmmatheny,

The MOTOR (that big round thing with the heat sink on it..) leads appear to be a larger wire guage than the battery to 3-in-1 leads.
As in: "My point is the difference in the size of the battery leads ( the power source) and the Main Motor (the largest power consumer)."

Heliko,
You make a good point on power rating of the switch, but would the axe draw enough amp.s in a high g move to melt the contacts in the switch? (if you answer 'Yes', I'm gonna look to you for an answer on the wire guage question, That on has me stumped.)
Most of the time you worry about the power rating to avoid arching issues (switch damage and/or welding the contacts closed) when switching, not under constant load. But, you still make a good point.

Splat

_____________________________

It's not the takeoff or the flying, it's the landing and repairing, so I can takeoff and fly again...

(in reply to MMatheny)

Post #: 12

RE: switch for AXE CP - 8/23/2007 4:09:52 PM

MMatheny

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Joined: 1/23/2003
From: Dickinson, TX, USA
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OK splat - now I get it - I kept thinking you were talking about the leads to the 3n1. Have you tried putting larger gauge wires on to see if there is any difference?

_____________________________

Mike
"Never use your shins as a blade tracking device" - Mike

(in reply to 123Splat)

Post #: 13

RE: switch for AXE CP - 8/23/2007 4:56:17 PM

123Splat

Posts: 413
Joined: 4/27/2007
From: Austin, TX, USA
Status: offline

Na, I'm waiting on Heliko's comment.
It just doesn't make sense to me, but Heliko's probablly got a spin on it that'll clear it up.

_____________________________

It's not the takeoff or the flying, it's the landing and repairing, so I can takeoff and fly again...

(in reply to MMatheny)

Post #: 14

RE: switch for AXE CP - 8/24/2007 2:22:36 AM

Heliko

Posts: 591
Joined: 1/16/2007
From: Long Island, NY, USA
Status: offline

quote:

ORIGINAL: 123Splat

tmmatheny,

The MOTOR (that big round thing with the heat sink on it..) leads appear to be a larger wire guage than the battery to 3-in-1 leads.
As in: "My point is the difference in the size of the battery leads ( the power source) and the Main Motor (the largest power consumer)."

Heliko,
You make a good point on power rating of the switch, but would the axe draw enough amp.s in a high g move to melt the contacts in the switch? (if you answer 'Yes', I'm gonna look to you for an answer on the wire guage question, That on has me stumped.)
Most of the time you worry about the power rating to avoid arching issues (switch damage and/or welding the contacts closed) when switching, not under constant load. But, you still make a good point.

Splat

Splat I agree that it doesn't make sense if motor wires are larger then battery wires unless the ESC was somehow stepping down voltage and stepping up amperage, remember amperage determines wire size, but I don't think that's the case here.

The battery leads should be sized for maximum safe amp draw therefore they can dictate wire sizes throughout the system. Honestly I think the stock motor wires are a bit oversized.

I wouldn't get too hung up on wire size though since most of the components are pre-wired. I only had to worry about sizing the wire on my BL tail harness.

As for the switch. It may be a little on the light side. It's close to the cusp. If you really want the switch, but are worried the only way I could think to test it is to hook it in, bolt down the heli, run it up to full throttle, and see if the switch gets hot. Usually they'll take a bit more than they're rated for plus the Axe will probably only exceed the switch rating for a short time during extreme manuevers.

Also larger wires aren't going to make a noticable difference unless the current wires are grossly undersized in which case the wires would be very hot after a flight. I didn't notice hot wires with my Axe when it was stock whether I was runnig the stock pack or Li-Po's so I think it's OK.

Hope this helps.

_____________________________

"Gravity is a harsh mistress." The Tick

(in reply to 123Splat)