Originally Posted by rcbirk21

all im saying is i think the higher voltage and the amps on the PL8 are a lot more stress on it. there is a ton of examples of very high amperage through the 45a pp's and they hold up very well

Voltage is irrelevant, it's the amps the generates the heat. Voltage only comes into play if you have so much of it that you exceed the breakdown voltage of the insulation. The voltage rating on the PP45s is 600. So, typical airplane setups don't need to worry about that.

What makes the heat is current. The connectors are rated for 45 amps, but if you look at the data sheet:
http://www.powerwerx.com/techdata/PP45.pdf
the picture is more nuanced than that. There's a graph on that sheet showing pulse current capability. If you use #10 wire, the connectors are good with 80 amps for 1.5 seconds, or 60 amps for 4 seconds, 40 amps for around 25 seconds, etc.

The airflow in flight probably helps cool them a bit, but mostly I think what makes it OK is the fact that you don't sit constantly at full throttle.

Charging of course draws the full current constantly for a long time, so I guess it's not surprising there might be some problems there.

Originally Posted by AeroKen

Voltage is irrelevant, it's the amps the generates the heat. Voltage only comes into play if you have so much of it that you exceed the breakdown voltage of the insulation. The voltage rating on the PP45s is 600. So, typical airplane setups don't need to worry about that.

What makes the heat is current. The connectors are rated for 45 amps, but if you look at the data sheet:
http://www.powerwerx.com/techdata/PP45.pdf
the picture is more nuanced than that. There's a graph on that sheet showing pulse current capability. If you use #10 wire, the connectors are good with 80 amps for 1.5 seconds, or 60 amps for 4 seconds, 40 amps for around 25 seconds, etc.

The airflow in flight probably helps cool them a bit, but mostly I think what makes it OK is the fact that you don't sit constantly at full throttle.

Charging of course draws the full current constantly for a long time, so I guess it's not surprising there might be some problems there.

That explains why the Heli fliers are moving away from them. They run 90% throttle the whole flight.

Also a factor in current draw is the load on the motor. Much like a car on the road, it takes more power to get it up to speed. Once it's at speed, the load is basically what it takes to keep the prop spinning at that speed. During the acceleration process is when the max amps are drawn. As it gets closer to the appropriate rpm, current draw will decrease.

Even with high energy flight, in 3D, we tend to cut the throttle back to enter stalled flight. This gives the connectors a break as well as the load isn't that heavy.

Chargers (the PL8) typically build to a specified current and maintain that current until the charge is nearly complete. I would also believe the resistance of the battery wanting to charge plays a part on the charging setup when it comes to heat on the connectors...

I think for the "short" duration of acceleration and heavy load on these planes would allow APP's to be used without too much worry. If it were drawing a high current with little airflow for the duration of the flight, I'd maybe be a little more worried...

I haven't studied graphs from in flight stats, but with my knowledge about electric powered motors, this is what I perceive as being defining points as to why the APP connectors heat up on a charger vs staying cooler on a plane.

I was running the apps on the power side of my pl8. I am only pulling 30amps from my powersupplies when l charge my 4s lipos at 40amps. The 45amp apps are rated at 45amps continuous. Thats 3 hours or more to be considered continuous. Well l am only pulling 30amps for about 30 to 40 minutes. This should be nothing for the connector. I am running all 10awg wire which is rated for a higher amp draw than lm pulling. So there is no reason I should be melting the app connector. None at all. They are failing under there rated current.

Anyone in need?

They are basically brand new, only a few flights.

I will make a good deal.

Originally Posted by losifanatic

I was running the apps on the power side of my pl8. I am only pulling 30amps from my powersupplies when l charge my 4s lipos at 40amps. The 45amp apps are rated at 45amps continuous. Thats 3 hours or more to be considered continuous. Well l am only pulling 30amps for about 30 to 40 minutes. This should be nothing for the connector. I am running all 10awg wire which is rated for a higher amp draw than lm pulling. So there is no reason I should be melting the app connector. None at all. They are failing under there rated current.

shorten the leads from the power supplies to the charger a little. solve my problem completley.. weird.. but it worked. I charge wide open and havent burnt a set since.
(watch ill burn the table down next outing babahahahahahah

I got my stiffeners today! Thanks Steve!

Originally Posted by Manta1

shorten the leads from the power supplies to the charger a little. solve my problem completley.. weird.. but it worked. I charge wide open and havent burnt a set since.
(watch ill burn the table down next outing babahahahahahah

Not sure why that would work. Unless perhaps the original crimp wasn't that good, and by the time you shortened the leads you had mastered the technique and gotten a perfect crimp.

Originally Posted by AeroKen

Not sure why that would work. Unless perhaps the original crimp wasn't that good, and by the time you shortened the leads you had mastered the technique and gotten a perfect crimp.

shorter wires means less total resistance. Its hard to screw up those crimps and still get them in the housing. I am a very gooder crimper man hehehehe.(automotive driveability tech 24 years been crimping and soldering long time)

Sure, but more resistence in the wires would mean warm wires, not melted connectors.

Originally Posted by Lardog

Sure, but more resistence in the wires would mean warm wires, not melted connectors.

true i reckon. i dunno. just weird. maybe I should make longer leads again and see if i can fry em.

Originally Posted by losifanatic

I was running the apps on the power side of my pl8. I am only pulling 30amps from my powersupplies when l charge my 4s lipos at 40amps. The 45amp apps are rated at 45amps continuous. Thats 3 hours or more to be considered continuous. Well l am only pulling 30amps for about 30 to 40 minutes. This should be nothing for the connector. I am running all 10awg wire which is rated for a higher amp draw than lm pulling. So there is no reason I should be melting the app connector. None at all. They are failing under there rated current.

The spec says at 45 amps duration is 16 seconds.

Originally Posted by Manta1

ya but you wanna know the weird thing about that? I'm gonna tell you anyhow lol.
I had to shorten the leads from my power supplies to my PL8 charger because the one set of power pole connectors melted one time. I shortened the leads and they now get hot if i charge at full tilt,but the housings dont melt. Never have had the connectors get hot on my planes tho,even when i ran 120 amps at wot in one one time. (lots of static run ups while feeling the connectors every now and again)
air circulating through the plane cool them ya think?

Course you know I could be full of crap,I'm thinking in terms of watts, so at a lower voltage it could handle more amperage. Erroneous thinking I guess, ah well, ya learn something new every day. If your paying attention that is.

Originally Posted by zmonster97

I got my stiffeners today! Thanks Steve!

Glad to hear it....am heading out to mail the last two that were ordered in just a few minutes, since I was able to get Darrin Anderson's address, and, I also had another order. I have one set left if anybody wants a set, but I am going to order some more carbon fiber, so will be able to make more...

SteveT

Well went to flying feilds hanger to install Steve's stiffeners to a friend's new slick. Well what do you know his 2700watt 8s powered slick is broken at the wing tube just like mine. His wing will move in ans out over a quarter of an inch. This plane has never been crashed, hasnt landed hard or anything. It's just been flown somewhat hard( l fly harder than him) so l installed the stiffeners and reglued the balsa and ply around the wing tube. Will put it threw its tests in the morning. I have a pic of the broken area loading to my photobucket account right now.
So thank you again Steve!