Voltage drop on JR heavy duty Switch?

[whirlyspud]

I have been useing the jr heavy duty switch's with the built in charge jack in all of my new builds for the last couple years. I bought a new battery tester this weekend, and I noticed some strange results, and I'm wondering if anyone else has seen the same.

What I notice is about a .6V voltage drop when comparing the voltage taken right at the battery versus the voltage taken at either the charge jack, or at the receiver connection. I checked 2 that are a year old, and one that was new in the package.
They all had similar results.

The voltages were checked under 1 and a 1.5 amp load. I then did the same with a brand new Futaba Heavy Duty Switch. One the futaba switch, I saw about a .15 voltage drop. Did I get a batch of bad switches, or is there something going on that I Am missing? The way it looks now, I need to replace a bunch of switches.

Thanks,
Mike

[aviti]

I just measured mine on some 3 year old JR switches and saw a voltage drop of .2 volts. I actually wasn't aware it was this high as I just installed new Fromeco batteries and thought the new packs we a little weak. I think .6 drop is too high but not sure. Maybe get in touch with Horizon.

[whirlyspud]

Thanks for the reply,

Installing new fromeco backs and checking them with the 8ball checker is what made me take a look at the switch's. On a fresh charged pack, if read thru the switch is gets down to the no fly zone real fast. At first I thought my packs were going bad, but when measured at the pack everything seems to be in order, and the numbers I am seeing are right where they say they should be. I've been using their packs for a couple years without any issues.

Mike

[JimC-MD]

All connections will have some voltage drop, usually very small. The fact that you have the drop at the check port as well as through the switch would have me looking at the connection at the battery lead first and not the switch. For testing purposes, you may want to put a new input lead on the switch. What setup do you have? Are you using the servo style lead directly out of the pack to power the plane or do the batteries have deans or power pole connections making the the other lead just for charging and checking? Do you have any pictures? How many servos are you running etc. There has to be a root cause for the resistance build up. I have noticed large differences in the friction fit of different connector brands. Some are VERY snug the first couple of times they are assembled and others........

In automotive work there are actually test pins for checking the tension of connectors when you are chasing circuit issues. They are not normally used because of the cost of a large set of them, but there can be enough of an issue to have made the R&D for them seem like a good investment

[OverTemp]

Try unplugging and replugging the battery to the switch 4or 5 times.

Also, I personally never use JR HD switches. They seem nice but I'm told they have thin contacts. My preferred mechanical switch it the SuperRocker from Electrotek RC. Rated for 16 Amps SWITCHING load, dual self cleaning contacts, lifetime warranty, roughly the same price. Can also be had with several sets of leads since each of the cheap little RC connectors is only good for 3 Amps.

I use the SuperReliaSwitch from Fromeco... it is essentially the reg with the switch built in. The standard regs can be modified to activate the switch function (it's present in all th regs.. the leads just aren't soldered on). I don't know how to do it myself though. My setup has 14 gauge wire from the battery to the reg through a Deans connector, then 3 leads from the reg to the RX.

[Fixed Wing]

Here's some voltage measurements I did a while back. One note is that I only use AirWild extensions now. I tested several other brands of extensions and got surprising results with many of them much worse. Hope this helps.

[Jim Woodward]

I saw an article in the local club news letter where Ben P. discovered the same type of HUGE voltage drop across his heavy duty switch. I removed the little connectors from their clasps and resoldered them, then reinstalled and the drop went away.
Jim W.

[whirlyspud]

My setup was just the battery connected to the switch with the load on it both at the receiver output and the charge plug. Then I did the same with the tester plugged direct to the battery. I cant see any reason for it. I'm going to work the switch a few dozen times and see if that does anything. I am planning on running it with 4 5945 and one 5955 hi tec's

I had them in 50cc plane last season. They have just over 5 gallons of fuel run time on them. I'll look them over when I get a chance and see if I can find anything conclusive.

Mike