2.4 GHz lockouts - pooling info

[nick]

howdy

as you know my faser punched in due to lock out not bad air or pilot error, but it could have been anything else eg switch, battery, rx position, im going with the faser on rx orientation, i now know it was a bit Sus in that plane, my fault

it was cramped in and i wasn't real happy with the way i positioned the aerials, it was a AR7000, i have now bought a AR9300 and will buy another one for my xperience pro.

i have had a few lockouts with my foamies, 4 cell eneloop batteries, good switch system, but there is better to which i might change to, but i think the main reason for lock outs with my foamies is the aerial is all on one plane in the wing, AR500.

i have never and i say never , touch wood had a lock out with any of my electric planes ;D ;D, may be because it's lipo??
or a better connection for the power?? constant voltage??
my electric use AR7000

when my skua was doing thermal turns all on its own at about 200 feet(lock out) i turned the tx off and it then immediately went into a dive and punched in, why did it respond to no tx but wouldn't respond to my tx imputs???

im not here for a debate i just want to tell you what has happend to me

regards nick

[thevon]

Thanks Nick.

A guy called Elmog on RCG posted this, and it is interesting to note that Spektrum actually sell a capacitor to plug into your Rx to cope with temporary voltage drops. Sounds like good insurance to me.

" A little known issue with Specktrum is that you shouldn't mix analogue and digital servos. Also, running too many servos can cause a large enough voltage drop that will cause the receiver to unbind and then could take up to ten seconds to rebind. In that case, kiss your glider goodbye. Specktrum does sell a capacitor that plugs into any unused port on the receiver to supplement a temporary drop in voltage. Also, some folks run a 6 volt receiver pack to address this issue. So then you could say that an old battery pack might be causing problems with your 2.4 system and something to check often by putting a load checker on your Rx pack. I have one and use it often to verify my packs. I don’t know if this information helps but it might be new news to some. Jim "

[nick]

hi there everyone

i just spent an hour with a very experienced jet flyer who uses 2.4 and he is very happy, he is in the communication and electronic industry so i believe what he says, he told me he doesn't know much about gliders but in jets the battery voltage is of an up most importance, servos that draw lots of current under load are a concern, he won't use eneloops, he uses A123 or lipo with regulators, any thoughts on that? it seems to make sence to me as i have never had trouble with electric as it's lipo

regards nick

[skyboyken]

Andrew,

I apologise.

I misread what you wrote.

BTW, that post you wrote about Elmog isn't appearing in this thread even though it is marked as being in here when I search for the last 40 posts. Will it fix itself given enough time, or is intervention required?

The more I think about it, the more convinced I become that the best advice is to use a 5 cell pack, or 2 A123 cells. I really do believe A123 is the better way to go, and I'll be doing that when I next buy cells. The A123's are a nominal 3.3V per cell, so their peak voltage is less than a freshly charged 5 cell nimh (good) they are incredibly robust (good), they have almost no self-discharge (good), they can deliver BIG current (good) and they are available from multiple suppliers in 2 sizes, 2300mAH and 1100mAH to fit various fuselages (good). They may be too big for some planes (bad) and they need a charger that has a mode for LiFe cells (so get one!).

The reason to change to higher voltage batteries is that with a nominal voltage of 4.8V, a 4 cell pack really doesn't give you much headroom over the approximately 3.2V that a Spektrum receiver reboots at. You see, in most cases it won't be one thing that causes a voltage drop to that level. It'll be a combination of things: for example a high resistance in the battery connector, long runs to several servos, and maybe a pinched wire somewhere causing intermittent strain on a connector, all of which impact on the voltage seen by the receiver, and then BANG, a servo stalls and pulls big current and there goes the voltage, down to below 3.2V and you have a lockout.

If nothing in the above scenario changes except that the initial battery voltage is 6-6.6V then suddenly you have a whole lot more headroom and no lockouts until that pinched wire finally causes the connector to fail, and that's an issue you've now been made aware of so you can be looking for it and fix it, can't you?

To follow the KISS principle, here are 4 things to do that will give you a far more reliable power supply than the standard most of us are at now:

1. Use a 5 cell nimh or 2 cell A123 battery of appropriate capacity and get yourself a decent charger to charge it with.

2. Use an LED battery monitor onboard in every plane possible. They may show you intermittent flickers to alert you to a problem, as well as ensuring the battery voltage is good.

3. Replace all servo connectors in your battery leads, especially if that's your on/off switch, with a more robust/reliable plug. Deans, mini-Deans and Multiplex (genuine) plugs are all good choices. Note this doesn't apply to the plug into the Rx - hopefully that one only ever gets plugged in once.

4. Wire in a dedicated charge plug if you're using a switch or switchjack (which is my preference), so you're not having to unplug any connectors to charge.

I like proper switchjacks because they are mechanically robust and because they come with a dedicated charge plug. I get mine from Canuck Engineering in the USA. The downside is they can get crap inside them to effect their reliability, and being a switch they can fail like any other switch and need to be watched. Hence another reason for the battery monitor always onboard and in use.

I hope this is of some use.

Ken.

[thevon]

No worries at all Ken!

Re: the Elmog post; I can see it (ie the bit I wrote with his quote in italics) in this thread. But his original post was in RC Groups. Can the other guys see it???

Cheers
Andrew

[nick]

sure is ken

thanks ;D ;D ;D ;D ;D ;D

[thevon]

Garth has just bought a new JR9x 2.4gig Tx, which Dave Pratley has on special for $650 or so. Comes with a great RX too. But the interesting thing was that the Rx manual states that there's a risk with using NiMh's because due to environmental or safety issues manufacturers are adding something to the batteries, which can make them give a false reading. This is my recollection of what Garth said - I'm not sure - Garth can you relay the info from the manual?

It could explain why it's only the glider guys who seem to have this problem. The LiPo users perhaps are doing better. If I go to 2.4 I'd consider getting LiPo's and regulators, which are quite cheap now.

[Garth]

this is from the dsx9 instruction manual "Tips on using 2.4hz systems"

"The latest generation of Nickel Metal Hydride batteries incorporate a new chemistry mandated to be more environmentally friendly. These batteries, when charged with peak detection fast chargers, have tendencies to false peak (not fully charge) repeatedly. These include all brands of Ni-MH batteries. If using Ni-MH packs, be especially cautious when charging making absolutely sure that the battery is fully charged. It is recommended to use a charger that can display total charge capacity. Note the number of mAh put into a discharged pack to verify it has been charged to full capacity.

Q: I've heard that the DSM system is less tolerant of low voltage. Is that correct?

A: All DSM receivers have an operational voltage range of 3.5 to 9 volts. With most systems, this is not a problem as most servos cease to operate at around 3.8 volts. When using multiple high current draw servos with a single or inadequate battery/power source, heavy momentary loads can cause the voltage to dip below this 3.5-volt threshold, causing the entire system (servos and receiver) to brown out. When the voltage drops below the low voltage threshold (3.5 volts), the DSM receiver must reboot (go through the start-up process of scanning the band and finding the transmitter) and this can take several seconds."

[Garth]

Today i got a Radio Gear Current Logger from Wired rc. It is a inflight current monitor and logger for radio systems. It has led lights that flash to tell you the max and average current for each time you turn on or each flight.. You match the lights with the chart to get your current..... it cost $21.00 and weighs 3g. I got it for the Blaster so i can find out how much the current i draw with every 5 min flight or every hour. So i dont get down near 3.5v and it will show up if you have a bad servo......... I hope that may help people on 2.4 with low voltage problems.



some new toys from Wired Rc www.wiredrc.com.au/shop/ top bloke and really good prices. DSX9 $660.00, AR6250 carbon fuselage 6 ch$135.00

[nick]

well i suppose i should put this here so here we go
i test flew the xpro today at bald knob with peter and wow, ( get it wowings) , on a windy bumpy day i was impressed, maybe just some fine tuning but it felt great, i need a thermal day that's light wind and im sure she will be fantastic ;D ;D
the flaps drop heaps and i had her going backwards beside me, no s*#t, soon see what happens in no wind

now when i was range testing her and it's 2.4 i tried everything and all fine except for when i put the transmitter right beside my leg in between myself and the plane, and peter also between the plane and myself, mmmm fail safe, then in sight again back to control, so that says to me 2.4 is line of sight, well derrrr, who flys a plane when you can't see it but that was interesting, like UHF radio i suppose

regards nick

[skyboyken]

Great to hear you've maidened the X Pro and that all went well!!

Ken.

[mikey100]

Glad it all went well Nick. I look 4ward 2 seein her in the air tomorrow at Harrisville. Cheers, Mikey.