rcfalcon56

While doing a battery cycle on my Ecplise Tx, the voltage reading went from 10.0 volts to 15.5 volts indicating that somehow the polartiy of the battery got reversed. Since the battery had already powered the Tx for about 30 minutes normally, is it possible for a battery to reverse polarity while under load? Or is it possible something in the power distribution circuitry got shorted?
The battery in quesiton is a Hydramax NiMH 9.6V 1450 mAh pack. The radio worked fine for about 3 months after replacing the original battery with this one. I know I'll have to send in the radio but I would like to continue to use the battery unless there is serious doubt about its reliability. At $55 for repair, I'd rather keep the radio up and running.

Thanks

Jim W

Brendan Lugo

The battery cannot reverse polarity like that. In order to see the 15.5 volts on the screen the battery had to either be plugged in backwards and turned on or shorted out while being on. If you have a battery cycler/charger you can hook the battery up it and test it to see if it's still good. On the transmitter, we'll have to take a look at it and see if it can be fixed by just replacing the burnt out IC's or if more serious damage has been done and the main pc board needs to be replaced.

Mustang314

My Feedback: (1)

A good reason for removing the battery from the transmitter while doing any battery maintenance.
Fred

rcfalcon56

I only have chargers, not a cycler. With NiCds, I never worried about really cycling them because after a days flying the voltage on the Tx always was near the 9.6V level anyway and the Rx batteries were at the limit as well. I used the Tx to cycle the NmHi pack due to the lack of a cycler. The thing that has me baffled is that it had been on for about 30 min with no problems and while I was twidling the sticks it went to the 15.5V and the Rx stopped responding. I have since charged the suspect pack on my Hobbico Quick Field Charger with no problems. I even put it in my Flash 5 Tx for a few minutes to see what would happen and it powers up fine.

There is a bit of history on the Eclipse however. I had used the same Hobbico charger to charge the Tx while the factory battery was in the Tx when for some reason the charger missed the peak voltage cutoff and overcharged the battery to the point where it melted the Tx case. I admit I was an idiot for charging it that way while it was unattended. I sent it to HiTec and they replaced the case and the battery at no charge even though the radio was way beyond warranty, but none of the electronics. (Gotta love HiTec!!) The radio functioned properly but the battery just didn't perform very well. After about 3 flights of around 5-8 minutes, it was done. That's why I got the NmHi pack. Since it still had plenty of juice after a full day at the field I wanted to cycle it before charging. I had learned my lesson from the melt down to not leave it unattended and the battery hadn't been out of the unit for several weeks. I used the keyed connector on the battery so it can only go on one way unless your a gorilla and I am scrupulous when it comes to matching poloarity. It's been checked with my DVM as well and red is positve, black negative as it should be.

I will be sending the radio in for service at some point because it's the only system I have that can handle my Ultra Stik with flaps and crow ailerons and I really love that plane!

rcfalcon56

Talked with the HiTec service dept today and the tech said something about the main power transistor going if you left the radio on too long with the antenna collapsed. Bingo, I DID have the antenna collapsed while doing the battery cycle. It was about the time I started to raise it that the whole thing went south. Live and learn. HiTec has the radio now and hopefully I'll get it back in the next couple of weeks or so.

A.T.

Unless the TX was turned on forquite some time after the cycle ended andcharger was disconnected, somethingelse must be wrong because an Eclipse TX battery cannot be correctly cycledwhilst still in an Eclipse unless boththe power is off and the diode has been bypassed.
Diode Jumpering Data Sheets - refer Eclipse.
When Eclipse TX is switched on,the charge circuit is disconnected.
(15.5voltage on screen typically indicates input polarity reversed, as Brendan noted earlier.)
Perhaps if charger was still connected after the TX was turned on, andantenna then raised, a foreign object or loose wire caused the problem

Regards
Alan T.
Alan's Hobby, Model & RC FAQ Web Links

rcfalcon56

When I say I was cycling the battery by using the transmitter, I simply turn on the transmitter to discharge the battery to about the 9.6V nominal reading on the display and then connect the wall wart charger for a slow recharge with the TX off as normal. There is no external gear attached to the TX. I am simply using the TX itself to discharge the battery to a point and then recharge. The Tx had been on for about 30-45 minutes with the antenna collapsed and had been doing fine until I noticed the collapsed antenna and then proceeded to extend it. That's about when it all went south. The RF module was quite warm by then so who knows.

I got an email today from HiTec and they have it now. We'll see what their techs say and how much it's going to cost.

A.T.

Ah asimple explanation. "Cycling" in earlier post wasread late night asuse of a fancy electronic cycleunit such as the Sirius or Triton etc....In the "Old days" output transistors burnt out very quickly if the antenna was not extended before the unit was switched on.
Modern output transistors do tolerate more heat and generally last quite some time/sessions beforeeventuallyburning out. As range checks are done with antenna down albeit only for a short period and not long enough for serious overheating, thismay lull usersinto a false sense of security that extending the antenna is no longernecessary exceptwhilst flying. Raising at least the lower two sections,whilst battery is being discharged, will assist prevent damage.
Twoprevious threads which may be of interest:
Can I burn my transmitter by colapsing its antenna?
Main output transistor on TX burnt out
regards
Alan T.

rcfalcon56

HiTec returned my transmitter and replaced two ICs that had burned out. I have since replaced the battery as I still have suspicions with it. Now however I am suffering from RFI such that the Stik is unflyable. The RFI is present even with the Rx completely removed from the plane and I tested it on three different Rx's with the same results, jittery servos. I also notice that the voltage reading fluctuates wildly (10.0-13.??) when either the left or right stick is moved to the extreme upper limit of travel. (ie full down elevator or full throttle in mode 2). Out of curiosity, I opened the transmitter case and the solder job that was done on one of the IC's is terrible!!. There's some kind of gunk ( I assume some sort of flux) smeared all around the vicinity of the IC and the SMT pieces look like they've been moved around along with a bunch of cold solder joints. (Yes, I know that leadless solder joints can look like cold solder joints but this is really extreme.) The whole repair area looks bad. It's about the size of an old 50 cent piece. I understand that when replacing a soldered IC that it won't look like new but compared with the other IC solder job, this is just bad all around. How long is the repair warranty, if any, and what do I have to do to rectify this situation? The transmitter is currently unuseable.

Thanks

Brendan Lugo

Sending a PM

rcfalcon56

I PMed you back and attached a photo of the suspect area.