DX7 Beeps - LV? - RC Groups
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Jun 11, 2009, 09:44 PM
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DX7 Beeps - LV?


OK, got my (used) radio, turn on DX7, battery reads 9.6v on display. Open manual and do model reset, then start by the numbers inputting model 1. When finished, depress Select and Down, display goes blank, radio beeps (fast then slowed to stop after ~ 20 secs). I finally turned it off after ~ 2 mins of silence and no display..
Now when I turn it on, I get 2-3 beeps, no display, then nothing.... is this a Low voltage/battery issue?
With my DVM, the battery reads 9.83v (no load), any ideas? Is there a master reset somewhere?
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Jun 11, 2009, 09:56 PM
Registered User
Quote:
Originally Posted by nelsonsdive
OK, got my (used) radio, turn on DX7, battery reads 9.6v on display. Open manual and do model reset, then start by the numbers inputting model 1. When finished, depress Select and Down, display goes blank, radio beeps (fast then slowed to stop after ~ 20 secs). I finally turned it off after ~ 2 mins of silence and no display..
Now when I turn it on, I get 2-3 beeps, no display, then nothing.... is this a Low voltage/battery issue?
With my DVM, the battery reads 9.83v (no load), any ideas? Is there a master reset somewhere?
sounds like low battery to me, mine normally show around 11.7 v when fully charged, never been below 10.

Ace
Jun 11, 2009, 10:42 PM
60 years of RC flying
Daedalus66's Avatar
I could well be a battery problem. While 9.6 or higher is perfectly normal and provides plenty for operation, it has to be under load. You could have a bad cell and a battery that drops below 9 volts under load.

First recharge the battery then try everything again. And make sure you are giving it a full 14-16 hour charge (assuming you have the 110 mA charger).

To answer your question, there is no quick reset. It would have to go back to Horizon if it did experience a problem that wiped out the initial settings.
Jun 11, 2009, 10:43 PM
60 years of RC flying
Daedalus66's Avatar
Quote:
Originally Posted by AiraceF1-11
sounds like low battery to me, mine normally show around 11.7 v when fully charged, never been below 10.

Ace
That simply means you have been using only about half the capacity of the battery.
Jun 11, 2009, 10:54 PM
Registered User
Thanks guys, I'll have to buy a charger, or come up with an adapter to charge this battery with my E-Station 301 DX, the pins are way too small :>)
Jun 12, 2009, 12:27 PM
60 years of RC flying
Daedalus66's Avatar
Quote:
Originally Posted by nelsonsdive
Thanks guys, I'll have to buy a charger, or come up with an adapter to charge this battery with my E-Station 301 DX, the pins are way too small :>)
Didn't you get the standard wall plug charger with the radio? It's by far the simplest and most reliable solution.

You can charge using a peak detection charger, but if you use a high charge rate with the battery in the radio, you'll blow the fuse. Also there may be problems with false peaks.

You should always at least condition and balance the battery by giving it a 14-16 hour charge at about 110 mA (or 30 hours at 50 mA) before considering using a peak-detect charger.

I gather you have a Bantam charger. It will do the job but will be less convenient than just plugging in for an overnight charge.
Jun 14, 2009, 12:44 AM
Registered User

Charger


I used the Bantam/e-station 301DX at 100ma rate and it put in 800ma before I shut it down. Works fine now. I'm thinking pull the battery out and cycle it 2-3 times, just have to get the banana jacks.
Seriously debating just buying the correct charger, but I have so many rarely used electical eqpmt already... (but of course none 9.6v 100ma when I was looking).
Jun 14, 2009, 07:11 AM
60 years of RC flying
Daedalus66's Avatar
Charging at 100 mA would be fine. No need to remove battery. Just be VERY careful to get the polarity right (centre pin negative) as it's opposite to most.

At that rate you need 16 hours or so charge. Peak detect doesn't work for such low charge rates, so it's just a matter of timing. Fortunately, it's not critical and overcharging (within reason) doesn't hurt.
Jun 15, 2009, 10:24 PM
Registered User

Tx Battery charging/cycling


Since the battery is a NiMh 1500mah, couldn't I do a standard Peak charge at ~ 1.0A charge rate, and cycle it with a discharge of ~200ma (the 301dx only adjusts by 100ma graduations).
Or would that be too fast of a charge (the fuse is 3A per other threads), but not sure why the provided charger would only be 150ma without a reason (which hopefully is only so it can be charged overnight).

Thanks for any insights
Jun 15, 2009, 11:48 PM
60 years of RC flying
Daedalus66's Avatar
The great thing about low rate charging (c/10 or up to 150 mA in your case) is that it is so forgiving. You plug it in, leave it overnight and unplug the next day. If you leave it on for 15-20 hours, no problem (best not to leave it plugged in for days, though that will just shorten the battery life a bit).

By contrast, peak charging means you have to worry about overcharging if the peak is not detected, undercharging if there's a false peak, and so on.

Also, you need to charge at a high enough rate to get a definitive peak for the charger to detect. I don't know if 1 Amp is enough to do it for a 1500 mAh battery.

For me, slow charging is just so simple I don't see any reason to do it otherwise. (Except if I forgot to charge and want to go flying, in which I might fire up the peak charger and give it a quick 3 A or so out of the Tx).

Cheers.
Jun 16, 2009, 11:36 AM
Registered User
pilotpete2's Avatar
And your batteries will love you
Seriously, they will give you more cycles that way
Pete
Jun 16, 2009, 12:13 PM
60 years of RC flying
Daedalus66's Avatar
Quote:
Originally Posted by pilotpete2
And your batteries will love you
Seriously, they will give you more cycles that way
Pete
Absolutely. I expect to get 5 years or more out of a Tx battery charged at low rate.
Jun 16, 2009, 10:46 PM
Registered User

Slow/Overnight charge


I guess that really answers the question then. I'll have to get/make a slow charger so I can free up the e-station for the LiPo's the night before :>)

Thanks for all the help, I'm sure I'll have many more "easy" questions for you as I go along. Hopefully not too many of them are of the dumb variety.

Thx,

Mike
Jun 16, 2009, 11:09 PM
60 years of RC flying
Daedalus66's Avatar
If you use anything other than a JR or Spektrum charger, be very careful about polarity!!!!


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