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-   -   DX7 lipo woe (Dont leave it on all night) (https://www.wattflyer.com/forums/showthread.php?t=36188)

Liquidity 06-25-2008 04:05 PM

DX7 lipo woe (Dont leave it on all night)
 
Darnit. It finally happened to me. I left my DX7 on all night, however it has a lipo in it. I do not know why I left it on, just a case of me we todd did.

Awhile back, I placed a lipo in my DX7 so I can go longer without having to charge it. While I still recommend this, you just have to be careful.

I am currently trickle charging it to see if I can save it. It was discharged to roughly 2.5 - 2.8V per cell.

firemanbill 06-25-2008 04:09 PM

Bummer....:( Hopefully you can save it.

Liquidity 06-25-2008 04:13 PM

I am watching it on the charger. it is doing well. Hopefully when I take it off it will be able to hold its voltage.

The tx does not pull a lot, so I am not too worried there.

I am more upset with my lackadaisical attitude last night when I did it.

firemanbill 06-25-2008 04:21 PM

Oh don't be too hard on yourself, we've all done it at some point.

I did it with my DX6 once but I heard the the low battery alarm on it going off out in the garage. It took me a few minutes to figure out what the heck that noise was!:p>:o

gfdengine204 06-25-2008 04:21 PM

Bryan,

No puffing? If not, you may be in luck. :)

A friend at our fun fly Sunday told me he had this happen in his TX and it puffed.....sucks, for sure.....

Liquidity 06-25-2008 04:26 PM

No puffing. Bill you know what is crazy, we heard a noise last night at 9pm. My wife asked me what it was, I said it was the tv show. Ooops.

I did not go to the garage until 9am. That is when I found it :(

Liquidity 06-25-2008 04:30 PM

It is hard to tell if there is puffing. The shrink is covering all the cells. The shrink wrap is not out of shape, so it should be ok.

gfdengine204 06-25-2008 04:37 PM

At least you found it before it puffed and vented and did damage to your TX or worse.....

firemanbill 06-25-2008 04:40 PM


Originally Posted by Liquidity (Post 431584)
No puffing. Bill you know what is crazy, we heard a noise last night at 9pm. My wife asked me what it was, I said it was the tv show. Ooops.

I did not go to the garage until 9am. That is when I found it :(

LOL... that's not funny, but it is...:silly:

Liquidity 06-25-2008 04:57 PM

Kev. I am glad nothing happened to the TX. On the flip side, if something did, I would be able to buy a x9303 :)

Bill. Yeah. Usually I am really attentive to any sounds in the house. Apparently I was lazy yesterday.

crash_out 06-25-2008 05:09 PM

Usually when I have discharged lipolies too far, they end up losing around half of their capacity. After you get it charged up, do a cycle on it and see how much of the rated capcity you actually get out. If it's above 75%, it's probably fine.

Larry G 06-25-2008 05:52 PM

This is why I'm really glad the DX6i I just bought has four AA batteries. I use rechargeable NiMH cells, and carry a spare set to the field just in case. Bought 4 2500mah cells with a rapid charger at WalMart for under 20 bucks.

Liquidity 06-25-2008 06:41 PM

Lipo charged up fine. It is now cycling. There is no puffing, it is not warm, I think I dodged a large on this time.

That is good since and X9303 was not in my budget. All rc money is headed to the Deuces Wild :)

firemanbill 06-25-2008 06:46 PM

That's good to hear.

That Dueces wild is a good looking aircraft. I should think you will really enjoy it.:D

cjg 06-25-2008 10:35 PM


Originally Posted by Liquidity (Post 431655)
Lipo charged up fine. It is now cycling. There is no puffing, it is not warm, I think I dodged a large on this time.

That is good since and X9303 was not in my budget. All rc money is headed to the Deuces Wild :)

I wonder if the TX has a built in low voltage cutoff to avoid overdischarge.

firemanbill 06-25-2008 10:45 PM


Originally Posted by cjg (Post 431780)
I wonder if the TX has a built in low voltage cutoff to avoid overdischarge.


That's a great question!;-)

Bill goes and looks for the manual...

gfdengine204 06-25-2008 10:58 PM

Glad to hear it seems ok Bryan.....those things are just too expensive to have bad stuff happen like that.....

Hopefully Bill finds some good news for all of us Spektrum owners.

crash_out 06-25-2008 11:02 PM

Most radios (probably the DX-7 included) have a low-voltage alarm, but will continue to function. Most of mine will begin to sound an alarm at about 9.6v, but to the best of my knowledge will still remain on, even with lowered voltage.

Liquidity 06-25-2008 11:13 PM

My tx turned itself off, however the voltage of the battery when i finally saw it was roughly 7.8V

firemanbill 06-25-2008 11:30 PM

Well I couldn't find anything in the manual about a low voltage cutoff, probably does not have it as crashout says since it came with a NiMh battery originally.

On a side note I did see where on page 100 it still says not to turn on your transmitter while someone else is operating on your frequency... LOL I guess they just copied the safety page from the JR maunal for the 7202:Q

flypaper 2 06-26-2008 05:05 AM

Low voltage warning goes off at 9 volts. Had it go off when I was flying. It would be disastrous to have a low voltage cutoff.

Gord.

Liquidity 06-26-2008 02:57 PM

Battery is fine. I flew it for about an hour last night.

gfdengine204 06-26-2008 03:40 PM

Great to hear Bryan. Glad you dodged a bullet. :)

firemanbill 06-26-2008 03:57 PM


Originally Posted by Liquidity (Post 432157)
Battery is fine. I flew it for about an hour last night.

good news indeed!:D

simibill 06-26-2008 04:58 PM

This from the JR X9303 2.4 Manual

Tip on Using 2.4GHz Systems

Q: Can I use a 3-cell Li-Po pack in my transmitter

A: No. All current JR and Spektrum transmitters are
designed to operate using a 9.6-volt transmitter pack.
A fully charged 3-cell Li-Po pack puts out 12.6 volts.
This higher voltage can overload the power-regulating
transistor causing damage and or failure, possibly
in flight. Many of our customers have experienced
failures using 3-cell Li-Po packs and their use in JR
and Spektrum transmitters is highly advised against.
The X9303 2.4 system will operate for over 15 hours
using a 2500mAh Ni-MH battery.

FWIW


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