Tired of AA's...

[zeropointbug]

Does the DX2.0 have a voltage regulator? Because it holds 12.7 for almost the entire runtime, and the M1 cell would normally hold 3.2volts average over the discharge.

[redshift]

jtr and nitro, easiet way is to remove 1 AA, jumper the tabs, remove another, repeat until you get the flash.

ZP that is awesome and I want to do the same with my DX3.0.

Does anyone know what voltage the alarm sounds on a DX7? I am trying to convince a buddy to ditch his Nixx's and use an older TP 3S 2100- but he's all scared he'll leave the TX on and puff a cell or worse.... anyone?

[redshift]

I was guessing <9V, out of curiosity I just used a 9V out of a smoke detector, at 8.6V on my DX3.0, no alarm. But we know that a DX7 has one because it woke him up one night when he left it on. He doesn't remmber the voltage it was reading tho. And the Nixx are hardwired on the DX7, and he wants to know before he clips the lead..... told him he was gonna have to put a jst connector on anyway- but he's friggin stubborn.

[rootar]

my dx3s goes nuts if you leave it on the voltage drops down, i has the same battery compartment as the dx3r so im thinking why cant we get a 2s lipo thatll fit in there and run the ccbec set on 5.5 volts and then even close to the lvc its would still be supplying .5 volts more than the bec is putting out..... you can get a novak blinking LVC and mount it ontop of the base and just wire your on of swtich BEFORE the lvc and bec

so youd have the lipo, plug, switch, lvc in parrell, and then the ccbec before it goes to the radio power leads .....

did i confuse anyone else or just me?

honestly i use the energizer lithium AAs and they last for 6 months getting used every weekend alot...

[zeropointbug]

Yeah, but how much do those primary Lithium AA cost again? $12 for 4? You can see that it wouldn't be long before a rechargeable transmitter pack would pay for itself, one year maybe. I would also get a LiFe pack, as weight is not a concern, plus it will last a decade at the very least running something as low powered as a radio.

[J57ltr]

OK, date with the wife got in the way of testing, but here are my results. This is in the TQ3 I have, have to wait till John comes back over to see what a TQ2 will do, but I don't expect any difference except for normal manufacturing tolerances.

At 8.03V the light starts to flash.
At 4.2V it starts to dim while flashing.
At 3.353V it's really dim and still flashing.
At anything under 3.25V it completely shuts off.

To test this I had to use an old Protoboard with built in power supply 0-15V. The meter I used is a Fluke 112. I did both rising and falling voltage to test hysteresis 3 times.

Jeff

do these cell phone battery not need to be balanced?

[J57ltr]

They should be they are just like any other Lo-po/Lo-ion, and now they are made into a pack, and they came from different devices that probably had different charge/discharge cycles. The ones I am using are from the same laptop pack and they are out of sink by up to a 1/4V, that's why I put a balance plug on mine. I also have a ton (about 50) of the Fat/Long aa size Li/ions and they act the same way in packs. No 2 cells are alike.

Jeff

[nitrostarter]

I took the Summit out today and the cell phone batteries worked flawlessly in the Tx. Awesome! Let see how long they last on 1 charge now....

[zeropointbug]

What is the mah and voltage on that pack?

[BrianG]

Sorry to hijack the thread, but I was thinking. What about simply adding 3 diodes in series with the battery in the DX3r? Each diode will drop around 0.6v at the current the radio draws, which would drop about 1.8v total. On a peaked 2s lipo, the radio would see 6.6v, which is fine (my freshly peaked 5X NiMhs have peaked higher). At LVC of 3.3v/cell, it would be 4.8v, which is the nominal value of the 4 X NiMHs the radio is designed for. Some regular 1N4001's would work.

The downside is that you'd have to add some kind of new charging jack so that the charger will not have to read through the diodes. BUt that should be done anyway to allow for balancing of the 2s pack.

Just an idea...

[zeropointbug]

Or just use 2s M1 pack?

[BrianG]

Still a tad too high. Peaked, they're 7.2v. Maybe with a diode in series.

The advantage to using a diode is that it drops roughly the same voltage all the time and therefore can use the radio's voltage display fairly accurately.