Transmitter power use

[razerdave]

Hey guys

Ok, I've now got all 4 (one's still being made) drive all day ants on 2.4GHz, and on those kid friendly E-flight Blade transmitter, but because I am worried about running out of batteries during the event (as happened with Bulletproof more often than I'd like), I want to put them on a power supply and have them on a cord. Now, they run 4 x AA batteries (4.8v), but I'm wondering: a: will they take anything higher (I'm thinking 5-6v should be fine, just checking), and what kind of power are they going to pull, bearing in mind I may well have all 4 running at once).

[Rapidrory]

Being run straight off 4.8v from the battery that probably means it doesn't have a voltage regulator in, and most of the chips will probably be only rated to 5v. If you were gonna convert it, i'd advise fitting a 5v regulator on the power rail to protect the components, and also allow you to use a wider range of input voltages.

I have to say though, it shouldn't run out of battery that fast; I just check the rechargeable batteries in my transmitter are recharged before every event, and after that I can leave my orange Tx on almost all day before they start running down. Would seem like the simpler option!

[BeligerAnt]

As far as I can make out, the Blade Tx is supposed to run off 4 standard 1.5V AA cells so will happily handle 6V. It just so happens that the endpoint voltage for both NiMH and alkaline cells is about 1V, so the Tx will work down to about 4V and will work with rechargeable or dry cells.

It's most likely that all the electronics runs at 3.3V (or less) and there is a regulator in the Tx to accept at least 4-6V.

Since the Tx output power is only a few mW I wouldn't expect the current draw to be more than a few hundred mA. A fully-charged set of AA NiMHs should easily last around 6 hours or so. You just need to charge them overnight for multi-day events.

Alternatively, a well-regulated 5V PSU rated at a couple of amps or so should be able to run 4 Txs. The other option would be to use 4 power supplies plugged into a 4-gang extension lead. In this case cheap USB-type phone chargers may be suitable. You would need to know how much current the Tx actually needs though.

[razerdave]

This is what I was asking, I can get a 5V, 1.5A power supply and link the 4 TX's up to that, but I'm wondering if 1.5A was enough for 4 TX's. By the sounds of it, it should suffice just fine, but it was worth an ask

PS: 1.5v is AA, so 6v, not 4.8v like I said, I'm so used to NiMH's that are 1.2v per cell

[peterwaller]

To be perfectly honest I wouldn't bother these days as the batteries are better and the transmitters lower power.
I found this out when I left one of the Blade transmitters on by mistake and after around a day it still worked quite happily.
I have just checked three of my transmitters and below are the currents and operational time on standard Alkaline AA non rechargeable batteries (around 2700mah capcity).
Trans....current......duration
DX5e......98ma.........27 h
Dx6i.......79ma.........34 h
Blade......23.4ma......115h
When you consider these times, the dificulties of having all the transmitters on long leads and the fact that Ikea batteries are around £1 for 10 it is hardly worth it.

[razerdave]

Fair point Pete

One of the things I get often at the events is kids that won't give up the TX's when they get called back to their seats, it's kinda good to have an off switch for them all in 1 place . But fair enough, I'll leave them as they are .