On Thu, Apr 21, 2005 at 08:06:56AM -0400, [EMAIL PROTECTED] wrote: | Doug McLaren <[EMAIL PROTECTED]> wrote: | | >Actually, the Triton can charge through a diode. It can't discharge | >(which makes sense), but it can charge. | | I don't know why you're saying that, but you're wrong.
No, I'm not. I do it all the time, and here's some pictures of me doing it : http://mclaren.frenzy.com/~dougmc/RC/triton-charging-through-diode/ You'll notice that I'm charging and measuring through the charge jack on these radios. None of them have been modified by me to bypass the diode, and I show this by measuring the voltage on the port with the charger not connected. Yes, a miniscule amount of current does leak through the diode, but I don't think it's enough to make a charger happy. Note that the batteries on these radios were not dead before I measured them -- they may not have been fully charged, but they were charged enough for the radio to work. I wanted to ditch the transmitters entirely for the picture, and show you a picture of a diode and a battery pack being charged through it, but couldn't find an appropriate diode. Maybe later, if I can find one in my stuff. | In normal operation the Triton stops charging for a few seconds each | minute in order to sense the battery voltage and monitor the | progress of the charge. With a diode in the circuit, the battery | voltage doesn't appear at the charging jack, causing the test to | fail immediately. | | (See http://www.rcgroups.com/forums/showpost.php?p=1081041&postcount=1 To be fair, that link says nothing about charging through a diode. As for the part where it periodically stops charging and checks the voltage, while I didn't take a picture of this happening (maybe I will shortly), it still does work, and gives an accurate reading even through the diode. I assume that it works by the Triton putting a miniscule current through -- perhaps 1 mA -- and then measuring the voltage needed to push that current through. 1 mA is close enough to zero that the voltage you get will be almost exactly the same if there was no current, but it's enough that you can get an accurate reading even through a diode. | In fact, a Triton won't even start charging in the first place if it | doesn't first detect the voltage from a battery on its output. With | a diode in the circuit, the Triton would only return a "no batt" | error message. My Astroflight 110D works as you say, and I was quite pleasantly surprised when I found that the Triton did work through the diode. | Also, even if the charger could somehow be rigged into charging | anyway, the forward voltage drop across the diode would confuse the | smart charging circuitry and give unwanted results. No. In general, a diode will introduce a 0.5 volt or so drop if you go across it in the right direction. But this voltage drop is pretty much fixed, so it just changes the voltage reading on the transmitter -- peaks and dips are still the same peaks and dips, and your charger stops charging just like it would without the diode. At least the Triton does. If I were to take the battery out and not charge through the diode, you'd find that the voltage needed would be smaller, but that's all the diode does -- it burns up some of the voltage. (It also absorbs 0.5v * (whatever amperage) in heat, so you don't want to charge at a high rate, or you risk ruining the diode.) Yes, a diode WOULD cause problems charging a LiPo pack, as your charger would not fully charge it. But these are NiCds, not LiPos, and there is no such problem, because you don't stop charging NiCds at a specific voltage. | It's very well known that peak chargers can't be used to charge radios | through their charging jacks unless any safety charging diodes in the radio | are bypassed. You'll find it in virtually any general FAQ about our hobby. I understand what you're saying, but there are ways around that, and the Triton does it. My pictures prove it. I believe that other peak chargers now work through diodes too. For example, this one seems to -- http://www.hobbico.com/chargers/hcam3005.html though I can't test it myself, as I don't have one. My Astroflight 110D definately does not, but my two Tritons definately do. -- Doug McLaren, [EMAIL PROTECTED] `Dear Lord: Please make my words sweet and tender, for tomorrow I may have to eat them.' RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
