TX fast charging

| All known modern TX, except AM, have diodes in the charging input

Not true.

Many have fuses (often self-resetting poly-fuses) rather than diodes, and these have no problems with charging or discharging through the charge jack.

Examples include the Futaba 9C and Multiplex Evo 9. (The Evo 9 actually puts the fuse in the battery pack itself, so even if you take it out you're charging through the fuse.)

| which must be bypassed to allow fast charging.

Not true.

Some peak chargers (let's say peak charger rather than the more ambiguous `fast charger') have no problems peak charging through a diode.

My Triton has no problems charging through a diode.

My Astroflight 110D cannot charge through a diode.

If you hook up a multimeter to charge jack on a diode protected TX, you will read zero volts -- that is normal. A peak charger can get around this by attempting to push a tiny charge current through -- like 1 mA -- and measuring the voltage. Using that, it can make sure the battery is there and the polarity is correct. During normal charging, it simply reads the voltage required to push X amps through

-- the diode doesn't hurt things there either (it just increases the voltage needed by a small, mostly fixed amount), and the small voltage drop that indicates full battery is just as easily seen.

| Note: do not charge at greater than 1.2A as TX circuit may be damaged.

Yup, diode or not. The charge jack and traces and such are not meant for high currents. In fact, if there is a diode, I'd suggest not even going that fast -- perhaps 0.6 amps would be better.

Reply to
Doug McLaren
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On 09 Jul 2007 15:24:18 GMT, "Doug McLaren" wrote in :

OH, duh! My only peak charger is a Triton. Maybe that's why I thought that my 8103 didn't have a diode.

I know it has a fuse, because I blew it up once upon a time when I put a Hitec/Futaba charger on the TX. :o(

Marty

Reply to
Martin X. Moleski, SJ

David,

I use 3 different units to cycle my transmitter batteries.

1 - Ace Super Smartest Battery Capacity Analyzer (discharge only) 2 - Hobbico Accu-Cycle 3 - Hobbico Accu-Cycle Plus ( not used often, I prefer a slow charge for my transmitters (personal preference))

All 3 of these units specifically state somewhere in the instructions that they will NOT discharge a transmitter that has a diode in the charging circuit. The Ace Super Smartest has a list of available Adapter Cables. They list a JR Tx cable, the only Futaba Tx cable they list is for Futaba 5 pin Tx. They specifically don't list a Futaba J Tx adapter, since Futaba uses a diode in most of their transmitters.

All 3 of these units discharge my 8103's, and 388 without a problem, and both the Accu-Cycles will cycle the transmitters also. According to the manuals this can not happen if there is a diode in the charging circuit.

Ken

"quietguy" wrote in message news: snipped-for-privacy@REMOVE-TO-REPLYconfidential-counselling.com...

Reply to
Ken Barnes

Well, Ken I cannot deny your experience, but you need to accept that my experience is different - I suggest we must be both right, but I am not sure why that is so. A difference between the US and the Aussie versions of the JR?

David

Ken Barnes wrote:

Reply to
quietguy

David,

Anythings possible. I know that there are some changes to some JR systems depending on the target market (U.S., UK, EU, Asia, Australia?). After all, what they sell must meet local goverment codes, and requirements. Possibly the Australian JR's are built to meet a code that requires a diode.

Ken

"quietguy" wrote in message news: snipped-for-privacy@REMOVE-TO-REPLYconfidential-counselling.com...

Reply to
Ken Barnes

You are lucky that that is all you blew up, Marty.

In the Nineties, a good friend of mine did a number on his JR X-347 by plugging in a Futaba charger. I do not know what the extent of the damage was, but he was not happy when he got the bill from the folks at Horizon Hobby.

Why companies insist upon being different from everyone (JR Tx polarity) is beyond my ability to grasp and comprehend.

Ed Cregger

Reply to
Ed Cregger

| Why companies insist upon being different from everyone (JR Tx polarity) is | beyond my ability to grasp and comprehend.

Are you saying that the JR polarity is `everyone' or the Futaba polarity is `everyone' ?

I've not found either polarity to be overwhelmingly more popular. But then again, that's why there's a diode or polyfuse in there in the first place.

Receiver shifts are similar -- it would be nice if everybody had picked positive or negative up front, but instead they didn't.

We should probably consider ourselves fortunate that servos are pretty much standardized (negative, positive, signal, with most servos taking the same signal), even if the plugs aren't always the same.

Reply to
Doug McLaren

When I began studying for my ham license in 1950, standard fo

concentric plugs was defined as center signal or positive while outsid was ground or negative. JR is the odd ball

-- Chuck

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Reply to
ChuckA

Isn't it pretty well a standard in the electronic industry that the power cord/socket has the shell negative and the center pin positive? JR is the only one I have encountered that does not follow this convention.

Reply to
Red Scholefield

| Isn't it pretty well a standard in the electronic industry that the power | cord/socket has the shell negative and the center pin positive? JR is the | only one I have encountered that does not follow this convention.

I stand corrected. I was thinking that Airtronics was center-negative too, but after checking, it is center positive. As is Futaba, Hitec, Traxxas, Duratrax and the Walkera helicopter controller I have.

Center negative is JR, Spektrum and my E-flite Blade CP controller. And JR provides most of the bits for the Spektrum radios, and E-Flite may also be by JR -- though I think the E-Flite radios are negative shift like Futaba.

And yes, most non-RC applications seem to be center positive. Not all, but most.

Reply to
Doug McLaren

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