ORIGINAL: bgw45 Thanks for the link, AT. I'm not sure why the "diode" in the circuit would keep the batter charger from recognizing peek, unless the charge leads are on the board side of the diode and charging would be through the diode. The diode in a Futaba is there simply to prevent damage to the board if a JR or Spectrum charger was attached. They cause a mess in a Futaba since they have reversed polarity.
A peak detect charger if used through charging circuits containing a diode as used by Futaba and Hitec, can only give a false peak. No True Peak Detect Charger can read the voltage when the feedback is impaired/interrupted. Even the quick blow fuse used by JR has caused problems for users. (mainly when blown by many users hooking a Hitec, Sanwa/Airtronic or Acoms lead up in error - reversed polarity, some more than once).
Clear statement from just one of the leading charger manufacturers (and repeated by others) =
Sirius Electronics-TX Diodes bridging
"Q: My SIRIUS CHARGE will not work with my Futaba transmitter. Why?
A: There is a diode in the charging circuit of most Futaba FM and PCM transmitters (Futaba AM transmitters do not have a diode). This diode prevents SIRIUS CHARGE from detecting the transmitter battery and turning itself on. The diode is very easy to defeat, and will not affect operation of the transmitter. If you would like to see how to do it, click here.
By the way, BEWARE of fast chargers that claim to work through a diode. It is impossible to do proper peak detection through a diode, due to the diode voltage drop changing drastically with temperature and current. Your batteries are at risk!"
With increasing use of Lipols. there are corresponding increase in reported incidents and recalls e.g
Battery Carriage Dangers
- November "Aviation News" - already some suppliers will no longer ship LiPo's by air.
1. "The transmitter has support for using a 2s lipo built into its programming. I suspect the diode is there to make sure you have to remove the battery from the radio before charging.
I had a customer call yesterday looking to replace a plane that had burned up from a Lipo fire. If that happened inside a transmitter it would make a giant mess, would destroy the transmitter and possibly burn down one or more structures.
For any manufacturer better safe than found negligent. Is it really that hard to pull the battery out to charge it? "
RCTom "TF" post # 273 above
2. "Ding ding ding! We have a winner.
It is there to help protect the transmitter/circuitry from having a battery over charged by a peak charger that fails to shut off. From a service stand point I have seen quite a few ''melt downs'' come across my bench because of this and the diode had been jumped in the radio. Granted, damage to the radio can still happen even with out it jumped but the severity of the damage has been way less and usually those radios can be fixed back up with out too much hassle. So in short, it's there to protect you and it's there to protect us. [8D]"
Brendan Lugo, Hitec USA post # 274.above.
Concur with above and posts 273 & 274, having also had Futaba and Hitec TX brought in for service which have been virtually destoyed by overdischarge/overcharged Lipol batteries or where diode has been jumped and a "trusty - not old" charger has failed, not pretty sights and overall repair + new battery or full replacement cost is high.
There aresound reasons why more than one manufacturer adds protection to the circuit and more than one has clearly advised "Do not charge Lipol batteries in the transmitter."
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