Greetings,

I'd posted this on the radio section, but got no (useful) response... May have better luck here.

I understand that the Spektrum AR9110 and other similar high end JR/Spektrum receivers that come with dual battery input leads (not including the Evolution/power box-type systems) can isolate the 2 batteries in the event one should fail. They also come with a switch that fails open, preserving power. In light of all that, the only possible advantage of using a PowerBox Sensor Switch instead of the stock switch on these receivers would be voltage regulation. Am I right? Am I missing any another advantage? If not, there would probably be no need for the Sensor Switch if A123s are used, while it would be required if LiPos are used. Also, is there any possible disadvantage to using these switches on these types of receivers, independently of the battery used?

Thanks up front.

you wouldn't want to use a PB sensor switch with any power safe receiver. i guess in theory you could, but you'd have to switch on the sensor switch, then switch on the receiver...........you'd be far better just using regulators, or A123's.

The Power safe Rx's will "powerup" as soon as you add power to the two leads, so if you leave the "soft" switch out you can use the Powerbox type switch (Sensor or Gemini) to run it and yes the only advantage is voltage regulation. Normally the Rx power goes in through the servo connections, but on PS Rx's it has no connection, this is why you can't really use the PS Rx's with a Powerbox unit.

I use the Sensor switch in most jets of BobCat/Flash/Bandit size, its been perfect, in fact the original one is still in the Prototype Classic Flash and has worked faultlessly since 2006.

If you use A123 unregulated, you are on the upper limit for many servos and for sure the servo life will be reduced. In a lab situation with smooth non binding control surfaces and perfectly set up flaps I guess servos will still last a long long time, but you will get away with less abuse at higher voltages with more heat produced.

Dw

Yep... I'm with them... why add something else to the system when it's not needed? Regardless if it will "Fail on"... nothing in this world is perfect. Also... the powersafe receivers can take a wide voltage input anyway... so just use A123's, or nickle packs. (I don't trust regulators)

i see comments like this quiet often, people don't trust regulators, matchboxes, etc...... they are made of the same components that make up your transmitter and receiver.............so why do you trust your TX/RX but not the regulators??

OK... I guess I should qualify/expand on that.

It's not that I TOTALY distrust any electronics... but it kind of goes back to my comment above.... "Why add something that is not needed?" By removing the regulator, you remove a potential failure point. Also... a regulator, by nature, is a failure point. In most "Hobby Grade" regulators, you use a transistor, and pulse it, so the "apparent" or "Seen" voltage is where we want it. So... you are basically taking a switch, and turning it on and off fast enough to control to voltage. The regulator now has to watch the voltage, as the current is changed, to maintain the proper voltage. This causes a 2 fold problem. 1) your voltage will sag as you approach the max current of the system. 2) As you approach max current... you are generating heat. (That is wasted power, and it's hard on the transistors)


With all that said... most good companies (like the one that makes the Matchbox) they over build. So if they say it's good for 10 amps... in reality... it's probably good for 15a. That way, it will run cool, and have a long life. But, some of the not so reliable companies will say "Good for 10 amps", but in reality, it can only take a 10 a blast for a short time, and that you are operating close to max most of the time.

I will say this... all of my small electric models run off the BEC of the ESC, and in all my years of playing with RC... I've only had one failure. (My T-rex 450 shut down in flight) In this case... I used a Castle 5 amp regulator, to solve the problem. (so I'm not 100% anti-regulator) But in a big model, that I don't need to try and save a few oz of weight... then why not just use a good battery, and not worry about a regulator?? (NiMh, NiCd, or Life/A123)


I'm not sure if you saw my thread on "I took a sick day, and look what I built"... but in that thread, I showed my quickly built Data Terminal for my AT-180 engine. So... I hope that would qualify me to have a reasonable opinion of electronic design. (you can see it here: http://www.rcuniverse.com/forum/m_10776422/tm.htm )


So... I guess I should say... "Use the least amount of electronics possible to achive your goal." AND... with the JR/Spektrum power safe RX... it already has a large operating window, and a "Fail on" switch... with redundant, isolated power.

Just my 2 cents.

+1

PaulD

I'm between...

I don't like Powersafe Rx's-but purely because for me there is not a suitable battery voltage available. As JR I want to run my servos just below 6v...as designed!
I use Powerbox products exclusively and trust them 100% (as much as any electronics-which I don't fully understand,so don't trust!)
I've never had an issue with any of my 30+ models currently using PB products...and that's as good as it gets as far as I'm concerned

Dw