Disarray

I had one of the 5 cell 2700 ni/mh packs. Battery was about 18 months old and cycled regularly. It was charged the night before and went dead 3 minutes into flight, no warning. I did not check the voltage before takeoff so I do not know if the battery died all at one or if it was weak when I arrived at the field.

What is your source for this information. You are saying that if I had just plugged a second battery into my reciever, this battery going dead would have not impacted on the integrity of my flight?

JoeAirPort

My Feedback: (41)

Did you take the pack apart and see if anything broke? Or is the failure invisible? ie a bad cell?

Having a second pack may have prevented it....hard to say from here. Some packs just need a good deep cycling to come back to life. They sit for a while and one or more cells go low.....you peak charge it.....it false peaks and you end up with a pack that can't hold up to it's rated voltage under load. Happens all the time. It's good to cycle a pack at the start of the season before flying. Cells do go bad too. Just wonder what was the case was with yours.

yarom

My Feedback: (82)

Yes. Exactly like a battshare. You plug both batteries in and if one goes bad, the Rx is capable of isolating the good one and working with it.

You will also get blinking lights on the side of the bad battery, to indicate there was an issue.

Disarray

Thats cool, but again, what is the source of your information. No offense, but people can say anything they want on the internet, doesn't mean I want to trust my plane to your word alone. I would like to read this from a manufacturer or someone who has written up a testing report. I could test it myself but I do not want to risk a receiver to do it.

Hammbone

My Feedback: (309)

This info comes direct from JR / Spektrum, but it only applies to their Powersafe rx's. I believe you will find the info on Horizon's website if you look at the description info for one of their Powersafe rx's.

Jim

I do believe though, that if you are going to worry about every little thing that can fail, this may not be the hobby for you. Things are going to fail, and you are going to crash planes from time to time. If you try to make your plane completely redundant and "failsafe", you are adding too much wieght and complexity to it. Batteries rarely fail.

JoeAirPort

My Feedback: (41)

I've been in the hobby 5-6 years (can't remember exactly). I haven't had failure from a switch or a battery.....or anything for that matter (just crappy running engines for whatever reason). I did see a Futaba FM 7 channel rx acting funny setting up my plane in the basement.....I never used that rx again. There were similar reports from other people (rudder servo jumping for no reason while another channel's servo was moving). Not saying that I will never have a failure....but much of it can be avoided. I've been using single batt's on all my 50cc planes. But I use really good batt's (NoBS 1950 FAUP) and a Smart FLY HD switch that was really designed for 40%'rs (Super switch, has two connections to the rx). I don't use Y harnesses. etc etc.

His question is a good one though. It would be cool if an rx would isolate the battery inputs in case one had a problem (for those who wish to use 2 batt's). There's nothing wrong with looking for the safest setup out there...as long as it doesn't get too heavy, cost too much, and in the end actually add more failure points (it happens).

For 33% and up I would no question use two switches and batt's, just not on 50cc planes. Not sure if I ever will go over 50cc to be honest.

yarom

My Feedback: (82)

The source of information is JR/Spektrum themselves, both in their advertising and the instructions that come with the receivers.

I own several Spektrum AR9100s and they work as advertised. All you need to do is plug in a battery fully charged and another one half charged and the Rx willd draw power from the stronger one until they are similar...

This is valid for the 5 to 6 models of HD receivers they have already commercialized.

Eagleburger

I have a A123 cell that had the tab poorly welded. It came off whilst I was making the pack. I run tow packs in everything 30%<. ALso run the new spectrum 9100.

2 x 2S 1100mah in 30%

2 x 2300mah in 35%.

Cheap insurance if you ask me.

Disarray

That is true, but after the way this plane went in, especially considering it was a larger plane worries me. It went full throttle, 1000' out of the box and crashed in the woods on the other side of a house and across the street from where 10 kids were playing. I feel some redundancy will be worth the weight and cost penalty for the added safety.

Josey Wales

My Feedback: (61)

This is why I run Smart Fly FO Kill switches on my gassers. It would not have helped save your plane, but as soon as the power was lost, your engine would have shut down and it would not have gone as far as it did.