Hey folks, I have a 64" wing P51, scratch build. Never flown YET. SK 130 engine, Spektrum DX7 radio. I do not want this plane to come down because of bad or failing electronics. I would like a two battery backup system. Do you have any ideas to help me out ? I put two videos on the member videos site. Thanks all

Use 5 cell batteries and just plug the 2nd battery and switch into any unused receiver port.

Doubling up anything doubles the potential problems!

My suggestion would be to use a single 6v battery with generous capacity and the best quality switch you can get your hands on.

If you do go with 2 batteries you will need to use two switches as well.

Terry

Like Steve said,

2 batteries and 2 switches.


Bob

Two batteries and two switches!!!! Redundant counts for a lot sometimes. Make sure that SK is broken in well on the bench too. I haven't tried the bigger SKs but I'm sure sold on there .91!!! Never had a dead stick!! I have sold a bunch of them to other guys at the field after they have seen mine run. I used the Ed Moorman break in process that he wrote about in RC Report and they have been perfect engines!!

Sorry for this question. I have a DX 7 radio and a AR 7000 rec. Two switchs ???

2 switches, one for each battery. Mount both
switches on the Plane, plug each one into a seperate
channel on your Rx.

Bob

Two batteries, each with its own switch. I tend to use packs of very modest capacity; but that'll depend upon the loads which you expect to serve.

One more thing.

Each 6v pack should have a diode in its output. This way, if one pack fails, it cannot drain the life from the remaining good pack. The diode means that you need a separate charging jack ... since you cannot charge your battery "against" the diode. There is a small volt drop across the diode, under load, but it's not a problem.

I have used this system for near 20 years, now. Have had one pack fail, but never lost a model through battery' failure.

You better knock on some wood. Or maybe that's a traditoon on this side of the pond.


"I have used this system for near 20 years, now. Have had one pack fail, but never lost a model through battery' failure. "


David

Sorry guys, could someone give me drawing. I do not want to make a mistake. My rec. is a AR7000 thanks

I was thinking just that as I typed my earlier post.

Can't draw anything for you but it isn't hard. You mount two on/off switches, you plug in a battery into each switch. You plug the two switch leads into any open RX ports. Same thing as only one battery set up but you are doing it twice. The RX doesn't know how many batteries are being plugged in.

big YES on the 2 batt 2 switch system.
in my 40 size models i'm using 2 futaba 6v 600mah packs that weigh 3.3 ounces each, and 2 switches. the batteries are under the servos. worked out great for my CG too[8D]

here is a diagram,

www.smart-fly.com makes a battery combiner called the "Batt-Share". Two batteries plug in, it draws from the stronger until balanced and then continues. Should one fail it drops that circuit. It also plugs into two jacks or just one if you prefer) in the receiver for additional redundancy. Two switches and you're well covered. Here's a diagram of how my Ultimate is set up.

Do like summerwinds diagram. It doesn't have to be any more complicated than that. Or expensive.

what does an SK 1.30 GO for these days?

Kangke Super Kraft has a nice web site with all up to date pricing. http:'//www.kangkeusa.com