bismarck007

My Feedback: (5)

I'm rebuilding my Giant Stinger and have recovered the tail and bought a lot of cool little upgrades. I went out and bought 6 futaba 9402 servos which are lightning fast and very powerful, and I bought some awesome carbon fiber pushrods and some very high quality control horns. I've also taken the time to strip the fuselage and add 1/16 ply from the nose back to the end of the wing saddle as I heard that the fuse tends to break at the forward end of the wing saddle. I was going to cut the wing in half to facilitate adding a stronger spar as I've heard that is the weak point, but I decided to just cut 3" off each end of the wing to make it fit in my truck bed, and hopefully the wing just wont break. I also have done a lot of repairing and just general work on it so.......,,,

my question is this. I've heard of devices that allow you to run two batteries, one as the primary and the other as a backup. Can anyone reccomend one to me? I've no idea if this is an available option, but I'd like to be able to have the charger charge both of them without me having to take them out of the aircraft. I'll post some pics when she's all back together but hopefully, someone will have the rigt product for me, I've spent so much rebuilding this monster that I don't want it to go in because of a bad battery.

Thanks,

C.P.

ben beyer

My Feedback: (23)

i just bought a second battery and switch harness and plugged it into a free channel on the receiver. you can also use a y harness to "y" it in to a channel like the throttle if need be.

stomper

My Feedback: (20)

Hey CP
Take a look here > http://www.rcbatteryclinic.com/

Click on.....> ( Parallel Operation Reliability and Flight Time) on the left side of Reds web page.

HTH

Hammbone

My Feedback: (309)

EMS Jomar makes a battery backer.

http://www.emsjomar.com/

Go to reliabilty enhancements and you'll see it there.
I have an extra one of these I'lll sell you at a discount if you're interested. PM or e-mail me.

Jim

branded

My Feedback: (9)

This is the only way to correctly implement this scheme. Simply plugging another battery, one that's not isolated from the other, is actually decreasing the reliabilty and robustness of your R/C system.

There's some words about this in the latest High Flight magazine.

bismarck007

My Feedback: (5)

Thanks,

If anyone has one of these that they'd like to get rid of give me a holler

C.P.

Icebird

As a matter of fact there ARE some words about this very thing in the latest High Flight magazine, however, there are also some VERY IMPORTANT inaccuracies. As far as your statement about decreasing reliability and robustness of the R/C system, I simply must take exception to that statement. There are a great many systems that do just that without problems, in fact many planes have been saved by just this type of system. If you don't believe me, just hook a 4 cell battery pack to a 5 cell battery pack, with an ammeter in between, and see for yourself what happens. This assumes that you don't bother to check your batteries before a flight, because if you did, you'd notice that one pack had improper voltage. If you take off with 3 cells working out of a 4 cell pack, you're not going to get far, I don't care how you hook it up.

Sorry, I guess you struck a nerve.

Jim

Stick Jammer

Yeah, I agree with Icebird. This statement is simply not true. Two packs of equal cell count, two switches with charge receptacles, plugged into two open slots of the Rx. It's simple and works great for redundancy. Tons of people do it that way. Each pack can be charged separately from the other through it's own switch, no need to remove the packs from the plane.

didiwatt

My Feedback: (38)

With the EMS Jomar battery backer, you must use 6V cells because the backer itself uses about 1 volt to operate. Therefore, you only get 5 volts to the servo's. I wanted the speed and torque that 6 volts gives you so I returned the backer and went to 2 batteries and 2 switches directly to the receiver. The advantage of the backer is that it can isolate a shorted battery and monitors each cell for even distribution. To bad it reduces the voltage so much.
Paul

mglavin

My Feedback: (31)

Have you actually performmed this test? What specifically were your results? I saw the information in High Flight too, something about 3A alarmed me as my findings in this regard were somewhat different.

Icebird

Yes, I have done it, and while I don't remember the exact currents, I do know that the multimeter I had at the time could not handle more than one amp dc, and it was nowhere near the maximum. I seem to remember it was around 350ma or so, but certainly not enough to discharge the charged battery very quickly. With both packs having the same number of cells, but one being charged, and the other being discharged, the amperage was quite a bit lower, something around 50ma if I remember correctly.

HTH
Jim

mglavin

My Feedback: (31)

Jim

Your findings parallel mine for the most part. My opinion of same is the purported charge is inconsequential in the scheme of themes.

Thanks for sharing.