Doubling up on flight packs
 

Sorry, I posted this in the wrong thread so I put it here.

I read in another thread here that if you plug a second battery pack into a spare receiver slot that you onboard capacity can be increased. This really intrigues me.

I have an Edge 540. I do not get out as often as I like, but when I do I try to fly as long as possible.

I have an 1800 mAh pack in my transmitter so I very infrequently have to charge it. In the plane I have a 600 mAh. I was considering getting a 2000+ pack for the plane. However, I do have spare 600 packs laying around. If I have 2 empty slots in the receiver, could I potentially increase my onboard capacity to close to 1800 mAh (3x600 packs)?

Could someone please verify if this can be done and that it actually works?

Thanks.

I am not sure if that would work the way you want, it looks like it will increase the voltage not capacity, I might be wrong.

What you can do that will work for sure, is that connect the packs in parallel. i.e. +ve to +ve and -Ve to -Ve from both packs with a Y cable and that will double you capacity and leave the voltage to 4.8 or 6V whatever packs you have, however, that will double your weight as well for the packs.

The best way is to get the higher capacity cells like yu have in your transmitter, same weight as your present pack and triple the capacity.

Here is how to use two packs. The author has years of experience and is and electrical engineer in nicad batteries. The site also blows away afew miths that seem to crop up now and then.

http://www.rcbatteryclinic.com/

On the left go to Parallel operation= reliability and flight time.

I have used this method for a number of years and saved at least one plane.

For doubling battery capacity (not voltage), plugging 2 batteries into 2 empty slots in the receiver will have the same effect as using a "Y" cable.

Here is anoyther site which has a "Dual Redundent Battery System".

http://www.electrodynam.com/cgi-loca...exe/?E+scstore

Doubling up on packs is ok for Nicads, but is it ok for Nmh?
Could not find that answer anywhere.

Ronm

I have posted this diagram a number of times in the past, taken directly from the RC Battery Clinic.

Using two battery packs this way does effectively increase the capacity to equil the two packs. Both packs have to be the same type of cells ie: Ni-Cad AA OR NiMh AA but do not have to be the same capacity ie: One can be 600 mAH Nicad AA and the other can be 800 mAH Nicad AA, effectively giving you 1400 mAH of capacity. It does work with both Nicad OR NiMh cells as long as they are the same type of cell and the same size of cell eg: AA.

In other words do not ever mix Nicads and NiMh cells and do not mix AA and Sub C's etc.

Yes, I've seen that Gary, the picture is self-explanatory.
But in Red's article, he mentions Nicads but does not mention Nimh.


I would think it should work the same for either type, I was just looking for confirmation of that fact.

Ronm

Hi Ron

I talked personally with Red at a battery seminar in Toledo just a few years back when NiMh were just starting to hit the scene. I was told that they would work the same in this configuration.

The only questions at the time was whether NiMh cells were as safe to use in model aircraft as were Nicads due to the fact that in confined space if they were to vent they would vent hydrogen gas which could be potentially explosive and could they take the same abuse as Nicads??? These questions have since been eliminated because of their widespread use today has not seen these problems, as far as I know anyway!

OK, thanks Gary.
I just wanted to make sure, because I'm going to put 2 5-cell Nimh packs and 2 switches in all my larger planes.

Ronm