Hi guys,

My new Harrier is a little tail heavy and I've got to add some weight up front. Rather than adding lead, I've got 2 extra 600 mah 4.8v nicad power packs that I could hook up together in parallel to add some weight.

What kind of power benefit would this be over a single 1200 mah pack? expo

well the only benifit would be less current draw through each battery since they would devide the current between them, less heat. so they would last a few more sessons just hook the batterys to a y harness and it will work just fine

Actually there is a tremendous insurance benefit as well as other good benefits.

If you have two batteries you have twice the available mAh, already mentioned. Obviously, the model will fly longer. You also have more demand capability that you wouldn't get from one pack that is twice the capacity. If anything, like a servo that's getting a heavier load than normal, wants to draw more juice than one pack has the capability to provide, it'll get the juice. You also have somewhat of a backup capability if one of the cells in one pack dies. And the biggie......

If you wire in your 2nd pack through it's own switch, you've got INSURANCE IN GOLD PLATE! Once upon a time, the system failure you most often saw was a switch failure. And it happened a fair amount. And next was a pack failure. The pack backup has already been mentioned. Now I'm mentioning the switch backup.

You put two switches in your airplane. Each goes to it's own pack. To fly, you turn them both on. If two switches sticking through the side of your plane bothers you, rig the GP "remote" switchs to work off one stalk. You do have to charge both batteries by themselves, but that's no real problem nowadays.

I think one of the battery sales places on the internet pushes this wiring deal and even has pictures. I don't remember who that is, sorry.

It works and it works GREAT.

darock,

Do I understand it works like this:
Each battery pack would be wired to a switch then both switches go to a Y harness and the single end of the Y would go to the battery terminal on the receiver? expo

yes that will work. it will also work buy pluging it into any open channel. the rx is wired as a simple power strip.

Back when we were doing it, we didn't want to use a Y harness. As redfox said, you can plug both switch harnesses into the RX wherever there are available slots. We wouldn't use a Y unless all the slots were full.

We'd put the two switches side by side and often taped the lines together to cut down on the mess all that wiring caused. Having the two charge jacks together also made things easier.

It was actually a very good return for very little extra work, especially since some years back, switches sucked. If you flew for more than a couple of months you'd probably get to see a crash caused by a switch going bad. People used to swap them out as insurance. And I've seen one plane that was landed because it felt funny to the pilot and turned out one of the two switches had just failed. Was that guy happy or what.

Going to your initial question of benefit between two 600maH packs or one 1200maH pack, you will see no benefit at all. The percent capacity draw from the two packs will be the same as just the one.

Now, with all of this said, you can have a redundant power source by hooking the two packs into the same receiver through two switches. If you are using cheap switches, you may see a lower voltage drop, but with a plane that is using a 1200maH pack, you should not see any great voltage losses.

Last, if you are using digitals or a lot of servos so that you could exceed 2 amps during flight, then you may see some drop do to your electrical connections.

What do you get with two packs? If you use a switch harness for each one and plug them into separate slots on the receiver, here is what the guy at NoBS Batteries says you get.

BTW, I bought a couple of batteries from the guy awhile back and wondered at the time if they were going to be a good deal or what. You know, you really got no idea how good a product is just from 72bpi pictures on the internet.

He got the order to me in a heartbeat and they looked good. But what sold me is that he sent along 5 or 6 pages of info and buried in it was the lowdown on the two battery/switch setup I've seen used for years. We did it because switches used to suck. Turns out we were getting lower impedence as well. GaahhhLee! We was smarted than we knowed! I always wanted less impedence and never knowed I was a gettin it.