I have a Syma S107 (with an 150mah battery)
and I also have a 400mah batt from an walkera 4#3Q

I was wondering about connecting a cable from inside the S107
dragging it to below, and attach the 400mah battery there (using a cable with a plug that fits that battery)

But on my first initial test, i did a simple test where i took the 400mah battery and connected the cable with the plug, and then i took the loose ends and touched the + and - where the original battery is soldered to the circuitboard, but when i touched the +- the main motor started spinning immedately, and this was in an OFF position (the powerswitch)
Also in the ON position the same thing happened.

So i was wondering... do i have to open the original 150mah battery and soldier off the PCB(as i believe you guys call it, im a newbie)
(PCB=the circuit inside the battery, in case im using the wrong phrase here)
and then attach the 400mah to that circuit, and then the circuit to the heli's circuitboard?

Any ideas as to why the engine starts spinning? and any ideas as to how I can use that Walkera 4#3Q 400mah battery with my Syma S107?

Simply want to do this because I have plenty of those batteries, and i want to fly a bit longer, and charge a bit faster (the charger for those batteries uses about 25min, and the syma charger is about 40min) so all in all, i would get some more flytime, and less chargetime, and id be able to fly a trip every 10min, instead of every 40min as of now...
(im aware of the engine heating, so thats why I'll have a break inbetween each flight) hehe

Thanks for good ideas or answers you might add!!

I dunno if a 400mah would be a good idea for a syma..... but I just haven't studied batteries enough to say for sure if it would explode into a unsatisfying fireworks display.

I would not recommend anything above 200mah. Honestly the s107 doesn't need any sort of tweaking other then flipping the tail motor to achieve faster forward speed.

The PCB on the original battery is used to prevent overcharging the battery, this is it's only function.
I sorry but I have no idea why the rotors start turning when you connect the Walkera battery

Originally Posted by alexdata

So i was wondering... do i have to open the original 150mah battery and soldier off the PCB(as i believe you guys call it, im a newbie)
(PCB=the circuit inside the battery, in case im using the wrong phrase here)
and then attach the 400mah to that circuit, and then the circuit to the heli's circuitboard?

There is a short in your copter: the smaller cell's thresh-hold won't kick on the motors, the larger one will.

Originally Posted by killbucket

There is a short in your copter: the smaller cell's thresh-hold won't kick on the motors, the larger one will.

I've also tested the 400mah battery on 2 other small heli's, and also on them the engine starts immedately...
So what do you mean by "short"? Shortcut? or something else?
And tresh-hold? what, how and where?


Also, ScotSoft, thanks for clarifying what the PCB is doing inside the battery...


I've tested the 400mAh on the following heli's and they all spin up when I connect the 400mah (originally they come with 150-180mah batteries)

- Syma S107 3CH IR
(http://www.helipal.com/syma-s107-mic...ro-yellow.html)

- Zhengrun Z008 Z-Series 3CH IR
(http://www.ehirobo.com/shop/product_...oducts_id=9822)

-Falcon 18 4CH RF
(http://cgi.ebay.com/ws/eBayISAPI.dll...#ht_4980wt_812)