Aero Ace Charge from my Field Battery??

[Sparkorama]

I was wondering if I can charge my aero aces from my field battery through my pro-peak prodigy 2 charger. I was thinking I could just add a connector from the AA transmitter's charging wire and connect it to the outputs from my charger. One person on another thread suggested it was more complicated than that. However, if I knew the mAh and the voltage, couldn't I just connect my charger to the in-plane connector and charge the lipo in the AA? If yes, then does anyone know the AA's mAh and voltage for the built in lipo.
Spark

[fhhuber506771]

I suspect the AA to use a single cell LiPo. (i have read a couple of reports that it is a LiPo, but none that said how many cells)

The proceedure to figure out what it has:

Charge the AA airplane.
clip the charge plug from the AA TX and make the adapter for your charger AND VOLTMETER. Hopefully you also have a Wattmeter...
Test the voltage and confirm the polarity of the plug pins.
Do a slow discharge measuring the current drawn.

You should at that point have all the info needed to safely charge using any compatible charger.

[Graham Smith]

I believe the AA built in rx battery is a 135 mAh lipo. (single cell).
I am sure you are aware that you can only use a dedicated lipo charger for these cells,

The other Graham

[Hauntme13]

Don't forget the input diode. Basically, it's a diode in series with the battery to protect the battery if the pins were shorted. The AA charger output is 4.8-4.9V to compensate for the voltage drop of the diode. Most lipo chargers won't 'see' the battery either and will just error.

To fix this, all you need to do is solder a wire jumper around the diode, bypassing it completely. I have done this to both my AA's and it works great. I'm using a Triton charger.

[Hauntme13]

Here's a pic. The diode is marked M7, you can't miss it.

[ChrisP]

All good ideas above.

What I did was this :

I had a spare AA transmitter. I connected a socket to the terminals (batteries removed). The socket is on wires that exit the antenna hole and matches the plug on the battery pack from my Twinstar (8 x 2400 mAh Nicad).

The 8 Nicads have near enough the same voltage as the 6 dry cells, so the charger works correctly.

I have never run it flat charging the AA. If I do, then I can charge the Nicad on my field charger in 20 minutes.

[LOV1]

Hello,

I just tested a DC-DC power adapter (12 V input/ 9v output) and connected on parallel to the Tx Batteries, then charged the plane as usual. I am going to add a plug on Tx to make parallel connection permanent and use with 12v field battery.

Charging circuit remains from Tx.

Regards

Luis

[peter frostick]

Hauntme
Thanks for the excellent and lucid explanation --- i guess it's OK to remove the diode from the PCB completely, and bridge its pads with a jumper?: some of us are fanatical weight-watchers, and every little saving really helps!
I still feel the stock plane's 350ma charge rate is bit abusive!! How say you?

Cheers Peter

[peter frostick]

Luis
I've posted a super-simple LM317T reg version on the main thread,working with the standard Tx charger like your's, : it works just fine, and is so simple and affordable --- you don't have to butcher the model either!!

Peter

[CaptEvo]

would nokia cellphone wall charger work?

[LOV1]

Peter, I saw your diagram and it is neat, could fit nicely inside the tool box.

CaptEvo, looks like X-twin charger/battery draws over 130 mah. Check on wall charger it is 9v output and over 130 mah. Power adapter I am using is made for auto use (plug on lighter), and can deliver up to 800 mah and 6 voltage ranges.

Luis