mount usbasp internally and use usb plug to charge radio ?

[rperkins]

Hello,

Still waiting for my 9x from HK, but am going to order a programmer. Thinking of going with the ebay unit that was mentioned elsewhere in this forum. http://www.ebay.com/itm/USBASP-USBISP-A ... 564571ffe4 . I would like to mount the usbasp internally similarly to this post, http://er9x.com/forum/viewtopic.php?f=2 ... 00e52#p428 , although I may go with a female micro usb connector where the old 72mhz antenna is located. Also envision removing the sockets from both ends of the usbasp, soldering wires straight to the board to reduce the footprint. I have read about the poor stock battery connection. I would like to replace the battery with a rechargeable battery and also be able to charge the battery through the usb port that will be added to access the usbasp programmer. Anticipate using any cellphone charger to charge radio, or an usb port on a computer. I believe these will allow up to 500ma of charging current. May have to use a dumb cable or some type of switch to put the unit in a 'charging mode' . ?

What battery /charger combination would work utilizing the usbasb usb 5v power source to charge the battery ?

my goal:
I am new into rc and have a mcpx . Currently using the included Dx4e. Wishing to ugrade to a computer radio so I can lower my rates and utilize an exponential to assist in flying. Purchased a used dx4e to rob the AMTX11 dsm2 module . Plan to mount AMTX11 and antenna in a jr compatible module. Havent commiteed to a specific firmware yet. All programming and eepe access from within linux.

TIA - Comments and/or advice appreciated

Randy Perkins

[GrootWitbaas]

1st off, how well is your soldering experience?
Secondly how do you want to charge a >7volt battery from 5volt?
Here is the battery i recommend, but you need a proper charger for it.

If your soldering skills does not include smd work, I strongly advice you get aSmartieParts board. If they are good then the above one will work, but many have broken their radio by trying the cheaper option. at $45 shipped the SP board gives you a very good deal and includes a proper el backlight


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[rperkins]

Hello, thanks for the reply.

Yes I can solder Ok. Wouldnt want to solder an entire smd Ic. 20+ years ago I soldered for a living repairing pagers, although very little smd. Then at Wavetek rf products got some smd experience. They actually manufactured stuff back then in USA. silkscreened paste, pick-n-place,ir oven, thru hole manual stuffing, semi automatic thru hole IC insertion, wave soldering, etc. Last 20 years been repairing machines in automotive stamping industry, so I am out of touch.

Was thinking someone would ask about charging >5v via usb. not sure about that. Maybe avoltage doubler? Would be nice to get a premade circuit board though. rcmodelreviews talks about using a 6v source. Wasted heat and all that. It just seems tidy only adding one neat hole to the tx to program and charge the unit. I guess I am charging my heli batteries already but they are only 1s. So I am going to have to buy a charger for the tx either way. would be nice to make it internal.

Yes I looked at smartieparts. I already had a backlight kit on order from HK when I discovered smartie. I was still considering the smartieparts but they are on currently on BO. So it seems like I am going to go down the ebay usbasp route, and order 2 of them. Will still be money ahead if I dont blow anything up

Are most in agreement about only needing 6v for the xmitter ? I will be running a dsm2 module in it.
What about a simple voltage doubler ? or am I making it too complicated ? anyone know a cheap 5v --> 12v voltage doubling board with overcharging protection applicable for this transmitter ? Feel free to move this thread to another subforum if deemed appropriate.

thanks again
Rperkins

[Rob Thomson]

You will be safer with 7v for the tx. Running as low as 6v risks the tx turning off rather suddenly!


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[GrootWitbaas]

If you order the SmartieParts board now you may have it before the TX arrives ...Steven is fast with his shipments.

If you don't have a proper charger for lipo/life you may want to invest in this. Personally I have the battery linked above, and it works fine with no changes to the tx (plug and play). This specific one has the polarity correct so you won't go down the road of "ooops i plugged it in the wrong way help!"
There are many ways to power the radio, but trust me on this one, it's the better option. Take note it use the "safer" LiFe battery!

I use one of the cheap chinese chargers and it works for me (I did however fix all the bad soldering inside it before i used it)

I will not recommend using the voltage doubler for charging a battery. Those circuits and the design behind it is great for anything that does not draw current, but charging draws current.

My recommendations made here is based on many hours and hours of reading and trying to help, and personal experience with the radio and general RC stuff. In my opinion this is your best choice. We have a saying in Afrikaans "Goedkoop koop is Duur koop", but you have to use google translate if you want to understand it

[rperkins]

Thanks for all the replies.

Does the turnigy version of 9x have a charging port? I downloaded a flysky? Manual and it mentioned a charging port, near the on off switch. If so, what is the size of charging port and details of charging circuit.
TIA _rperkins

[Rob Thomson]

Yes. It has a socket on the side.

Not certain about the polarity.

It is protected with a diode so you cant charge the wrong way.

Rob

[ShowMaster]

I believe the charge jack comes wire as a Futaba with rhe center pin plus(+) and the barrel minus(-). There is a diode in line to protect it if the polarity is wrong. I fly all JR and Spektrum so I flipped the wires on the jack to be the same as JR.
I'm using the HK 1500ma life battery and charge using the jack if needed at the field at 800ma to not overload the 1 A diode. I balance charge every 2-3 charges if i think about it. At $7 I'm not worried about the batteries life span. So far after 2 mo I'm still OK.
SM

[erazz]

Attempting to charge the radio via the USB is akin to trying to drive your car on the starter. Not recommended.

You would have to make some kind of voltage converter (not simple) and then you'd only be able to charge at stupidely low currents. Not to forget you want to charge lipo - not reccommended to charge in your radio.

My suggestion is DROP THE IDEA. Charge via a balancing charger outside the radio.

Stay safe.