Guys, though I am an electronic tech, I did not want to remove the charging circuit diode for fast charging, not for fear or hurting the A9 but for warranty purposes etc. I decided instead to do a neat little mod which I am almost sure wont void the warranty.
PLEASE TAKE NOTE THAT:
1. I AM IN NO WAY RECOMMENDING THIS MOD TO ANYONE
2. THAT I AM A TRAINED AND CERTIFIED ELECTRONIC TECHIE SINCE 1987
3. THAT I HAVE BEEN DESIGNING AND BUILDING ELECTRONIC CIRCUITS SINCE JESUS WAS LEARNING TO WALK ON WATER
4. THAT THIS IS NOT A "DO IT YOURSELF" WRITE UP, BUT SHOWING WHAT I DID AS A SOLUTION TO "MY" NEED
5. THAT IF YOU DECIDE TO DO THIS YOU ARE DOING IT AT YOUR OWN RISK AND I DO NOT ASSUME RESPONSIBILITY IN NO WAY SHAPE OR FORM
I find the 13000mA battery more than enough for the A9 and so wanted to ensure fast charging without constantly removing it to do so. So after looking at the space in the battery compartment, I realized that I can mount an auxiliary fast charging jack on the battery cover.
So I bought a nice good quality (US made) surface mount charging jack which has a different size from the stock one on the A9, did some measurements on the cover and how it sits on the A9. I purposely chose to use a different size so that I can’t mix up the chargers.
I soldered the wires observing the polarity of the charging jack, shrink wrap them, drilled a hole on the battery cover, threaded the jack firmly onto it, removed the battery from the TX, removed a small amount of insulation from the battery pack wires AT TWO DIFFERENT POINTS. It’s an old preventative measure I use so that if for some ungodly reason the insulation or heat shrink did come off, the exposed wires can never make contact.
I pre soldered the wires from the jack and the two wires on the battery back, soldered them and insulated them really well. I did not want to cut the wires on the battery pack, so I just peeled off a bit of the insulation, but this meant that I cannon get shrink wrap over them. So I soldered the charge jack wires onto them, used some brush on insulation, let that dry and then still wrapped them with a generous amount of electrical insulation tape.
I tucked the wires in the nice space in the A9 battery compartment, looks like it was another AA battery space meant for an 8 cell pack, and jack fit perfectly well and did not rub anywhere.
I used my Triton battery charger which BTW has reverse polarity safety, placed it at .5C (650mA) and she charged beautifully. As I said I am an electronic spark head so I set up my termination, top up charge rate, sensing current rate and time, and all the other programming to make sure it’s all safe and sound.
I am happy with my mod and it worked like a charm. I preferred this mod than using a LiPo and having to remove it constantly to charge. I think the stock battery is just fine, pilots have been using (myself included) NiCad’s for years and years and I did the NiMHy conversion since they became popular in the mid 90ies and was always happy with them.
Cheers Guys.
