changing controller from 4xAA batteries to a lipo / rechargable pack

saylor · Jul 21, 2015

anyone done this mod? I could not find much on the interwebs about it.

im up for it, just wondering about getting a 7.4v battery pack down to ~6v, just add a regulator / step down or what?

- saylor

Johndo · Jul 22, 2015

The voltage of stock 4x AA battery at full charged is about 5.8v-6.1V, so it would be fine if you can use a stepdown to lower the voltage of 2S LiPo pack (8.4V when full charged, not 7.4V) to that voltage and use it to power the Phantom Tx.
However, finding a LiPo pack to fit into the battery bay of Phantom Tx may not easy.
Or you can get an Eneloop battery, which is rechargable and your Tx will last much longer than it did with the stock pack. It may not be the cheapest option, but it definitely is the best for the Tx battery.

Ti22 · Jul 22, 2015

It’s very possible the controller can handle 2S (8.4V fully charged) RC LIPO. Most devices utilize a regulator and can handle significantly above designed battery voltage.

The hat trick is, finding this out without frying the device?

I’m pretty darn confident it should work but I would probably not try it without opening the unit to follow battery leads to PCB and trace to whatever chip they’re using to regulate VDC. Grab a part # and look up the specs.

The other solution would involve adding a small “buck” DC voltage convertor. Once adjusted, it can input 7-8.4VDC and output 6V. But those things can be tricky to adjust properly without some metering, load and test gear.

HK (hobby king) sells low C rate Lipo TX batteries with BMS which offers a good option. Finding one to fit the cavity might take some digging/browsing but it’s certainly a viable possibility.

I’ve been thinking about doing this too…

N017RW · Jul 22, 2015

Not meaning to be one of those "why do you want to do that' guys, but why?

LiPos have one of the best power density to weight ratios commonly available but can be high-maintenance compared to alkaline or NiMH.

I understand if you just love to mod but IMO this would be for mod's sake only unless the controller is too heavy for you.

Ti22 · Jul 22, 2015

N017RW, you’re totally correct. Not much reward unless you’ve got time and interest and/or just wanna lighten the load a bit.

I actually have a great source of commercial Alkaline AA’s but my interest is more about powering or tapping power for a video RX/FPV monitor. Spare, older 3S flight batteries with reduced C rate seem to be a common by-product of this hobby.

But as you point out, low reward and relatively high-risk to go playing around with something so critical as this.