Anyone tried one of the Hyperion TX packs in a DX3R? - RC-Monster Forums

MTBikerTim · 02:55 AM

Having a look on the Hyperion website I found these HP-FG305-2080-2S http://media.hyperion.hk/dn/fg3radio/. Looks like if might fit in the 3r with a few mods.

Quote:

HP-FG305-2080-2S is a replacement for CAR Tx (or any) which use 5-cell NiMH "flat" packs, such as Futaba 4PK Pistol grip Tx.

* Absolute Max charge rate is 4.8A, as this is the rating of the PCM safety chips used inside the packs. Still this is quite a high charge rate, and allows recharge in 30-45 minutes, typically.
* The PCM device protects the pack from over-voltage charging. It also allows the pack to remain installed in the transmitter, and then be charged with the standard NiCd or NiMH wall-charger which comes with most transmitters.
(wall chargers up to 12V max for 3S packs, or 8V for 2S are usable)

JERRY2KONE · **Nice -** 09.22.2009, 03:35 AM

Nice pack for the TX. I have the standard "Hydormax" nmh 5 cell pack for mine. That LiFe pack looks like it should be ok for the DX3R. For clarification on voltage BrianG has the scoop for max voltage on the DX3R. He has a modification thread on here for that radio and has used his flawlessly with a 5 cell battery pack, and there have been lots of discusions on here about the PRO's & CON's of using Lipo packs in a TX. Some guys have been using them for a while now without any issues, but some say why take the risk when nmh packs work just fine. From what I have read the LiFe packs are much safer to use than the Lipo packs are due to the fire hazard factors.

jayjay283 · 09.22.2009, 03:59 AM

Is that pic just for comparison ? its 6.6v ..do they mean Rx ?.. Ive run a 3s "11.1v" max amps in my airtronics TX for a year-ish now. i have to keep it at 12v or lower because my controllers crap, if I over charge it I just hook up a little heli engine too it for a few minutes and retest. It lasts a month without recharging and never fried.. Keeping it installed at 12v

BrianG · 09.22.2009, 09:59 AM

Jerry is right; the DX3R is made for a 4 NiMH cell pack, which is 6v (using Alkalines). LiFe nominal voltage is 6.6v, but fresh off the charger, it's 7.2v, which may be too high. You could add a diode in series to drop ~0.7v to maintain a proper voltage.

snellemin · 09.22.2009, 10:52 AM

Or you can be goofy like me and use a DM park bec to keep a constant 5V.

BrianG · 09.22.2009, 11:44 AM

Yup, that works fine, but there are two disadvantages: 1) If the BEC fails, full battery voltage could blow the radio, and 2) the voltage display on the radio won't be accurate so you have no idea about the actual battery voltage until it falls below the regulator drop out voltage, which could damage the pack.

snellemin · 09.22.2009, 12:32 PM

true true. But I use those little flat LI-Ion batts and have yet to see a DE park bec fail.

MTBikerTim · 09.22.2009, 08:21 PM

So 7.2 volts is too high you think. I'm tempted to try it anyway.

JERRY2KONE · **Make sure -** 09.22.2009, 09:38 PM

Quote:

Originally Posted by MTBikerTim

So 7.2 volts is too high you think. I'm tempted to try it anyway.

You may want to check with Spektrum first before you take the chance of frying your DX3R. I know it just seems like such a small amount of difference in voltage, but the cost of losing a radio worth $200 - $300 is not worth the risk of curiosity in my eyes, when the Hydromax 5 cell nmh works just fine, or even 5 eveready rechargable AA batteries. Yes we understand your want to use that pack because it looks good and will probably last longer than the alternatives, but just how much money are you willing to gamble with? Just my 2cents. Spektrum would be the place to ask. They can even test out your theory without it costing you a dime.

MTBikerTim · 09.22.2009, 10:04 PM

Quote:

Originally Posted by JERRY2KONE

You may want to check with Spektrum first before you take the chance of frying your DX3R. I know it just seems like such a small amount of difference in voltage, but the cost of losing a radio worth $200 - $300 is not worth the risk of curiosity in my eyes, when the Hydromax 5 cell nmh works just fine, or even 5 eveready rechargable AA batteries. Yes we understand your want to use that pack because it looks good and will probably last longer than the alternatives, but just how much money are you willing to gamble with? Just my 2cents. Spektrum would be the place to ask. They can even test out your theory without it costing you a dime.

Yeah it is a bit of a gamble. My issue is that the Dx3r seems to have issues at range with the pico switch what I and many others use as a cut off 5th scales. I am not sure if a bit more voltage at the transmitter will solve the issue so I really need to do a bit more testing first.

I am also thinking that using that pack with it's built in charging circuit and a nimh charger designed for the dx3r won't actually fully charge the pack anyway so the voltage won't be so high. I will have to do more thinking and more research anyway.

My DX3R is 3rd hand and I think it has that binding issue that the original ones had and it feels like was designed for hands smaller then mine also. I'm not really feeling the love.

BrianG · 09.22.2009, 10:25 PM

Like I said before, if you want to use 2s LiFE, just use a single diode in series. That will make the voltage to the radio around 6.5v (from personal experience, this voltage is fine) fresh off the charger, and around 4.8v (which is what 4xNiMHs are nominal) near the end of the cycle. And since diodes drop a static 0.7v, the voltage display will give an accurate indication of the charge level (just add 0.7v).