Adding a Flightpower 3s LiPo to the DX7

[minimalitia1]

maybe someone could draw up a small sketch? its probly so incredibly simple but all this reading ab how everyone did theirs slightly different confuses me on how to wire the diode and the l.e.d. i have a 3s thunder power 2200 lipo from my 450 i want to put in my dx7 but am worried ab messing up cuz im confused. thanks

[Quisp]

Here's a picture from another site that shows how to hook up the diodes.
I connected the two diodes together first, made a hook on each one and crimped together then solder. Put heat shrink on, the do the same physical connections on each end and solder.
If you are using a standard lipo, you'll need to modify the output connector to fit your radio.
As added safety, I put a little tape around the entire battery, holding the diodes against the battery, so they can't move at all.

[HeliSmith]

Yeah we have these too but it voids your warranty. Guys doing this don't charge the lipo all the way up. Only to 11.1v or so. Then recharge as normal because the lipo can be all the way as low as 9.2v it isn't under load. Kind of a pain in the butt we need a regulator. Be nice to have a nice regulated voltage of 11v.

[dennis22g]

Hi guys, I have been watching this post with interest. Since my last entry I have had no trouble and a brilliant operation. My DX7 has performed perfectly. I don't have any photos at the moment but, I have attached a simple diagram of BOTH my circuits.
(1) The cable I have made to simplify the plug-in for a balanced charge.
(2) The connection for the diode to the battery that I have used for over a year. (For those who are not sure about the circuit, look at the bottom right of the drawing for the battery wiring only)

The diode in the battery circuit has both lowered the output voltage down by .6v to just under 12v at the radio, as well as protected the battery from accidental charging through the radio charger plug.
There is no reason you cant use two diodes in line (series) if you want to go lower. Two will give you about 11.4v at the radio.

Hope this helps...

Dennis

[Quisp]

Good graphic Dennis. I tried to paste a graphic from another site, and wasn't successful.
I went with two diodes, and at a full charge see 11 to 11.1 on the transmitter.

I need to make an extension for the balance plug. Just so happens that the lipo I'm using has a short balance lead, which on one hand is good for storage in the transmitter, but on the other hand not super easy to plug into charger.
But heck, after several weeks of use, I'm down to 10.7 volts. So once a month or so isn't too much to deal with.
I just pull the lipo out the back of the transmitter, but don't disconnect from the transmitter power lead. Charge it for a little while and push it back in the case for another month.

[HeliSmith]

Oh cool I see what you guys are doing now. And the lipo is protected because the radio will shut off long before 9.2v actual on the battery.. Nice...

[dennis22g]

I just took a couple of quick pics. Hopefully you might be interested. It may shed some light on what I have been trying to show with my diagram.
The balance plug is extended to go to the battery in situ.
Please excuse the rough piece of electrical conduit but it works!

[allanQ]

hi guys ... i just added a 3S 1C 2650mah lipo to my dx7
question .. i can only set the alarm to be at 10v max in the service menu .. can it be set higher to lets say 11.1v (dont wanna kill the lipo) or so ??
question .. what does that adjustment below the set alarm level in the service menu do ?? does it just calibrate/adjust the input voltage from the batt to the tx so that the tx is showing the correct voltage from the batt or does it do something else ??

[gww528]

Originally Posted by allanQ

hi guys ... i just added a 3S 1C 2650mah lipo to my dx7
question .. i can only set the alarm to be at 10v max in the service menu .. can it be set higher to lets say 11.1v (dont wanna kill the lipo) or so ??
question .. what does that adjustment below the set alarm level in the service menu do ?? does it just calibrate/adjust the input voltage from the batt to the tx so that the tx is showing the correct voltage from the batt or does it do something else ??

Put a diode in-line with the battery and then you will not have to worry about about draining the battery.

[allanQ]

yes .. i am planning to get the diode in but have not gotten to it yet .. the diode only lowers the voltage output of the batt but does not change the alarm setting
what am i curious is even with the batt fully charged and i checked with DMM showing 12.5v .. the display on the dx7 shows only 11.1v depending on how i adjust the setting in the service menu shows full charge on the bar

[gww528]

Originally Posted by allanQ

yes .. i am planning to get the diode in but have not gotten to it yet .. the diode only lowers the voltage output of the batt but does not change the alarm setting
what am i curious is even with the batt fully charged and i checked with DMM showing 12.5v .. the display on the dx7 shows only 11.1v depending on how i adjust the setting in the service menu shows full charge on the bar

If you add one (1) diode or two (2) in parallel the TX will show 11.9 or 12 volts. Then you can use the DX7 TX's low voltage alarm as is and the battery will be safe. I always charge when it is around 10.xx.

[allanQ]

if its 10.xx then the alarm will not go off .. thus defeating the purpose of the alarm and having to look at the voltage regularly .. LOL
the alarm in my dx7 could not be set higher than 10v .. if it can be done then i would appreciate any info on how its done .. thanks

[gww528]

Originally Posted by allanQ

if its 10.xx then the alarm will not go off .. thus defeating the purpose of the alarm and having to look at the voltage regularly .. LOL
the alarm in my dx7 could not be set higher than 10v .. if it can be done then i would appreciate any info on how its done .. thanks

Why do you want to set the alarm around 10 volts?

[allanQ]

Originally Posted by gww528

Why do you want to set the alarm around 10 volts?

i wish i could set the alarm to 11.3v or something thereabouts ..
the thing is the alarm warning setting only allows me to set it at a maximum of 10v .. it will not go beyond that ..

[allanQ]

fitted my lipo with 2 x 1n4001 diode in series
there is a drop of about 0.75v at the output to the TX .. so now my TX will never see anything more than 12v even with the 3S lipo at full charge

[Quisp]

2 diodes in series on mine. Fully charged pack reads 12.6 at the charger, and through the 1.5 volt drop of the diodes in series is 11.1 at the radio display.

[gww528]

Originally Posted by Quisp

2 diodes in series on mine. Fully charged pack reads 12.6 at the charger, and through the 1.5 volt drop of the diodes in series is 11.1 at the radio display.

You will have a longer run time if you use (1) or two in parallel. It will show 11.9 or 12 volts on the radio and you will still be safe.

[Rodney]

I have as low voltage alarm I added to mine. Goes off when my Infina Models Ion battery gets to 10v But has LED in radio to show status before that. The ION battery runs my DX7 about 20 hours between charges.

[dennis22g]

Check out my recent posts on this subject. There are a couple on other threads..
Regards

[traeside]

AllanQ did you ever get an answer to your question? i read this post long ago before i put my Rhino 2660 with diode in. but i wanted to do the same as you. as it is now if my voltage reads around 10.3 or 10.4 i am at about 16% when i put the pack on the charger. i don't like taking it that low so i also wanted to be able to set the low voltage alarm to 10.6. i would think that setting it to 11.6 would be to high with a diode. 10V might save a fire but i am not sure the battery is going to be very happy.