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Two 2400 mAh Trustfire Lithium Ion batteries for as little as $8 postage paid from Deal Extreme. The rationale behind the selection together with the links is at R/C Model Reviews here:

http://www.rcmodelreviews.com/tendollarbattery.shtml

Using the Er9x firmware one does not have to do the fiddly modification to get the battery voltage to read correctly and the Battery Warning to work at the correct voltage. Just go into the calibration screen (left button hold: screen 1/6) and set the warning voltage to whatever you are happy with - I use 7 Volts. I have fitted these batteries to my Er9x Eurgle Tx and can report excellent service over about one year. I fitted two plugs to the pair - one jxt for my field charger and the output plug from the originally supplied dry cell carrier for the Tx supply. There is plenty of space to hide your fly lead from the smartieparts board or in my case from the main board (I use the smartieparts board externally with soldered connections instead of relying on the pogo pins)

Mutchy

Thanks, I found that mod and wondered what this group thought of it. I'll order some today.

Or you can go my route.

viewtopic.php?f=26&t=59

Br , Hasse.

Hello!

I wanna reanimate this thread because I have a question:

When charging this Trustfire cells, do you pull the output plug or does it stay connected?
Do you use a fieldcharger? In case one has the cells with this overcharge protection, which program of the field charger should be used?

Thanks

You need to charge them just like any other lipo. The protection is just that, a "last resort" safety net, you shouldn't rely on that to end charge.

Thanks Kilrah. Do they need to be balanced?
What about the output plug? Does it stay connected while charging via the second charging plug?

I bought a couple trustfires for one of my transmitters. The first thing I did was removing the protection. I have read that sometimes they go bad and I don't want my TX to power off in mid flight.
I balance charge the pack outside the radio and inside the lipo bag, just like any other lipo.

Koarl wrote:Thanks Kilrah. Do they need to be balanced?
What about the output plug? Does it stay connected while charging via the second charging plug?

Yes of course, again they work just like any lithium battery.

Regarding the output plug it all depends what charger and charging cable you use. You can leave the output cable connected, but then your charger might need the main cable to be connected to the battery in addition to the balance cable, in which case you either need to disconnect the output cable to connect it to the charger, or you can make yourself a charge cable that connects both of the charger's ports through the battery's balance plug. Again 100% lipo standard stuff.

Thanks guys!
I abuse this thread for one last question so I don't have to open a new one:
Since I ordered the 2000mah battery for my Taranis I have the supplied 600mah battery in spare. Since I have a gruvin board installed this one should work fine too. Can I charge this one through the transmitters charging plug? Or isn't that possible with the gruvin board? Is a field charger used for this purpose or is any wallcharger similar to the one supplied with Taranis better? Do you think it's a goog idea to use a nimh battery for the 9x which is my spare transmitter regarding the higher self discharge?

Thanks

ATTENTION: The taranis doesn't come with a wallcharger. That is a power supply. The charger is inside the Taranis.
You can use the 600mA NiMh pack for the 9x radio, no problem, if the Gruvin board can work with a 6 cell NiMh pack. I don't know that board. You can also charge NiMhs inside the radio as they are much safer than Lithium batteries. Please make sure the polarity is correct.
I'm not sure if the original Taranis battery is low drop.

João

Thanks for the advice! And sorry for the wrong terminolgy!

As far as I know the gruvin board can deal with 6 Volts. At least this is what I understood from this discussion:
https://groups.google.com/forum/m/#!top ... O8ft-6cWkI

Is positive on the center pin or on the outer shell of the plug?

Thanks for your help

The 9X has center positive.
Note that as unlike the Taranis the 9x does not have any charging circuitry, a "real" charger has to be used.

The Taranis needs a power supply, NOT a charger.
The 9X needs a charger, NOT a power supply.

The original Taranis battery is low self discharge.

Mike.

Thanks Mike. So, no worries then, perfect for your other radio Just watch the polarity..

João

Ok, thanks! So I just use my normal charger in Nimh mode. But I would feel a bit safer If someone more experienced like me would confirm that the Taranis battery is fine for the g9x board.

I just looked up the 5 volt regulator on the Gruvin board. It is specified to have a dropout voltage of 0.67 volts at 100mA, so should work fine with an input voltage down to 5.7 volts.

Mike.

A NiMh cell is considered discharged at 1.1V per cell. That makes 6.6V for a 6 cell pack. Well above the minimum for the regulator..

João

Thanks! I'm gonna use this battery!

MikeB wrote:The original Taranis battery is low self discharge.

Are you sure? The new 2000mAh one is, but I don't believe it's the case for the old 800mAh one he has.

I understood it was, and mine seems to hold its charge fine.

Mike.

I've fitted the battery and made a charging cable and it works great! Thanks again!


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