Lithium packs for TX

[Bunky F. Knuckle]

	Quote: Originally Posted by pllove
	I have revieded this thread and the diy thread by Bunky. As I understand it the major concerns on using Lithium pack in the tx's are: 1.) Accidently leaving the tx on and destroying the lithium pack due to under voltage and possibly a safety issue. 2.) The low voltage alarm on the tx not sounding in time depending on radio used. I have the Futaba 9CAP (not super series) 3.)The possiblity of the built in charge port being used with the wrong type charger. Again saftey concern. After reviewing all this and trying to come up with a way to elimate all possible concerns I found these batteries from all-battery.com. They are a cylindrical cell with a built in pcm circuit for each cell. I believe this would elimnate the undervoltage discharge concern with accidently leaving the tx on. http://www.all-battery.com/index.asp...ROD&ProdID=461 As far as the the low voltage alarm I believe I could use 1 or 2 diodes to drop the voltage enough so the low volage alarm in the radio will go off before I reach the recomended 9.0 volts. To remedy the possibility of the external charge port being used with the wrong type charger could easily be fixed by plugging the charge port wth a non conductive sealant, thereby forcing the battery to be removed from the tx to charge it. Could also just tape over it and make sure you are the only one that attempts to charge your radio. Maybe even use a lablel with a warning on it about this radio uses Lithium batteries - Do not charge! just to be cautious. Does this sound correct? Thanks

1.) Leaving the Tx on, potentially a problem. Not only having a undervoltage, but you may end up loosing the pack due to that. I had a brainfart the other day, and left a 2 cell Lithium on in a plane. Completely DEAD!!! Long story short, I slow charged the pack, and it is up to snuff!!!

2.) Low voltage alarm. Usually in the Futaba's, the LV alarm comes on at 8.5V. Yes, too low for any 3S Li pack. What if you labeled the Tx for a 10.5V LV no fly...............

3.) Theoritically yes, potentially no. If you plug a standard wall charger into the Tx charge socket, and start charging and remember that you goofed 2 hours later, then there isn't no harm in that. Check your wall charger output, as this could be a false statement. I know my (JR) wall chargers charge at 11.6V +/- .2 VDC at 80mAh. The Tx charger has such a low charge current that I think that there would be no fear in using one of those. Any output over 12.6V is no good for charging Lithium packs. But always PRACTICE safe chargings, with the approperiate equipment. Noone can stress that enough!!!! I use the Orbit line of chargers, and with the Lipo in the Tx, I charge on the ION mode.

The 18650 cell is the absolute best LiOn cell out there!!! Try them!!! Not sure about the PCM attachment on the cells, but could be a good thing......

Only way to make things idiot proof is to be sure that you do things yourself.

[pllove]

Do you see any problems with charging a 3 cell pack using these batteries with the protection circuit with a triton or the Fromeco Ion Cube chargers. Will the protection circuit cause any issues or just charge as normal? If I decide to put a diode in the circuit will this cause any charging issues?

It looks like the JR battery module has a pcm circuit in the module/tray.


Thanks

[pllove]

Looks like I could build 2 packs myself for the cost of a premade pack without any protection circuit. I will be ordering these cells and switch my tx over to lithiuim.

Also working on switching my planes over to litium as well.

Patrick

[Bobbydog]

Heres a good idea... Just buy a 2500mah NiCd and be done with it! Solves all of these potential problems you guys are having. There is no benefiet to a Lipo in a Tx other than it being a tad lighter! A 2500mah Lipo stores the same amount of energy that a 2500mah NiCd does! If its so you can tell people that you have a Lipo in your Tx, then just put a NiCd in it and then LIE...

Bob

[pllove]

Sorry but there are other advantages to using lipo or lithium ion in the tx.

No more cycling. (pain in the butt)
No memory effect at all.
Self Discharge rate is much much lower.

Lithium Ion and LiPo can safetly be used in the tx. All you have to do is get a protection circuit module. The same type used in cell phones and laptop batteries. If you want to still use your low battery alarm in your tx then you just add 1 or 2 diodes in series.

No big deal and a lot less hassle then nicad or nimh.

[Azhar]

Bobbydog,

With a 2500mah Lithium pack, I can fly all week without recharging. You can't do that with a NiCD or a NiMH. Especially on a 9Z.

[XJet]

	Quote: Originally Posted by Azhar
	Bobbydog, With a 2500mah Lithium pack, I can fly all week without recharging. You can't do that with a NiCD or a NiMH. Especially on a 9Z.

Hey, you can now get 2700mAH NiMH packs and that's 200mAH *more* than your lithium pack.

A mAH is a mAH, regardless of the technology from which it's derived.

I use 1600mAH NiMH Sanyo packs in my transmitters and they give me an easy 4-hours of continuous use -- after which I can recharge them in under an hour for another 4-hours flying. Or, more often, I just throw them on the charger when I'm having a break after a half-dozen flights or so -- that way, a 15-20 mnute charge every now and then means I can fly for as long as my flight batteries and field-box battery last.

No fire risk, no undervoltage risk, transmitter balance unchanged.

And, on the rare occasion where I've had to go a month or so without flying, they're still amost fully charged -- to the point I can still get well over 3- hours flying out of them before they even start getting low.

I think that transmitter lithiums are a solution in need of a problem.

[Spaz]

problem with the 2500-2700 nimh is you have to slow charge them (50mA is recommended for the 2700) making field charges not practical, if i forget to charge my li-poly i can have it full in an hour or less..
looks like the future is li-ion, just taking manufacuters a bit to catch up.

[Azhar]

xjet,

my 2700nimh pack would barely last 5-6 flights before requiring a recharge. For some reason they discharge a lot faster. I will let the batt experts explain that one. And I have tried two different ones over the years.

[plaster93]

For $38. you can not go wrong. No charging for few weeks, sweet. I got mine for the 9303 works great!
http://www.graysonhobby.com/catalog/...php?cPath=8_47

2 dogrc.com has em also.

[vernonf]

I had packs made up of NiMH 3200 mah at a local Batteries plus store. They fit perfectly in the 9Z plastic battery case. They were about $20.00 a pack. I get about 4 1/2 till the warning light comes on. They work great. I charge them a 3.2 amps.

Forrest

[chitty3d]

Use the flight power 1500 3 cell I have been using it for several months!! it is awesome Flight power is awesome!!