Hi,

I desire to change my Tx Bat which is NiCd to ACE RC 11.1V 2200mAh 3S1P Li-Po Battery.
So how to convert , what are the consideration?

sid

Simple question Why you want to do that ? NiCd are much better than LiPos and Tx don’t need much of the battery instead using a Lipo for Rx still make sense. 
This require replacing the battery connectors that it.  .

Lipo is the best choice for Tx. U wont need to charge it for a month or two and it holds the charge for a long time. If u specify ur Tx model then I can give u better options so u wont have to change the connector etc. It will fit directly to ur current Tx.

What is overlooked is that you will not be able to charge the battery with the existing charger. Do factor the additional cost of a suitable LiPo charger, unless, of course, you have one already. But you will still have to disconnect the battery every time you need to do so.

Dear,
Tx is Futaba 7c

Thanks sushil, i have BC6+ Bat charger/ balencer

sid

For me going Lipo was an advantage (on RDS8000).

Considerations:
1)Am not sure if 7c supports 12.6 V (voltage when lipo is fully charged)
2)Your TX will not auto cut off/alarm when lipo is weak. U need to have a constant eye on the TX voltage and charge the lipo when it approches 11.3 V to be safe(u may forget).
3)U need to remove the lipo out of the TX to charge.

Advantages:

low self discharge
less frequent charging.
Its Cool! 

1)Am not sure if 7c supports 12.6 V (voltage when lipo is fully charged)
do i need to fix any kind of V regulator in between Lipo bat & Tx?

2)Your TX will not auto cut off/alarm when lipo is weak. U need to have a constant eye on the TX voltage and charge the lipo when it approches 11.3 V to be safe(u may forget).Advantages:

Right now I use NiCd so my Tx alarms when it undergoes 9v or around, but sure, that, it alarms a lot   

All the advantages are available with LSD NiMh packs. 

True. At the time I got, I was not able to find those LSD NiMH soldered packs. Ujjwal uses them and was happy. Anyways, I still love the Rhino 2650 3s.

How much running time do you get on a fresh charge? Maybe your pack is ageing.

150 min after total charge

my bat is 600mAh

Are you uncomfortable with that? What kind of times are you expecting? What about your Rx pack?

with Rx i use 1 bat 4000 NiMh and if i get time left & bat goes out, then i install 1600 Nimh other bat,
But my Tx bat goes out after 7 so... , it start's to alarm

I have seen multiple people claim that for the same mAH rating, a lipo lasts longer than NiMH.  My own personal experience also suggests the same.  Why would this be ?

While on this subject, would any one be kind enough to let me have a battery pack for my Optic 6 Sport Tx? The pack that came with it turned out to be a dud and doesn't hold charge beyond an hour. Attaching a picture of what I need. 7.2V 1200maH. The triangular shape is important for it to fit into the battery compartment.

Willing to pay for materials and labour if someone can make this pack for me out of 6 NiCd cells.

Or does someone else have any other alternatives to offer?

Thanks.

I use the below battery in my 7C and it works perfectly. never had a problem. I have used it on full charge also 12.6v. U can go upto 10v discharge safely. but why wait for it drop so low when u can charge once a month. it only takes 15 min.

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=6955

I think that somewhere the point I am making has got lost. And that is : why would one, practically, want/need to have a flying time of over 2 hours in one session? And if it was needed - I would still like confirmation on this - a 2500 mAH would guarantee virtual dawn to dusk activity!

And Anwar, it is not only possible, but even likely, (am aware of NiMh limitations - wish the "green" lobby had not condemned NiCd technology) that a similar capacity LipO would "last longer".  But again , in practical usage, does it really make a difference? Is it not adequate that ANY pack lasts more than what you NEED?

I am not "pro NiMh" but an - intensely - practical person, who does not carried away by theoretical or "flavour of the month" considerations.

Phew! This is certainly my longest post and I would really welcome further debate on this.

Well, the charging times are much lower than NiMH, so that would give lipos an edge.  Yes, one may be charging once a month, even then being done with it faster certainly has some charm

Exactly my point of view, i don't really need any thing which would last me more than one flying session or may be one weekend, but like Anwar said charging time is a big turn off.