karolh

I have a G- Force 1800 3s 9.9v Tx Life battery that I plan on using as a replacement in my Futaba 8UAF Tx. but have a couple of questions.

1) What voltage should I consider as the safe cut off point in the Tx.

2) In it's discharge cycle mode my Turnigy Max 8 charger has a fixed discharge voltage of 2.0 v per cell, is this okay.

thepamster

Hi Karolh,
I am not sure of the answer to your first question but would like to know also as I want to put a 3S Life in my Futaba T7C. Perhaps you should reask your question in the Futaba Direct Support Forum.
The answer to your second question I believe is no, that is not ok.
I have two chargers, but essentially the same, a Venom and a Hitech X1, and they also have a fixed discharge cutoff of 2v per cell for Life batteries. I believe the Life manufactures say do not discharge below 2.5v per cell. I have discharged my 2S Lifes and on a couple of occasions I got a "low Cell" warning doing that and 1 cell was down to 1.49v, and thats too low. That could damage a cell.
You need to catch it when it gets down to 2.5v per cell, 5v for a 2S and 7.5v for a 3S, just to be safe.
What you could do is discharge your 3S life until it gets down to the 2.5v per cell and reinstall it on your radio and see what your display voltage says. Maybe that will give you an idea. Obviously you don't want to drain your transmitter battery down that low while flying but you might get some useful info anyways and perhaps a rule of thumb to go by.
I hope that helps.

karolh

I had called Radio South to check with Tony Stillman but he was out of office, however I plan on calling back to hopefully get an answer to my first question, which I will share with you. Your suggestion of discharging the pack down to 2.5 v per cell and seeing what the display voltage in the Tx reads is a good idea, but I am thinking of using 3v per cell instead, as I recently read an article on Life batteries which suggests that at 3.0 v the cells are very close to dead.

thepamster

3v sounds reasonable. But I believe there is still charge remaining at that point, perhaps not much. When cycling them to check capacity I would go all the way to 2.5v per cell.
I would imagine that a fully charged 3S will probably read 10.0v or 10.1v and stay there for awhile, maybe quite awhile. So if you see 9.9v on your display you may ought to land. Lol.
Let me know how it all works for you as I am very interested as well.

karolh

Just off the charger a Life battery should read 3.6v per cell but will quite quickly stabilize to around 3.4v or thereabouts. I just did a search on this forum which turned up some very informative info on these batteries, and is seems that a safe cut off point is anywhere from 9.8 - 9.6v for a 3S.

thepamster

Thanks for the info. I bet, depending on how often you fly, it could take 2 months to get down to 9.6. Thats what I'm talking about. Lol.
Is your battery compartment shape that of a typical 8cell nicad?
I was just wondering if your battery just drops right in there.

karolh

My G- Force 3S 1800 Life battery is pretty much the same size of a std. 8 cell Nicad Tx pack but just a tad shorter so it fits quite nicely in the battery compartment of my Futaba 8UAF.

rt3232

My Feedback: (6)

I have the 8U and the 7C both are 2.4 and both battery compartments are the same size So will the 3c life bat's be good replace ments for the current nimh's ? and i asume you have to take the bats out to charge.

a real newbe to the new battery types

Thanks for your responce

Cheers Bob T

karolh

A 3S LIfe battery is an excellent replacement for NIcad or Nimh Tx batteries and will drop right into your Tx. The only disadvantage is that the Life battery has to be removed from the Tx for charging.

rt3232

My Feedback: (6)

First Thanks for the reply

Ok next Question I have Triton EQ and 2EQ so will I need a different charger ? Like I said I am a newbee to this new stuff. with the minimal voltage drop I am currently getting on my Trx Batteries I am sure they will last this flying season, so planning on changing late in the year,

Again Thanks for your replies

Cheers Bob T

karolh

Those are two excellent chargers both of which are designed to charge / discharge / cycle several different battery types including Life batteries.

rt3232

My Feedback: (6)

Karolh

After I made the post went back to the shop as it dawned on me that I had read in the instructions some thing about the life bat's
So all is well, and I think I now have it stright in this old brain.

Thanks for your quick reply

cheers Bob T

karolh

No prob, glad to be of help

Karol

rt3232

My Feedback: (6)

New question with new lopo's should they be cycled or just charged before using ? Have heard different stories from a a coupla of our club sparkies,

Cheers Bob T

karolh

Unlike Nicads and Nimh batteries new Lipos don't need to be cycled, just balance charge them and use.

rt3232

My Feedback: (6)

Karolh

Thanks again for the quick reply that is kind what I have figured out for my self but just thought I would ask, as you know there seams to be a lot of mis/controversy info about lipo's out there.

Cheers Bob T