[Dig it]

I bought a 2200mah Li-Po battery for my new Extra 300 and charged it up about 2 weeks ago. Since then I have used it for setting up the servo's and etc and the volt watch still shows 100% capacity. Is that normal? Do they keep there charge that well over time?

[Noin]

Lipos will hold a charge for a surprisingly long time. They do self discharge but at almost an unnoticeable rate. Thats the beauty of them charge them up now, if the weather sucks they will be ready when the weather is better. No time wasted waiting for a battery to top-off. Just grab it and go fly. Sweet isn't it? Welcome to the world of convenience.

[Youngguy]

Absolutely. I have charged my Li Polys, also 2,200 Mah, gone flying and doing 6 flights, flew again two weeks later again 5-6 flights, without charging in between. Discharged the batteries on my Triton after and got 800 Mah out of the battery. The airplane is a DP Extra 330 with a full load of digital servos and the flights were all 10 minutes in duration.
These batteries are great for holding a charge over a period of time as well as being lighter than nicads or nimhs, the disadvantage is that you should remove them from your airplane when charging and they are senitive to changes in ambient temperatures. I have had them gain 1/2 volt removing them from a cool garage and driving to the field in the back of a warm van.
Also, I have not been able to get a good indication as to the number of cycles they will do and what the signs of failure are. So I watch them very carefully.

[Dig it]

Well, alright then. Gotta love technology.

So, if they change that much with outside temp are they any good for winter flying. Say -10 and up?

[reo]

I agree with the rest in this thread.....the lipos are great. I use a 4400 mah on my TCU/pump for the turbine and two - 2100's for the receiver (with adjustable regulators) and I have flown up to 11 flights in one day without charging.

but....and there is always a but, isn't there?....it is recommended (and rightly so) not to charge these things unattended and to treat them with the respect they deserve.

Ron Oscar

[reo]

Also, I have not been able to get a good indication as to the number of cycles they will do and what the signs of failure are. So I watch them very carefully.

Bruce, I have heard the number of cycles with the lipos tossed around the 100 mark. I don't know how true that is but we know for sure that they will not last like the nicads do.

My personal experience has been that as they get 'tired' they will show lower voltage under a one amp load than they do when brand new. Not sure if this makes sense or not, just my experience.

Maybe someone wiser than us will fill us in on what to look for.

Ron

[Guest]

Originally Posted by reo

Also, I have not been able to get a good indication as to the number of cycles they will do and what the signs of failure are. So I watch them very carefully.

Bruce, I have heard the number of cycles with the lipos tossed around the 100 mark. I don't know how true that is but we know for sure that they will not last like the nicads do.

My personal experience has been that as they get 'tired' they will show lower voltage under a one amp load than they do when brand new. Not sure if this makes sense or not, just my experience.

Maybe someone wiser than us will fill us in on what to look for.

Ron

Cycle life is dependant mostly on a couple of things...

overheating during discharge, allow pack to get no more than 50-55C during discharge
depth of discharge (80% discharge being the maximum recommended for long life)
discharge current, obviously the lower the better and certainly not over the rating of the pack.

100 cylces is yesteryear's stuff, the current 15C-20C generation packs (TP Prolites and such) are capable of 200-300 cycles if used properly, even in the huge stuff (10s packs) that we are doing (2500W, 65-70A draw) cycles are getting into the low 100's without problem. More or less double over last year.

RX's packs, should last for 200+ easily with proper care. So with 10 flights a charge thats 2000 flights.

As packs age capacity loss is what goes, voltage drop for similar load may or may not occur depending on the pack. Voltage testing (especially at 1A) is not the correct method to determine a dead pack, you really need to check the capacity and when you have lost 20% the pack is gone.

[Dig it]

What do you fellas recommend for a charger/cycler. I'm looking for brand name and item number if ya have it?

Thanks

[Canhos]

Here's some good info submitted by others here.
https://www.rccanada.ca/bb/viewtopic.php?t=18562

Here's a link to the 2 most common ones I've seen at the electric fields I frequent

http://www.electrifly.com/chargers/gpmm3150.html

http://www.hobbico.com/cyclers/hcap0280.html

I use the Hobbico one, as it was in stock locally and I had heard of it previously (I just returned to the hobby, and this was the first thing I bought). I've used it for my normal NiCad tx and rx batteries, and I'm also using it for Lipo's now. It can only charge at 2Amps max, so with your 2200 mAh battery, it's at less than max charge (most likely) and it can be used to cycle as well. I'm happy with it, but I know of others that swear by the Tritons. There are a host of dedicated Lipo chargers out there as well. I'm not 100% electric though, so dual function is the key.

A question regarding Lipos. Are they only at risk of causing a fire when charging/discharging. Are the packs considered "safe" or "stable" when they are just sitting there? I want to store them with my transmitter and stuff for when I'm on the road. Is this acceptable, or should they always be stored in a fireproof container?

Is a balancer worth getting for use with these batteries, will that increase the lifespan substantially?

Thanks for any input on this
Mike

[Dig it]

Is this the Triton one people are using?

http://www.towerhobbies.com/products.../gpmm3150.html