http://www.rcgroups.com/forums/attac...5&d=1299261126

Originally Posted by astronaut

Nope, it does not have any display unfortunately. I will get a better charger someday, but not just yet.

Is there any other way I can do this?

Hmmm.

What you can do is charge the pack and then run it static outside your house with the plane for about 50% of the time, that you normally would fly.

Pack is then about half full and if you do not fly for a longer period.
Of course this is not very precise, but if you do not fly for several weeks...wise to do.

My lipos are only charged at the field, or on the way to the field.

Mine stores them around 3.8V per cell so 7.6V for a 2 cell, 11.4V for a 3 cell and so on...

Mo.

Is there an inexpensive discharger to bring the full packs down to 50% and then cut off? Some days you just don't get to fly all the packs you charged.

Brad

Originally Posted by byoung

Is there an inexpensive discharger to bring the full packs down to 50% and then cut off? Some days you just don't get to fly all the packs you charged.

Brad

This one can be used to discharge your pack.
In case of a big pack... it only takes long.

http://www.hobbyking.com/hobbyking/s...dProduct=10328

Cheers,
Rob

Originally Posted by byoung

Is there an inexpensive discharger to bring the full packs down to 50% and then cut off? Some days you just don't get to fly all the packs you charged.

Brad

Inexpensive runs from a couple of 12volt tail light bulbs to a 500 amp (about 50 bucks on sale) carbon pile battery tester from harbor freight or make up a resistor bank. Put on some deans instead of the gator clamps and remove the timer/beeper and it is ready to go. You can pull 10, 20, or 500 amps with it. (I don't recommend 500 amps for long or on a small battery.).

You must monitor the battery and not leave it while discharging. Use a reasonable current like 10C if you are dealing with 25C batteries and keep a small fan on the battery to keep it cool. I don't let mine get above 90 deg F while discharging to about 3.85 V per cell. Use your watts up meter to measure the current watch the voltage and adjust the load during the discharge process.

Never ever go below 3.3 v per cell.

Many recommend 3.85 volts per cell for the storage voltage. This is usually the same level as I receive the batterys from the seller so that is what I use.

Don't ever walk away from it while you have the load connected to the battery.

Originally Posted by jjr2001

Inexpensive runs from a couple of 12volt tail light bulbs to a 500 amp (about 50 bucks on sale) carbon pile battery tester from harbor freight or make up a resistor bank. Put on some deans instead of the gator clamps and remove the timer/beeper and it is ready to go. You can pull 10, 20, or 500 amps with it. (I don't recommend 500 amps for long or on a small battery.).

You must monitor the battery and not leave it while discharging. Use a reasonable current like 10C if you are dealing with 25C batteries and keep a small fan on the battery to keep it cool. I don't let mine get above 90 deg F while discharging to about 3.85 V per cell. Use your watts up meter to measure the current watch the voltage and adjust the load during the discharge process.

Never ever go below 3.3 v per cell.

Many recommend 3.85 volts per cell for the storage voltage. This is usually the same level as I receive the batterys from the seller so that is what I use.

Don't ever walk away from it while you have the load connected to the battery.

I'm wanting one with a 50% level cuttoff that I don't have to sit and watch since most of these take a long time to work.

Brad

Two very inexpensive and effective 'set it and forget it' options that will bring charged packs into storage range and will not destroy your packs if you forget to disconnect them:

http://www.rcgroups.com/forums/showthread.php?t=1131817

http://www.rcgroups.com/forums/showthread.php?t=1255751

Mark

Originally Posted by everydayflyer

The longer a LiPoly is at full charge the faster the IR increases. The higher the IR the lower the true C rate.

If you need highe C rate (lower IRs) and pay more for them then why abuse them? If you get 6 minute flights then that is an avaeage 10C discharge rate which most likely means that 20 or 25C is all you need. Question now becomes do you purchased 20-25C LiPolys and take care of them or replace them often or do you purchase higher C ones such as 40 to 65C and abuse them and hope they still deliver the reall 10C avg. 20 to 25C burst you need.

I have read that some of the 65C ones should be only charged right before use. That would fit my logic if one needs their max. capabilities.

Charles

The 65c XPS batteries are charged Max 2 hours before use.Your absolutely correct Charles. Jim Drew,the owner of XPS strongly recommends charging one hour prior to use.What if you had a 4 hrs drive to the field?? I guess charge at the field!!

I keep my packs in storage charge.......but I dont fret about them being fully charged for a few hours.
The only time I dont storage charge them is if I forget to discharge them.

My ZLIN-XIII I only fly a few times a year.

Keeping the pack at storage, makes that it is still in mind condition:
http://www.hobbyking.com/hobbyking/s...idProduct=9505

Purchased almost 2 years ago.
Yesterday I did messure the IR with my iCharger (at storage level):
2/2/3 (balancer cables)
Main lead has 7mOhm.

Outstanding figures for a 3600mAmh 30C pack of almost 2 years old.
Of course I notice this also during flight. Much punch!

So keeping them at storage... wise!!!

now i feel like an idiot. ive been leaving my packs charged for extended periods of time and i have a few that seem a little squishy. what i mean by that is that the battery is still hard as a rock, yes, but if you squeeze it gently the shrink wrap will collapse like 1mm on each side of the battery. was gonna cut the shrink off one of the worst ones and see if it was the cell casing or the shrink wrap causing it. i run TP 2250 45C packs in my furion 450, and i haven't been flying for months now due to a lack of time. now i'm starting back up again and i hate to see my batteries shot because i was stupid and left them charged. can they still be used if they're a little puffed like i described? i'm cycling them as i write this and they still seem to hold a solid charge and capacity. by the way, i'm using a tp820 charger on a 40 amp 12v power supply. i only charge at 1C.

It's not the shrink wrap.

I think a slight puffiness is getting to be standard with the lower priced lipos after a couple months use. They still work fine at the C-draws I use (5-18C) but definitely a little squishy before and after flying. Some of the older packs would get a little puffy after a flight and then shrink back down but these new/cheapos just stay a little puffed.

I thought I did last time I charged them (err 2005 or 2006) - but it really did not make much difference . New lipos are on order - might cycle the old ones to see what is left of them before I salvage the plugs and submerge them.
--
oh, they were cheep lipos then too.