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Electric Stunt => Gettin all AMP'ed up! => Topic started by: John Hammonds on September 14, 2012, 08:20:59 AM
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Hi All,
I use a "Hyperion EOS 1210i" and "LBA10 net" balancer for most of my charging needs and despite being a bit long on the tooth by today's standards they have served me well.
One thing which disappoints me though it the discharge option. You can discharge packs down to between 2.7 & 3.6 volt per cell. I usually store my packs at around 3.8v per cell and as I am still using packs 3 years old I guess this is not doing them any harm.
Currently I discharge them down to the 3.6v then recharge them back up to my preferred storage voltage before final balancing.
Is there an "off the shelf" item I could buy with an adjustable voltage cut off I could set to 3.8v per cell? I'm not expecting to find something which works at cell level, just something I can connect in series with the pack which I can then set to the appropriate overall pack voltage (So 11.4 for a 3 cell pack, 15.2 for a 4 cell pack etc). I know the charger will detect a pack voltage error and sound the alarm when the battery connection goes open circuit but I don't mind that. All I want is something which I can use and then afterwards plug the pack into the balancer for final preparation for storage.
Thanks in advance
TTFN
John.
Ps I'm off on holiday for 2 weeks tomorrow so if I don't reply it's not because I'm ignoring you. :)
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I do not know, but in any case you can use chargers like Cellpro which will CHARGE discharged battery (after flight) back to 50% (3.8V)
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Hi Igor,
Thanks for the reply.
My EOS1210i will also do that and I use the facility after every flying session. The situation which bought about this post though was because I had around 6 fully charged packs I wanted to return to storage. (I hoped to get a cheeky session in before going on holiday so charged some packs in anticipation but the wind over here had other ideas). So I found myself with 6 fully charged packs and no likelihood of flying for at least 3 weeks. I don't like leaving packs fully charged for that length of time so I have been returning them to storage voltage and was finding it a laborious process.
TTFN
John.
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Hi John
My GT-A6 chargers discharge to storage at a max of 1A - takes FOREVER.
I recently discharged using a flight set-up with a small prop at lower than normal RPM. Using the programming card I can set an Arrowind ESC to shut-off at a selectable voltage. I set for 11.1V, then proceeded to discharge several 3S packs using an airplane. NOTE since the max time I could set was 6 minutes, a couple of the packs went through a second session until they hit the ESC's cut-off voltage.
Looking ahead, I think I will build a couple bench rigs with ESC's & motors, probably some old IC wood props. One rig for 4S, one for 3S, one for 6S, then use them at the end of the flying day. With dedicated rigs I will set the RPM so I achieve a fairly soft discharge - say 5A - then just line up the packs and start discharging.
I wish I could plug the packs into my Laptop and drain them down that way to a safe cut-off voltage... HEY ELECTRONICS GRUNTS, YA LISTENING???
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Hi Dennis,
Now that is a brilliant idea. #^ So obvious when you think about it, I racked my brains for ages trying to think of a workable solution and you have already done it. I have enough CC Phoenix esc's spare at any one time to set up a rig just like you suggest. OK, that's my 1st job when I get back from my hols. y1
Thanks again.
TTFN
John.
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I am totally ignorant about discharging packs before storage. Right now, I only have three batteries, One has been used for testing the system, the other two have not been out of their boxes yet.
What do I need to know? About all I have done is put them in LiPo "bags". ???
Thanks!
Bill
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Bill, As Igor said storage mode for Li-Poly batteries is at about 50% of capacity which translates to 3.8 volts per cell. Some chargers will have a "storage" mode that will drain the battery down to 50% and stop others do not. Some have a "storage" mode that will charge a battery up to 50% and stop but will not drain a charged battery down to 50% (at least some CellPro chargers for instance).
For long term storage you need to get your batteries into the 50% range or the battery life will suffer. Some folks will leave their batteries charged for several weeks (or longer) but I do not like to have mine out of storage mode for more than a few days (I have already spent too much on batteries ;D).