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Visual Perfection
06-21-2010, 12:17 PM
I just bought some used 2s 4900mah 20c Lipos and the previous owner shipped them to me charged and balanced.

I REALLY want to test them out in my Shockwave 26 brushless however I do not have my charger/balancer yet.

Will it be okay to use them for like 5 minutes each or less (stop use well before LVC kicks in) and then store them without charging for a couple weeks while I wait for my charger? What if I run them down to the LVC?

Just dont want to do something wrong since I am completely new to Lipos and would hate to ruin them before I can fully enjoy them so trying to find out how they can be stored for a few weeks at a time.

Thanks!

RaceMechaniX
06-21-2010, 12:26 PM
NOOOOOOOOOOOOOO Hold off and wait till you have a charger and balancer.

Lipo's need to be stored around 50~60% SOC to keep them healthy. Leaving them near their lower limit will detiorate them bad especially if left alone for weeks.

Tyler

Visual Perfection
06-21-2010, 01:03 PM
well crap...that means I cant even see if they work for a few weeks. 20 days to be more exact..

However, after reading what you just said...If they give 10 minutes of run time, and they are now fully charged...why is 2-3 minutes going to hurt..that would bring it down to 70-80% so they would be stored just fine wouldn't they?

RaceMechaniX
06-21-2010, 01:14 PM
Do so at your own risk. Are you certain the batteries were fully charged and not just "50% store charged"? You can use a multimeter to check the pack voltage, but still I would hold off on running the boat till you have a charger and balancer. For a 2S pack you can pick up a cheap balancing charger under $50.

Visual Perfection
06-21-2010, 01:19 PM
Yup I have a charger already picked out..a Thunder AC6...I asked for it as a b-day gift though thats why I have to wait 20 days lol

I just tested them and am getting 8.30 on one and 8.28 on the other... what should it read if fully charged?

RaceMechaniX
06-21-2010, 01:27 PM
Early B-day present then! Fully Charged should be around 4.2V/cell, so they are reasonably full.

Visual Perfection
06-21-2010, 01:47 PM
and I dont want to run them below 3.3 volts ever right? so 6.6volts for a 2s pack..I will have to see what the LVC is set for in my shockwave

RaceMechaniX
06-21-2010, 01:53 PM
Correct. You can go to 3V/cell when you get familar with charging and running, but 3.3V/cell is safe. Still I don't recommend running till you have a charger.

Visual Perfection
06-21-2010, 02:05 PM
Thanks for your help!

785boats
06-21-2010, 02:36 PM
With all due respect, I'm afraid I'm going to have to disagree with you slightly RaceMechaniX.
Storage voltage is best at around 3.8 V/cell. And leaving them lying around for a few weeks fully charged does more damage to them than being under charged. So I would run them for a couple of minutes & check the resting voltage. If it is still above 3.8v/cell run them a bit more & check the resting voltage again.
Don't get carried away & over do it though.
The batteries can be stored for a long time at 3.8V/cell
All the best.
Paul.

Visual Perfection
06-21-2010, 02:55 PM
Thanks for your response!

RaceMechaniX
06-21-2010, 03:06 PM
I agree its bad leaving them fully charged and ideally he would run them down to a safe level.

Instead of running them in a boat though I would do it with a discharge bulb or similar. Too easy to go overboard when running a boat.