Discharging?
01-28-2011, 04:28 AM
#3
No discharging Lipos is not needed and they don't like to be over discharged (Below 3.0v Per Cell). They like to be stored at 50% capacity. Really the only reason ever to discharge a Lipo would be to get it to 50% capacity to store it if it has a good charge on it.
01-28-2011, 04:51 AM
#5
What I recommend for the first five charges and discharges would be to only discharge the battery to 50%. When charging the battery I charge the battery at half C for the first 5 charges. Some say this is not needed, but I do it anyways and I have noticed a bit better life time from the batteries.
Just so you know what to charge at 1C means here is a explanation. Basically you divide the Mah rating by 1000.
If you have a 5000mah battery. To charge at 1C would be to hit the battery at 5amps.
If you have a 3300mah battery. To charge at 1C would be 3.3amps.
Some batteries can be hit a more then 1C. But if you can't find any instructions saying you can charge a battery above 1C. To be safe, only charge at 1C or lower.
Just so you know what to charge at 1C means here is a explanation. Basically you divide the Mah rating by 1000.
If you have a 5000mah battery. To charge at 1C would be to hit the battery at 5amps.
If you have a 3300mah battery. To charge at 1C would be 3.3amps.
Some batteries can be hit a more then 1C. But if you can't find any instructions saying you can charge a battery above 1C. To be safe, only charge at 1C or lower.
01-28-2011, 06:11 AM
#7
Many battery companies recommend discharging batteries to 3.6v to 3.8v per cell if not using them for more than 2 days. It extends longevity and performance capabilities of the battery over an extended period of time.
01-28-2011, 10:03 AM
#9
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How you discharge them is up to you. I'm a racer and when my packs come off the track they're normally between 6.8v and 7.4v so I don't need to do anything to them for at least a few weeks. Do NOT store them fully charged this has can increase IR and decrease capacity.
01-28-2011, 10:16 AM
#10
Lipos are not like NiMh, discharging doesn't improve performance. Since lipo cycle life is finite, discharging is somewhat of a waste. I only do it for storage purposes and if a lipo needs a lot of discharging, I just put the lipo in an RC and run it for a while.
01-28-2011, 10:25 AM
#11
How you discharge them is up to you. I'm a racer and when my packs come off the track they're normally between 6.8v and 7.4v so I don't need to do anything to them for at least a few weeks. Do NOT store them fully charged this has can increase IR and decrease capacity.
needless to say i will not buy another SMC.. to the OP..make sure your ESC is in lipo mode first before running it... its also not a good thing to run it to the lipo cut.. once you see the power drop off.. pull the car off.. just make sure you NEVER OVER DISCHARGE A LIPO.. it will be garbage if that happens.. and you risk a major fire if you try and recharge a dead pack
i charge all my packs at 1c .. i was going to about 1.5c but was told this can damage them as well.. even if it says you can..stick with 1c. so it takes an extra 10 mins to charge.. big deal
01-28-2011, 10:33 AM
#12
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X2 i learned this the hard way.. i was new to lipos.. kept my SMC 2s 5200 fully charged for about a month.. after that i noticed it would go flat real quick and take very little to charge.. it balanced fine.. but there was something wrong.. i called SMC.. they pretty much told because of leaving it fully charged i ruined it.. (i didnt know this was a bad thing) and to basically .. well you can imagine where they would like me to stick it needless to say i will not buy another SMC..
to the OP..make sure your ESC is in lipo mode first before running it... its also not a good thing to run it to the lipo cut.. once you see the power drop off.. pull the car off.. just make sure you NEVER OVER DISCHARGE A LIPO.. it will be garbage if that happens.. and you risk a major fire if you try and recharge a dead pack
i charge all my packs at 1c .. i was going to about 1.5c but was told this can damage them as well.. even if it says you can..stick with 1c. so it takes an extra 10 mins to charge.. big deal
needless to say i will not buy another SMC.. to the OP..make sure your ESC is in lipo mode first before running it... its also not a good thing to run it to the lipo cut.. once you see the power drop off.. pull the car off.. just make sure you NEVER OVER DISCHARGE A LIPO.. it will be garbage if that happens.. and you risk a major fire if you try and recharge a dead pack
i charge all my packs at 1c .. i was going to about 1.5c but was told this can damage them as well.. even if it says you can..stick with 1c. so it takes an extra 10 mins to charge.. big deal
01-28-2011, 10:52 AM
#13
How you discharge them is up to you. I'm a racer and when my packs come off the track they're normally between 6.8v and 7.4v so I don't need to do anything to them for at least a few weeks. Do NOT store them fully charged this has can increase IR and decrease capacity.
Not sure if any of you have ever heard of "Ohm's law"
:
I=current
E=voltage
R=Resistance
The formula is I=E/R.
So in this case IxR = E
Because Amps x Resistance = the Voltage rating... and the Voltage rating is at a maximum constant during storage... resistance over time will decrease due to loss as it's pushed to maximum; thus decreasing I (current) as they are relative to one another.
Just some food for thought. The recommendation is 1/2 the maximum allowable charge for storage & I can see that given it will not be pushing current and resistance tolerances for a pro-longed period of time.
And I agree with another post in here... discharge isn't necessary on Lipo's. if you want to discharge it; run your rc.
01-28-2011, 10:55 AM
#14
This makes sense.....
Not sure if any of you have ever heard of "Ohm's law"
:
I=current
E=voltage
R=Resistance
The formula is I=E/R.
So in this case IxR = E
Because Amps x Resistance = the Voltage rating... and the Voltage rating is at a maximum constant during storage... resistance over time will decrease due to loss as it's pushed to maximum; thus decreasing I (current) as they are relative to one another.
Just some food for thought. The recommendation is 1/2 the maximum allowable charge for storage & I can see that given it will not be pushing current and resistance tolerances for a pro-longed period of time.
And I agree with another post in here... discharge isn't necessary on Lipo's. if you want to discharge it; run your rc.
Not sure if any of you have ever heard of "Ohm's law"
:
I=current
E=voltage
R=Resistance
The formula is I=E/R.
So in this case IxR = E
Because Amps x Resistance = the Voltage rating... and the Voltage rating is at a maximum constant during storage... resistance over time will decrease due to loss as it's pushed to maximum; thus decreasing I (current) as they are relative to one another.
Just some food for thought. The recommendation is 1/2 the maximum allowable charge for storage & I can see that given it will not be pushing current and resistance tolerances for a pro-longed period of time.
And I agree with another post in here... discharge isn't necessary on Lipo's. if you want to discharge it; run your rc.
Bah, Racer is right. It's not "decrease" resistence & current, it's "increase". And no, you won't get more push out of the battery, you will get less...
Sorry for the confusion.
01-28-2011, 11:13 AM
#15
Lipos are not like NiMh, discharging doesn't improve performance. Since lipo cycle life is finite, discharging is somewhat of a waste. I only do it for storage purposes and if a lipo needs a lot of discharging, I just put the lipo in an RC and run it for a while.