Team Associated RC8Be Thread
03-22-2011 | 10:58 AM
#4696
03-22-2011 | 11:12 AM
#4697
I balance charged my Zippy when I first got it, and after the first cycle (which I short cycle my batteries quite a bit when I first get them), the cells were imbalanced by almost 1V. I don't recall exactly, but it was something like 2.97V, 3.9V, 3.9V, etc. So I had one cell that was way out of whack, and below 3V. They should discharge at roughly the same rate, so not sure why that happens, but it does. Anyway, after cycling it a few times (and balance charging it each time) it does not do that anymore.
Thus, my issue with the 3V per cell cutoff on the Tekin RX8. If you let the battery run down to the 4S cutoff (12V), and your pack is not balanced, you're likely going to have a cell below 3V. Let's say you have three cells at 3.2V, then at 12V, the fourth cell is at 2.4V, which will likely ruin the battery... This is why I set my Tekin to 12.8V for 4S packs.
Congrats on becoming a dad, but you know we have an OT thread just for things like that.
Too many people complaining about OT posts in this thread... 
03-22-2011 | 11:27 AM
#4698
Suspended
Joined: Feb 2011
Posts: 197
A fully charged LiPo should be right at 4.20V per cell. Fully discharged, it should be no less than 3V per cell.
I balance charged my Zippy when I first got it, and after the first cycle (which I short cycle my batteries quite a bit when I first get them), the cells were imbalanced by almost 1V. I don't recall exactly, but it was something like 2.97V, 3.9V, 3.9V, etc. So I had one cell that was way out of whack, and below 3V. They should discharge at roughly the same rate, so not sure why that happens, but it does. Anyway, after cycling it a few times (and balance charging it each time) it does not do that anymore.
Thus, my issue with the 3V per cell cutoff on the Tekin RX8. If you let the battery run down to the 4S cutoff (12V), and your pack is not balanced, you're likely going to have a cell below 3V. Let's say you have three cells at 3.2V, then at 12V, the fourth cell is at 2.4V, which will likely ruin the battery... This is why I set my Tekin to 12.8V for 4S packs.
Congrats on becoming a dad, but you know we have an OT thread just for things like that. Too many people complaining about OT posts in this thread...
I balance charged my Zippy when I first got it, and after the first cycle (which I short cycle my batteries quite a bit when I first get them), the cells were imbalanced by almost 1V. I don't recall exactly, but it was something like 2.97V, 3.9V, 3.9V, etc. So I had one cell that was way out of whack, and below 3V. They should discharge at roughly the same rate, so not sure why that happens, but it does. Anyway, after cycling it a few times (and balance charging it each time) it does not do that anymore.
Thus, my issue with the 3V per cell cutoff on the Tekin RX8. If you let the battery run down to the 4S cutoff (12V), and your pack is not balanced, you're likely going to have a cell below 3V. Let's say you have three cells at 3.2V, then at 12V, the fourth cell is at 2.4V, which will likely ruin the battery... This is why I set my Tekin to 12.8V for 4S packs.
Congrats on becoming a dad, but you know we have an OT thread just for things like that.
Too many people complaining about OT posts in this thread... i WILL KEEP AN EYE ON MY BATTERY, WHEN YOU SAY CHARGE AND DISCHARGE, ARE YOU USING THE DISCHARGE ON THE CHARGER OR JUST RUN THE PACK? i HAVE MY CUT OFF TO 13V ON MY (oops caps) Rx8.
Yes I know there is a OT threat but I was super excited!! We have been trying for a little over 5 years now and it finally happened!
03-22-2011 | 12:20 PM
#4699
Good move.
Congrats. I couldn't imagine my life without my son!!!
Now, back on topic.
For the cycling, you can either discharge using the discharger in your LiPo charger, or go run the car for a few minutes. Since my discharger is slow (only 20W), I go run the car out in the street for 5 to 10 minutes or so (not continuous speed runs, if you do that, shorten the time). I usually run it down to 3.7V or so per cell. I then put it on the charger and check balance, then balance charge. I think you might find that the pack gets out of balance quite a bit during the first few cycles (first cycle being the worst). Balance charge to 4.2V per cell and repeat a few times.
Now, back on topic.
For the cycling, you can either discharge using the discharger in your LiPo charger, or go run the car for a few minutes. Since my discharger is slow (only 20W), I go run the car out in the street for 5 to 10 minutes or so (not continuous speed runs, if you do that, shorten the time). I usually run it down to 3.7V or so per cell. I then put it on the charger and check balance, then balance charge. I think you might find that the pack gets out of balance quite a bit during the first few cycles (first cycle being the worst). Balance charge to 4.2V per cell and repeat a few times.
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03-22-2011 | 06:21 PM
#4709
