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Old Apr 02, 2015, 06:49 AM
Ohmic is offline
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Quote:
Originally Posted by helicopteer View Post
hi,
i was wondering what is the condition necessary for pl8 to stop a charge on preset #3.
is it the voltage difference among cells or the end current?
what would be the values in each case, please?
thanks a lot.
If you haven't done so already, you can also download and install the Charge Control Software (CCS) which will allow you view all the configuration parameters associated with every preset. If you mouse over the field label a popup will display additional information about the field.

You can take the CCS for a test drive even if you don't have a PowerLab charger.

http://www.revolectrix.com/downloads.htm
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Old Apr 02, 2015, 07:20 AM
ggcrandall1 is online now
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Quote:
Originally Posted by bryon01 View Post
Agree, I only ended there because I wanted to verify functionality since I just bought a PL8 and an old pack was way out of balance when brought down to 3.3V with no balancing.

Because everyone seems very concerned about my cutoff voltage choice I will tell you why I was there.

When I run this in my quad, I have to set the cutoff artificially high to not pull the crappy cell way out of range. I wanted to measure how much capacity I was losing by having a dud cell and if I should go through the work of opening several packs and matching the cells, so I set to a slightly lower voltage than the worst cell and discharged the others to it. I choose 3.2V since as soon as you pull current the offending cell was near 3.2V. Turns out, I am loosing about 65mAh of capacity due to this, which btw was not enough for me to cut shrinkwrap and start soldering.

I was surprised when it did not stop even after pulling all cells to the same voltage. Biggest issue is that the logic clearly should not allow violation of cutoff voltage since this is a fire hazard and I don't know if this logic bug exists in any other modes or functionality.

Regarding the wiring:
I used the adapter board that comes with the combo to go from the FMA wiring mode to my zippy 4s pack. I had the mains connected as well. I was only discharging a single pack.
I believe the highlighted passage is incorrect. Discharging below 3.3v/cell is not a fire hazard. In fact discharging cells to 0V is used to make the cells inert. However discharging below 3.2V/cell is detrimental to the life of the cell. Cells should not be discharged below 80% of their capacity, which is about 3.3V under load (3.7V resting).

Glen
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Old Apr 02, 2015, 08:07 AM
bryon01 is offline
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Yes that is more accurate as even though the internal resistance is going up it is unlikely the discharge current is high enough go generate a fire. I agree to replace fire with cost me money.
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Old Apr 03, 2015, 12:25 AM
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I just got a powerlab 8 and I cant get it to go past 10 amps on the menus on the ccs they only go to 10A
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Old Apr 03, 2015, 01:37 AM
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I got it only one preset goes to 40A ? I charge 6s 5300s and 6s 5500 HV lipos 4.27v per cell I would like to have two Hi power pre sets one for 5300 4.20v per cell and one for 5500 4.27v per cell is there any way to do this want to charge 4 - 6 packs in parallel of each size
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Old Apr 03, 2015, 08:04 AM
Ohmic is offline
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Quote:
Originally Posted by rcpilot_971 View Post
I got it only one preset goes to 40A ? I charge 6s 5300s and 6s 5500 HV lipos 4.27v per cell I would like to have two Hi power pre sets one for 5300 4.20v per cell and one for 5500 4.27v per cell is there any way to do this want to charge 4 - 6 packs in parallel of each size
Yes, using the Charge Control Software (CCS) you can make a copy of any preset and modify it giving you the two presets you're looking for. You do this using the CCS and the FUIM3 USB interface.
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Old Apr 03, 2015, 11:45 AM
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Quote:
Originally Posted by rcpilot_971 View Post
I got it only one preset goes to 40A ?
FAQ - Powerlab Quick Start Guide - Wiring modes, Supply Limits and 1s charging

The latest firmware includes the HV Blend presets. But they must be loaded using the CCS.
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