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Old May 09, 2012, 10:20 PM
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Quote:
Originally Posted by mrforsyth View Post
Agreed that the PL6 will have lower total charge times, but not by ~33% when charging 6S lipoly from a 24 volt source.
As discussed in more detail in the test, this was done to show the maximum power output of Powerlab6 on a 24v vs other chargers such as the 306b which have a 30 amp limit. This chart was intended to compare the wattage and charge times for the bulk charging phase, where maximum power is important.

I deliberately left off the balancing and constant voltage stage. This was done because every charger has slightly different balancing current as well as balancing behavior. Also different chargers have different current cutoffs for the CV stages as well as tolerances for current values. As the test was only intended to show the maximum wattage, including the balancing and CV stage would include unnecessary and misleading data.

Quote:
A ~15-20% increase in charge power does not equate to a ~33% reduction in charge time.
The chart is using real data recorded from actual charges. Both tests were done with the same pack, from the same state of charge using the same power supply.

From that data, we see that a charger's maximum wattage cannot be defined by a single number, as many believe. For instance the PL6 example is 860 watts from start to finish. Whereas the 30 amp limited (ala 306b) starts around 700 watts, reaching its peak of 756 watts at the end of the charge. So if the 306b is only putting out its max wattage at the last minute of the charge, 760 watts it can not be fairly compared to Powerlab6 that is putting out 860 from the start of the charge.

While I did attempt explain this in the test, I know that boiling this down to a single number (CC stage in minutes) seemed a much simpler way to summarize the wattage differences.
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