Regular vs LiHV

We get asked allot about carrying LiHV packs and the reason why we don’t is due to the rules of racing not allowing packs to be charged above 4.20V per cell.  Also when it comes to RTR ESCs some of them will not support packs charged to 4.35V.  For example it will think a 2S pack is an over discharged 3S if the voltage of the pack is at 8.70V and will not allow the ESC to work.


Some of our competitors who like to hype up the latest and greatest put out claims such as LiHV packs will have a flatter discharge curve when charged at 4.20V compared to regular Lipos so the voltage is to remain higher due to this flatter voltage curve.   Such claims made me want to do some testing of various companies LiHV packs as in previous testing of LiHV we never found this to be true.  We’ve never seen a LiHV cell at the same size/weight have better internal resistance then our Extreme Graphene non LiHV cells.


We purchased packs from different companies to compare these packs to our SMC packs.   The packs are all normal 25mm height shorty packs.  The testing consists of getting the IR of the cells in the packs using the ESR II meter that is available to purchase on the SMC site.   Then the packs were fully charged on the same charger and then discharged at 35 amps down to 6v per cell on our pack discharger.   The last test is our Power Factor test which discharges the pack down at 100 amps for 5 seconds.   This shows how much voltage drops at higher amps.  This is closer to what a pack will do under heavy acceleration.


Here is the list of packs tested listed in the order they were tested.


SMC 5100 Extreme Graphene
Sunpadow 5100 Gold Label
SMC 5000 DV.  Our recommended pack for mod racing as it will have less punch which is typically not needed in mod.
Gens Ace 6000 Redline LiHV
Performa 6000 LiHV. 
IP6000  HV4 LiHV
Sunpadow 6000 Gold Label LiHV
 
Test 1:  IR of the cells using the ESR II meter with packs at storage charge tested at 22 degrees Celsius



Test 2:  35 amp discharge test from 4.20v per cell down to 3v per cell.  As you can see by the graph the LiHV packs really don’t discharge flatter than the SMC 5100 Extreme pack.



Test3:  Power Factor test.   On the SMC site we list the Power Factor test per cell so if you take the last voltage reading which is at 5 seconds and divide it by 2 this will give you the single cell voltage.



In conclusion if charging to 4.35V is ever allowed in racing we will offer LiHV packs but in the meantime we feel there is no need to offer these packs as there is no advantage in using these when charging at 4.20V per cell. 


Hope this test is helpful and if any one has questions about the tests feel free to email us. 






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