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Old 02-23-2012, 07:37 PM   #99
_cy_ OP
Beastly Adventurer
Joined: Sep 2011
Location: Tulsa, Oklahoma
Oddometer: 6,386
just found this chart on Shorai web site that closely matches what I posted in an earlier post #44.
note discharge rate is extremely flat. only 1/2volt change for 80% of rated capacity. measuring voltage requires a known to be accurate meter.

Unless you've got a buddy with an electronics lab. a free way to calibrate your meter is to visit a local HVAC store that sells Fluke meters. take along a CR123 lithium cell, which puts out stable voltage. measure same cell with both meters. a new Fluke 87V meter will be dead on.

note lead acid trickle chargers are designed to charge PB to float charge level which is 13.05v for gel. then add 150 milliamp = 13.20v .. assuming charger is delivering voltage within spec's. a lithium phosphate battery will be 70% charged at 13.20v. if trickle charger is delivering less volts. at 13.05v battery is only 35% charged.

more reasons why a li-ion specific charger with cell balancing should be used. Progressive RC offers some of the finest li-ion chargers anywhere. they come highly recommended by the RC crowd.

The Progressive RC folks have been doing load testing with lithium iron phosphate batteries for quite sometime. they have extensive testing data on all sorts of li-ion batteries for motorcycles and automotive use. hopefully they will agree to share a bit of the extensive database of A123 discharge testing.

more on this later...

From Shorai faq

_cy_ screwed with this post 02-23-2012 at 10:07 PM
_cy_ is offline   Reply With Quote