Battery Life, 50A load discharge test method/results

[Dale(294engr]]

more info on battery life:

Per current Exide 18AH ES & EX Battery Spec:
at 20C=78F colder = LESS time
Current Amps Time to discharge End V
0.9 20 hrs 11
4.5 4 hrs 10
10.8 70 min 10
18 40 min 8
36 18 min 8
54 8.5min 8 (last data from graph)
72 4 min 8 following not on graph = extrapolated
90 2 min 8
108 60 sec 8
116 30 sec 8
134 15 sec 8
152 7.5 sec 8
170 3.7 sec 8
188 1.8 sec 8
196 0.9 sec 8

230 Amp for 5 sec = Max discharge current

Measured actuals:
(see also my post on Batt Test @50A load and Excel results attached)
Team 294 robot with 4 CIMs (125A), compressor (11A), Vandoor (13A), 2X FP (10A) + control electronics (2A)
consummed 161 A of average current when pushing against opponent, robot not progressing but with wheels turning slowly on carpet, max throttle.

Note that all motors draw Stalled rotor current at max throttle at start up for around .2sec (with resultant transient droop in battery voltage for that time)

Motor Stall Currents:
4 CIMS ~400A, 2 FP 100A, Vandoor 60A, compressor 34A, (globes 20A)
totalling over 600A for .2 to .3 sec each event (if all Maxed together)!!!

Dale(engr294] since 1998 (TRW / Northrop Grumman)
Dale.Hall@earthlink.net 310 374-8323

RSVP Comments invited, was info useful, clear, or need more ?

also attached: my Slides from Oct 2005 CSUN FIRST Workshop (LA, Calif area)
oops never mind
CD doesn't allow .ppt

ADMIN note: Lets add extension: .ppt !! to share education data