Quote:
Originally Posted by AlexH
If you shock a battery with a taser you can sometimes bring it back to life. However I DO NOT RECOMMEND THIS with large batteries. I've only done this with NICad 18v drill packs.
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!!!! DANGER !!!! SLA AGM's may have unvented internal hydrogen gas pockets!!
Taser provides high peak energy spark blasts (of a few joules ea?) that could ignite the hydrogen.
BOOM!!!@!#$!@#$ safety vent valve is designed for slow gas release.. not impulse of blast proportion.
Note MK spec max charge current
5.4A else warranty is void & as it reduces battery life! [from internal heating, causing disassociated gas release]
if battery is sulfated
OR there is an Open
(fused/melted open conductor, aka Pb Lead Vshaped-fuse link between cells)
likely be UNable to draw 5.4A unless voltage is substantially raised above 15.
Taser may be 100KV!! causing spark jump discharge blast between open ends!
(I have used electrolytic Capacitors charged up to ~200V to blast NiCads to successfully charge where conductive whisker growth short is defect mechanism not appropriate for SLA AGM chemistry!!!)
What is defective battery mfr date code?
SLA AGM left dormant (uncharged on shelf) for years may NEVER accept a charge!
=sulfated = high internal battery resistance, think K or Megohms) so draws NO noticable current even at max spec charge voltage of 15.0 v
even if it does initially draw a few uA & gradually charge, drawing mA's to A's
the final internal resistance achievable will likely be much higher than spec 0.01 ohm i.e. much lower load current available to robot & at lower terminal voltage i.e. limited & lower available robot power, unacceptable for nominal robot performance, due to battery internal resistance Voltage dip I^2R
motors especially: will exhibit decreased start-up peak power plus depressing terminal voltage to only a few volts- possibly causing dynamic cRIO resets
OR sluggish deeply sagging varying running power.
CIMs normally draw 100A-125A ea for .1-.3s upon full throttle depending on load being pushed (fixed wall, robot pushing head-Head=WorstCase) state of health & charge of a good battery is able to maintain terminal voltage above 9v under such load)
Rule of thumb: Most batteries in-use awhile drop 1v at terminals for each 50A drawn by the robot
(PM me for 50A load Vterminal Vs time, 10s incr 9min plot)
one CIM=100A peak @full throttle: 12.6-2 =10.6 brief terminal voltage sag
(observe with oscilloscope)
Who uses just one CIM in their drive?
2ea CIMs full throttle = 8.6v terminal dip for (~.1s?)
with healthy properly charged (& topped off after fast charge) non-abused fully charged battery:
dip time decreases quickly with increasing motor RPM as robot comes up to speed, and reason why when pushing bots geared down transmission-low permits higher motor RPMs while providing highest torque at reduced robot speed saving extending battery and keeping Vsags from resetting cRIO!