#robotics Logs

Aug 14 2014

01:26 MrCurious http://www.ebay.com/itm/9-Cell-Laptop-Battery-for-Apple-MacBook-Pro-15-A1150-A1175-MA348G-A-Silver-New-/400349653463?pt=Laptop_Batteries&hash=item5d36b2e9d7
01:26 Hyratel1 MrCurious, but what's the WH/$
01:27 MrCurious 10.8V 60WH for $20
01:27 Hyratel1 lemme put it in the chart
01:27 MrCurious remember the perk of charge controler, discharge controler and charge level monitor
01:27 MrCurious included for free :)
01:35 Hyratel1 the WH/$ is eh
01:36 Hyratel1 3.05, comparable with Turnigy lipo from hobbyking
01:37 Hyratel1 and the WH capacity is a pittance
01:37 Hyratel1 and the C rating terrible
01:43 Hyratel1 MrCurious, hey
01:43 MrCurious ?
01:43 Hyratel1 you didn't reply
01:43 Hyratel1 https://docs.google.com/spreadsheets/d/1hAHfLJN0cwo0ZgO68Hn3EXThfr4vXLOB_4a85thiPAM/
01:43 Hyratel1 see if that link works
01:44 MrCurious nice
01:44 MrCurious its what i use. kept a rpi and a odroid u2 up for 24 hours
01:44 MrCurious using a pair of them
01:44 Hyratel1 very nice
01:45 Hyratel1 if you're not worried about weight, an SLA from andymark is pretty damn cheap
01:45 Hyratel1 18AH 12v SLA, $45 ea-pr
01:45 Hyratel1 $90/pr
01:46 MrCurious sla has weight, discharge rate memory? and plate buckling probs
01:46 MrCurious i settled in li-ion for my power source of choice
08:47 rue_bed no memory on sla
08:55 robotustra morning
08:56 robotustra what is sla?
10:14 mrdata some kind of salad i guess
15:38 GargantuaSauce lead salad
15:38 GargantuaSauce with sulphuric dressing
20:40 rue_shop2 oops I broke the tractor
20:40 rue_shop2 too many bricks, a wheel collapsed
20:40 rue_shop2 sealed lead acid
20:40 rue_shop2 sla
20:47 anonnumberanon broke the axle as well?
21:29 MrCurious SLA pisses me off
21:32 Tom_itx rue_shop2, you found the load limit ehh?
21:44 Hyratel1 MrCurious, whyso
21:44 MrCurious heavy
21:44 MrCurious plates can buckle and kill battery if over discharged
21:44 MrCurious and i think, but not sure, that they develop memory
21:45 Hyratel1 I think memory has been disproven in most chemistries
21:45 MrCurious after my initial investigations, i locked in on li-ion price/weight/size/energy density
21:48 MrCurious but i am fallible. my opinion may be wrong.
21:48 Hyratel1 https://docs.google.com/spreadsheets/d/1hAHfLJN0cwo0ZgO68Hn3EXThfr4vXLOB_4a85thiPAM/edit#gid=0
21:48 Hyratel1 if you have a battery cell/pack you want me to add, pass me a link
21:49 MrCurious i did other night
21:49 MrCurious the MBP $20 cheap bat packs that include charge/discharge/monitor controler
21:50 Hyratel1 unfortunately, i wasn't able to find a weight for it, and "with smart charge management included" isn't really a part of my calcs but that does sound like it'd be beneficial
21:50 MrCurious and it has the added perk that you can short it and use it as self destruct in emergencies :)
21:50 MrCurious if you can drop $20...
21:50 MrCurious would make a great data point
21:51 MrCurious would use the ones i had, BUT they are insanely hotglued to my bot
21:51 Hyratel1 hotglue is a mixed blessing
22:18 omegalpha yay i didnt get kicked!
22:20 omegalpha wahst SLA?
22:20 Hyratel1 Sealed Lead Acid
22:21 omegalpha hello rue_shop2, you broke a tractor? like a john deere tractor tractor?
22:21 omegalpha Hyratel1: ok thanks.. i learned something new :(
22:21 omegalpha :)
22:21 Hyratel1 flooded PbA with a high pressure cap that restricts venting
22:53 omegalpha Hyratel1: PbA = lead acid?
22:54 omegalpha flooded it with?
22:54 omegalpha didnt realize batteries vented.. thought they were completely sealed air tight
22:54 omegalpha speaking fo batteries. i want to talk about this subject with a battery head... HHO.. whats your thoughts?
22:54 omegalpha aka browns gas?
22:56 Hyratel1 yes
22:56 Hyratel1 PbA is lead acid
22:57 Hyratel1 and flooded with battery acid of course
22:58 MrCurious anyone have any speculation on if the series "extant" is related to "helix"?
22:59 rue_shop2 na its a kinda electric diy tractor
23:00 rue_shop2 the frame was made in like 1965 or something, one of the wheels I added to it broke off
23:02 Hyratel1 omegalpha, yeah - acid batteries create electrolytic outgassing, even moreso if the electrolyte boils due to overvoltage during charging
23:03 Hyratel1 if the terminal voltage during charging excedes 14.5v, you're boiling it and likely to cause major gassing
23:05 rue_mohr2 Tom_itx, apparently I was like 50 lbs away from the limit :/
23:05 rue_mohr2 anyhow, its my brazed joints that gave out, I'll weld it up and it should be fine for a while