Design Power System

[PayneTrain]

Meet with adviser this Monday to discuss preliminary system

[PayneTrain]

MAE nerds, can one of you sit down with me and explain me the torque calculations for the motors...I'm working with maxon to understand current vs voltage profile and need the torque rangers

@hmartiro @boleary134 @towlett @Hughzie

[Hughzie]

Based on change in potential energy and friction, I calculated the Power used by the robot.

-Standing up: 11.2W total -Walking: 2.46W (x3 to take into account leg and body deflection moving over uneven terrain) so 7.38W total

The 2.46W comes from 0.56 Joules per step (mg*deltah), times 4 steps per second (each leg steps twice per second, two offset sets of legs), plus friction

Does this help?

@PayneTrain

[hmartiro]

take a look at this puppy

http://www.liquidware.com/shop/show/BB-BJC/BeagleJuice

[PayneTrain]

Research complete, adding results to Wiki

[PayneTrain]

Submitted purchase ordering form to ELE department for LiOn Battery and charger. Decided NOT to get additional power for CPU at this time because of weight concerns and USB issues...will explain in WIki when I finish my pset

[PayneTrain]

Received email from ELE purchasing department that battery must be bought a minimum of 10 at a time per battery website, finding alternative company.

[hmartiro]

good. take a look here http://www.hobbypartz.com/98p-25c-2500-6s1p.html

this site has way better batteries for a lot cheaper. browse around a bit, they have video reviews!

[hmartiro]

Also:

C Rate x Capacity (in amp hours) = Discharge Rate in Amps

so when they say 25C for a 2.5Ah battery, that means that it can provide 62.5 amps -> :octopus: :zap:

[PayneTrain]

^ Note my note:) https://github.com/hmartiro/project-thesis/wiki/battery+and+power

Yeah I've been talking to hobbyking.com, kind of a sketchy site but I'll take a look at the hobby partz too, I bet they are cousins.

[hmartiro]

i would think 3100mAh is too heavy for us

[PayneTrain]

This seems awesome: http://www.rc-battery.com/app/menu.php?op=show_one_product&id=351

Really lightweight(352g), 2.2 AH is a little low but for the price I say we try it out since Hal put such a premium on weight. Only thing is its sold out by Gens Ace distributor (the site haj found hobbypartz)

Here is a similar battery, but heavier (390)http://www.nitroplanes.com/77p-sl2200-6s1p-20c-6666.html but also out of stock.

I think I'm going to call one of these companies tomorrow and see when they would expect to have batteries in again, luckily for now we are fine running on benchtop power

[Hughzie]

Baller car commercial with the battery

On Tue, Nov 27, 2012 at 4:22 PM, PayneTrain notifications@github.comwrote:

This seems awesome: http://www.rc-battery.com/app/menu.php?op=show_one_product&id=351

Really lightweight(352g), 2.2 AH is a little low but for the price I say we try it out since Hal put such a premium on weight. Only thing is its sold out by Gens Ace distributor (the site haj found hobbypartz)

Here is a similar battery, but heavier (390) http://www.nitroplanes.com/77p-sl2200-6s1p-20c-6666.html but also out of stock.

I think I'm going to call one of these companies tomorrow and see when they would expect to have batteries in again, luckily for now we are fine running on benchtop power

— Reply to this email directly or view it on GitHubhttps://github.com/hmartiro/project-thesis/issues/22#issuecomment-10777720.

-- Greg --

[hmartiro]

how about this little guy

http://www.hobbypartz.com/83p-2200mah-6s1p-222-30c.html

[Hughzie]

I stuck a link to a fuse box in the Power wiki, http://www.delcity.net/store/6!way-standard/p_10959.r_IF1003?gclid=CJD9p-qu97MCFQyk4AoduikA2Q 65 amp max $4.55 I assume there's nothing complicated about fuse boxes / no reason to not get this cheap little guy I just needed something to CAD so I chose this one

@PayneTrain @hmartiro

[hmartiro]

can you change the purchases page to reflect the new stuff you bought

[PayneTrain]

I just put the PO on hold with the ELE department because I can now see that we are drawing 1/10 of an A at 8K RPM w/ no load, will do some back of the envelope power calcs to check order and then report back here

[hmartiro]

order to be resumed and add the cost to the purchases page

[PayneTrain]

Purchase page updated.