Amp draw and LiPos

[Flag Captured]

Finally got round to being able to order some batteries for Hardwired II at long last, I already have the speed controllers (320A ones I found on eBay pretty cheaply) but I was just wondering if anyone has any figures for the amp draw for (four) standard 12v drill motors (36:1 gear ratio)? I'm going to be using 4s packs, but I'm not entirely sure what discharge rate to aim for, or fuses for that matter...

I've seen this pack here - http://www.hobbyking.com/hobbyking/s...arehouse_.html but I don't know the suitability of it for this kind of application. I don't know if this'll help either, but I'm going to be using wheels that are around 80mm if I can get some that do the job well enough...

Thanks in advance, I'm really sorry about spamming up the boards with my blatant inability to robotics, I am getting the hang of it though!

[psychostorm]

It's fine. Capacity to last you about 3 fights. Discharge (C) is fine for a lifter.

[geeza]

I know its American but use this link to calculate your approx. current draw. You might have to approximate which motor you have from the list.
http://architeuthis-dux.org/torquecalc.asp

Are they really 320A controllers? or is that just a peak rating?

[Porker]

http://www.ebay.co.uk/itm/High-Volta...item20cffabd44

[Ellis]

That pack is the 4s brother of the 5s we use in Tormenta 2. It's nothing flash, but it'll do nicely.

You can get "maxi" fuses and fuse holders on Ebay. We bought 80a and 100a ones, we're running the 100a. The 80a or even 70a models should do fine.

edit: oh and as for the speedos, the size of the wires should tell the story, that 320a is oh so far from the truth. :P

[Flag Captured]

Fantastic, thank you both! I'll get one of those bought then I don't know what's good for 4 drive motors at once, my only other bot ran using servos and microswitches and two motors, so this is all new!

The ESCs were called '320A speed controller for car/boat/buggy' as well but I really can't find anything other than that... the description wasn't too helpful either! I think it might be a peak - sounds a little bit too good to be true, seeing some of the amp ratings on some of the ESCs out there, but they do only go up to 14.4v. They were the same model as these if that helps - http://www.ebay.co.uk/itm/High-Volta...item20cffabd44

[Flag Captured]

Ahh, I took too long to respond there haha! Thanks Ellis too, that's a big help! I'll definitely get that ordered then and have a look for those fuses!

I have no doubt it's a bit of creative licensing there too - £12 for a 320A ESC sounds a bit too good of a deal!

[plargen]

i have two of those esc in each of my bots run on a 4s lipo, in the 4wd they don't even get warm during a 3 min battle but the motors are baking

and i use a lipo with a 150A peak and a fuse rated to about half the peak amps, not blown 1 yet

[Porker]

Where is the BEC on those speed controllers?

[plargen]

its built in you have to remove the red wire from the rx plug to disconnect it

[Porker]

So you don't need to plug anything into the battery channel on the receiver?

[plargen]

yup no external bec just disconnect the red wire from 1 of the esc so they don't fight each other

[Porker]

Wow, thanks. How does that work?

[plargen]

i think its just basically a bec circuit built into the board that's wired into the input supply and the feeds the required power to the rx via the 3 wire plug

not great with electronics to be honest but the can have all sorts of different voltage circuits running through circuit boards

[Porker]

And by the 'red wire', I assume you mean this (in the blue oval):$T2eC16NHJGkE9no8gGY+BROLHpEF,Q~~60_12.JPG