@Halbj613
Same here! As you may remember I tried to advertise my services, but now I am trying to gain more experience as well.
3 Likes
LoL
Much reading to do
2 Likes
I understand wanting to overbuild a battery, but thereâs really no reason one would expect to pull in excess of 100 amps from a 12s5p on a Prototipo.
If youâre 200lbs, accelerating uphill, youâre likely not even pulling 50 unless youâre towing something behind you.
At least, Iâve never (ever) pulled that much on one, or any board riding on pavement. Even when I was fatter.
As youâre learning how to build batteries and also working on your soldering techniques, I wouldnât give myself THAT much more to manage than was realistic for the actual build.
Unless Iâm wrong, and youâre actually expecting to pull that kind of current. Then have at ye.
3 Likes
Me either. I check my metr logs after every ride and the highest Iâve ever seen on my 2wd is 55A
Thatâs like peak acceleration
3 Likes
yep exactly that means a single copper braid is all i will need
i want in theory it to be enough to handle the max current the battery can output (just in case even if that scenario never happens)
That as well!
Yeah one is fine
Besides, pulse loads arenât going to heat up the cables. Thatâs why I usually go for 2 to 3 12awg wires for my series connections
1 Like
yeah with p42a 12s5p+ is 2 12awg cables
12s8p+ is 3
Keep in mind I still use 10awg for the main leads though just because it fits XT-90 better
Also because thatâs where the peak current hits.
1 Like
Youâd likely damage something else if your ESC is pulling 200 amps from that battery. Hitting the discharge top end of 5x P42a isnât a joke inside a board like that.
2 Likes
i thought so to but then i realized spot welders are the exact thing a pulse load is and very quickly big cables heat up
Lol thatâs not comparable at all. Those are 1000a for like milliseconds. Not the same
Thatâs why you can run 1000a through 10awg wire for milliseconds
1 Like
this is a quarter the amps but 10x more time
AlsoâŚitâs a Prototipo. 100 amps into an ESC and doing who knows what current into motors, is going to not only knock most people off, but itâll take off into the air, hit a pigeon, the pigeon will explode, the motors will catch fire and spark a series of events that will have a chunk of your neighborhood on the evening news cycle.
Is that what you really want?
1 Like
focboxes
i think they can only handle 50amps each eitherway (maybe a little more)
Yeah but even when you peak out you arenât pulling 200a for more than like 10 seconds
You have to think about where the current is going. You use a ton of current to accelerate and hill climb. Whenever you accelerate itâs a short event. You accelerate for a bit and then you get to speed and your current goes back down to like 20 amps
Obviously on a track or something where you are accelerating and braking all the time things will tend to heat up more
lmao
1 Like
fair enough
would be interesting to see a graph on how pulse loads affect temperature
something like
200amps for 2 seconds
20amps for 30 second
200amps for 2 seconds
20amps for 30 second
200amps for 2 seconds
and then see how hot different connectors get (wire / xt90 / copper braid etcâŚ)
if anyone wants to do thisâŚ
1 Like
Largely dependent on ambient conditions, but you can make simulations assuming even distribution and known thermal/electrical properties. If youâre feeling super fancy you can do nanosecond steps using temperature dependant curves for electrical resistance and thermal capacity
1 Like
think you mean
Haha not feeling Matlab savy rn?
1 Like