Come join us online and in-person at the 2023 Power Racing Series Season Summit! Loose agenda as follows:
2022 Season Winners Announcement
The Great Arguing of the Rules
Please meet us at Kitchen 17 in the bar area at noon to set up! We will have physical trophies with us and can mail them out after the summit. Shenanigans are TBD but might include parking lot/alleyway kart racing. Afterparty will be at Moonie and Andrew’s house, address will be announced at the summit. Drinks will be available at the bar and we will have all kinds of pizza for sharing.
We had an unresolved question at the summit regarding whether to allow higher (~60V) battery voltage. This decision was postponed pending research on availability of suitable fuses. I have done some searching (can’t guarantee absoluteness) but here is what I have found:
A 60V battery voltage would require a 24A fuse. I was unable to find a suitable 24A fuse.
The 32V MIDI and BF1 fuses that we use are available in 23A, but once again rated 32V…
The 58V BF1 fuses are not available in 23A
The 25A 80V Littelfuse FKS-ATO fuse would blow much faster at a given percentage of its rating than the MIDI or BF1 fuses (based on I^2*t rating and curves at 2x and 3x rating). I would be 100% confident that this would not give a performance advantage over lower-voltage systems even though it is rated 25A and not 24A.
I do not recommend the 25A 58V Littelfuse JCASE fuse. It should blow faster than MIDI and BF1 based on I^2*t rating but its current-time curve shows it being identical to BF1 at 2x and 3x rating. This means that the available 25A fuse @60V would give performance advantage over lower-voltage systems.
The 30A 58V Littelfuse MAXI fuse has a lower I^2*t rating than the 30A 58V BF1. This should imply that the 25A version would also be suitable. This series does not have current-time curves in its datasheet so I can’t guarantee that it would be a fair option.
The Littelfuse 25A 80V FKS-ATO fuse would be suitable (although at performance detriment under typical PRS racing conditions) if we decide to allow 60V battery voltage to enable usage of a larger number of readily-available motors.
I do want to clarify the consequences of fuse voltage rating. Operating a fuse above its voltage rating will not cause it to blow. Operating a fuse above its rating will not prevent it from interrupting the circuit when it blows (at least at the voltages we are dealing with). However the voltage rating pertains to that voltage at which it will “safely” interrupt current. If operating above the voltage rating, there is no guarantee that the fuse won’t explode or catch on fire when it opens.
As far as safety regarding battery voltage. 50VDC/30VAC is generally considered the limit of “safe” low voltages. I would generally be inclined to stay with this guideline. However, electrons don’t acknowledge a hard limit of when they decide to go through you in plethora. One could argue that (although higher voltage does make thing more dangerous) going to 60V doesn’t add a higher percentage of risk than when we increased the limit form 36V to 48V.