At what battery % does it become unsafe to GUN IT at full throttle?

[Vam Monaco]

By default, my wheel  (RS 19) likes to tilt back when it’s under 40% to remind me that I’m running low on power, and I thought about lowering it to about 30% or maybe even 20%, but is that unsafe? And is it also bad to drain the battery that much?

Is there a way to tell the cycle count, or the health of your wheel’s battery?

[alcatraz]

Measure the packs' internal resistance. You can buy IR meters on aliexpress. IR increases with age. It means they heat up more and more over time for the same current draw and charge speed.

That's why riders should reduce the torque as the packs age, to stay within the same safety as when the packs were new.

In eucworld there's minimum voltage. You can do an acceleration on a newer pack and an older pack and compare the min voltage numbers. You'll notice that the older packs' voltage drops a lot lower. If it drops low enough you get an overlean situation.

On wheels with lots of parallel cells 6P or 8P you can "gun it" even when the wheel has aged a bit (2700-3600Wh). On wheels with 4P packs (1800-2400Wh) you'll quicker see a performance drop.

If you run high current cells an aged pack can beat a brand new high capacity pack.

Edited August 2, 2023 by alcatraz

[Robse]

i made up my own simple rules of safety: I never go faster in kmph than the % battery left. This first applies from 65% and downwards. Be carefull, the RS is like Jekyll and Mr. Hide. So powefull and f* fast... and 15 minutes later on that fun speed run you are down to 60% where the danger begins. I never do any fast and powerful acceleration when I'm below 60% , that's to risky, and you can't trust the RS tiltback feature. The only thing to trust is your own awareness of the actual situation. That's the Gotway way of riding 😁

[Chriull]

9 hours ago, Vam Monaco said:

By default, my wheel  (RS 19) likes to tilt back when it’s under 40% to remind me that I’m running low on power

Begode has tiltback setable at some charge %?

9 hours ago, Vam Monaco said:

and I thought about lowering it to about 30% or maybe even 20%, but is that unsafe?

Don't know were actual voltage % limits are, so i'd assume 3.15V per cell for 0% and 4.15V for 100%. This leads to 3.35V for 20% and 3.45V for 40%. Max (lift cut off) speed at 4.2V is about 100km/h(?), at 40% reduced to 100/4.2*3.45=82km/h and at 20% reduced to 77km/h.

One of course can not reach (easily) lift cut of speed during riding, but one gets by this numbers an idea of the "charge % induced speed reduction". 

So at 40% one already lost ~20 km/h and at 20% another 5km/h until overlean (at the same burden)

At low charge % ranges the loss could be even bigger, as internal cell resistance rises. Don't know if there are notable effects already at ~20%.

9 hours ago, Vam Monaco said:

And is it also bad to drain the battery that much?

For a well balanced battery with still about similar cells this should be no problem - the cells are well above the 2-2.5V limit.

Just, as one (some) cell is the first to become weaker it will be discharged lower as the others while the average cell voltage is still around 3.25V. Even with battery packs that still balance nicely and charge to full voltage.

This gives some higher stress to the already weaker cell - if it's easily possible best to avoid higher burdens at lower battery % and/or not empty the battery too much to "caress" the cells. If not, it's just the normal "wear and tear" for using the EUC - li ion cells are finally still consumables.