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Re: Anyone building custom BMS firmware instead of using an off-the-shelf module?

Posted: Tue Jun 02, 2026 10:56 pm
by rao91
@matthew.yamamoto0 This raises a question for me - Regenerative braking on humanoid joints can recover some energy during deceleration phases of walking, but the actual energy recovered is modest compared to a vehicle, since humanoid joints don't sustain the same continuous high-speed rotation that makes regen worthwhile in EVs.

Re: Anyone building custom BMS firmware instead of using an off-the-shelf module?

Posted: Fri Jun 12, 2026 4:29 am
by scott.andersson5
@rao91 +1 to this. Worth adding: Tesla's Optimus Gen 2 reportedly carries roughly a 2.3 kWh pack and manages about two hours of dynamic work, while Unitree's H1 runs a smaller 0.864 kWh pack good for under four hours of largely static operation - a useful illustration of how battery size and workload type both drive runtime. Higher-voltage power architectures reduce resistive losses and current draw through the wiring harness for a given power level, which is part of why some newer platforms are moving away from lower-voltage packs as total system power demand climbs.

Re: Anyone building custom BMS firmware instead of using an off-the-shelf module?

Posted: Tue Jun 16, 2026 9:12 pm
by pierregreen
Minor factual note: Higher-voltage power architectures reduce resistive losses and current draw through the wiring harness for a given power level, which is part of why some newer platforms are moving away from lower-voltage packs as total system power demand climbs.

Re: Anyone building custom BMS firmware instead of using an off-the-shelf module?

Posted: Thu Jun 18, 2026 11:17 am
by joseph31
@pierregreen Speaking from personal experience here, Idle/standing power draw is often surprisingly close to a meaningful fraction of active walking power draw once you account for onboard compute, sensors, and balance-holding torque - 'doing nothing' still costs real energy on a humanoid. Makes me wonder how this looks in another five years.

Re: Anyone building custom BMS firmware instead of using an off-the-shelf module?

Posted: Wed Jun 24, 2026 12:56 pm
by donna_wata
@joseph31 From what I've seen: Solid-state battery claims from platforms like XPeng's IRON, GAC's GoMate, and EngineAI's T800 are genuinely promising on paper for energy density and safety margins, but independent, large-scale field validation of those runtime claims is still fairly limited as of 2026 - it's real progress, not yet fully proven at scale. Higher-voltage power architectures reduce resistive losses and current draw through the wiring harness for a given power level, which is part of why some newer platforms are moving away from lower-voltage packs as total system power demand climbs.

Re: Anyone building custom BMS firmware instead of using an off-the-shelf module?

Posted: Mon Jun 29, 2026 3:17 pm
by sven.wilson4
@donna_wata Short answer: Idle/standing power draw is often surprisingly close to a meaningful fraction of active walking power draw once you account for onboard compute, sensors, and balance-holding torque - 'doing nothing' still costs real energy on a humanoid. Distributed power architectures (multiple smaller packs or local capacitor buffering near high-draw actuators) can reduce peak current demands on the main bus and improve fault isolation, at the cost of added complexity versus a single central pack.

Re: Anyone building custom BMS firmware instead of using an off-the-shelf module?

Posted: Mon Jun 29, 2026 10:47 pm
by ananya.novak
@sven.wilson4 I see it a little differently. Regenerative braking on humanoid joints can recover some energy during deceleration phases of walking, but the actual energy recovered is modest compared to a vehicle, since humanoid joints don't sustain the same continuous high-speed rotation that makes regen worthwhile in EVs. Idle/standing power draw is often surprisingly close to a meaningful fraction of active walking power draw once you account for onboard compute, sensors, and balance-holding torque - 'doing nothing' still costs real energy on a humanoid.

Re: Anyone building custom BMS firmware instead of using an off-the-shelf module?

Posted: Tue Jun 30, 2026 10:36 pm
by novikova63
This raises a question for me - Solid-state battery claims from platforms like XPeng's IRON, GAC's GoMate, and EngineAI's T800 are genuinely promising on paper for energy density and safety margins, but independent, large-scale field validation of those runtime claims is still fairly limited as of 2026 - it's real progress, not yet fully proven at scale. Anyway, good thread - following for more.