CPAPtalk.com

amenite wrote: ↑

Wed Jun 25, 2025 5:11 pm

McSleepy wrote: ↑

Wed Jun 25, 2025 3:18 pm

The total energy use was 470Wh, thus, a ~500Wh power source will run it all night just fine.

If we're talking battery power it's good idea to avoid discharging to that depth. Using 50% of available, OK. 80% less OK. In the example above - using 94% - no bueno for some batteries, lead acid ones in particular.

That is always a good idea, which is why I recommended that Energizer power station with 960Wh capacity; but even with lead-acid chemistries, there are AGM deep-cycle batteries that are designed to be fully discharged each time; and with LiFePO4 batteries, the listed capacity is not the full chemical capacity (same with electric vehicles) and it's perfectly safe to "fully" discharge it as it only truly discharges to a safe level. Plus, what I presented as an example was a near-worst-case scenario, so in my case, a 500Wh solution would be acceptable. For others - YMMV.

McSleepy

McSleepy wrote: ↑

Thu Jun 26, 2025 2:28 pm

...there are AGM deep-cycle batteries that are designed to be fully discharged each time;

I just looked one up and their estimated duty cycles are cut by more than 2/3 when repeatedly discharged 100% - 1000 cycles vs. 300 cycles. Personally I would just go with the one I could use without severely shortening its lifespan.

amenite wrote: ↑

Fri Jun 27, 2025 11:52 am

McSleepy wrote: ↑

Thu Jun 26, 2025 2:28 pm

...there are AGM deep-cycle batteries that are designed to be fully discharged each time;

I just looked one up and their estimated duty cycles are cut by more than 2/3 when repeatedly discharged 100% - 1000 cycles vs. 300 cycles. Personally I would just go with the one I could use without severely shortening its lifespan.

Of course, that is always the case, with any chemical battery. Modern technology, like LiFePO4, are quite good at it. But in the end, there is the purchase price involved, too, and if you consider that, too, it's hard to say which is better.

McSleepy