I dunno about the rest of it… since I don’t even have mine to test with yet… But I I am certain… The #1 factor is getting a great battery to put in… Samsung 35e… or Sony vtc5a? Lg mj1?.. many batteries are super overrated …
I had some that claimed 6,000 mAh, but I also have a tester. They actually came in between 600 and 800 mAh. The other instantly noticeable thing was they were so light. Good cells from known good sources weigh way more.
there is a great thread on the DevTerm on battery choice - I have ~2800 mah batteries from the battery store - they have lasted more than two years but they do have a life on the devterm (without printing) of only ~4 hours (depending on back light) … but since I have a way to recharge it’s not an issue . I used the DevTerm to ssh a linux laptop during an event I supported as a volunteer. I may have used it for several hours…
I have the CM4 uConsole with two Samsung 35E cells (so 7Ah * 3.7V makes well above 25Wh) and when I put the governor to powersaving and reduce the backlight brightness, the litte machine runs fricking forever.
Can you describe freaking forever with a number? I am really looking for something to code on without access to an outlet for extended periods. If I could bring few of extra sets of batteries and be able to use it for 25-30 hours total, that would be ideal.
I would advise against bringing extra batteries, since they are more difficult to swap than they were on the DevTerm (I own both devices). While on the DevTerm I have hot swapped 18650s, I am using an external power bank for the uConsole.
It should not be hard to switch out the 18650 holder on the battery board with a 21700 holder, you’ll get about 40-80% more battery life, depending on the 21700 you use.
Sans the size change 21700 are drop in replacements for 18650 from a circuitry stand point. Same voltage, just much higher capacity. (Charging circuit uses voltage to measure capacity, so uConsole will have no issue charging them to full.)
I have the DevTerm in the field I have a power box with USB out - I use that to keep the DevTerm charged while in heavy use. (Power box is 12 volt battery - lipo4fe - has usb , 12 volt, anderson power poles…)