Winter time here, really cold nights, so the S50 has been using the power bank i think because it won't change at these low temp. I'll test again when it gets warmer.

I have never seen the S50 battery level drop below 99% when powered from an external power bank, even after a full night of use with the anti-dew heater on.

Which power bank do you have?

Some powerbanks has a auto shut of if you drain to little current. So i would check with another powerbank and/or see if the one you have has this limitation.

Actually, I'm not so sure anymore. I asked the engineer, and he said to use both first.

yDrqQBnb If the power bank cannot provide enough power then the internal battery will be used. Check the specs of the power bank. Many do not provide enough current in each individual USB port but the specs refer to the sum of the USB ports. So if your power bank has 4 ISN ports it will only deliver 5 W per port. With 5 V that provides 1 A per port and the SeeStar will need more with the dew heating on.

yDrqQBnb Please provide the link to the one you have so we can look at the specs. I have the same question that wvreeven has about its ability to supply all the energy needed so that the Seestar doesn't need to tap into the internal battery.

Support@Seestar You posted some time ago that with an external power source the Seestar will use power from the internal battery and simultaneously re-charge the internal battery from the external power source. I believe that is absolutely not correct. Based upon my specific testing of this, so long as the internal battery is fully charged, it will not draw power from the external power source and the Seestar will use the power from the external power source exclusively until it is drained, so long as the external source has sufficient power/current capability to supply all that the Seestar needs to operate.

This is one way to avoid discharging the internal battery below the spec limit of -10C. Fully charge it and then run from an external power source and the internal battery doesn't need to discharge below the lower limit. If the external source is from AC then one is "in like Flint". If it is another lithium ion battery it could be put into a small cooler with some hand warmers to keep it warm enough not to damage it's internal cells.

Best Regards,
Curtis

HI. If your external power bank supplies enough power (current), then the SeeStar will happily use this in preference to its own internal battery.

However, if the external power bank doesn't supply enough power, then there may be some sharing done, with the SeeStar using its internal battery to make up for the shortfall.

Additionally, if the external power bank isn't smart enough to auto-turn on when a client device (SeeStar) requests power, then it may (as suggested above) turn off and leave the SeeStar having to power itself.

curtismacc

Yes, I agree with you now.
In my opinion, Seestar should not continue to charge after full charge, if you have been connected to an external power supply, Seestar will not continue to charge, but use the power in the battery. Seestar does not use power from an external source until Seestar runs out of power.

yDrqQBnb The ports all seem to be rated at 3A at 5V which should be plenty to power the Seestar without tapping into the internal battery. I have measured the power draw of the Seestar under different operating conditions and here is a summary:

        Tracking & imaging                     4W
        Slewing to a new target            7-8W
        Opening/Closing Arm               7-8W
        Fast slew                                  10-11W
        Dew heater                                0.4W

So a supply with 15W capability should be plenty unless you are operating a really low temps where the external source may be a bit sluggish.

Support@Seestar Your response appears to be contradictory. Maybe it is a Chinese to English issue, I am not sure.
You say " Yes, I agree with you now. In my opinion, Seestar should not continue to charge after full charge, if you have been connected to an external power supply, Seestar will not continue to charge ..."

This statement does agree, as you say, with what I posted above and have confirmed by measurement. A fully charged internal battery will not provide power to the Seestar if an external power source is connected and has sufficient current (3A) and power (15W) capability.

Now here is where you response seems contradictory. You go on to say

"... but use the power in the battery. Seestar does not use power from an external source until Seestar runs out of power."

This is the exact opposite of your previous statement. Again, it may be the translation. I would appreciate knowing what ZWO tech support believes is true for this question.

Best Regards,
Curtis

I use a ugreen 145W power bank that mounts on the side of the S50 body in a clip-on cradle. With the dew heater on I can observe dusk to dawn. The power level on S50 always stays at 100%. So, power drain comes from the power bank. I also use a 18" usb so there's no fear of entanglement. As dawn approaches, the power bank has about 20% left. It works.

@ curtismacc
Last night I used the Seestar S50 for 10 straight hours using the same external power source that I use to recharge an iPhone. Both the Seestar battery & the external battery were at 100% at the beginning of the night. At the end of the night the S50 indicated 100% Seestar battery life while the external battery was 27%. The battery I used was this: