My 1st try was:
Anker Prime Power Bank, 9,600mAh Battery Pack with 65W Output, Built-in AC Plug, Supports PD 3.0 and PPS, 30W Fast Recharging:
https://a.co/d/adRfksH
I picked it for convenience (built in charger), smaller size/weight (just 0.67 lbs or 303 grams), a nice pleated cable it comes with, and what I thought is sufficient capacity: it is 3 times larger than the Vespera’s built in battery. My thinking was that if Vespara 2 lasts 3h on the built in battery then this external battery should last about 9h. Plus 3h Vespera already has it will give me 12h: enough for the longest night and more. But unfortunately this is not what I saw.
Charging the battery was fast: about 2h
Then I connected it to a fully charged Vespera and turned it on. My session lasted 2h 23m with 1 initialization and 1 target imaging (then clouds rolled in). Vespera was always showing 100% battery with the charging indicator. The Anker showed 37% charge at the end of the session (63% was used).
I decided to proceed the next night w/o re-charging anything: Vespera 2 was still at 100% and Anker was at 37%. I wanted to see what happens when the external battery is fully depleted to make sure there is no interruption and the internal battery just takes over. This happened just fine as expected.
2nd session lasted 2h 52mins. The Anker was fully depleted and Vespera had 45% left. The Anker went from 37% to 34% during Initialization of the scope and then lasted for 1h 15min.
Overall the 9600 mAh Anker lasted 3h 38min. Someone who is younger than me and still remembers college courses please explain why the bank lasted so little given the Vespera was drawing around 8 mAh :-)
Given this battery did not give me a full night (10 - 12h of imaging) I decided to return it and got :
ANKER 737 Power Bank, 24,000mAh 3-Port Laptop Portable Charger with 140W Fast Charging
https://a.co/d/3kqLfid
The charging of bank started very fast. It would probably take about 2 hours but my tiny wall 45W wall charger was getting too hot: the bank was drawing in 41W. I did not like this so stopped the charging and ordered an Anker charger for 120W (100W max on each jack):
Anker 737 GaNPrime, 120W USB C Charger, PPS 3-Port Fast Compact Foldable Wall Charger
https://a.co/d/9dyWyIS
The bank was drawing 91W and charging very fast: about 1h. The charger got warm but not dangerously hot. Personally I would prefer slower and more cooler charge and not push the bar so high for the speed but after some research I had discovered that the chargers are optimized for efficiency and they do get quite hot when charging powerful devices and designed to work while hot.
Now I was set for the Vespera tests with this 737 bank. Had to wait a few days for the rains to stop. Started the session with Vespera charged at 95% (it lost 5% just sitting turned off and waiting for the weather) and the Anker battery at 100%.
Imaging session lasted 2h 25m, Vespara got charged from 95% to 100% during the season and the Anker had 72% remaining (lost 28%). A much better result: the 727 Anker should last for about 8h 30m or more because during the session it charged Vespera from 95% to 100% and I also played with moving the scope from target to target and not just imaging 1 target.
Plus 2h 30min in the Vespera battery should give total of 11h or so. That is plenty for me.
I hope someone who is shopping for an external battery for a Vespera can find this useful.
Cheers!
Edited by BrickInTheSky, 06 June 2025 - 07:10 AM.
