I have used Jackery's 500 and 1000Wh solar generators over the last year and would have no problem recommending them. Yes Jackery is one of the more expensive solar generator manufacturer's but when you look at the components inside you will see they are very high build quality and have been around for a dozen years. In contrast, there are lots of battery tear down videos which show how poorly manufactured some of the cheap solar generators or bare lithium batteries are made. There are also some less expensive ones which seem to be very well made based upon the tear down videos I have seen. Check before you buy.
I have tested several different LiNiMnCoO2 solar generators and LiFePO4 batteries over the last year plus both in my home observatory and in the field. I have shared a lot of what I found in the presentation I gave on The Astro-Imaging Channel back in June. Skip ahead to ~ 31min into the presentation to see the part about Li batteries and solar generators.
A few comments relative to the information in some of the above posts:
1. First, all of the solar generators and lithium batteries I have seen on the market have a Battery Management System (BMS) imbedded inside. If you find one that does not, avoid it. The BMS is in there to protect the battery from misuse, damage, fire etc.
2. Because of the BMS all solar generators and lithium batteries are designed to be discharged until the BMS shuts down the output. This will happen when 100% of the manufacturer's capacity specification has been reached. There is no need to shut the power supply down at 80% or 90% of capacity. The BMS will not let the individual cells inside be discharged below a safe minimum to prevent damage to the cells and loss of longevity of the battery/solar generator. In other words, while most NMC power sources specify 500+ full discharge cycles and most LiFePO4 power sources specify >= 2500 full discharge cycles, you will not reduce the number of cycles by running the power source until the BMS shuts it down. But yes, you can increase the number of discharge cycles of lithium batteries by stopping before full discharge. But think about how long it will take you to use 500 full discharge cycles. Remember, these batteries are only spec'd for a 10 year lifetime. Also, if you use the full capacity for the 500+ cycles, the battery will not be dead, but will have had its capacity reduced to ~ 70 to 80% of its original value. So, it will still have life.
3. While the discharge curve of NMC cells falls off faster than LiFePO4, all of the power sources using NMC that I am aware of, such as the Jackery solar generators, regulate the output voltage. As an example, I measured the output voltage of the Jackery 500 from 100% SOC until 0% SOC with a power load of 60w. The output voltage started at 12.9V and finished at 12.8V when the BMS shut the output down and the Jackery's LCD showed 0% capacity left. This is not unique to the Jackery 500. This is how they are designed to work.
4. I have just measured the voltage discharge curves of two different LiFePO4 batteries which commonly are not voltage regulated. I tested one from Battleborn and the other from Bioenno Power. The Battleborn 100Ah battery maintained the voltage above 12V until it discharged to 95% of its full capacity. Interestingly, that happened after delivering 105.5Ah of power wihich is 5.5% above the battery's spec. It happens because Battleborn builds their batteries with cell packs that exceed the rated spec by ~ 4 to 8%. The Bioenno 50Ah battery maintained the voltage above 12V until it discharge to 91.5% of its full capacity. Measurements were at room temperature which was ~ 85 degrees F.
5. I have also used a Talentcell battery like the one Lee linked to above. Mine is 8.5Ah capacity and has been used when I need much less energy such as when I am using a very simple EAA setup for outreach. As pointed out, they have some convenient output options including 5V, etc. It is hard to find complete details on the small form factor Talentcell batteries so it is not clear which chemistry they use except in the few they indicate are LiFePO4. I have seen the inside of one of their batteries and it did have a BMS as I expected.
Hopefully this helps others thinking about lithium power solutions.