Can someone explain what is considered one charge cycle out of the 3,000 before battery reduction? If I charge for 15 minutes is that considered one charge cycle? If I charge for 5 hours is that one charge cycle? If I have solar charging every day is the charge cycle from first light until the sun goes down? Thanks Mike
@Mikeg
A charge cycle is specifically defined as the full charge and discharge of a battery. If disaggregated, a charge cycle consists of a full charge (0%–100%) and a full discharge (100%-0%) process.
Great thanks for the explanation!!
Noting your explanation “Bluetti Support” if a power station with LiFePo4 batteries is regularly discharged to 50% then full charged to 100%, would the cycle life be more than the specified 3,000 cycles?
Yes, as an example the B300 has a nominal capacity of 3072 Wh of energy.
At 100% state or charge it contains 3072 Wh nominal.
Discharged at 50% it contains about 1536 Wh and that operation it could be compared to being discharged by spending half a cycle.
I understand that it’s simple math, however, does it increase the number of cycles over the life of the power station?
Yes, it does. As an example discharging it from 100% to 50% twice it equals to 1 cycle.
This not taking into account non-linear discharging and charging curves and more complicated maths that will add some error which we can safely ignore since cycles are just an approximated estimation.
Thank you for the info. I have several 100Ah LiFePo4 batteries in my RV and use a similar observation. As they are different construction, voltage etc I wanted to confirm the similarity. My 100Ah’s are rated to 4,000 cycles at 80% DOD, however my usual DOD is around 30% and at that I might expect 6-7,000 cycles according to the manufacturer. At my age, they will likely outlast me, lol. Thanks again for your assistance. 
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If you want a somewhat easier visual confirmation you can do a web search for lithium iron phosphate discharge graph. Do a image search you’ll see several there. Most are pretty straightforward and easy to understand. To extend the life cycle I’m trying to keep mine between 20 and 80%. If it goes below 20 it seems to drop off quickly and if it tops off above 80 it doesn’t gain much more and it reduces the life of the battery so it doesn’t make sense to keep it at 100 or to go over 80. I’ve also got in the habit of keeping my mobile devices with the lithium-ion battery between 45 and 85% in order to extend the battery life.
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Welcome to the community @Metallicat.420 ! And I’m with you! Since dabbling with these portable power stations and getting more and more into the tech behind everything, I too find myself paying more attention to charge rates and battery SOC levels on all my appliances! 
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Interesting. I have the same experience with the last 20%. My AC180 once it hits 20% remaining DOES NOT mean 20% remaining! I thought it was a fluke when it happened once but sure enough if it hits 20% remaining and I only have a slight draw on it , it will turn off and be dead shortly after that.
Yeah I was having a similar thing happen with the AC 200 Max but if you find one of the graphic charts online for the battery depletion it gives you a visual of how that process works. It’s sort of a plateau slow decline between 80 and 20% but once it hits 20 it’s a pretty sharp drop. Although even when it drops to zero there’s still some minor charge in the batteries I’m sure that’s how the factory set up these devices otherwise it would be fully depleted and unable to recharge. There’s also a numerical charts with the life cycle that shows how many cycles you can get out of it but they’re online a quick web search will find you some of that information overall I like the product a lot though I don’t regret purchasing it at all
What is the reason that holding these batteries at 100% causes a reduction in overall battery lifetimes?
That’s a good question there was a website I saw called battery University that talked about lithium-ion batteries and life cycles for products such as cell phones and tablets. They did testing and found that keeping those batteries between 45% and 85% extended their life cycles. I think they did discuss why it’s better not to keep them at 100%. I don’t exactly remember the details now but it should still be on their website.
I checked the battery university site and didn’t see much discussion specifically oriented toward the LiFePO4 that Bluetti uses. One quote under the LiFePO4 section seemed to suggest that that chemistry is more robust than the other lithium types when fully charged: “Li-phosphate is more tolerant to full charge conditions and is less stressed than other lithium-ion systems if kept at high voltage for a prolonged time.” They seemed to be making the case that, since that type starts out at a lower nominal voltage when fully charged than the others, that it’s more tolerant of it. Unfortunately that doesn’t really tell us much about why a full charge should or shouldn’t be avoided in that particular chemistry.
I don’t think the number of charging cycles will limit the service life, but rather the electronic components. If you calculate one charging cycle per day, that would be 9.5 years with 3,500 cycles. Anyone who believes that, with exceptions, the devices will last for 10 years of continuous operation will also believe in miracles :-)
Greetings Marcus