I purchased an AC180 and EB3A as backup for power outage. I discharged each and recharged to 100% before repacking them. It is going to be at the three-month checking them in about two weeks, but what am I supposed to do? Do I discharge them until they turn off or show zero percent. Or do I see if they have a charge. What do you mean by checking them at 3 month intervals when storing them long term? I may never need them if the power doesn’t go out.
I understand that people may have different opinions on this issue.
From a technical point of view, a stored battery pack does not need to be recalibrated since it has not been used. Recalibration is necessary because a pack consists of many cells and they may have small differences in their internal resistance, so when they are charged and discharged multiple times at different voltages they may become unbalanced. Recalibration is necessary to bring them back into balance.
Also, discharging and charging the battery pack is usually necessary for the internal BMS to update the total battery capacity and display a correct SoC (0-100%) during charging and discharging by tracking the current.
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When the unit is off the battery gets very slowly discharged but the display % won’t get updated, because the unit is off, so by turning the unit on after a long period of storage you could see 100% at the display even if the internal battery is not at 100% anymore.
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Since you are just storing the battery for long periods my only suggestion is to connect it to charge every 3 months to top-up the cells back to a 100% charge state.
If you also completely discharge the battery at this time and then fully recharge it, you can update the internal capacity to get the most accurate capacity % possible over time.
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I use my power stations in a similar manner to other LFP batteries I own. My RV (Caravan in AU) generally hibernates for around 5-6 months during the hot summers.
With these I drop the SOC to 80% after my last trip of the season for storage. (2 x 100Ah LFP in parallel) I can totally isolate them.
When I fire them up, as I did a few days ago, the battery management system usually gives me an error code meaning, “battery maintenance required”. This translates to charging them to 100% using the grid (240VAC) to 100%. I don’t do a discharge/recharge recalibration unless I see strange (unexpected) data on the display when using them. (I’m off on a trip in less than 2 weeks)
As a consequence, I treat the 3 x AC180s and 2 x AC70s the same way when at home. I store them at 80% for grid outages as required. As I have extra capacity, I have options to quickly get them to 100% during these occasions. When the grid comes back, I keep using them until they read 80-85%, for storage before reconnecting devices to the grid. I recently did a recal. on all of them and won’t repeat until there’s an issue.
When I go off grid camping, I charge 1 x AC180 & 1 x AC70, I take with me, to 100% before leaving home. 
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I forgot to mention, I did do a recal. on my RV LFPs recently, just to make sure, lol. They are over 3 years old, it’s the first one I’ve done on them and, even then, probably not needed.
BTW the extra capacity I have, is an older AC200P with 2,000Wh available. I can quickly wheel it around the 70s & 180s to top them all up. Then take the 200P out to solar, vehicle or generator to recharge it. (It’s on a dolly trolley)
I would not store them at 100%. However I have multiple ways to recharge my two AC180 if the grid is down: generator, solar panels, car. I got the batteries to minimize my time running my generator. The owners manual says to store them at half charge (page 7), but if you would have no way to recharge them, then storing them at 80% to 100% would be smart.
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For storage, set them at 50% SoC. That’s usually what manufacturer’s do to LFP batteries.
Re-check every few months.