There's a lot scattered around the forum on using batteries and inverters for both stationary and mobile electrical power production and what I'm about to add may have already been addressed elsewhere, perhaps even in the videos in this thread. Since it seems that there is still a mix of legacy lead-acid and other batteries powering the different configurations here and because of recently experiencing an aspect of battery-inverter connection that is more pronounced and/or more of a concern with lithium batteries (and in the future, potentially other batteries that utilize a battery management system (BMS)), I'm posting this here. Please refer to the link
https://permies.com/t/179996/Sprinkler-pumps-shallow-pumps-irrigation for my introduction into using some newer 12V LiFePO4 batteries to run a booster pump for garden watering.
In the past, using a 100 Ah 12V lead-acid deep cycle battery and a 1500W modified sine wave inverter, I had grown accustomed to making inverter to battery connections and experiencing a mild spark at the battery post when making the final connection, quite similar to that when attaching a car battery under the hood. It appears from having perused many videos now that this spark, when dealing with lower voltage batteries and inverters, is relatively inconsequential and not harming to either the battery or the inverter. Once all cables are attached, proceed as usual. Thus my concern recently when I first attached a newer 12V 100Ah LiFePO4 battery with a 3000W 12V pure sine wave inverter...and experienced quite a dramatic spark with the initial contact. Subsequent contact was fine....and I've since learned that this is due to having 'pre-charged' the capacitors in ther inverter. The greater spark was due to larger capacitors in the larger 3000W inverter. The fix for this is all over YouTube and in different forms. Essentially, the spark is from the capacitors demanding full in-rush current from your battery when you touch the cable to the pole: By placing a resistor of sorts beween the battery post and the cable going to the inverter, that rush of current is reduced and no substantial spark occurs. It's a bit vague what to use as the resistor, but alternatively many will use a 12V automobile incandescent battery to serve as the 'resistor'--when the connection is made, the light illuminates and fades rather quickly, signifying that current has passed through the bulb to fill the capacitors, but once filled, they do not discharge back towards the battery. Once complete....over only several seconds....the connections can safely be made. The point is driven home that the spark is not necessarily trivial. It can cause tiny fragments of hot battery post to spit off towards you, so hand, arm, and face/eye protection is recommended if doing for the first time. If this already has been addressed in (a) past posts, please feel free to disregard. Hope this of use to others.....and if interested in more, search on the terms "battery inverter capacitor pre-charging".