Don't let the Shorai battery (or any like it) discharge below 11V for an appreciable amount of time.
If the battery is drained below 11V, put it on a battery tender and allow it to recover back to fully charged state.
If the battery is drained below 11V and allowed stay that way, it may not ever recover.
And never let the battery fully discharge as that will chemically alter the battery permanently.
For troubleshooting, it may be best to use a lead-acid battery until your problems are found and fixed, then put it back on the Shorai.
Also, if you Shorai (or other lithium) are sitting on the shelf, periodically check the charge state, and if it's dropping down below 12V, put it on a battery tender until fully charged, then remove. Don't leave the battery in maintenance mode on the battery tender.