As stated about 100 posts ago, ABYC doesn't allow solder to be the only connection. Crimp or crimp and solder but crimping is a must.
ABYC does make an exception for battery lugs which can be soldered without crimping. Also, ABYC is not the law, their standards are advisory only and entirely voluntary. Lots of electronics equipment wiring connections are soldered only. Soldering is fine as long as you provide adequate strain relief on the wiring to prevent flexing of the soldered joint.