ffs mount options or tuning to prevent corrupted fs on power-outage

Hi,

can someone give me a recomendations for ffs mount options or further
tuning to prevent file-system corruption on power-outage?

I run a PC-Engines APU2c3 with -stable in a rural place where power-outage
takes place approx. once a month. Most of the time every things starts fine
when power is back, but sometimes (now the third time in one year) I end up
with an corrupted /var and I´ve to go to that place and do manual fsck_ffs
which could always repair the fs.
I already tried with the softdep option but it didn´t prevent fs-corruption.

$ mount
/dev/sd0f on /var type ffs (local, nodev, nosuid)


/var lives on a mSATA-SSD

Thanks
Thomas