Yep, simple diode bridge. Add a capacitor to smooth it.
If the amps are low, its under $5.
Bad part is the 160+ VDC will charge the batts REAL fast and blow them apart. It would only work if you had more batts in a series to get closer, say 12 of them.
A basic charger would be much safer
Not my drawing :
Wish I could take credit for it