A far as I can tell it was due to me running "python-light", installed the full python3 on a external usb as suggested and that fixed it.
Copied the output from installing python3, in case someone wants to dig into what the cause might be.
root@Omega-225A:/# opkg install python3
Installing python3 (3.4.3-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/python3_3.4.3-2_ar71xx.ipk.
Installing python3-light (3.4.3-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/python3-light_3.4.3-2_ar71xx.ipk.
Installing python3-base (3.4.3-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/python3-base_3.4.3-2_ar71xx.ipk.
Installing libffi (3.0.13-1) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/libffi_3.0.13-1_ar71xx.ipk.
Installing libbz2 (1.0.6-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/base/libbz2_1.0.6-2_ar71xx.ipk.
Installing python3-asyncio (3.4.3-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/python3-asyncio_3.4.3-2_ar71xx.ipk.
Installing python3-codecs (3.4.3-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/python3-codecs_3.4.3-2_ar71xx.ipk.
Installing python3-ctypes (3.4.3-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/python3-ctypes_3.4.3-2_ar71xx.ipk.
Installing python3-dbm (3.4.3-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/python3-dbm_3.4.3-2_ar71xx.ipk.
Installing libdb47 (4.7.25.4.NC-4.1) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/libdb47_4.7.25.4.NC-4.1_ar71xx.ipk.
Installing libxml2 (2.9.2-3) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/libxml2_2.9.2-3_ar71xx.ipk.
Installing python3-decimal (3.4.3-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/python3-decimal_3.4.3-2_ar71xx.ipk.
Installing python3-distutils (3.4.3-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/python3-distutils_3.4.3-2_ar71xx.ipk.
Installing python3-email (3.4.3-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/python3-email_3.4.3-2_ar71xx.ipk.
Installing python3-gdbm (3.4.3-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/python3-gdbm_3.4.3-2_ar71xx.ipk.
Installing libgdbm (1.11-1) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/libgdbm_1.11-1_ar71xx.ipk.
Installing python3-logging (3.4.3-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/python3-logging_3.4.3-2_ar71xx.ipk.
Installing python3-lzma (3.4.3-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/python3-lzma_3.4.3-2_ar71xx.ipk.
Installing liblzma (5.2.1-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/liblzma_5.2.1-2_ar71xx.ipk.
Installing python3-multiprocessing (3.4.3-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/python3-multiprocessing_3.4.3-2_ar71xx.ipk.
Installing python3-ncurses (3.4.3-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/python3-ncurses_3.4.3-2_ar71xx.ipk.
Installing python3-openssl (3.4.3-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/python3-openssl_3.4.3-2_ar71xx.ipk.
Installing python3-pydoc (3.4.3-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/python3-pydoc_3.4.3-2_ar71xx.ipk.
Installing python3-sqlite3 (3.4.3-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/python3-sqlite3_3.4.3-2_ar71xx.ipk.
Installing libsqlite3 (3081101-1) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/libsqlite3_3081101-1_ar71xx.ipk.
Installing python3-unittest (3.4.3-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/python3-unittest_3.4.3-2_ar71xx.ipk.
Installing python3-xml (3.4.3-2) to root...
Downloading http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/packages/packages/python3-xml_3.4.3-2_ar71xx.ipk.
Configuring python3-base.
Configuring libffi.
Configuring libbz2.
Configuring python3-light.
Configuring python3-pydoc.
Configuring liblzma.
Configuring python3-email.
Configuring python3-decimal.
Configuring python3-xml.
Configuring libxml2.
Configuring python3-ncurses.
Configuring python3-distutils.
Configuring python3-codecs.
Configuring python3-multiprocessing.
Configuring python3-asyncio.
Configuring python3-ctypes.
Configuring libdb47.
Configuring python3-dbm.
Configuring libgdbm.
Configuring python3-gdbm.
Configuring python3-logging.
Configuring python3-lzma.
Configuring python3-openssl.
Configuring libsqlite3.
Configuring python3-sqlite3.
Configuring python3-unittest.
Configuring python3.