"Flip" Saddle

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
It's not the saddle that flips, it's the seat-pin. Most people refer to the seat-pin as the seat-post, but the seat-post is actually the tube that the seat-pin sits in.
 

sjpt

Esteemed Pedelecer
Jun 8, 2018
3,838
2,759
Winchester
Thanks, I see it now. My tube is 27mm too small for Aliexpress
Check if it is 27mm (quite common a long time ago) or 27.2mm (still standard for 'narrow' tubes). Seem rare in 27.2 (closest I can see is https://www.ebay.co.uk/itm/282369337340), probably impossible to find in 27mm.

If you've got quick release seatpost clamp it is just as quick to remove the post altogether to fit/remove the battery.