interesting to charge phone and voltmeter in sight

[Barbastro K6]

https://es.aliexpress.com/item/1005007614330107.html?aem_p4p_detail=202603270419062335489001709060000245845&algo_exp_id=7fda384b-2f25-4952-9490-0e133ce90ad0-11&pdp_ext_f=%7B%22order%22%3A%2212779%22%2C%22spu_best_type%22%3A%22price%22%2C%22eval%22%3A%221%22%2C%22fromPage%22%3A%22search%22%7D&pdp_npi=6%40dis!EUR!18.72!5.57!!!145.94!43.44!%402103892f17746103460512923ebba9!12000041506007029!sea!ES!135463698!X!1!0!n_tag%3A-29919%3Bd%3Aaa01b472%3Bm03_new_user%3A-29895%3BpisId%3A5000000203066076&curPageLogUid=eWKzJjtDfClC&utparam-url=scene%3Asearch%7Cquery_from%3A%7Cx_object_id%3A1005007614330107%7C_p_origin_prod%3A&search_p4p_id=202603270419062335489001709060000245845_3#nav-description


on handlebars or under the seat and/or next to rear optic tube  attached

[Mr Gee]

If you have a Optimizer/Charger lead fitted, you can simply plug into that. Been doing it, for years. 

[Eric GSX1400K3]

Have a look at quadlock.com.au, you can mount your phone and charge either via USB or directly.  Pretty sure they do a GPS mount as well.

Get a lithium battery as well.