Isn’t Amazon have these for $27??

TalentCell Rechargeable 12V DC Output Lithium ion Battery Pack for LED Strip/Light/Panel/Amplifier and CCTV Camera with Charger, Multi-led Indicator Black (3000mAh) https://www.amazon.com/dp/B00MHNQIR2/ref=cm_sw_r_cp_api_i_NDS7RM25EGHA7V6WJ8X8?_encoding=UTF8&psc=1

Adaptors

DC Power Cable 12V 5A Plugs Male... https://www.amazon.com/dp/B07C7VSRBG?ref=ppx_pop_mob_ap_share

Battery

TalentCell Rechargeable 12V DC... https://www.amazon.com/dp/B00MHNQIR2?ref=ppx_pop_mob_ap_share

There’s a link on the same page as the one The_BusFromSpeed posted. But here

It’s a 12 volt. This one: TalentCell Rechargeable 12V DC... https://www.amazon.com/dp/B00MHNQIR2?ref=ppx_pop_mob_ap_share

I made my Spectra portable with this battery pack. https://www.amazon.com/gp/aw/d/B00MHNQIR2?psc=1&ref=ppx_pop_mob_b_asin_title

After reading all the comments and seeing other similar posts, it amazes me so many people don't know about this solution. I learned this one from Josh Yeo of Make Art Now who uses it and pointed to a tutorial video for it.

I specifically use this one TalentCell Rechargeable 12V DC Output Lithium ion Battery Pack for LED Strip/Light/Panel/Amplifier and CCTV Camera with Charger, Multi-led Indicator Black (3000mAh) https://www.amazon.com/dp/B00MHNQIR2/ref=cm_sw_r_apan_i_QH8F255YS9KW3JPBN75Z?_encoding=UTF8&psc=1

You need to modify a bmpcc charging cable to connect to this, but I have 4 of these and I get about 2.5 hours of runtime on each. I 3d printed a custom attachment for it to mount to my cage and I get a nice tight rig without a giant V mount blocking my monitor.