sorry to hear about the accident. I’m glad your husband has access to ices tech. to make portable the c5, you would only need an external usb battery. a 20,000 mAh battery or greater would be what you would want. however, you’ll find the lower powered protocols such as the ones that have timed pauses in the pulses may not work with most modern external batteries that have power saving features. those batteries turn off if the power consumption is very low. for example, just cycling thru the menu system alone, my c5 or m1 turns off bc the external battery i use doesn’t detect any power being used by the device. protocols that have timed pauses in their pulses definitely don’t work (battery doesn’t stay on).
you can try different batteries on Amazon to see if you find one that doesn’t time out since Amazon has a great return policy.
this particular brand i like, but may have the same energy saver timeout sensor that Bob has mentioned (in other posts) many modern external batteries have these days:
Anker Portable Charger, 325 Power Bank (PowerCore Essential 20K) 20000mAh Battery Pack with High-Speed PowerIQ Technology and USB-C (Input Only) for iPhone, Samsung Galaxy, and More https://www.amazon.com/dp/B07S829LBX/
that said, once you find an external, you’ll want to get at least 2 as these batteries do take awhile to charge depending on size and price. with at least 2, you can continue to use the c5 portably after the first battery runs out.
since you are using the 2x2 coils, you might not need the coil wraps they sell on Amazon. i use the wraps to help minimize the tangle of cables from the pair of coils that i use.