I bought several of the 96wh(?) IDX versions of the BPU90 with the two P/D-taps and USB to power my audio bag, but rented them out recently to someone that needed some spares for a shoot. I think he shot all day on half a batt. They’ll also charge off of the “smart d-tap”.
Already have four of the Swit batteries but if I was buying today would choose the IDX. The D-Taps are much better placed on the IDX, & Hawk-Woods, but Hawk-Woods are twice as expensive as the IDX on this side of pond.
One suggestion is to ck Adorama or B and H Photo in their used department for BPs. You can often get perfectly good used ones at a good price. Also, picked up a couple on eBay too, but trust Adorama and B&H more than eBay.
I have different batteries as i have about 6 cameras that goes with the BP-U battery, I have Dynacore ,Hawk-Woods Swit and Sony but my preferred batteries are the Core SWX Nano-U98 14.8V Battery ,great duration and D-tap power and usb, I always power my FS7 and smallhd monitor and usually two batteries are enough for a shooting day,even if i always bring more than two...a lot of options out there,one thing is sure,I don't buy Sony batteries anymore,no D-tap and usb is a no no for me!
Plus 1 more for the switts... i havent used my fs7 for quite a while (more than 8 months) as well as not having charged the batteries and keeping them around 50%. Pulled out the kit last night. The batteries were completely drained but left them in overnight and today they are at 100% ...
From what I recall the 96w switts would give me almost 4 hours of shooting at 1080 25.