The Canon 5D MK III and IV had the battery life I needed for this shoot. I could have easily left the camera at the launch site for days if and when there are delays. It could also shoot at aBattery. The Canon EOS 5D Mark IV uses the same LP-E6N Rechargeable Lithium-ion used in recent EOS DSLRs. This is backwards compatible with the slightly lower capacity LP-E6 ones used in the previous 5D series models. With an LP-E6N the camera is rated at 900 shots per charge by CIPA standards or around 300 shots in live view mode.
I've never seen failures with real Canon batteries in the body itself, but Canon's grips are notorious for this problem. Loosening the grip a little and retightening it will typically fix the problem is that's the issue.
PowerTrust 2-Pack 2650mAh LP-E6 LP-E6N Battery Compatible with Canon EOS 80D, 70D, 60D, 7D Mark II, 7D, 6D MarkII, EOS 6D, EOS 5DS R, 5D Mark II, 5D Mark III, 5D Mark IV 4.3 out of 5 stars 24 £19.99 £ 19 . 99 ( £10.00 £10.00 /Item)Canon 5D III Battery Door. Canon EG Eyecup. Canon LC-E6 Battery Charger. The EOS 5D Mark III is a full-frame 22.3 MP DSLR with 61-point autofocus and 6fps 65tk8n2.