The ReVIVE DUAL-ion+ dual battery charger from around $20 can handle both Canon and Nikon DSLR batteries as well as other small cameras and non brand batteries via interchangeable adapter plates.
ReVIVE DUAL-ion+ Dual Camera Battery Charger
Dual Battery Charger allows you to charge two batteries at the same time quickly and efficiently, Status LED Display for Real Time Charging Progress, Auto-cutoff enables trickle-charging when full, Utilizes MPC Technology for Fast and Smart Charging. AC, DC world-ready 100-240 volt, Charges either 1 or 2 Batteries! Additional interchangeable charging plates for other battery types are also available.
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