I'm looking to buy Nikon SU-800 flash and I noticed that it uses CR123A batteries. I found a lot of options on eBay and Amazon but most of them have low or mixed reviews. Does anyone use these type of rechargeable batteries and chargers and have recommendations?
The problem with rechargeable batteries is they are always lower capacity and usually have different voltage ranges. Capacity matters a great deal for high draw items like a flash. Voltage range tolerance depends on the specific equipment (manufacturers never specify). 900mAh seems to be the highest a rechargeable can get compared to the standard 1500mAh. That right there is worth a comparison during a long photo shoot.
Many rechargeable CR123As peak off the charger at over 4V. That could be a problem. While other batteries may not specify their peak voltage range, certainly a 3.6V battery will peak higher when fully charged. With some looking I've found 2 notable contenders, both of them boldly stating their safe voltage:
I can't find capacity mentioned for the Delkin and it's more expensive so Tenergy is the winner. Note: there are two different Tenergy CR123A rechargeable batteries. One is lower capacity at 750mAh with a 3.2V nominal peaking at 3.9V. Avoid that one.
Last note: the linked site sells single batteries but also has a 4 pack, with charger and free shipping for $19 right now. Best choice and best deal.
I have used Tenergy Li-ion CR123A batteries in the past but that was a few years ago. Link here They worked well and I never had any issues with them, but not having tried any other ones I cannot compare them to the competition for you.