Did I kill my batteries?

[tecboy]

I have two versions of eneloop. One is eneloop pro with 2450 mAh, and another is XX 2400 mAh. I accidentally mixed one version of a battery to another version of the batteries in the speedlite while the power was on, and I accidentally mixed one version of a battery to another version of the batteries in the charger while charging. So, my question is, will these batteries deteriorate soon?

 

[Alexr25]

You certainly did not "kill" your batteries. The worst that could happen if you are using a cheap charger is that the higher capacity batteries may not get fully charged but since NiMH batteries don't suffer from memory effects that will not damage them in any way.
Cheap chargers monitor the total voltage across all the cells stop charging when any one of the batteries reaches full charge. More advanced (and expensive) chargers monitor and control charging of each individual cell so all the cells get fully charged regardless of capacity.
If your charger was an advanced type then mixing the two types of battery will have on effect. If it was a cheap type and you are worried about getting the maximum capacity from your batteries then you could sort your batteries into types and give them a top-up charge just to make sure but given the small difference in battery capacities between the two lots I wouldn't bother.

 

[KmH]

The mAh numbers simple state how much charge the battery can hold.
NiMH describes the battery's chemistry - Nickel-Metal Hydride - and not NiCd or Alkaline.
The different battery chemistries have different maximum charge storage potentials.
We use NiMH in our speedlights because they hold the most charge and deliver the shortest speedlight recycle time between flashes.

AA battery - Wikipedia the free encyclopedia

 

[Overread]

They should be fine. The whole "charge and use batteries in groups" approach is about organising your batteries so that they have the same recharge and discharge cycle. That way they should have roughly the same life-span and performance; plus it also makes organising and charging a lot easier when you've formal sets of batteries to work with (there are loads of 4 battery holders on ebay/amazon - get a few and put each speedlite battery set of 4 into its own case when not in use - helps keep them together and is far better than elastic bands wrapped round them).