Canon 580EX II... Lithium or Alkaline Batteries

I'd expect these to fry a speedlite. Better recycle time because there was more voltage offered to the capacitor for recharging. What impact it would have on the electronics is an open question and that's what would fry.

Your flash is made to run off of 4.8 vdc. 4 of these produce 14.8 vdc. Sure, go ahead and load it up. Let us know what happens.

steeeeevo wrote in post #15187774
Would I fry my flash with 4 of these puppies?

Yes.

Use 4 NiMh cells instead.

steeeeevo wrote in post #15187774
Sorry... old thread but wanted to ask about these batteries:

The voltage per pieces is 3.7 which is crazy high compared to normal. Would I fry my flash with 4 of these puppies? I read someone somewhere saying he used 1 of these and 3 regular batteries (with a nikon flash) and got much better recycle times.

Thoughts? Anyone tried this?

Yes, you will definitely fry your flash with 4 cells at 3.7v each. You are likely to irreperably shorten the life of your flash (to weeks, maybe even days) if you use 1 @ 3.7v and 3@ 1.2v. If you want better recycle times, get an external power pack - it's much safer for both the flash and for yourself.

dedsen wrote in post #15187975
Your flash is made to run off of 4.8 vdc. 4 of these produce 14.8 vdc. Sure, go ahead and load it up. Let us know what happens.

This will be after your bandages come off.

Invested in the Powerex MH C801D charger, Powerex and Imedion NIMH batteries. They work great.

is it a myth or should NiMH batteries be replaces every few years?

I found a few sets of mine don't hold charge as well anymore after a few years.

Claimed life cycle for NiMH cells varies (according to make and type) between 500 and 1500 cycles (see arrows on attached). Like each of us, they get older and eventually need replacement - although environmentally far superior to disposable batteries, they are not the ultimate panacea. Failure to hold their charge is the usual indicator that replacement time is upon us.

Ordinary NiMH accumulators (ie not the low self discharge types like Eneloop or Imedion) slowly lose their charge over a period of time. An ordinary rechargeable cell can be expected to go from fully charged to 'flat' in a couple of months and this is perfectly normal. The selling point of the LSD type is that this loss of charge takes place over a much longer period (a couple of years is the usual figure bandied about). Each type has their place and neither is 'perfect' - it all depends on your application.

As stated, the lifetime is supposedly about 1000 cycles...and if you do not regularly use and cycle the batteries, those cycles might well go past the 3 year timeframe, as some POTN members have experienced.

I recently started using Eneloop's, now I will be purchasing the Eneloop xx's.

dexy101 wrote in post #15196982
I recently started using Eneloop's, now I will be purchasing the Eneloop xx's.

Eneloop XX and Imedion cells are to some extent a compromise. They trade off the extreme longevity of charge retention of (eg) Eneloop for a greater nominal capacity. A by-product of this is that the number of charge cycles expected drops down to levels we'd normally expect from non-LSD cells.

Eneloop standard:
Claimed capacity: 2000mAh (1900mAh minimum).
Claimed average cycles: 1500.
Claimed charge retention: 75% after 3 years.

Eneloop XX:
Claimed capacity: 2500mAh (2400mAh minimum).
Claimed average recycles: 500.
Claimed charge retention: 75% after 1 year.

For sheer capacity alone, an ordinary non-LSD type (eg Powerex 2700mAh, Sanyo 2700mAh) has yet to be surpassed. For longevity, the pure LSD type (eg Sanyon Eneloop white) currently rule the roost. The Eneloop XX & Powerex Imedion fall between these two extremes, a compromise. Each type of cell has it's uses and none are "the best" for everything. There is room for all three types in our armoury (if we can be bothered messing around!). There is little or no value using LSD types if you are continually using/discharging/rech​arging; the value comes with intermittent use where charge retention is a factor. The only reason for the emphasis here on Sanyo cells is that they are much more readily available in the UK than Powerex - no reflection on the virtues of Powerex other than availability at a decent price.

Incidentally, you may come across higher ratings for ordinary NiMH (2900mAh is common, I've even seen claimed 3800mAh). These seem to work by using ever thinner seperator coils inside the cells but the thinner the seperator, the more subject they are to damage and a realistic maximum at present is 2700mAh. Higher than that and the cells aren't likely to last as many cycles as the slightly lower rated ones - especially if they get hot hot. Sometimes the pursuit of "the highest rating" comes with a hidden cost.

Edit: Available from October, standard Eneloops HR3-UTGB now claim 1800 cycles lifetime. Charge retention has been amended to 90% after 1 year and 70% after 5 years.