Speedlights and battery issues

[Simpo Two]

Needed to take some record photos of a house yesterday - nothing special but used an SB800 on the hotshoe. NiMH batteries had been fully charged about 3 weeks ago, then left.

I switched the flash on and although it whistled happily the ready light didn't come on. Anyway, it flashed with the test button so I started work.

Normally you'd expect a flashgun with low batteries simply to give dark photos. But in this case the exposure was all over the place. Sometimes it was right, sometimes 2-3 stops under, sometimes totally black (although the flash fired so it must have been a synch issue).

I took the batteries out of the camera, turned the flash off and on, tried manual exposure and still the exposure was all over the place - one of my wedding nightmares! (and no, it wasn't set to bracket mode).

Eventually I fitted a fresher set of batteries, the ready light came on and then everything worked fine.

I just wondered if anyone else had experienced the same issue. Normally when flash batteries die after a long day's work they just start giving underexposure.

[Pete Baraka]

Ni-MH's are great for speedlites, especially for fast flash recycling, but...

"There is one blemish on the record of Ni-MH's. They self-dischage faster than alkalines ... I tend to top them off (no memory - top them off any time) within a couple days of when I am going to need them."

http://strobist.blogspot.de/2007/09/feed.html

I run 8 sets of 4 AA's & always top them up the evening before a shoot.

Pete

Edited by Pete Baraka on Friday 5th October 12:54

[covboy]

Not sure down on power batteries should affect exposure. Shirly the batteries are there to charge the capacitor (or something !) which in turn provides the oomph for the flash

(Obviously very non technical)

[LongQ]

I find rechargeables very erratic. Whilst I would not expect that much drop off in a 2 or 3 week period I often find that one battery of a set has reached a terminal state since the last charge and so takes the set out. The effect of 3 partly charged and 1 discharged cell can be very erratic whether in camera or speedlight.

The trouble is if it's partly working you don't always notice until it's a bit late to do anything about it.

AA's are not as bad as AAAs which, in my experience, seem to be very prone to early failure.

[Whitefly Swatter]

I have had the discharge problem with NnMH batteries until I found Uniross HYBRIO AA and an intelegent charger (Technoline BL-700 Battery Charger) from these guys http://www.batterylogic.co.uk/default.asp

Never looked back, batteries still hold the charge months after charging sat in the storage box

[Simpo Two]

Thinking back, the battery in the camera was low too and had to be changed after maybe 20 shots. But even so, normally all that happens is that the camera simply refuses to fire - not throw in random exposures and synch failures.