On 6 Jan 2001, at 12:47, Mark Cassino wrote:
> A few months ago I broke the foot off a Sunpack MZ440AF flash. I sent it
> back for a repair, paid the $40 repair estimate, and in return Sunpack sent a
> brand new flash. I popped in some rechargeable alkaline batteries. The flash
> worked OK but would take forever to recharge, and seemed to have little staying
> power when being used as fill (i.e. - it would run down where the old flash
> would just keep popping along.) I tried several different sets of the
> rechargeable alkalines, most right out of the charger, and had the same
> experience.
>
> Last week I put in some regular alkalines and the flash charged up nice and
> quickly.
>
> I figured that my rechargeables were going bad. But, I wound up leaving
> the flash on, and the next day the regular batteries were dead. I switched back
> to the rechargeables - and the flash still is charging up quickly. I just pulled
> it out again, after it has sat empty for several days, and it still is charging
> quickly.
>
> So -- if there something about priming a flash with optimum batteries when its
> brand new? (I'm sure my rechargeables are not as good as fresh single use
> batteries).
Hi Mark,
The flash capacitors (high voltage electrolytes) can loose capacity (de-form)
if they are left un-charged for long periods however given that the flash is in
fact new I would not consider this to be the problem. I would guess that the
new design is more sensitive to the lower terminal voltage of the re-chargable
cells. If this is the case I suspect you may find the same problem with all the
new-improved units :-(
Good alkaline cells can have an initial terminal voltage of 1.58v whereas NiCd
are not likely to be over 1.35v at full charge, so the cumulative effect over four
series cells might be the differential of almost 1 volt. To test the effect of cell
voltage vs charge time you would need to substitute a variable power supply
for the dry cells and time the charge rate at various voltages.
Cheers,
Rob Studdert
HURSTVILLE AUSTRALIA
Tel +61-2-9554-4110
Fax +61-2-9554-9259
UTC(GMT) +10 Hours
[EMAIL PROTECTED]
http://www.ozemail.com.au/~distudio/publications.html
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