Rolleiflex flashgun

Generally NiMH cells are easily substituted for Nicads because they're both about 1.2V per cell. I don't think the flash will care one jot if NiMH are used, but the new battery should be recharged with an NiMH charger, not a Nicad charger.

If an exact equivalent to the original battery can't be found, it's easy enough to make a stack of 4. The main problem is fitting them into the space provided.

In general NiMH are all round better than Nicads - they hold more charge, store longer, and aren't ruined by 'memory effect'.

Dave

I have had a reply back from, All Batteries, no go with them as they have no batteries to suit.

As SOD says perhaps make up a pack to fit the space in the casing? which batteries though.

Thanks to all who have contributed to my query.  Clive

Edited By Clive Hartland on 19/10/2022 22:17:15

Clive

If the battery voltage is IRO 3.6V you might consider changing to a single Lithium cell which for the same storage capacity can be much smaller than equivalent NiCad/NiMH cells. A very cheap lithium cell charge control circuit can be purchased from eBay and this allows you to use a standard mobile phone charger. I don't know what mechanical changes may be needed but if push comes to shove the charge controller circuit board can be fitted in a small external adaptor.

CS

Back home again and able to comment further, but not sure how helpful this is.
My aforementioned M&W Micro 2000s & Microstat were originally supplied with a NiCad stack of either 3 or 4 button cells depending upon the model.
The folk who now maintain them, and supply spares, sell NiMh as a direct replacement, and assure me that everything will be fine.
Up to press, that appears to be the case.
Previously I've made sure that I only charge NiMh batteries in a NiMh charger, though I do sometimes charge NiCads in a more modern NiMh charger.
They, are all larger cylindrical NiCads from AAA to D, rather than button cells.
One of my early NiMh chargers actually has a switch to set the charging schedule depending on the battery technology; the later ones claim to work with either.


Battery University does suggest that NiMh in a NiCad charger can overheat, but I don't know how much this applies to the smaller button cells, which will have a very low trickle charge rate, and originally be designed for it.
https://batteryuniversity.com/article/bu-408-charging-nickel-metal-hydride

Since NiCads are all but unavailable in the size you need due to H&S regs re the Cadmium part (a bit like silver solder), it's all a bit of a moot point

I can only suggest a suck it and see approach and try a NiMh stack, but monitor how the flash gun charges the cells, with volt & ammeters as well as a non contact thermometer.
You can measure the mAh charge rate, and knowing the capacity, should get a good idea of the charge time(ish)

If need be, one could always use a timer to prevent over charging; I suspect leaving them on permanent charge would be bad for either technology.

Bill

It seems I picked the wrong spec for the battery, it is a 3.7v. 500mAh.

So I will have to start looking again.