Brown F900 flash

I have one With no battery so I need to find out the Voltage on the battery. Anyone out there who knows?

I could also like to have a servicmanual because the one I have is form a later Version of the unit than the one I have.

If we are talking about "Braun" F900 a German flashgun with separate generator pack: 8 V, from 4 Pb cells. - Not easy to find. - Ponder replacing them with 6 or 7 sub Cs or get a really capable HAM radio PSU that you can dial down to 8 V. - I only tried out the latter. The unit draws a lot of current at the beginning of it's charging cycle, surely more than the comparable Metz 60 CT4. Unfortunately PSUs deliver less current at dialed down Voltage. - Something 30 A at 13.8 V works for me, when dialed down to 8 V. - Good luck!

I had a similar, but older, Braun "Hobby" outfit. It used 3 x 2v lead-acid cells. I replaced them with 5 'C' Nimh rechargeables, and it worked just as well.

 

You'd need 7 NiCd or Nimh cells to replace 4x 2v Pb cells. Sub C sized cells are commonly used in electric drills and other rechargeable tools. Sub Cs are easily bought in solder-tag varieties for easy connection, and in capacities up to 3 or 4000mAh.

 

They'll be lighter and cheaper than trying to find suitable lead-acid replacements. There may even be a switch or 'jumper' to make the charging circuit more suitable for NiCds.

 

According to the manual - HERE - the Braun 900 was available with lead-acid or NiCd accumulators.

If we are talking about "Braun" F900 a German flashgun with separate generator pack: 8 V, from 4 Pb cells. - Not easy to find. - Ponder replacing them with 6 or 7 sub Cs or get a really capable HAM radio PSU that you can dial down to 8 V. - I only tried out the latter. The unit draws a lot of current at the beginning of it's charging cycle, surely more than the comparable Metz 60 CT4. Unfortunately PSUs deliver less current at dialed down Voltage. - Something 30 A at 13.8 V works for me, when dialed down to 8 V. - Good luck!

Thanks.

8 V seems to fit from what I read out for the Electronic. No problem to make 8 V out of a 9 V battery, simply ad a silicondiod in serie. The slicondiod use 0,7 V so that it it.

"No problem to make 8 V out of a 9 V battery, simply ad a silicondiod in serie. The slicondiod use 0,7 V so that it it."

 

- Well, maybe you could let us know how you got on finding an off-the-shelf 9v battery capable of delivering the 6 or 8 amps a flash inverter circuit needs.

 

Perhaps the OP wired 20 or 30 PP3s in parallel?

I think in the design they took into account that the battery which has nominal voltage of 8V won't be able to deliver 8V when delivering the high current draw for the inverter circuit. I think if you connect it to a high current capable, regulated power supply of precisely 8V it would damage the flash.

Small Lead-acid "accumulators" can deliver at least 10 Amps without their terminal voltage dropping significantly.

 

Any properly designed inverter circuit should have built-in current limiting in any case. But it almost certainly won't recycle in any sensible time from a zinc-carbon 9v battery.

Edited January 14, 2018 by rodeo_joe|1

I think if you connect it to a high current capable, regulated power supply of precisely 8V it would damage the flash.

No worries; it really worked for me for quite a while.

Upon batteries: I am not sure if the F900 would work with a slightly lower Voltage than 8V, still above 6V. I suggested 6 Sub C cells for the simple reason that soldered Tamiya race packs can be had for cheap. - If you happen to know any RC car enthusiast try borrowing an old one and look and see if it is enough or not. 8.4V packs are less common (and priced accordingly) but available too. To me it seems that confectioned race packs tend to be cheaper than single cells bought on their own. Thats why I'd equip the Braun with either Tamiya or AMP plug and use RC car batteries. - The cheapest should do well enough!

Good luck!

Oh and don't fuzz about the 0.4V more it is unlikely to damage the flash. - No clue how much is too much though.