Metz 60CT4 power pack setting for NiCad vs Dryfit

Discussion in 'Lighting Equipment' started by BeBu Lamar, Jan 2, 2021.

  1. About rebuilding the battery. I have no idea what the inside of the Metz battery is like, if and how it can be rebuilt/recelled. I usually make that decision after opening the battery case and studying what is inside. Then determining it it can be rebuild/recelled and what replacement cell I can use. Sometimes I have changed cell chemistry, sometimes not.

    Charging is a matter of process.
    After a shoot, I charge the batteries. So they are put away fully charged.
    Prior to a scheduled shoot, my SOP is to charge my flash batteries a few days prior to a scheduled shoot.
    When I shot more randomly, I did a top off-charge every other month.
    With NiMH batteries you can charge them at 0.5 to 1C, so all you need is a n hour or two before the shoot, and you can top up/charge the battery.
    Make charging a standard routine, and it stops being an issue.

    You can also look for tabbed low discharge NiMH batteries.
  2. Metz offered 2 types of batteries for the 60 series.
    One is the Nicad battery which consists of 5 sub C NiCad.
    The other is a gel lead acid battery (which I had) and Metz call it dry fit. The dry fit battery don't have separate cells. It's a plastic case with 3 compartments each is fitted with the lead electrodes and filled with gel electrolyte (instead of liquid acid like a regular lead acid battery). In that way you can not replace the cells. You could pry it open and and put some water in it (like Ben did) if the electrolyte dried out.
  3. Given what you said, I would say the dry fit is not rebuildable.
    But, if you are industrious enough, you might be able to build a new bottom, load it with 5 NiMH cells, then "attach" the new bottom to the old top. How practical or even possible this is, I have no idea.

    I have had zero success in restoring dried out AGM SLAs. Gel cells might be different.
    I add distilled water, then let it sit for a week, hoping that some of the distilled water will soak into the electrolyte to make it active.
    Sometimes they start to take a charge, but in the end, they all failed.
    Last edited: Jan 26, 2021
  4. Best use for an old dryfit is as a casing for some NiMH or NiCd cells.

    They come apart reasonably easy at the top seam, by cutting with a fine saw. Trying to prise the glue/weld apart is a fool's errand.

    I've done this with two of the darned things. There's plenty of room inside for sub-C, or even C sized cells. A standard capacity is 4000mAH, so no different from the Dryfit. The top contacts are also in exactly the same place as on a Metz NiCd pack.

    A length of sellotape wrapped around the cut seam holds the casing together again more than adequately.

    The black, screwed-together Metz NiCd pack simply has 5 C cells and some foam packing inside. It has a pathetic capacity compared to modern cells.

    A shame that Lithium-Ion cells didn't come to the attention of Metz's designers, but they never did seem to get much beyond 1970s technology.
    Last edited: Jan 27, 2021
  5. Here's a shot of the Dryfit case fitted with NiMH cells. You can just about make out the clear tape holding it back together.
    Next to it is the top half of an 'official' Metz NiCd holder with its mouldy old cells on show.
    The cells are full C sized ones BTW.

    Oh, I forgot before now. The cell-separators in the Dryfit case have to be removed to make room for the new NiCd/NiMH cells. I used a wood chisel and Dremel tool for that.
    Gary Naka likes this.
  6. I'm not 100% sure about this since I never purchased from this seller, but you can find a replacement battery here: Metz Dryfit Battery Cell 60 Mz5320 for sale online | eBay
  7. Thanks! I will consider that. It does require to use the charger that comes with the battery. The Metz charger won't work. Right now I got it working with the pack that I built.
  8. Expect long shipping times since they are coming from South-East Asia...
  9. Most surprising thing is that they've sold 76 units.
    There are 76 people in the world that still care enough about a Metz 60CT to spend $85 on a battery?!:eek:
  10. Yes I would! All the Nikon flashes don't have enough power for my need. They are typically GN120 @ ISO100 and 35mm coverage. I am considering Quantum flashes but they are quite expensive.
  11. Use two!
    They'll still be less bulky and weight less than a Metz CT60.... and recycle quicker.
  12. Using 2 for on camera flash is quite cumbersome.
  13. The 5 cell NiMH 5000mAh I got are OK. Still have good power after 2 months so self discharge isn't all that bad. Compared to the dryfit it's about the same. Doesn't recycle any faster.
    Yesterday I built a pack of Li-Ion using 4 18650 cells. They are in series/parallel configuration to get double the mA rating at 7.4 V. Fully charged the.voltage is quite high. I kinda worries a bit. It's about 7.9V open circuit. I does recycle the flash in half the time. Not sure I want to use it as it may stress the circuit too much. The NMH pack charged OK with the Metz charger but the Li-Ion must be removed and charged with my a different charger.
  14. Brave man!
    The charging thing is what would put me off using cheap vaping 18650 Li-ion cells. (A good source of which is old laptop batteries BTW)

    I have a set of 3 Godox 'Ving' Li-ion powered speedlights. They're a definite improvement over NiMH cells. But again, you're back being limited to the availability and price of a proprietry battery, just like those old Metz things.
  15. I study the charging and found li-ion is actually easier to charge than NiMH. I use a programmable bench power supply.
  16. Except NiMH cells aren't prone to thermal runaway and bursting into flames!
  17. Metz 60CT flashes are getting old, but are well-made and very powerful – too good to discard when their normal batteries die and can’t be replaced. Lithium cells are common now, and have a high energy density – the 18650 type achieves a capacity of 3000mAh or more - but they do need careful handling. I’m down to my last good (rechargeable) lead battery, and my last decent Dryfit can’t recharge beyond 5.6v, though I have several dead ones (won’t recharge beyond a volt or two). A battery for a 60CT, containing removeable and rechargeable lithium cells, would be great to revive my old gear. A lithium battery replacement for the Metz 60-38 battery has appeared on an internet auction site, but is expensive, is not often listed, and no battery-protection mechanism is evident.

    I decided to investigate a DIY solution, allowing individual cells to be removed for charging – a couple of pounds buys you a single cell USB powerbank incorporating battery protection. Here’s what I did . . .

    Neatly saw top off Dryfit, 14mm from top, and remove contents. See here for detailed instructions (thank you, seller “vintagephotographica”). Drill out lead stubs of connecting pieces, to minimise accidental contact (leave the corner stubs of the + and – terminals [Mk 1 version has bolt-holes drilled through]). Cut away tops of partitions in lid.

    Mk 1 version wasn’t very ambitious: two pairs of two cells in a reconstructed Dryfit case (partitions cut out). An 18650 cell slides smoothly into 21.5mm (o.d.) plastic overflow-pipe (giving good insulation), and two pairs of 72mm lengths of pipe, glued together, fit easily into the case.

    [​IMG] [​IMG]
    Cell connections are brass paper-fasteners (8 needed). The tails of the top paper-fasteners are melted through oval 21mm x 43mm x 2mm plastic end-pieces, the end-pieces are glued onto the pipe, and tails are soldered to wires ending in ring-connectors.

    [​IMG] [​IMG]

    Ring-connectors attach to countersunk-head bolts in holes drilled through the original + and – terminals in the lid. For the bottom connections, fasteners are threaded through 19mm rubber bath-tap washers, their tails are soldered together, and the washers are glued to another pair of plastic end-pieces covering the pipe-ends for complete insulation. The bottom end-pieces are loose, just held in place with rubber bands to allow easy removal of cells for recharging. To assemble, insert cells head-to tail in each pair, ensuring correct polarity; add bottom end-pieces and secure with rubber bands. Invert the wired cells in their pipes, drop the ring-connectors onto the bolts in the lid, and secure with nuts. Press together and check voltage, fit into 60CT case and test flash performance.

    Mk 2 version has 50% greater capacity: three pairs of cells in a Dryfit case with partitions in place for insulation but the top 5mm of each partition cut away to make space for wiring.

    Two 18650 cells just fit into each of the three sections; however, to make insertion & removal easier the pairs are staggered and a little gouging of the case walls may be needed.
    [​IMG] [​IMG]

    Each pair of cells sits in a simple cage comprising loose rectangular plastic end-pieces 17mm x 37mm with brass paper-fasteners as above, and an insulating piece between the cell cases (because casings are at different voltages when connected head-to-tail). End-pieces are notched in the middle and turned up at the corners to hold the batteries in place. The notches accept a thin cable-tie that holds each pair tightly without increasing cage width. Fit the three pairs in place and tuck loose ends of cable-ties into the spaces.


    The cages sit with the positive top-ends to the front of the Dryfit case, and negative top-ends to the rear; the three + tails are soldered to one wire, and the three – tails to another wire; wires should extend with springy loops or spirals which are bent to touch the lead terminal stubs when the lid is closed (and when it is forced further down as the 60CT battery-pack cover is pushed into place). The lid can be attached with a duct-tape “hinge”. Load battery into 60CT case and switch on – the red LED flashes merrily (slight over-voltage?) and connect a flash. Even using old 2600mAh laptop cells (identified here) recharge time was only a few seconds and the outfit seemed to remain healthy for several dozen flashes over a few minutes. That’s fine for me! For recharging in a powerbank, remove the entire contents of the Dryfit and push a cell out of its cage: everything drops apart easily.


    Separate the casings of head-to-tail cell pairs using insulation, as casings are at different voltages when connected in series. Double-concave plastic pieces are built into some laptop battery packs.

    Use stiff wire (solid copper, not stranded) everywhere to minimise heating during high current flow. Overheating of lithium batteries can cause fire or explosion. Ensure + and – wires never touch.

    Ensure correct polarity of cells, to avoid damage to 60CT pack.

    A battery protection system (BPS) board can help to recharge cells outside the battery. I made a 2-cell pack with BPS board rated at 20 amps, and it recharges cells fine - but that pack failed to work when fitted in the 60CT box. I don’t know why - perhaps something to do with current/voltage limitations during discharge.

    I hope the pics get included - I've not contributed before! :-(
  18. Sorry, pics don't seem to be visible. How do I include them? I did use the right URLs. Are jpgs allowed? Thanks. Ian.
  19. Aha! Drag & drop. Hope this clarifies my tinkering.
    This is Mk 1
    IMG_3418a.JPG IMG_3417a.JPG

    This is Mk 2
    IMG_3427a.JPG IMG_3424a.JPG
    Gary Naka likes this.
  20. Very powerful?
    Not according to my testing. They deliver precisely one stop more light output than a good hotshoe-mount speedlight; but with twice the weight and more than twice the bulk and about double the recycle time.
    Here's the same subject, at the same distance, lit with 1) a Metz 60 CT-4, and 2) a Nikon SB-28 speedlight.

    I had to raise the ISO to 200 to get the same exposure level with the SB-28 - Big deal!
    All samples are SOOC with no adjustments except re-sizing.

    As you can see, there's almost no difference in the quality or colour temperature of the light. And no shoulder pack to bother with using the SB-28, which takes readily available and cheap AA NiMH cells.

Share This Page