How to convert Metz 45CL4 bat. pack for HiMH use

Hi,

after reading a lot, but not finding the right info, I have changed

my alkaline battery pack of my Metz 45CL4 unit to accept NiMH

rechargable batteries. The difference is that regular and NiCd pack

have different ground pins.

You are welcome to take a look at the:

<a

href="http://www.pbase.com/dvas/metz_45cl4_battery_pack_conversion">LI

NK</a>

 

While doing this, you will NOT be able to use your NiCd pack. If you

do, you can destroy your flash unit!

I searched for an answer to my 2 dead NiCad clusters (same part #) for my old Metz 45CT-4 as well. I broke one in order to learn and save the other. I also checked around the web for solutions. Here are my own conclusions:

 

1. The NiCad cluster uses its own custom charge circuit module; the AC/DC adapter is just a dumb converter, not a charger. NiMH, on the hand, is very sensitive to over charging. It is NOT worthwhile to solder 6 AA NiMH and run into problems later.

 

2. The Alkaline battery holder and the NiCad cluster have different +/- contact positions to the 45CT/CL-4 body. The only guess I have is the difference in battery's internal resistance (due to different chemistry). Metz must have gone this far in designing these different contact positions. Metz never responded to this question or offered any warning.

 

3. The save solution appears to rebuild the NiCad cluster. People can remove the bottom of the NiCad cluster (the end marked 45-40 NC-batterie with +/- contact holes). There are 8 small slots on the edge of the plastic plate. Use a small watchmaker screw driver (flat edge), and insert into the edge, one by one, while pushing up the bottom plat (insert with your finger nail). BE VERY CAREFUL not to bend the edge, as it will crack the plastic.

 

Once the plate is removed, you will have access to a screw (cross head). Unscrew it and unsolder the +/- Red/Blue leads. The plastic holder frame can then be removed in order to access the AA NiCad cells. DRAW on paper all the old soldering positions, as you will need it later. You can buy replacement cells (use only "button top, tab AA NiCad" cells; about $2 each), and solder them together according to the old ones (you can remove and re-use these plastic insulating rings from the old + side of battery cells). The tabs will not be aligned in the same directions, but you can use wires to solder between the tabs. Put them back in reverse order.

 

I think this is a lot saver and cheaper solution, as I don't see Metz will make a new NiMH cluster any time soon. This is what I'll do next.

 

Thanks to all contributors that lead to my conclusion. Good luck!

Hello there,

 

thanks for the inputs... THe yellow NiCd cells that you can see on my pics in teh NiCd pack are not the original ones... Several years ago I have replaced them inside (something similar to what you wrote). But since this is not my main flash and I use it rarely, I came to the decision of what I did... It is not worth of selling the flash, but since I use it rarely, for me is the best solution of converting the flash as i did....

 

sasha

Hi, Likewise, I use very little of my Metz 45CT-4. That's why I don't see spending $70 for a new NiCad cluster - about half of what I paid the entire flash 20 years ago. These clusters do go bad only after 2-3 years of not so frequent use.

 

I do have another thought. If I can bypass the cluster's build-in charger module (I may be able to do that as it is screwed/soldered on), the pack would be equivalent to a 9V battery (6 x 1.5 Alkaline cells). I can then replace the cells with NiMH instead, and use an external 9V NiMH charger. That may be a good and lasting solution. What do you think?

 

/DK

I didn't give much thought why there are two different connectors inside the flash. But, the difference between alkaline and nicd is voltage and current: 9V and 7.2V and nicd can provide much higher current then alkaline... therefore, i wouldn't do it.

 

sasha

Both NiCad and NiMH have the same 1.20V per cell; therefore, either pack will deliver 7.2V (it is still considered as 9V using 1.5V Alkaline as the reference).

 

I agree that NiCad may be able to deliver higher current (not higher energy density), which means faster flash cycle time (that maybe why Metz still uses NiCad). I think the pack's built-in charger module may not have the latest "pulse" charging technology, which is to remove the memory problem. If so, I can bypass the internal charging unit and replace with new NiCad cells. Then, I can use a better external 9V NiCad charger that includes deep discharge and pulse charging capabilities. Does this make sense?

If you aren't using it much why not get a couple of AA battery holders? I bought a few off a Ebay seller. The holders are third party so a fair bit less then the real Metz ones. They work just fine with the rechargeable batteries I put into them. The holders fit the flash just fine but when you pull them out you need to push in the tabs that hold it together. I'm not sure if the real Metz does that to but it isn't a big issue once you figure it out.

 

Best part is the same AA batteries and charger can be used for other things.

Actually this is another question (using NiMH cells in AA holder) that I never got an answer from Metz. Hope Metz will see the "total customer satisfaction" is not just reflected from the flashgun itself. I had 2 NiCad packs that went dead only in 2 years. Same thing happened to a few of my friends'.

 

When I saw 2 different +/- contact configurations to the flashgun for these packs, I wondered why and hesitated to use any rechargeable in the alkaline cell holder that I also have.

 

I would love to use rechargeable cells in the AA battery holder, if that does not create problems to the flashgun.

The ones I'm using are called "Pure Energy" Alkaline rechargeable. The only problem I have is the charger takes a max of four batteries at one time. It takes awhile to charge the batteries. That would be okay if the charger could handle all six at once but with only four you need to do it in batches.

Rechargeable alkaline is, perhaps, the reasonable and safe alternative for use in the battery holder. I think that the discharge current is about the same, therefore, slower than NiCad or NiMH.

 

There is still no answer to using NiCad or NiMH cells in the holder to achieve faster flash cycle time (than any Alkaline). My Metz NiCad packs did not last long. It could only hold about <40 flashes per charge before their death. As I recall, that caused a few surprises when I really needed them.

 

By the way, the real Metz alkaline cell holder has cell release tabs 90 degree across the pack holder tabs. It does not pop out.

These do to. But if you don't release the cells then the holder won't come 100% out of the flash.

Sasha's solution may work as the best combination of using individual AA NiCad cells in alkaline battery holder (shortest recycle time, allowing better external charger, easy new replacement or spare NiCad cells). But, I am not sure if I have the nerve to open up the flashgun and relocate the contact lead. Metz is known for refusing service for units with mod.

hi,

 

my Metz is old, and there is no warranty for it anyway. Since there is no Metz here in Israel, only reps, they will do any repair anyway for $$$.

 

I just wanted to share what I did, so others can benefit from it.

 

Sasha

This is the spirit of sharing. In USA one of Metz dealers did refuse service from my friend, even after warranty; the reason - the unit came into the country not through authorized US distribution channel. But, he ordered it from New York City.

 

I checked your LINK pictures. Are these 2 "ground" solder points leading to those 2 different contact locations for the NiCad pack or the alkaline holder (they share one same contact location)? Are they contacting the (-) side of individual packs?

 

If so, we can simply disconnect the "old" NiCad lead. That will avoid the risk of using the original NiCad cluster.

 

Thanks!

TO disconnect the 'old' nicd pin inside the flash is excellent idea! thanks! i will do that.

 

sasha

Your solution will be perfect, if:

 

1. You can confirm these changes of leads in the flashgun to safeguard against any accidental use of original NiCad cluster. Obviously, Metz did not change its design for 20 years (Can anyone confirm part # 45-40 NC battery is also used in 45CL-4?).

 

2. "Anyone knowledgeable" confirms that the alkaline's (both single-use and rechargeable) internal resistance is higher than that of NiCad or NiMH.

 

I "think" higher internal resistance is the technical reason that limits the discharge current, that in turn slows the flash cycle time. Unfortunately, Metz did not respond to my questions of "why different contact positions". Again, the voltage (1.2 or 1.5 per cell) is not the issue, as a freshly charged NiCad or NiMH cell has 1.39 - 1.41V.

 

In basic Physics, the high discharging current WILL potentially damage the equipment. For example, one cannot short the +/- terminals of a high power NiMH battery. It can melt the wire at contact point.

 

If this point (alkaline battery's internal resistance) can be confirmed, then your modification will work with any form of batteries (NiMH, NiCad, Rechargeable alkaline and regular alkaline). State-of-art external chargers are readily available, and much cheaper than a single NiCad cluster. Metz may not like it, but the solution will benefit many.

actually, what i did is a simple solution. Metz sees now a rechargable pack... as simple as that.... just i am using a different 'housing' for my NiMH....

 

sasha

Can the battery case of the mecablitz 45 series be loaded with NC or NiMh batteries?

A battery case supplies a flash unit, such as the Metz mecablitz 45, with 9 V power (6 x 1.5 V). However, if NC or NiMh batteries are loaded in the battery case, then only 1.2 V (6 x 1.2 V = 7.2 V) will be available on account of the cell?s lower voltage rating. This results in a significantly smaller guide number, thereby greatly reducing the maximum flash range in automatic and TTL flash mode. It also means that manual flash operation becomes impracticable because a guide number is no longer available to calculate the camera?s aperture setting.

The contacts of our NC battery pack 45-40 are located at a different point so that the existing voltage difference is compensated. The NC batteries incorporated in this pack are special cells that are rigidly connected with metal strips to cope with the high power consumption of the flash unit. Consequently, an empty NC battery case cannot be loaded with other commercial rechargeable batteries.

 

Furthermore, the high currents of an inadvertently incorrectly loaded NC battery may destroy the electronic circuitry of the flash unit. Consequently, we urgently advise against the use of NC batteries in the battery case.

 

That is what Metz says.

Hi,

 

it looks like some missunderstanding. First, Metz can not support any custom change its products. Second, the voltage is not affecting the 'guide number' since the batteries are loading the capacitor... Regarding the strips in the holder... i will take my chances...

 

sasha

I use the Official Nicad Pack and charger generally, and the Battery Holder with seperately charged NiMH batts, as a stand by with no noticable effect on performance or damage to the flash.

Harry

<p>I have an old Metz CL-45, and the rechargeable Nicad battery pack went quite dead. I tried reloading it with new (AA) size Nicad cells, but the spot-welding that appears to be needed is too hard. Soldering doesn't do it, at least for me. (Instructions on disassembling linked to above)<br>

Pertinent to this discussion Metz now (7/2009) sells a NiMH unit with a different charger. I don't know how long it lasts, but I'm going to try it out.<br>

Also, maybe pertinent to the discussion -- of the 6 Nicad cells, 2 were totally dead, and leaking out one end. the other 4 are, I think, close to 100%, at least after putting through a (non-Metz) MAHA brand charging unit that fully discharged them first.</p>

 

<p>This is a very old thread but may still be useful to some as information. I have read many posts on this issue and there is probably some inaccurate information here.</p>

<p>It appears that the operating system of the 45 series flash was designed around the voltage of the 6 NiCad battery pack which is about 7.2 volts nominal. However, to accommodate the use of 1.5 x 6 = 9 volt alkaline batteries, a second initial circuit is provided with a dc voltage converter to reduce the voltage to 7.2 volts. This also allows the use of the Quantum Battery 2 which puts out about 9 volts, however was probably not a thought in the original design. It is possible that a higher current, but lower voltage, battery pack could damage this converter, however, I have never read of one confirmed case of the lower voltage NiMH batteries damaging the 9 volt circuit.</p>

<p>All modern flashes have no problem handling alkaline or NiMH batteries in the same battery holder (but not mixed), despite the different voltage profile. I am not sure why Metz could not have designed similar flexibility. Even the newest digital version still only offers sealed battery packs if rechargeable batteries are used. How many sales of flashes were missed because Metz did no offer the option of using individual, less expensive NiMH batteries like they do for their shoe mount models?</p>

<p>I thought I'd add some personal experience to this old thread.<br>

I just replaced the dead NiCds in a Metz 45-40 pack with new NiMH cells. The NiMH cells are standard, Energizer (p/n: NH15-2300) 2300 mAh cells, available from Digikey (p/n N703-ND).<br>

I have the advantage of having a small spot welder, designed to weld strips to battery packs, purchased at work from Harbor Freight or Ebay, for around $100. You cannot solder to batteries, but a cheap spot welder (which comes with tin-plated jumper strips) makes that a non-issue.<br>

<br />Anyway, I carefully disassembled the old, leaky, NiCd pack, making note of how the cells were connected. A smartphone camera works well to document the process. Then, using the old pack housing to align the new cells, I welded straps between pairs of cells, then turned them upside down, and welded the top straps. Constantly checking to make sure the connections matched the old pack.<br>

Before making the final solder connections, I used a multimeter to verify that the pack voltage read 7.2V (it was 7.8, but these are fully charged NiMH cells). Then I made the final solder connections, checked the voltage again and tried the pack in the flash. Success!<br>

Along the way, I investigated some myths that are circulating about the Metz 45-40 NiCd pack.<br>

There is no resistor to limit the current -- the cell stack connects directly to the flash contacts. So, technically, you could build a drop-in charger for these packs. (and you might want to, after you read the next bit)<br>

The "charge circuitry" in the pack base consists of four rectifiers and an incandescent bulb. I'm guessing that the Metz charger is nothing but a transformer, and the diodes rectify its output to produce a DC charge voltage. The bulb acts as a very crude variable resistor, designed to taper off the charge voltage as the pack reaches full charge. In my opinion, this is a very old design, and not kind to the NiCd cells it was designed to charge. This may be why the 45-40 packs fail so early.<br>

The "charge circuitry" connects directly to the cell stack, in parallel with the flash unit contacts.<br>

So, don't throw out those old 45-40 packs. With a little work (my first one took me about an hour) and a spot welder (look on ebay for "battery tab spot welder" from China, of course...they're about $150 when I checked today), you can rebuild them with NiMH cells.<br>

If I wanted a better charger, I'd get one of the all-in-one chargers that are marketed to model racers -- they're about $60 and can be set to charge almost any kind of battery chemistry and cell count. Connect it directly to the flash contacts on the pack and charge it a bit more carefully.</p>

<p>Hi all you fellow Metzbotherers<br>

...after reading the above and experimenting here's the most recent findings:<br>

Note: the flash was set up on a tripod and the subject constant throughout. All batteries freshly charged to makers spec using a bench power supply with V and I limiting and a timer.<br>

The most rapid re-cycle-times are obtained using Nickel Cadmium batteries - in my case "Sanyo Cadnica" 700mAh.<br>

The high-capacity (2.6Ah) NiMH "Energiser"and "Duracell"batteries have higher internal resistance and are not very good in this application for that reason. Their high capacity not really much of a bonus. 3sec NiCd vs 10s re-cyclle times with NiMH. Subjects get bored, shots are missed.<br>

Fresh Alkalines (Duracell Pro-Cell) are intermediate and also give a slow re-cycle time. We must ruefully accept that nasty poisonous NiCd are the boys for the job, lesser capacity notwithstanding.<br>

Those jolly gents above who proclaim that the existence of differing contacts on the battery packs is a nicety one can ignore are wrong. Those using NiMH are getting away with it as NiMH has a high internal resistance and cannot provide the current for a rapid re-cycle thus saving the bacon of the transistor doing the work in the oscillator circuit. (looks like BD233 or maybe 238 on my ratty jpg circuit diagram). It seems plain that the metzmen would not have gone to the trouble of doing two different battery holders and contacts had there been no problem with NiCds roasting the oscillator transistor.<br>

Testing the Cadnica 700mAh batteries an in alkaline battery holder with an ammeter in series shows a peak of around 6 amps*. (*a transient estimated looking at the meter - not an oscilloscope trace as I lack a precision 0.1R resistor) Transistors BD 233 and 238 are 2A transistors - says 6A peak at <5ms. <br>

Bottom Line.<br>

1) Fast cycling times need NiCd AND the right contacts in the flash.<br>

2) Anyone accepting long re-cycle-times can use a high capacity NiMH in the Alkaline batt holder.<br>

3) Lastly, to fulfill 1) you need an empty or secondhand NiCd holder or do a naff conversion job on the alkaline holder to move the contact. Given the average joe's manual dexterity I shiver at the thought of battery pack capable of around 10A lurking and shorting-out to produce melted plastic and smoke.<br>

Mind you - it might make a good photo eh?<br>

Phil Weatherley UK</p><div></div>

<p>Thanks Philip. I found your post extremely useful - it helped clear up a few grey areas. Thanks for taking the time to share your findings. Cheers. Sudden</p>