Metz hammerhead charger / batteries DIY help.

[KingRoach]

Hi everyone.

Just received a joblot of Metz hammerhead flashes that includes

○ Metz 45 CL-1 with Alkaline battery holder.
○ Metz 45 CT-3 with Alkaline battery holder.
○ Metz 50 MZ-5 with controller, 1xNiMH and 1xNiCD battery packs but no charger for either.

◘ Metz charger for CL/CT series NiCD packs but I don't have any of these so this charger will be useless for now.
◘ one bracket for all three flashes.

So the only drawback is the lack of power to even test them. I put some NiMH batteries in the Alkaline battery holders. The 45's turned on (continuous beep charging sound) but never charged up enough to turn on the LED or fire. I suppose it is a battery problem. I can easily troubleshoot that by getting some actual Alkaline batteries instead.

I am therefore left with the crown jewel, the 50 MZ-5 that came with no charger for either batteries. This flash is the reason why I bought the joblot.

I have a few options:

1- remove the internal cells, connect the intestines of the battery pack to an external battery holder in which I can use separate rechargeable NiMH or NiCD AA's accordingly, and a regular suitable AA battery charger. It should not be a problem to re-iterate the capacitor found inside the original pack in the external DIY holder if anybody knows if that's necessary.

2- DIY a charger for either the NiMH or NiCD PACK, but I need some info: original Metz charging unit voltage and current outputs, whether it is a smart or dumb charger, etc., because then I will be charging the entire pack of 7xAA's as opposed to charging single AA's in the previous solution.

3- Any other ideas you can give me.


Can anybody help with any info or suggestions? Basically anything except buying a Metz charging unit or batteries because as you well know their prices are ridiculous and I'm on a budget.

Many thanks in advance.

 

[ic-racer]

I now charge most of my photography gear with a charger like this.

 

[Andrew K]

the 45's should work with any battery - are your batteries fully charged? If they keep beeping but not charging fully the capacitors could be shot?

Sorry I've never used a 50MZ-5 so can't help there, but there are lots of universal chargers that will charge any battery pack you can buy for a few dollars - just make sure you have the polarity the right way around!

 

[ruby.monkey]

You need alkali batteries in the battery holder - rechargeables won't provide a sufficiently high voltage for the flash to work and there is a risk that they'll damage the flash.

 

[baachitraka]

With CL-4 it is possible to use NiMH RC battery pack.

You may need to solder two wires that take 7.2V instead of 9V and connect to the battery.

 

[KingRoach]

Thanks all for the suggested option.

ic-racer: this is the first time I see this charger an it looks amazing. I will have a few questions about it. If I have a set of AA's connected in a series (in battery holder) can this one connection charge all of them (say, 8 batteries) connected that way?

Or is this kind of series-charging only suitable for the particular arrangement in RC battery packs in which a device can test and charge each cell individually?

Andrew K: can you point out a suitable charger for me to look into? I'm very wary of cheap chargers. Will prefer one of my solutions above in order to avoid the caveats of going really cheap to the extent that it is not even economically efficient on the long term.

baachitraka: thanks a lot. I came across this common solution for the 45's. I will consider it of course if I cannot achieve the battery holder above. The point for me is to have one solution for all. If I buy one of these RC packs, I will have to get the right charger for it. I am trying to look into as many options as possible in order to find the one-for-all solution that will save me the most money.

You have a nice brolley set up there. I should show you my Vivitar 365 setup. Similar to yours with YN-622c and its own VariSensor for automatic metering, but I'm DIYing a manual controller for it soon anyway. ^_^

 

[baachitraka]

I was looking kind of pluggable solution, but I was little impatient and went on soldering two wires.

Ideal would be,

- One battery basket for alkali batteries.
- Another battery basket pref., NiMH and do a MOD to bring cables out from the basket and connect to RC pack.

With RC pack you may have very fast recycling times...

 

[Peter Simpson]

We bought a couple of these for work: http://www.all-battery.com/Tenergytb6ac-charger-01322.aspx
They are incredibly versatile, will charge pretty much anything. The user interface and instruction manual are sh*t, though -- typical Engrish and little to no help. But it's easy enough to figure out in 1/2 hr of playing with it.

I always replace NiCd with NiMH and have had no problems to date. It's OK to charge a string of NiMHs, and the above charger will do that fine. It will also tell you if you have a shorted (bad) cell. Oh yeah, and one more thing: technology has improved since those Metz NiCd packs were made -- you should get better life and higher peak current out of high quality NiMHs.

Places like this will build packs for you to your spec: http://www.all-battery.com/custommadepackforms.aspx

Edit: Looks like ic-racer has the same charger in a different package. Notice you're in the UK, so the US company probably won't help you. All this stuff comes from Shenzen, so there's probably a guy in the UK that makes up packs for the RC racing set and distributes exactly the same stuff. I had a custom pack made for my son's paintball gun and it was surprisingly inexpensive.

 

[KingRoach]

I have just recharged my NiMH's and both Metz 45's fired.

There is a common misconception about battery voltages as people think rechargeables are simply 1.2v while alkalines are simply 1.5v, constantly, and then they add these values up in packs. In fact, all AA's should offer around 1.5v. For Alkaline, this is a bit more constant and longer lasting but will drop near the end anyway.

Rechargeables, due to their nature, offer up to 1.4v when fully charged and down to 1.0v when flat. The convention in naming rechargeable batteries is to give the mean value, the mid point, which is 1.2v. So, in effect, when fully charged, each cell is giving the whole 1.4v which is pretty much the same as Alkaline 1.5v cells.

This makes a big difference if you simply add them up.
6x1.5 alkalines = 8v
6x1.2 NiMH = 7.2v

However, even 7.2v is a nominal mid point. A pack of 6xNiMH's should offer anything between 8v when fully charged down to 6.4v when drained.

Which again shouldn't matter for the electronic device long as a sufficient amount of current (amps) is going through. It is important not to go over the device's tolerance for voltage in order not to fry it, but a bit less should still work. You can go over in amps as the device will only take as much as it actually uses, but not less.

All I'm saying is that 1.2v is not the real voltage, it is a nominal midpoint, so when people simply add up and think you get lower voltages when using rechargeables, this is simply wrong.

Charging those different chemistries of batteries, however, is a different story. Mainly because their internal resistance is different. They are recharged by different currents. This is where you should not mess around. Metz is about the only flash company that I know which designed different compartments for NiCD and Alkaline batteries (with a different contact arrangement) to avoid mix up. Some say this is because of the different internal resistance of batteries so the circuit would behave slightly differently for each kind to avoid overheating for example.


I am not excited about my NiMH's recycling times on Metz 45, but at least they work and I'm not in a hurry.

 

[KingRoach]

Peter Simpson and ic-racer:

I looked up these chargers and found a few rather cheap ones from china. Some of them have 50w charge, 5w discharge circuits. Some, twice more expensive have 80w charge, 10w discharge circuits, and there is a Venom 100w charging power, and there is a Venom version which offers up to 500w charging power.

I do not know what this power difference will bear in practice. It may only be a maximum charging current (the last one offers up to 25Amps charging current). I am wonder if going cheap on this is a bad idea and more importantly WHY.

 

[ic-racer]

A five amp charger (like the one I use) will charge a 5000ma battery in one hour. What is the capacity of your batteries?

 

[KingRoach]

Well, if a single NiMH cell is up to 2400mAh, and we're talking 6-7 cell packs, I'm guessing that just adds up right? 2400x7=16800.

The thing is, the one thing I don't understand about electronics is the requirements of recharging power. Even if the charger is giving less current in mAh, it should simply take longer to fully charge them. Then again, providing more current won't do anything because there is a maximum value that any device will take and will simply leave the rest.

 

[Peter Simpson]

Well, if a single NiMH cell is up to 2400mAh, and we're talking 6-7 cell packs, I'm guessing that just adds up right? 2400x7=16800.

The thing is, the one thing I don't understand about electronics is the requirements of recharging power. Even if the charger is giving less current in mAh, it should simply take longer to fully charge them. Then again, providing more current won't do anything because there is a maximum value that any device will take and will simply leave the rest.

For the example you gave, your charger would supply current based on the capacity of one cell: 2.4 Ah. That's called "C", the current corresponding to the cell capacity in ampere-hours. So a charge rate of C (2.4A) would charge any number of 2.4Ah cells in series in one hour (at the appropriate stack voltage, of course, which, for 7 cells, would be about 9.8V). Normally, though, you'd charge at 0.1C, or 0.240Ah (240mAh), for about 10 hours. That's what the battery data sheet will tell you to do. You can often (see the cell data sheet) charge at 1C or higher: 2C, 3C, etc, but you have to carefully monitor the cell voltage and temperature to avoid damage to the cell(s).

Dedicated chargers are designed for a particular number of cells and a particular charge rate. Programmable chargers require you to enter the number of cells (or the stack voltage) and the charge rate. "Fast chargers" are more expensive, charge at 0.5 or 1.0C, but contain the necessary monitoring circuitry to prevent overcharging (which will kill the cells and could cause rupture).

Source: electrical engineer who designs with batteries and chargers for portable equipment.

Re: the question about "going cheap" -- the $50 charger I referenced has given us good service with LiFePO4, LiIon, NiMH and Pb packs over a couple of years. I would recommend it, with the usual caution about Chinese imports...the one you get may be bad. Their quality control isn't always the greatest. The advantage of the $50 charger is that it will charge pretty much anything you have, but you do need to set it up correctly for each pack (chemistry, number of cells and charge rate). If you want something that you can just pull off the shelf and plug in, you're probably looking at a custom charger for your mix of chemistry, cell count and charge rate. They're easy enough to design but finding one might be a problem (you could always buy the Metz one). If you do find a NiMH charger for a 7-cell pack at a charge rate less than 2.4A, you could try it, but you'd want to make sure you watched it through a charge cycle before you left it unattended.

 

[KingRoach]

Thanks a lot Peter Simpson that answers many questions. I cannot find, or afford, a Metz charger, otherwise I would have got one.

Now the problem with charging the Metz pack using that multi-charger is the fact I do not know the C value of the internal cells. I do not think it will be written anywhere if I open the pack.

I'm tempted to buy one of the multi-chargers no matter what. No problem changing the settings every time. I like to have a one do-it-all piece and cut down on the total number of chargers at home.

 

[Peter Simpson]

Does your battery pack look anything like this?

I'm thinking it might have the charger circuitry inside, because the charger looks like a standard wall-wart. I think you might need to do a bit of reverse engineering.

First, check the power connector on the pack, where the charger plugs in...if it's a 2-wire connector or a standard coax power connector, you've probably got a charger board inside, and it's just looking for a DC voltage on that connector.

If it were me, I'd sacrifice the NiCd pack. The cells are probably toast from being left discharged anyway. Open 'er up and see if there's a charger circuit board inside. If so, it's probably the same design in the NiMH pack. Now you can replace the NiCd cells with NiMH ones and reseal the pack. The charger should handle them, there's not that much difference between NiMH and NiCd, cell voltage wise. Any new AA NiMHs you buy will probably have a larger C than the original NiCds, so no worries about too high a charge rate.

If there was a charger board inside the pack, it's just looking for a DC supply. Perhaps you can get a friend to measure the voltage output of the correct charger for your packs, or maybe stop by a photo store and try to read the output voltage off the original charger? Worse comes to worse, guess. Take the number of cells x 1.4 and round up. So if it's a 9.8volt pack, I'd bet on a 12V input. I'm just guessing here, but that's what I'd do.

Edit: Googling a bit, I'm almost positive the P76 power pack has an internal charger and the wall-wart is just a source of DC voltage. What DC voltage is unknown. Amperage matters only insofar as it's high enough. I would say 1A might work, 2A is better and 3 would be great. Here's a guy who has had his P76 re-celled for $35. Maybe he or the re-celling place (Batteries Plus) can help you with the power input requirements.

 

[KingRoach]

Sorry for the late reply.

The battery pack I'm trying to charge is this one: http://www.adorama.com/images/product/MZB7656.JPG

Green pack is NiMH. Black pack (same form factor exactly) is NiCD. I have both.

If there was a charger board inside the pack, it's just looking for a DC supply. Perhaps you can get a friend to measure the voltage output of the correct charger for your packs, or maybe stop by a photo store and try to read the output voltage off the original charger? Worse comes to worse, guess. Take the number of cells x 1.4 and round up. So if it's a 9.8volt pack, I'd bet on a 12V input. I'm just guessing here, but that's what I'd do.

My point of asking for the voltage/current on a Metz charging unit is exactly what you said. If it's just a dumb transformer, then the charging circuit is inside and all I need is to provide the same voltage and Ahr.

The connector on the battery pack is indeed a 2-wire plug. (the plastic plug is the same in both NiMH and NiCD, but one pin is located differently. So it's [0-0x] for the NiMH, and [0-x0] for the NiCD) I still don't know if it's the same charging unit used for both. If this is the case then the unit provides two voltages/amps, one for each pin.

I've actually opened up the NiCD pack and there doesn't seem to be a circuit inside. Only a capacitor soldered to the two ends of the cell series.
Will have to do more dissecting to confirm it doesn't have any other electronics inside.

 

[KingRoach]

I've got some info from another friend who knows some electronics about batteries, chargers and currents, and consequently felt safe enough to do the following:

Attachment pic 1:
I connected the NiMH battery pack to a 12v DC, current is either 0.8A, or 18A, I'm not sure which but likely 18A which I know is friggin much.
PLEASE NOTE: in the picture, the polarity is reversed, they are connected WRONG. I put it there quickly for the picture and the PSU was off, then I noticed and corrected.

Flat charge voltage was a mere 0.16v which indicates dead batteries.
Left it overnight, charge went up to 0.20v. Still dead batteries.
I opened the pack and indeed the batteries looked dead with that looks like the effect of a leak or something.

Attachment pic 2 shows the disassembled NiCD pack, which actually gave a flat charge voltage of about 8.8v, indicating the batteries were at least alive, but flat.

Attachment pic 3 shows inside the pack. There is NO CIRCUITRY WHATSOEVER inside the darn thing, they are selling a pack of 7 cells for 70 quid!

NiMH and NiCD packs should be the same inside aside from the different chemistry cells and the different charger pin location, so I made what turned out to be a very stupid move.

A very stupid move: I connected the same DC as I did above with the NiMH pack to the NiCD pack. Kept an eye on it for about 10 minutes checking for heating batteries but there was no heat. So I left it and went for a shower. 20-30 minutes later, the pack was smoking slightly, slight leak on my table and what would have developed into a hole right under the pack, likely caused by the excessive heat. The smoke may have in fact been the burning table. Plastic wrap around the individual cell had melted. Attachment pic 4 shows the pack 'unpacked'. After the second cell in the series you can see one of those things that disconnect if the batteries overheat.

Needless to say the cells are now officially dead. Voltage dropped to about 4.5v which is surprising for dead batteries. I will recell it at some point, likely with NiMH cells and replace the pin location and not give a damn what Metz thinks.



So both packs are now officially dead but I can tell there is nothing in there except for 7 Cells of AA batteries of an unknown capacity, right?

Right.

Attachment pic 5:

So I connected 7 fully charged NiMH cells, seen in the last attachment pic in my Vivitar 365 flashgun's battery holder (disguised as C-size cells thanks to plastic camouflage) and connected it to the inside of the flashgun using the correct polarity as guided by the original packs, using my multimeter's probe wires. Should be exactly the same as inserting an original Metz pack the way I see it.

The result?

Batteries were fully charged, just off the charger, but the flash gave an empty battery signal.

???

 

[KingRoach]

Can anybody help me explain why 7x AA NiMH cells did not fire up my flashgun like its own NiMH pack would, even though it is the same chemistry and the same voltage?

Also there are no other contacts going into the flashgun (like Sony's extra contacts which they use to 'chip' the battery so that fake batteries don't work). It is only a positive and a negative so pure DC input.

 

[sameerkm]

Hi KingRoach. Thanks for the pics. Any luck with the battery yet? Why don't you try with 6 cells instead of 7? Looking forward for your results. I too have a similar pack which is dead.