Battery rebuild

[Bobc5m2]

Has anyone tried to rebuild a battery for the metz 70 series flash? It seems do-able and they are pricey for a new one.

 

[Ian Grant]

I rebuilt the battery pack for my Metz 402 last month it was easy,I bought new NiCads from Hong Kong, total cost was £7.90 inc postage.

Uan

 

[Steve Smith]

I have done it a couple of times. It can be done with ordinary rechargeable AA cells but you usually need to file off the plating on the terminals to get to get the solder to stick.

I'm assuming it uses AA size cells similar to other Metz flashes.


Steve.

 

[AgX]

I rebuilt the battery pack for my Metz 402 last month it was easy,I bought new NiCads from Hong Kong, total cost was £7.90 inc postage.

Why did you use NiCd and not NiMH cells?

 

[bdial]

Why did you use NiCd and not NiMH cells?

NiCd's and NiMH's require different charging profiles. If the flash's charge circuitry isn't built to accommodate both, then rebuilding with the original type cells is the best option.
There are also voltage and current capacity differences to take into account.

 

[AgX]

I know, but I guess when doing low current charging that does not matter. (But stil,l the different characteristics of cells are confusing.)

 

[flavio81]

NiCd cells actually have the advantage that they hold their charge for longer time (more days) than NiMh cells. Also they are very rugged.

 

[frobozz]

I have done it a couple of times. It can be done with ordinary rechargeable AA cells but you usually need to file off the plating on the terminals to get to get the solder to stick.

I'm assuming it uses AA size cells similar to other Metz flashes.


Steve.

Careful soldering to batteries! Too much heat and you have a mess on your hands (and face, and lap, and...) Just enough heat, not too much. Obviously buying batteries with solder tabs already spot-welded on is best. I've rebuilt a bunch of Canon motor drive and flash NiCd packs.

Duncan

 

[wiltw]

NiCd cells actually have the advantage that they hold their charge for longer time (more days) than NiMh cells. Also they are very rugged.

'It depends'...

• NiMH (not low self-discharge NiMH) lose almost 1% per day.
• NiCd self discharge at about 10% per month
• LSD NiMH lose only about 15% in one year.

 

[Peter Simpson]

My experience with NiCds is that if you don't use them, you lose them. They tend to grow crystals and one cell will short out,killing the pack. I have had much better luck with NiMH.

NiCd and NiMH charge profiles (except for fast charge, specifically voltage and temperature detection of end-of-charge) are very similar, so in many cases you can sub one for the other. If the charger is a typical 0.1C charger, you should be fine. The good quality NiMH calls are spec'd to tolerate 0.1C overcharge for a long time. Even if you're using a fast charger, it may be quite simple to modify it to support NiMH.

I have replaced NiCds with NiMH and almost without exception, the NiMH cells have much higher capacity than the NiCds they are replacing. Watch out for output current rating, though. For a flash, you want to spend the extra money on high-current output rated cells.

NiCds are getting hard to find, due to the Cadmium being hazardous waste. Googling will bring up a couple of places that sell all kinds of raw cells, and will even spot-weld them into packs for you.

I should also mention that there are chargers available, designed for the hobby remote control market, that will charge multi-cell packs. This may be simpler than modifying a fast charger. They run about $50, and they're Chinese, so the first one you get might be bad, but we have two we have been using in our lab for a couple of years without any problems (many manufacturers, they all look like this one, though): http://www.all-battery.com/Tenergytb6ac-charger-01322.aspx

Source: working EE - I design portable equipment with NiMH and LiIon cells.

 

[MartinCrabtree]

Here ya go.