Best practices to maintain a photo-strobe power pack that is used sporadically

[dadler503]

I have had two strobe units for photography.  Both eventually blew capacitors.  This is (apparently) due to infrequent use and the fact (I have learned) that capacitors are tricky and need to be 'exercised'.  I suspect these are large capacitors because of this particular use.

(and a quick acknowledgment that I don't know if the beginners forum is the right place for this, but I'm a beginner here, so...)

I would like to understand better how to maintain photo-strobe-power packs that are only used occasionally.
I have tried to find this info, but it is in short-supply and inconsistent - sort of all-over-the-map; that is why I am seeking more info/perspective.  I will list some of the suggestions and advice below.

*Note - my power pack is Dynalite, which went out of business about two yrs ago - so no calling the mfg for mfg-specific best practices.

From a seller of a Dynalite pack:
“While the power pack has not been used regularly for photography recently it has been turned on and left on for 24 to 48 hours per month. This is what Dynalite told me to do in order to keep the capacitors in good condition.”

From Holly Flash, CA
Your flash likes to be exercised frequently to stay in good shape. Sitting on the shelf for long periods causes the capacitors (where the energy for the flash is stored) to degrade or, as we techies call it, ”deform”. An electrolytic capacitor is an electro-chemical system that depends on voltage being applied to it to maintain its dielectric (high voltage insulating) characteristics. Regular use keeps the internal insulation system working. The same capacitor technology is used in all flashes, big or small. To keep your flash working well and ready to serve when needed, we suggest you do the following every month or so:
1. Set the unit to full power and plug in a head. 

2. Turn the pack on and let it idle without flashing for at least 30 minutes. Longer is better. 

3. At the end of the idle time, it’s ready for the job, or to be put back into storage. You can flash it a few times just to make sure everything else is OK. 
For battery pack users, this is a good time to recharge the battery because long-term storage can deplete the battery so far it may not take a charge later.

I read several other suggestions - one referred to turning the unit on for a few seconds, then off for five minutes; and then gradually ramping that up - 2 sec on, 5 min off, then 20 sec on, then 1 min on, then 5 min on.  This was to 'reform' the capacitors after they were left unused for a period of months.  But he also wrote that was for a particular (Bowens) unit and that each unit is different... sigh...

Not looking for a perfect, clear, absolute, procedure. (actually that would be great, but I don't expect it).  Rather, looking for general advice and perspective so I can understand better what I am doing and why.  If nothing else, it seems one should turn on the unit for 30-60 min every month or so.

attaching a photo of the recently deceased power pack (blown caps anyway...)

Thanks in advance, Doug.

[jeffjmr]

I have a 45+ years old Mecablitz 402 as well as a 20+years old Novatron V600 and both still work like new (I did have to rebuild the Mecablitz battery pack once with new Nicads). Both units are all original except for the Metz batteries.

I pull the Mecablitz out a few times a year, charge up the battery pack while turned on for about 30 minutes, then turn it off WITHOUT discharging the capacitor. Same if I actually use it.  I fully charge and store without discharging the cap.

When finished using my Novatron, (as well as some slave strobes), I turn the power full up to fully charge the cap, then turn the unit off and store WITHOUT discharging the cap.

As they say, YMMV but this has worked for me.

Jeff

[BeBuLamar]

Where would you find replacement battery for the 402? You must have replaced the battery a number of times in the 45 years right?

[jeffjmr]

Actually just once. It went unused for a few years. I passed on the expensive aftermarket complete battery units. Instead I took the original unit apart and found it to consist of 7 (I think) C-type nicad batteries soldered in series. I bought new nicads from Amazon, soldered them together (not easy as solder did not want to adhere to the battery leads. It’s been awhile but I think I got some flux suitable for stainless steel).

I’ll take it apart again partially and take pictures which will also show you the brand and model number of the nicad cells I bought, next chance I get.

I would have replaced the main capacitor as well but it still tested good on my LCR so decided not to fix what ain’t broke.

Jeff

Added:

It is 5 of the sub-c nicads as pictured. The Tenergy cella have been holding up pretty well so far but I don’t use the 402 very often.

[dadler503]

Interesting.  Thanks for getting back with your experience.  Great that they stayed good that long, and of course, if you are on this forum - you know more about this stuff than I do.
Mine is a Dynalite power pack that just blew the caps.  It is 500 watt second unit and I blew a different one with 1000 watt seconds.  Learned from the first one that it needed to be charged up periodically.  And learning now, that it needs to be charged up and left on more than I was doing.
If I have the caps repaired, I will try to power it up and leave it on for a day or two every month.  With my lifestyle, I will probably blow them again eventually. 🤷🏻‍♂️