Vivitar 285HV SLA Battery modification

Hi All,


In another post, (http://community.the-digital-picture.com/forums/t/1067.aspx) Sean Setters and I got off on a lengthy discussion about our Vivitar 285s. I had mentioned an upcoming battery modification and wanted to post what I did for those that may be interested in a very inexpensive method of high quality off-camera flash.


Materials Used:


1) 6V 4.5 Ah SLA Battery from BatteryMart.com - $7.95 I bought 3, shipping was 8.18+1.19 tax


2) 15 amp bus fuses from Lowes - 2 for $2.27 I ended up buying 4 packs. Actually fried one; Opps!!


3) Black 16ga lamp cord. $0.31/ft I used 4 ft on each mod. so 1.24 each


4) Pack of spade connectors - $1.98 I only needed the females so I have 6 males left over.


5) Body Glove compact camera case - $5.00 clearence, bought 4 - one for my son's A590


The nice thing about bus fuses is that they're copper and can be soldered to. I used fine grit sand paper to brighten up the end before soldering. Using flux core solder I had to prime the iron tip with solder then wait patiently as the heat was transfered to the copper end on the fuse. When it reached the right temp the solder flowed out at which time I soldered the pre tinned end of the lamp cord wire to it. After the fuses cooled down I wrapped the ends opposite the solder joint with a strip of gaffers tape to keep them from making contact with one another where the ends stick out of the holder. That's how I fried the first one. A wood dowel and screw head doesn't have that problem.


I also modified the battery holder so that AA's can still be used. I used a 1/8" drill bit like a side cutter to create wire channels through the holder to route the wire out so that I can almost completely close the battery door. I could notch the door, but really don't find it necessary.


You'll notice in the photos I colored one of the fuses and one of the connectors, with a red Sharpie, so that I knew which one was plus.


Recycling time: What I hoped for based on other web posts was not what I got. I'm an engineer by trade so it was logical to get the results I figured I'd get. The recycling times are no different than having a full set of (4) 1.5V alkalines in the flash. I knew this to be true. Just because you have a battery capable of delivering a lot of current, doesn't mean the flash will use it. 6V is 6V and the flash head will only draw current at a pre-set rate. There is a mod where someone is using 7.2 volts with a little faster recycling. Someone tried 12V and fried their pack!! So, it goes about like this:


Full power: flash to green light = 4 sec.


1/2 power: flash to green light = 2 sec.


1/4 = < 1 sec .... 1/16 very fast.


The great thing is that these times are repeatable for a very long time. How long? I'll find out this weekend.


Here are the shots:


Wired fake batteries and battery holder (still usable with AA's)


http://i169.photobucket.com/albums/u...G_8639_480.jpg


Wire routing


http://i169.photobucket.com/albums/u...G_8637_480.jpg


Body Glove compact camera case from Wally World. Man!!that's one tight fit.


http://i169.photobucket.com/albums/u...G_8626_480.jpg


Close Up of cactus trigger. I don't trust it as a strobe stand.


http://i169.photobucket.com/albums/u...G_8628_480.jpg


Finished look: I used velcro strap to hang the body glove on the light stand.

http://i169.photobucket.com/albums/u...G_8625_480.jpg


Time involved: A few hours on Saturday.