Elinchromish Ranger RX Speed Replacementr Battery

So, if you have this particular Flash Generator and your battery craps out, you will notice that the manufacturer only sells the small capacity replacement at eye watering prices. 
As mine was bought second hand, I ripped the battery apart to see what was broken. Turns out it's just a case for a common motorcycle battery.

I put this one in.
The wiring is simple enough and 12V isn't out for vengeance, but the circuit breaker seemed like a sensible addition. So I added this holder, which came with the necessary 40A Circuit Breaker.
I wired everything up with 1mm² wire. Calculation says 0,75mm² would suffice, but erring on the side of caution here.
The three metal plates should rest on something soft. I'd suggest a piece of kitchen sponge. There is a surprising amount of play needed between the battery sliding into place/locking and the plates making contact

Necessary Materials:
- Battery, obviously. I used a 12V, 12AH Led-Gel Battery. 
- Cable at least 0,75mm² about 40cm
- 3x Metal Plate 1mm thickness. 96x16mm (max, can be a bit smaller, I used Aluminium)
- 3x M2 countersunk screws with nuts and washers (To clamp the leads to metal plates)
- 1x Circuit-Breaker-Holder + 40A Circuit breaker (Don't skip this please)
- 2x M3 Screws for Circuit breaker holder. Flathead , Sockethead, longer than 3mm
- 1x Kitchen Sponge to act as a cushion
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Optional:
- 12x M3 heat insert ( ideally short ones)
- 8x M3 countersunk screws ~5mm max
- 4x M3 countersunk screws ~5mm min

I designed it with those optional parts, but Elinchrom used tape to hold their sponges in place and if you use a drop of superglue to close the lid, I won't tell anybody.

Assembly:
Drill 2mm  holes in your metal plates and screw the uninsulated wire in place. Should be very off-center.

I had some trouble because my aluminium had a nice oxide finish, which is a pretty great isolator. Had to sand through that with a Dremel sanding drum.

Do the rest of the wiring, two cables go  together, one gets the circuit-breaker added in the middle.(Feel free to crimp some actual connectors,  I did that, but they kept sliding off -.-) 
See wiring Diagram.

Put plates in place, wired-end goes to the side with the cut-out. The one with the circuit breaker needs to be the middle.
Add sponge-slices and BuzzBar-Holders. Either screw into place or tape. Bar-Holders should be flush with the rest of the Lid, Metal plates should be gently pushed against the top.

Connect wiring to Battery and slide that sideways into the body. Side with the connectors goes to the cutout.

Screw Circuit-breaker-holder into place. 

Lid goes on but not in, stuff the rest of the cable into wherever you find space. You might find out you left the cables to long.

If wire-management  works out, take one of the Lock Tabs. It goes in through the cutout in the side, around the top and slides into the little grove at the very top.
Use the lid to push and hold it into place.

Same maneuver on the other side.
Admittedly fiddly, but ideally you only do that once.

Screw lid into place
You're done.

WARNINGS
- This is a DIY electronics project, I am not there to hold your hand, if you somehow manage to electrocute yourself with 12V, thats on you.
- Same for any damages to yourself or your Flash Unit. Slide finished battery in gently and see it it locks in/turns on
- This block can only be charged by charging it inside the Flash-Unit. Might be inconvenient for you, but it was a sacrifice I was willing to make
-The whole locking thing: There is very little play between “Locking tabs engage” and “Battery still makes contact when unit is lifted” I had mine turn of during shoots when moving it

TO DOs
I found it's sensible to have some additional feet under the Battery, helps it slide deep enough. Will add this when I get around to it. In the mean time: glue some felt-feet for chairs under?