I know, I know......... drawers have been done to death but have a read anyway, I'm pretty sure you'll pick up some new ideas 
There were a few things I wanted to do to set the Jack up for day trips and camping, my wish list looked something like this.
- dual battery system
- Alternator charging
- Solar charging
- storage drawers
- 240V power
- able to sleep onboard (for quick overnighters)
- maybe build in the portable compressor (because I'm lazy 
)
- do it all on a tight budget
SO............ looking around at what was available........... F@#$ ME........ certainly nothing that I could afford. I put the whole idea on the back burner and decide to just sort out the extra battery and power system.
I already had a 100ah AGM in a portable box and a pair of folding solar panels, I just needed to figure out a nice way to fit the battery and some sort of on board charging system. After a fair bit of research on dual battery systems, I realised that it would be better for my AGM battery to live in the back rather than under the hood but the last thing I wanted, was a battery stuck in the back with wires everywhere so I decided that it was time to get creative and entertain that old saying......... "if you want it done properly, then DIY"
A picture's worth a thousand words, so I'll let the pictures tell the rest of the story 
The Black strips on top are Uni Trax 1000 Tie Down Tracks which I rebated into the top surface for a flush finish. Power panel on the right, drawers are different widths to meet my specific needs and that little white thing on the left is a four way remote control switch (its just sticking to the carpet with velcro) currently it is only being used to turn the compressor on/off when I'm crouching at the tyres, but the other three switches may come in handy for lights etc.
The Power panel.......... (top to bottom) 600W/1200W inverter, Dual USB sockets (left) and Merit socket (right), Dual standard accessory sockets, Solar Panel input (red anderson plug), combination Volt and Amp meter (shows both charge and discharge amps), Dual 50amp anderson plugs (the grey ones). The vertical row of red buttons on the left are all circuit breakers, I couldn't find a nice place to mount a fuse box so I went with breakers which also eliminates the need to carry extra fuses. The black thing next to the grey anderson's is a quick release air line fitting, just plug in the air hose and switch on and off with the remote.
looking from the other end, with the rear seats folded up so we can see. The compressor is bolted down to the base panel, the black dot just forward of the right side of the compressor plate is one of 5 high tensile countersunk bolts which hold the two boxes down to the original tie down points (the fifth is in the centre child restraint point)
on the drivers side is where the battery lives, the red knob is the main isolator switch, it switches off everything at the power panel but leaves the charging circuit operational, the red anderson is for linking in an extra battery if needed. (if its cloudy and the portable battery needs power, then it can be linked in for charging off the alternator or it can just be linked in to double the on-board capacity)
back to the business end, one thing I hate on a day trip is not having somewhere to make lunch or put a cooker, so I made up hinged bench tops for both drawers. Instant table or bench and one less thing that I need to pack. Drawer runners are heavy duty self locking type and yes, I can stand in the drawer when it's fully extended.
both drawers out with the tables lifted and that's a lot of storage space. Internal measurements - The large drawer is 820x520x240 and the small drawer is 710x340x240. (the small drawer is shorter because the battery is wider than the compressor)
Under the right side wing. I decided to box in over the wheel arch, it was a bit fiddly shaping around the extra row seat mounts etc, but it meant that I had a nice way to mount the inverter and the Ctek 250S Dual. All the wiring was done below the fill-in panel and incorporated into the unit. (that means that I can undo 5 bolts + 1 earth cable + one power cable and the whole lot can be removed in two pieces in about 10 minutes)
Under the left wing. thats the problem with doing one side all pretty, you feel compelled to make the other side look nice too 
So once again, boxed over the wheel arch but this time I stopped at the end of the arch, leaving a full depth cavity which made a perfect pocket for the first aid kit and still allows full access to the original bottle jack and tools.
A closer look at the Uni Tax 1000 tie down system. Simple and bloody strong. According to the manufacturer, when tested to destruction, the track fails first at 2000Lb so that gives me a safe working load of over 300Kg per tie down point !!!!!!
The Portable (campsite) battery, strapped in and linked in for charging and/or added capacity - (Who me...... power hungry.......... Noooooo 
)
Right then....... back to the check list....... what have I forgotten.......
Oh yes, the ability to sleep on-board...... OK, I didn't really forget, this was the part of the requirement that determined the exact height of the storage unit. You see, the rear seats shorten the storage area when they are folded up but if you just fold the backrest down, they are incredibly strong and will hold a lot of load stacked directly on top. Thats where these extra four panels come in to the game. (they store away in the large drawer when not in use.
with a little bit of planing and some careful routing, keyhole fittings (the kind used for hanging cabinets on walls) do the job of locking the four panels together
All locked in, it only takes a couple of minutes to convert to a full flat bed and the perfect size for a double mattress. So why did I split the extension panels into four separate panels? and why are they different sizes?
Well firstly, I wanted them to fit in the drawer so that they were always onboard when needed and secondly................
sometimes, you need an extra seat
and sometimes you need and extra two seats 
A bit of careful design and now the storage space can be configured to suit simply by removing two of the four extension panels to allow for extra seating.
Ok, so that's my DIY storage unit and triple battery system. It was a fun project and yes, I did all the work myself. I hope you have picked up some ideas for your own vehicle or at least enjoyed the post 
Craig