Want to install a small modern battery and LED lights - What exactly do I need?

I’ve spent hours trawling forums over the last couple of months, so I’m hoping someone can just spell it out for me.
I’m working on my 1981 Xj550 (but with a 600 engine installed before I got it) and going for a Brat/Tracker style look… I want to place a smaller gel type battery under the seat. Also want to do complete LED lights all round. Im looking please for a plain English explanation of what I need to do – and any recommendations on which battery to use.
I believe I’m going to need a modern voltage regulator for the battery? And conversion kits for the lights? – and also maybe modern relays? Im at a loss as to what to start with thou.. Im going to replace the fuse box, but also now wondering if I should replace the whole electrics, although they all work fine – so why fix it?
Can you help me out with a definitive, idiots guide as to what I actually need to do this!? Thanks!

 

a gel battery isn't really any smaller than a old style lead/acid type, same for the AGM type but the gel and AGM can be mounted on their side. the really small/light ones are LiFePo batteries and they cost a lot.
LED headlights plug right into what you have now but again they cost a lot and i don't know what's legal over there
turn signals are just a matter of using the right flasher relay.....it's on here somewhere.
brake and tail lights are no problem they just plug in.
the problems with most of the conversion come from the warning lights in your instruments, get rid of that and most of the problems go with it

 

for the turn signals, here is what you want to do. scroll down to the last post for the wiring diagram.

http://xjbikes.com/forums/index.php...s-and-still-have-everything-work.14068/page-2

CN

 

I've replaced all my bikes taillights with these:

https://www.superbrightleds.com/mor...watt-high-power-led-w-brake-flasher/923/2274/

It's really bright and the flashing feature is nice. I've never bothered with the turn signals as I've felt they're adequate. They'll have all the other lights you need too. CN's link should get you covered on the turn signals.

 

Thanks all....Ive had to replace the whole back lights, and have gone for this..

http://www.ebay.co.uk/itm/331042714978?_trksid=p2059210.m2749.l2649&ssPageName=STRK:MEBIDX:IT

Its cheap, but its exactly the shape I wanted and it seems to work..Im still struggling with the wiring - and it looks likes im going to need a voltage regulator as the indicators stay on when the new LED unit is in place....(I believe this is cos the LED doesnt use and therefore allow as much power thru to the ticker)

There was no wiring diagram, so trial and error...

 

They do make a replacement flasher relay to fix that. The led don't put enough load on the flasher relay for it to heat up and open.

 

http://www.carhidkits.com/led-turn-signal-flasher-fix-384.html
Something like this

 

is that bulb a simple plug and go thing or did it require any additional wiring or relay?