FRIDGES & WHAT MAKES EM GO ???

Rexy,
Why is your existing DBatt system no good? What sort of vehicle?
Now to answer your questions as well as I can....
1&2&3) I run 2 "normal" batteries. The standard starting battery and an Exide Extreme for the aux. Deep cyclers are really designed for applications like running motorised wheelchairs and those trolley's the oldies tend to use etc. They need to be well re-charged and I don't believe an alternator has the ability to do a good enough job of that. CCA are the measure of how much cranking capacity a battery has at a certain temperature. Others will explain that better than me.
4) I wouldn't trust a standard-type of cigi plug. They have a bad habit of vibrating loose...the only thing holding them in place is the tension of the negative spring-loaded gizzmo on the side of the plug. Go for a positive fitting or hard-wired even better.
5) By "fridge power things" I'm guessing you mean the units like "THUMPER" etc which also double up as an emergency engine starter etc. I haven't had any 1st hand experience of these, but some blokes in our club use them for running lights etc and they seem pretty good, even if somewhat overpriced for the amount of "bang" you get out of them. EG: I think the biggest is around 56AH and costs around $500-. Compare that to a good starter battery of say 100AH for about $120- plus a few fittings. The advantage is that the Thumper etc are not wet cells and are safer to carry inside vehicle cab etc. You could opt for a Exide Orbital spiral cell battery but they're nearly $400- but would run rings around a Thumper.
6) As I've siad on previous posts, I believe in keeping things simple, but also being in control and in touch with what my vehicle is doing. For that reason, I don't like fuly automated systems that charge the starter batt first then automatically change over to charge aux batt. I prefer to have gauges and switches so I can control these things. However, I freely acknowledge that there are those among us who just don't want the hassle of having to remember to switch something on/off etc.
Let us know what's wrong with your current system please.
Cheers,
Roachie

The question you really need to ask yourself first and foremost, do you really honestly need a 90 litre fridge.
1) Yes
2) No, that suggestion is foolish, unless you are going to run 2 x deepcycles connected to a proper battery charging system.
3) Why do you think a cranking battery is going to work as a deep cycle? Why do you think they make many different types of battery?
4) Only dummies use cigarette lighter plugs above 2 amps.
5) Absolute rip-offs and complete waste of money.
6) A Redarc battery isolater with a 90Ah deep cycle battery and a GMC850 generator from Bunnings for $198. A 90 litre fridge takes a *substantial amount* of power and a 90Ah battery will generally not last 12 hours on a Waeco.
Once you go over 50 litres or even up to a 68 litre with a BD35 compressor, but once you step up to a Danfoss BD50F compressor you need a decent battery setup to keep it going. When we talk decent battery setup we are talking decent money.
You cannot actually buy a decent batter setup, it needs to be done by somebody that knows what they are doing

Mate your ok, no need to panic! Your Smurf has two fairly small sized batterys, hooked up as one big battery.
ie You flatten one, you faltten both. They do last a long time while hooked up like this though. Putting an isolater between the two batteries is a very easy and cheap process, you just need to choose what kind you want. I used a Jaycar build it yourself type kit, but sounds like you may need to purchase a ready made jobby and just put it into the car. Basically if your surf is a 3.0l td, your passenger side battery will become your starter as it has all the big FO cables that go to the glow plug relay and starter motor, that cable that goes along the top of the raditor links the second battery on the drivers side. The main fuse box joins up with that cable and connects to the second battery.
What you do is simply take the cables off the positive terminal of the second battery, buy a battery lead from super crap autos or some place similar, put a bolt through the ends of the two cables and connect it to your isolator. Then tape them up with plenty of insulation tape and cable tie them out of the road. Then get another battery cable from the for mentioned place and hook it from the isolater to the battery. All done. there might be some other wires for voltage detection etc that need to be done but that's the basics.
The other thing you will probally need to do then is get a bigger starter battery as the little one will do the job but won't last long, especially through winter. A NZZ70 (landcruiser size) battery will fit perfectly in place of the smaller factory one.
If you want photo's or any more detail of how I did it let me know, also I use a Hella 16amp plug for my fridge, bloody brilliant, clicks in nice and tight, doesn't melt like some cig plgus do, and it has an adaptor so I can plug it into a normal cig plug in another vehicle for some reason.

Thank alot for your help guys, i really apriciate it. in answer to the majority of questions,

I am going to get an auto elecy to help me set it up. but as a few of you have pointed out, i as told by an auto leky that surfs were 24 v. hense i went "oh crap".
and aftwer that opinion i started doing a bit of home work and you would be suprised how many people think that smurf mobiles are 24v. Im going to give it a go myself., cause at least then i can learn something more about my truck and B4 i actually crank it up ill get a mobile auto lekky to come over and checkit out to make sure that i am not about to frag everything out
once again guys

thanks alot

Rexy