Dual battery question

[Deanosan]

Posting for the first time here hope I get it right. Can someone advise me the best way to go in regards to a dual battery system. What would suit better for my 2006 str. An auto electrician doing the whole job, do it myself, the kits look reasonably straight forward to fit, or get one of those power boxes that house the battery, isolator and all necessary wiring and plugs for your fridge etc. Added is the fact I would like to put the battery in the rear tub (canopy equipped), so I can add a larger battery like a 100 amp plus and the ability to remove it when not in use

 

[rescue]

I've got 2 100Ahr AGM batteries in the tub 1 each side of the drawers

 

[Matt76]

I am no where near a confident sparky but I did mine myself mate, it was pretty easy, the hardest bit was running the wires.

I ran heavy cables right from the back to the front through the chassis (inside a piece of flexi conduit), some will tell you to earth it to the chassis at the back to save cable but I didn't. Give it a go, and then you will understand the whole system better once it's done.

 

[KraftyPg]

Confidence is the key, if you're confident you can do the job it is an easy job, the hardest parts are the wiring like Matt said and deciding just where you want everything.

It is worth doing a little homework and getting the kit that suits you best, there are many kits around and while they all do a similar job there are differences, things like using solenoids or isolators, using a big battery or a monster battery, running the cables internal or external.

There is quite a few of us who have done our own batteries on here and there are a few write ups but that doesn't mean each one will suit your needs exactly so before you start the job it does pay to do some research.

One advantage doing it yourself has over an auto elec is that you will have the final say over everything from parts to fitment, paying someone else to do the job you might not get such freedoms. However having said that, if you not confident it is better to pay someone who knows what they are doing rather than risk a disaster.

 

[Old.Tony]

When you are making a decision about which way you're going to hook things up, consider this as well:

Your alternator produces a decent voltage but the car regulator holds the voltage at between 14.4 and 14.7V. In order to fully charge a lead acid battery, you need over 15V (more like 15.5V). Just using the alternator, most times you'll only get 70 to 75% charge in the battery.

Then, since you should only discharge the battery to 50% of its full state, you're actually only giving yourself 20-25% of the battery's rated power.

An alternative that works very well is:

Car battery --> 30A Fuse --> relay --> cable into tub --> inverter --> battery charger --> 2nd battery

Use a good multi-stage (like a C-Tek unit) charger and your battery will perform better and last longer. A 300W inverter is more than enough. The relay only turns on the power when the ignition is turned on, so you can't flatten your vehicle battery. Cable should be 6 sq mm (60Amp), double insulated and run through grommets where it passes through any metal. You don't need to fuse the far end, because you're not drawing power from the battery, it's isolated.

 

[Dave]

Have you got a snorkel ?

If not and your thinking of it get a YD25 snborkel and put the second battery where the pre filter is.

Dave.

 

[Bill Parks]

Im not confident.
Had the Auto Electrician put mine under hood.
Passanger rear corner behind where the snorkel comes into the engine bay...
Bill