WRND 20A DC-DC Dual battery system for Cheap

[NEW]

Okey, so end March will be the first Bundu-ish (no power) bash with GV for 5 days.

Need to sort out the Battery box for the fridge. In the Jimny I had some thick cables, and fuses, from the front battery with a manual switch and a battery box with hella plugs and volt meter. All connected together with brad harrison plugs.

I now bought a WRND 20A DC-DC charger from 4x4 Direct. (Awesome service by the way, delivery within 24 hours and extremely good price). I will attach it to my batter box.

Next week I will fit 8mm2 wires with brad harrison plugs in the GV. (Total costs, around R 800, through a normal car audio installer) (I think that is why it is so cheap. If it was safari and outdoor, they would have ripped me a new one).

And thar she blows. A fully plug and play dual battery system that will function independently for less than R 3K. (I did however already have a battery and the box and plugs). The nice part is, the WRND is an MPPT solar controller as well. Solar can thus be added by the mere purchase of a panel.

[Paul#25]

8mm2 is a bit on the thin side. For that application the recommend minimum is 16mm2. I got the cables from National Luna which is close to me.

[NEW]

I understand you need 16mm2 when you dealing with a solenoid only, as the full brunt of the alternator will be pushed through. Hence I had 16mm2 in my old setup as it just functioned directly form alternator.

A DC-DC charger only takes a certain amount of amps to a max. In my case 20A, maybe slightly more and whatever other load is put on the charger. In my case just a fridge. So I am looking at 25-27A max , which 8mm2 can handle? This is how I understand it. Might be wrong...

The other aspect is voltage drop. WRND advises in its manual that for 8mm2 wires can do 6m (I will use much less), the general advic being that there must be lest than 1V drop in the wire.

[NEW]

Right, wires installed and system is working! At least on first test.

Total cost: R 5 500

Initially: battery box, wires, connectors & plugs, volt meter and semi-deep cycle battery - R 2 600 (My semi deep cycle, Exide Silver Calcium, is still going strong after 5 years!)
WRND DC-DC charger - R 2 050
Some more plugs and fuses & holders - R200
Installation of cabling - R 650

And some elbow grease, bad language and soldering...

[BushWacker]

For my HCDP the multistrand heavy current
wiring was difficult to clamp and bend etc
for the junction box ... so my advice is to use the largest diameter multistand cabling that can be effectively accommodated/clamped by the WRND unit
... and pref finer multstrand>thicker