Two fridges and a Dmax What 2nd battery?

Hi Andy
Are you sure about that 800 amp hour. Or did you mean 80 amp hour???
You would need a crane to lift an 800 amp hour battery.
Just checking.
Cheers, Bruce

Hi Bruce, sorry typing mistake it is 80ah

G'day Phil G: I was interested in your comment on the need to repalce the wiring in the Tvan after 7 years: was that just some parts of the van's wiring or all through?
Camperman2

Gday Gordon,
When I bought the Tvan, I found there was a lot of voltage drop between Anderson Plug and battery. Had a look at the wiring and the thick copper wire had gone black - earth more than the pos. Heres a photo showing the conductors that I did at the time:


Its called "black wire corrosion" or "black wire disease" and is pretty common. Just google it.

The copper conductor in marine wire is tinned to stop corrosion, so that is what I like to use. The current rating is a bit less and it costs a little more.

Thanks Phil - good clear pics & appreciated. With a new Tvan coming next week, it is something for me to look out for. I will also follow up on Google as you have suggested, but in the meantime, is the corrosion related to the atmosphere or simply something that happens from the current flow? I assume that it can happen on any vehicle or appliance?
Camperman2

Thanks Phil for the Google reference. That took me to the Tvan forum where you have also reported the problem. A contributor there stated: “Common in any current carrying untinned copper wire exposed to moisture. For some reason black insulated wires or negative wires seem more prone.
When you replace it make sure you prevent moisture ingress into the cable. This can be done by using dielectric grease and sealing the cable end connection with heat shrink, or alternatively using glue lined heatshrink, available at Jaycar.”
The problem seems very common in radio controlled model planes (affects NiCd battery packs) and on reflection, in much earlier model railway days, I had seen it on 12v wires in that field as well and can recall the difficulty in soldering affected wire.
Another Google reference stated: “The condition almost always occurs on the negative leads, although it can occur on the positive leads as well. Black-Wire Disease occurs when the electrolyte (concentrated potassium hydroxide paste) leaks from the NiCd via the vent or seals, and comes in contact with the wire. Once copper oxide is formed, it acts as a wick, gradually drawing more potassium hydroxide along the wire, further and further from the pack. This wicking action can be very destructive, and Black-Wire can and will pass through switches, and continue to spread throughout …. the circuitry.
This is very interesting & a potential problem we should be on the lookout for, particularly where there is an obvious loss of power between battery and van/car appliances. The jury seems to be still out on whether it is caused by a leakage of battery fluid into the negative wire, whether it is a breakdown of the untinned wire, maybe through moisture penetration and oxidisation or both! Obviously, one solution to the problem is the use of quality tinned wire when vehicles are being manufactured but that is unlikely to happen any time soon as manufacturers struggle to remain price competitive and in most cases, the problem does not occur until well outside of the warranty period.
Lesson: consider black wire disease as a potential cause of loss of power in all situations.
Camperman2