Two fridges and a Dmax What 2nd battery?

The Dmax is finally mine,,,, my future son in law picked it up for me today and I get to see it in a weeks time.

Now to the issue. I mentioned in a thread a while ago that I would be putting in 2 fridges in the pod on the Dmax.

I'm looking at a 120 ah (hope I got that right) Fullriver deep cycle AGM.

I am going to the auto electrician to get the wiring done.

In my old vehicle I have wiring about the thickness of my fat little finger , about the dia of a pencil, running from the battery to the fridge in the back of the troopy and all has always been good.

I think that I should stick to the same thickness of wiring from the Dmax battery to the full river in a tool box below the pod. Then too the fridges.

I presume I need two 20 amp circuit brakers between the full river and the fridges and they should be about 200mm from the battery.

I am then presumiing that it wouldn't hurt to attach a ctek trickle charger to the full river when I am in the caravan pk.

Am I going in the right direction?

Any help would be appreciated.

Back Expand Un-Read 0 Moderator

Reply By: Member Andys Adventures - Saturday, Oct 01, 2011 at 19:12

Saturday, Oct 01, 2011 at 19:12
Hi BooBoo, I have just put 2/ 800 ah deep cycles to run 2/ 40lt engials 1 as a fridge and one as a freezer. I use a ctec with a DC /DC charger and 180 w solar. It just keeps up with them if you are opening them all the time. Have not had them long enough to give you more info.

Lifetime Member
My Profile  Send Message

AnswerID: 466507

Follow Up By: Member - Bruce C (NSW) - Sunday, Oct 02, 2011 at 08:41

Sunday, Oct 02, 2011 at 08:41
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
At home and at ease on a track that I know not and
restless and lost on a track that I know. HL.

Lifetime Member
My Profile  Send Message

FollowupID: 740658

Follow Up By: Member Andys Adventures - Sunday, Oct 02, 2011 at 09:14

Sunday, Oct 02, 2011 at 09:14
Hi Bruce, sorry typing mistake it is 80ah

Lifetime Member
My Profile  Send Message

FollowupID: 740660

Reply By: Ozhumvee - Saturday, Oct 01, 2011 at 19:50

Saturday, Oct 01, 2011 at 19:50
120ah isn't much battery capacity to run two fridges especially if observing the 60% rule for conserving battery life. Only gives approx 50ah to use before starting to drain the battery below the ideal level for longevity. Two fridges would suck that out pretty quickly if not travelling.
Your wiring sizes sound ok, for best results run both positive and negative direct from battery to fridges.
Preferably use good quality manually resettable circuit breakers rather than the automotive auto reset ones which can and do burn out due to poor quality contact material.
AnswerID: 466515

Reply By: Member - Phil G (SA) - Saturday, Oct 01, 2011 at 20:20

Saturday, Oct 01, 2011 at 20:20
Gday Booboo,

#1 With the full river battery, you'll need to restrict the current to 24 amps or less otherwise it will die an early death like my Remco. The cheaper AGMs have charging limits. (Spec sheet)
Best way to do that would be to fit a DC/DC charger like the Ctek D250S. It also doubles as an isolator. If you use the Ctek, you'd be fine with 8Ga wiring - don't need it as fat as your little finger!!!

#2 You will need a fusiblelink/fuse/circuitbreaker at each pos terminal (both cranking and aux) for short circuit protection. The capacity of the fuse should be a little less than the rating of the wire.

#3 You need a big fat earth lead going back to to cranking battery earth (hence motor and alternator).

#4 I prefer tinned wire (marine grade) because it's unlikely to corrode. I had to replace the wire in my TVan because it was corroded after 7 years.

I also run 2 fridges (both as fridges - one as a meat fridge at 2 degrees and the other as a cooler for veg and drinks at 6-8 degrees). 120Ah should get you a full days use in warm conditions. If you use one of your fridges as a freezer, and aren't driving or near a powerpoint, it would be worth considering getting an extra AGM.

AnswerID: 466518

Follow Up By: Member - Gordon T (NSW) - Saturday, Oct 01, 2011 at 22:05

Saturday, Oct 01, 2011 at 22:05
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?
FollowupID: 740639

Follow Up By: Member - Phil G (SA) - Saturday, Oct 01, 2011 at 22:21

Saturday, Oct 01, 2011 at 22:21
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.
FollowupID: 740643

Follow Up By: Member - Gordon T (NSW) - Saturday, Oct 01, 2011 at 23:16

Saturday, Oct 01, 2011 at 23:16
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?
FollowupID: 740648

Follow Up By: Member - Gordon T (NSW) - Sunday, Oct 02, 2011 at 11:44

Sunday, Oct 02, 2011 at 11:44
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.
FollowupID: 740673

Reply By: Member - Boo Boo (NSW) - Monday, Oct 03, 2011 at 07:27

Monday, Oct 03, 2011 at 07:27
Thanks for the advise gentlemen

I will go and talk to my auto electrician when I get back to Scone, and I do like the idea of the ctek acting as a cicuit breaker as well.

AnswerID: 466631

Reply By: Member - Boo Boo (NSW) - Tuesday, Oct 04, 2011 at 18:10

Tuesday, Oct 04, 2011 at 18:10
Talk about frustrating. The only Fullriver distributor in Sydney is at Wetherill Park.

I rang them about 20 minutes ago and the realised that Queensland is an hour and 20 years behind NSW. LOL

It's a bit out of the way so what are your recommendations for an alternative to the Fullriver.

I was looking at something around the 120ah deepcycle AGM.

Can anyone help me out.

AnswerID: 466785

Sponsored Links

Popular Products (9)