Dual battery advice

[Herman4x4]

Hello,
Im looking at setting up my dual battery in the NS.
I have taken the isolator out of my NP, a Projecta 150 amp, as well as the ARB battery tray. But i am now thinking of mounting the battery in the third row seat well.
I have bought 8 b&s cable as i was going to run this to the back for the fridge and a merit plug running off a fuse block.
But now as i am thinking about putting the battery in tree back, would that cable be big enough?
Thanks,
Andrew.


Sent from my CPH1611 using Tapatalk

[sharkcaver]

Hello,
Im looking at setting up my dual battery in the NS.
I have taken the isolator out of my NP, a Projecta 150 amp, as well as the ARB battery tray. But i am now thinking of mounting the battery in the third row seat well.
I have bought 8 b&s cable as i was going to run this to the back for the fridge and a merit plug running off a fuse block.
But now as i am thinking about putting the battery in tree back, would that cable be big enough?
Thanks,
Andrew.


Sent from my CPH1611 using Tapatalk

I used 8B+S to the rear distribution point in my gen 3. It was fine. The battery was under bonnet though with a VSR.

I run 6b+S to a dcdc and a battery in the rear of the NX and that is fine too.

There is not much difference between 6 and 8 ga. If using a dcdc, I reckon 8ga will be ok, but not if using a VSR.

Just my opinion.....

[Herman4x4]

That's for the reply. Might get some bigger cable. But i did see in the bargins thread sparesbox is having a sale...... Maybe a dc to dc instead.
Cheees,
Andrew

Sent from my CPH1611 using Tapatalk

[Herman4x4]

Looking at one of these now.

https://frankiesautoelectrics.com.au/thunder-tdr02040-40a-dc-dc-charger-with-mppt-solar-regulator/?gclid=CjwKCAiA98TxBRBtEiwAVRLqu7McvY7YvwT5jA9xIMDdZKqoRvlERNYxRwpc1w8Yf0ZWGqaxJqijzRoC11QQAvD_BwE

Thanks,
Andrew

Sent from my CPH1611 using Tapatalk

[Dicko1]

Looking at one of these now.

https://frankiesautoelectrics.com.au/thunder-tdr02040-40a-dc-dc-charger-with-mppt-solar-regulator/?gclid=CjwKCAiA98TxBRBtEiwAVRLqu7McvY7YvwT5jA9xIMDdZKqoRvlERNYxRwpc1w8Yf0ZWGqaxJqijzRoC11QQAvD_BwE

Thanks,
Andrew

Sent from my CPH1611 using Tapatalk

I run 6 B&S ALL THE WAY FROM STARTER TO CAMPER VIA THE THIRD ROW SEATS AND HAVE 2 X DCDC CHARGERS( ONE IN TUB AND ONE IN CAMPER)...ALL WORK WELL. i HAVE A pROJECTA 25AMP DCDC CHARGER i DONT USE...YOU CAN HAVE IT FOR 100 DOLLARS PLUS POSTAGE....Lot better than the Thunder. It also has a built in MPPT solar regulator.

[Mundy55]

I think you'll find the 8 B&S to be quite sufficient. I have the 2nd battery under the bonnet but the Intervolt controller in the rear seat well. this means I have two 8 B&S cables running between engine bay and rear seat well. (I know everyone will say this is stupid but it works for me). Anyway, the system works perfectly with no appreciable voltage drop. The controller in the rear means its out of the heat of the engine bay. The battery under the bonnet means I can fit my 40L water tank in the rear seat well.

[Jasonmc73]

This chap has some quite good info,

https://www.fridge-and-solar.net/dual_bat.htm

I run 8 B&S for a fridge & my camper has Redarc BCDC1240 (40Amp charger), I run 4B&S for that with 120AMP Anderson plug.

6B&S would be fine for less amperage say 25amps.

Cannot be underestimated how joints & fusing is approached in my opinion. For me it's Mechanical crimp & solder with glue lined heat shrink & bolt down Midi fuses where applicable.

[Herman4x4]

I run 6 B&S ALL THE WAY FROM STARTER TO CAMPER VIA THE THIRD ROW SEATS AND HAVE 2 X DCDC CHARGERS( ONE IN TUB AND ONE IN CAMPER)...ALL WORK WELL. i HAVE A pROJECTA 25AMP DCDC CHARGER i DONT USE...YOU CAN HAVE IT FOR 100 DOLLARS PLUS POSTAGE....Lot better than the Thunder. It also has a built in MPPT solar regulator.

Thanjs Dicko. What would postage to Kurunjang 3337 be?
Cheers,
Andrew.

Sent from my CPH1611 using Tapatalk

[Dicko1]

Thanjs Dicko. What would postage to Kurunjang 3337 be?
Cheers,
Andrew.

Sent from my CPH1611 using Tapatalk

Unsure. I will post it for $120 and include 2 x 50 amp genuine anderson pluigs as well ..for your wiring. You may not need the plugs but use them elsewhere.
Let me know asap as someone else is keen on the unit.

[Herman4x4]

Im keen. I'll send you a pm.

Sent from my CPH1611 using Tapatalk

[disco stu]

What is b&s cable sizing? First time I've heard of it and I'm not new cable sizing etc. It seems to be close to gauge, but I'm not sure

[Kingbrown]

AWG is same as B&S and is referenced in vehicular applications.
'Real' electrical people use metric (mm2).

Cable Size Metric and AWG_B&S.docx

[nj swb]

As others have pointed out, Brown & Sharpe (B&S) and American Wire Gauge (AWG) are the same, and often just referred to as "gauge". I like Wikipedia's page on the subject: https://en.wikipedia.org/wiki/American_wire_gauge

Although I'm not a big fan of "gauge" sizing I prefer it when discussing automotive application, as too many sources sell "automotive" cable with a "mm" sizing that isn't the mm squared sizing that the Australian electrical industry generally uses. When automotive forums start discussing "mm" sizes of cables it can be difficult to tell if they're talking copper area or cable overall diameter (which I think is an absolutely useless measure of a cable's size). Talking "gauge" removes that potential source of confusion.

Also note that "ampacity" ratings, as included in Kingbrown's table, list different insulator temperature ratings - but these ratings are for a defined ambient temperature. If wiring in the engine compartment, consider the ambient temperature to which the wiring may be exposed - if the wire will experience a 60 degree ambient then a 60 degree rated insulation isn't good enough for load carrying applications.

Personally, when recently re-wiring my 20 A Redarc, I used 8 ga for most of the wiring, protected by 40 A fuses where I thought necessary. For a 40 A Redarc, I wouldn't go below 6 ga - Jason's 4 ga is a good choice.

[Jasonmc73]

"Amp" rating is not very useful,
Example, you won't run 50 amp down a 50 amp rated auto wire, more likely it will melt, safe working load, not what its meant to carry.
The mm in auto wire is completly useless,
A lot of the time thats including the insulation & misleading as NJ SWB points out.

There is a huge difference between 8,6 & 4 B&S as far as the amount of copper & as the chart below link shows as NJ SWB points out amps that's rated at 30 degrees, link shows the derate factor & twin core is different again, down rated.

https://www.tycab.com.au/battery-starter/

I also like looking at it like a garden hose, the longer the hose the bigger the hose needs to be to get the same volume out the other end.
Same goes for 12 volt wiring

A big wire can carry a fine amount of amperage so fuse it well & no good having nice cables & not taking the time to join terminate etc properly & use decent fuse types.
For heavy amperage I like bolt down Midi type fuses.

My opinion only is soldered joints alone prone to crack off, but soldered & mechanical hydraulic crimp with good length of glue lined heat shrink tube gives me less chance of ever having to find a busted wire or corroded joint.
Many say proper quality heavy duty hydraulically crimped fitting is best with glue lined heat shrink I can understand that as well, theory being soldering makes it brittle.

Hydraulic crimper only around $50 on EBAY work really well for my application as long as you don't over stroke the cylinder, you'll pop the seals.
The 10 Tonne one I have even came with spare seals, haven't had to use them yet.

Do it rite the 1st time & your done. I hate dodgy wires

[nj swb]

Basically I agree with everything Jasonmc wrote, but need to comment on this:

... soldered & ... crimp

If you're going to do both, crimp first then solder.

The crimp systems we're discussing are designed to crimp onto stranded conductors that move and deform during crimping, but once the cable is soldered it effectively becomes a single strand - the move and deform process can no longer happen, the crimp can't form as intended, and the mechanical grip will work loose over time.

Crimp first, then solder.

If worried about the copper becoming brittle, support the next centimetre or so of the cable - quality heatshrink will help, glue lined even better.

How many soldered connections do automotive manufacturers use in our cars? When done properly, crimping alone is fine. But automotive manufacturers spend millions to ensure they are crimping properly - so I often crimp and solder.