My dual battery installation

[ozwapet2 Advanced Member Find all posts View Profile Close ozwapet2]

Re: My dual battery installation

Hmmm... did you get the Redarc user guide from their website. I think they specify a thicker guage wire between batteries if using the override switch ( 19 mm or 4 B &S )
http://redarc.com.au/static/files/Smart ... t-A5-3.pdf
I use a Traxide controller but the principle's the same. I have circuit breakers in the positive lead between the batteries and the controller, and mounted near the batteries. This is just in case there's ever a short in the inter battery wiring or the controller. I think Redarc specify this too.
I know you said you're running twin red/black between fridge and battery, but it's not shown on your drawing there.
It would probably be better to just run the black straight to the aux battery neg terminal rather than earthing it.

[leachy_9 Advanced Member Find all posts View Profile Close leachy_9]

Re: My dual battery installation

. The 8 B&S wire running to the fridge will be twin sheath and earthed in the engine bay somewhere.
Cheers
Corbo

I guess since you are installing the override switch you plan to be able to crank off the aux. battery if needed. If so i would suggest that 2B&S would be more suitable than the 6B&S you have shown. This will also improve the au. battery recharge rate.

While your at it you might also want to look at upgrading the standard cable from the alternator tot eh crank battery.

Likewise, since you are showing an anderson plug connection I assume this is to power/charger a camper. If so, because of the distance, I would suggest changing the 8 B&S to 6 B&S to reduce the voltage drop.

Terminate the negative of the twin (anderson) cable directly to the Aux. battery negative terminal.

If, as drawn, you get the supply for the overide switch directly from the Aux. battery you need to fuse the control wire as close as possible to the aux. battery.

Leachy

[Corbo Junior Member Find all posts View Profile Close Corbo]

Re: My dual battery installation

Thicker gauge wire and fuses it is.

One more quick question, is it safe to run your wire across the front of the engine bay? as it looks like a couple of people have done this in their photos but thought i would double check before doing the same.

Cheers
Corbo

[drivesafe Senior Member Find all posts View Profile Close drivesafe]

Re: My dual battery installation

Hi Corbo, your 6B&S is fine, not only for charging your auxiliary battery but to use as cranking cable.

With your 6B&S cable, it’s rated at around 90 amps when used in a continuos load situations like a dual battery set up and when used as starter motor cable, it has a short cycle rate in access of 250 amps.

So in your case, while charging in one direction, unless you have a 150 amp alternator on one end and a bank of auxiliary batteries on the other end, or unless in the other direction, you intend to jump start a tank, your 6B&S is all you need.

Again, depending on the size of your 3 way fridge, up to a 15 amp fridge, your 8B&S cable is fine.

Most 3 way fridges fall into three current usage levels, around 9 amp, 15 amps and 23 amps and unless you are running the bigger fridge, 8B&S is fine and even with a 23 amp fridge, your system will work but not quite as well as if you had run 6B&S, and the little improvement by going to 6B&S probably wouldn’t warrant all the cost and work.

[Corbo Junior Member Find all posts View Profile Close Corbo]

Re: My dual battery installation

Finally got around to installing my dual battery and thought I would post couple pics. Ended up going for 3B&S (25mm2) cable between battery's, fuses and redarc. I also ran 10mm2 twin sheath wire to the rear anderson plug for the fridge. All up took a few hours and was fairly simple DIY.

[JJT Junior Member Find all posts View Profile Close JJT]

Re: My dual battery installation

Hi PradoPoint,

I need some help selecting cables and fuses for my dual battery setup, I have been trawling this forum and others but can't find alot of info related to choosing the correct cable sizes and fuses. Also after some input relating to the positioning of the fuse box for accessory outlets. There seem to be alot of variations between setups in this area. Hope someone can help out? Opinions and recommendations based on experience.

This is what I am looking at so far:

2B&S 32.5mm2 For Auxiliary battery positive to redarc isolator (SBI12) then to original battery.
2B&S 32.5mm2 For Auxiliary battery negative to earth point on engine.
100 amp fuse at each Positve terminal. Need reccomendations for suitable fuses and enclosures. Where to get them?

Fuse box for accessory outlets located within 30cm of the Auxiliary battery (4x4 monthly recommended). What rating fuses do I need for the applications I have listed below? Need recomendations for suitable fuse box.
6B&S 15.0mm2 cable to connect the fuse box to the auxiliary battery(positive & negative)?

8B&S 8.0mm2 TWIN CORE 100AMP for rear accessory sockets x 2, Can I use the same cable for both outlets or should I use 6B&S 15.0mm2 for the run to the back of the car?

Twin sheath 3MM Gauge cable for momentary override switch to allow starting off auxilliary battery. What Fuse rating should I use on this cable? Should fuses be used on both ends, i.e. the override terminal and the auxiliary battery.

Want to power Waeco CF40 fridge + occasional use of inverter to charge camera batteries and use netbook for short periods. Probably only need to run the fridge 24hours, some battery suggestions would also be great. Trying to keep the weight down as much as possible.

Need some suggestions on where to get good waterproof fuses / fuse box, web order or in Melbourne.
Sorry about the long post, but thought it best to include as much detail as possible.

Thanks for any help.

[drivesafe Senior Member Find all posts View Profile Close drivesafe]

Re: My dual battery installation

Hi JJT, as posted above, 6B&S is all you need for a dual battery system. You can fit thicker cable but your wasting time and money because there will be very little gain. And the gain being that if your auxiliary battery is very low, you may need to drive for 10 to 15 minutes more to fully charge it if you use thicker cable.

Again, for jump starting 6B&S, will only rated at around 90 amps when used in a dual battery system but is rated at around 250 amps when used as starter cable, more than enough for jump starting.

If you are planning on doing a lot of jump starting, you need to workout why! Most people either never need to jump start a vehicle or might do it once or twice over the life span of the vehicle.

With most dual battery set ups, a 50 amp auto resetting circuit breaker will give you the best all round protection and they need no servicing.

Your rear set up, if you plan to use your inverter for any length of time, hours at a time, then the 8B&S is fine but would only be rated at a maximum constant current of 65 amps, so you select your protection based on this current rate, not on the 100 amps a lot of ill inform sales people sell it at.

The reason for knowing the exact safe maximum current load of cable is to allow for the selection of the correct safe size of protection.

Like most things relating to dual battery systems, selecting the correct safe size of fuse or circuit breaker is not as simple as the cable is safe at 65 amps so a fuse or circuit breaker just has to be the same or slightly smaller.

The fact is that if the fuse or circuit breaker is automotive rated then it will tolerate 135% of it’s marked current for nearly 30 minutes. This means a 50 amp fuse or circuit breaker will allow up to 67.5 amps for 30 minutes and higher current for shorter time periods.

So as you can see, if you use 8B&S to the rear of your 4x4, pick the current rate of the protection carefully, a 30 amp auto resetting circuit breaker would be idea.

With your Jump Start, I take it your talking about using a solenoid to connect the auxiliary battery to the cranking battery. this is just a suggestion, fit your solenoid as close as possible to the auxiliary battery and wire one side of the solenoid’s coil wires to the solenoids terminal that has the cable coming from the auxiliary battery and the other coil wire is then run into the cab, via a switch to earth. The solenoid then does not need a fuse.

Now, when setting up for jump starting, you will need to bypass your protection devices at both ends of the cable running between your two batteries. I’ll leave that one up to you.

NOTE, these are just suggestions.

[mwb50 Lurker Find all posts View Profile Close mwb50]

Re: My dual battery installation

Heres a few photos of my set up I used a Piranah bat. tray. I use the kiss principal and rarely pay any body to do anything on my girlcruiser. The 6 way fuse panel is available from Autoban. Amp. wire carries enough current to the rear power panel. My HF and ARB air comp. are also wired to the aux. battery.


The other wires in the photo are ant. and tuner wires for HF and UHF. All wiring enters through the left hand grommet



It all works a treat one other thing I only use Marine type dual purpose battery with bonded plates. They outlast deep cycles by heaps and some brands come with up to 2 yr warranty verses 6 mths for d/cycle. Cheers.

[Trekrider Banned Find all posts View Profile Close Trekrider]

Re: My dual battery installation

Can someone tell me the lug size for the Redarc switch? I have a 100A SBI12 (2010 model) on order - taking longer than expected and I need to get the cable lugs ready for my install. So, do I need 6, 8 or 10mm lugs?

To answer my own question (in case anyone else wants to know) the lugs are 8mm.

[MartyK Lurker Find all posts View Profile Close MartyK]

Re: My dual battery installation

Hi All,

Well finaly got round to installing my dual battery setup today, base my design as per what Drew has done (Thanks Drew hope it was not copyrighted) but with a few slight alterations but it all works treat.

Used,
Redarc SBI, 2 x 100amp circut breakers.
Not shaw weather going to hook up the overide swith yet.

Will post some pictures once I work that out will have to read the How Too section for that, once I have achieved that I will do a My Rig Buildup posting as well.

Cheers MartyK

[Trekrider Banned Find all posts View Profile Close Trekrider]

Re: My dual battery installation

Finally got round to taking some photo's of my install.

This is the factory battery with 100A Mega fuse. Used 6B&S cable from both the positive and negative through a 19mm split conduit across the front.



Second battery is fitted to an Offroad Downunder battery tray.



Relocated Power Steering reservoir following the instructions with the tray.



Redarc switch with another 100A Mega Fuse to the second battery. Got a six way fuse holder connected directly to the Redarc.



Fitted an override switch and warning LED. Funny, I didn't notice the scratch until looking at this picture - can't see it under normal light.

[winniliss Avid PP Poster! Find all posts View Profile Close winniliss]

I am drafting up parts to use and ways to install a dual battery system. So far I have come up with the following, starting from the alternator:

1. Installed a diode to increase alternator voltage output. Output varies between 13.7 and 14.1vdc

2. Replace main battery with an Optima Yellow Top D27F AGM battery ($380plus p/h autocraft – do google search for battery)

3. Run 2G / 35mm2 160amp cable ($14.50p/m – Jaycar example) from main battery to the Aux battery via a Redarc SBI12 isolator ($89 Ebay). Use a momentary switch with the SBI12 which allows me to use the Aux battery to assist in jump-starting and or winching if required. Isolator will be mounted next to the main battery (as advised by Redarc). Cable will be routed along the radiator to keep it short.

4. Install a Piranha dual battery tray behind the driver’s side headlight.$170 approx

5. Aux battery to be the same as the main battery

6. Install a Redarc BCDC1240 DC – DC charger ($475 Ebay) to charge the Aux battery. The BCDC1240 allows me to connect an unregulated solar panel. Looking at 120 to 180watt system.

7. Install a battery monitor. I am looking at ABR sidewinders but his uses negative switching for the battery isolator. I found this other one that uses positive switching:
http://www.ebay.com.au/itm/Dual-Batt...item2a1334165a

8. There are two thoughts on either to crimp or solder or both, the lugs onto the cable. There is also another thought to tin the wire then crimp the lug onto it…What are peoples thoughts on this.

9. What are people’s thoughts on fuses between the main and Aux batteries. Keeping in mind I wish to use it for cranking / winching. If it has to be fused I am looking at 200amp circuit breakers on Ebay.

10. Will be buying a hex crimper $125 Ebay (other places wanted $400)

http://www.ebay.com.au/itm/Battery-Cable-Lug-Crimp-Tool-10-120mm2-HEAVY-DUTY-/330543892821?pt=AU_Car_Parts_Accessories&hash=item 4cf5f38955

11. Looking at a smaller ratchet crimping tool- p/n 56512 Narva website for the smaller cables. What are people’s thought’s.

http://www.narva.com.au/products/browse/tools

12. Will be using corrugated tubing and dual wall (resin)heat-shrink for the cables etc

13. Battery terminals, looking at 2 types:

http://www.ebay.com.au/itm/4-Wire-Gold-Battery-Terminal-2G-4G-2x8G-Negative-/280700892548?pt=AU_Car_Parts_Accessories&hash=item 415b13b584or

http://www.ebay.com.au/itm/DUAL-BATTERY-SYSTEM-TERMINALS-HEAVY-DUTY-FORGED-BRASS-/310340285393?pt=AU_Car_Parts_Accessories&hash=item 4841b8f3d1

Have people got other suggestions?

That’s about it. I think I have covered everything.

[sparksy Senior Member Find all posts View Profile Close sparksy]

Go the second battery terminals, Just put them on my install this week and they clamp the bare cables extemely well.
Mount the redarc isolator as close as you can to main battery.
Unless youve got a real need for a crimper that size, check out battery world etc, They will crimp cables for next to nothing and probably nothing if you get your battery from them. Ebay crimpers look ok though.
DONT tin cable before crimping. Solder doesnt conduct as well as copper and the whole idea of crimping is to try to make the cable and lug a solid piece. Solder will after time "creap" which means the joint will be compromised. No electrician solders then crimps and 99% of the time crimping is best. Solder has a habit of, no matter how hard you try, of flowing down the cable and this stiffens the cable.

Everything else looks good.

[winniliss Avid PP Poster! Find all posts View Profile Close winniliss]

Cheers for that. My thoughts about soldering as well. I found a PDF document about the pros of crimping instead of soldering http://www.rbba.us/documents/crimping.pdf. Got a reply from Optima batteries who suggested the D27 for the Aux. I am just confirming if he means the D27M Blue top and also if its ok to be charged using a Redarc BCDC1240

Winston.

[LiveFreeAndRoam Avid PP Poster! Find all posts View Profile Close LiveFreeAndRoam]

1. Installed a diode to increase alternator voltage output. Output varies between 13.7 and 14.1vdc

6. Install a Redarc BCDC1240 DC – DC charger ($475 Ebay) to charge the Aux battery. The BCDC1240 allows me to connect an unregulated solar panel. Looking at 120 to 180watt system.

The inline diode is not needed if you use the BCDC. I suggest not using the diode. The BCDC will boost (or lower) voltage to the level that is appropriate for your aux battery type as well as providing optimal, staged charging.

FWIW, I have the BCDC1220, and it has performed beautifully.

LFaR.