Dual battery setup

[lorrieandjas]

Hi everyone - I know there is a lot of posts on the forum on dual battery setups however wanted some opinions. I have GU 8 Patrol and want to fit a second battery - OK easy enough. The setup I am looking for is as follows:

1. Want to have the dual battery be able to be a "crank assist" battery as well
2. Want it to support a Waeco and some small accessories. Thinking about 30Amp hours per day
3. Have a winch fitted so need to keep that in mind
4. Want to be able to easily use solar panels to recharge when stopped
5. Want to fit rear Anderson (easy enough) and internal power sockets for the fridge and bits and pieces

So the questions I have:

1. What size battery is needed - 100Amp hour?
2. How solid is the ARB setup? They are quoting about $2200 for this type if install
3. Any other things I need to keep in mind?

Thanks - and I know some of this is a duplication of previous posts but each setup is different and I have yet to find a one-size-fits-all answer!

Jas

[oncedisturbed]

Pirhana do a dual battery isolator which includes the ability to use solar panels. I believe they also include an "over-ride" switch to link the batteries if neededfor for cranking. Therefore only 1 unit is needed.

100-120ah battery would be enough.

Yendor or Evil Twin would be your best contacts to answer your queries.

You should be able to do lot for under 1k especially if you do it yourself





Tap, Tap Taparoo

[Lieney]

No dissagreement with oncedisturbed. There are some nice systems but if I was quoted $2k plus i'd be walking, or seriously impressed by the system. But i am tight.
Consider how much current the solenoid unit part of the system can cope with if you were to start through it.
An example would be that your SLI battery is flat, so you push the manual override switch to link both batteries and crank her over.
As starting uses a few more amps, and varies between vehicle types, it can burn out the solenoid after a few goes.
Once small thing I came across a while back.
:)

[threedogs]

can't go past rearc aus made affordable. I' Steer clear of the ARB set up looks like you pay more for the sticker than actual product, I'll send you a PM regarding the Solar panel

[harro959]

DONT GO TO ARB. My dad got a dual battery system for his pajero installed by arb with two anderson plugs in the back. They did a shocking job, only ran one lot of wires to the back then piggy backed it when it got there. The dc-dc charger they installed incorrectly for the type of battery dad had, plus they put a horrible little fuse holder in that kept on melting. Dad went back to arb 3 or 4 times before he got sick of it and fixed it himself the lazy bugger.

Ideally if you have the time to learn and setup something yourself it will be far better and cheaper than what arb could ever do, plus you know how everything has bee run so you can fix it in the future.

I vote for the pirahnah model as its made of mill spec components and designed to operate at higher temperatures than the redarc in conjunction with a big heavy marine switch for cranking and winching. The down side off the top of my head is that i believe that the pirahnah doesnt actually have a solar regulator in it, just a feed in.

If you are interested in doing it yourself, then this book is an awesome resource to understand everything http://www.caravanandmotorhomebooks.com/books/motorhome_electrics_caravans_too.htm


No affiliations, just trying to share some of the stuff ive found from researching for my own truck :)

[threedogs]

Pics are of my RED arc products rear unit gives me plenty of outlets plus battery condition. under bonnent is the dual batter monitor .I have an Anderson plug under towbar to charge battery in camper whislt on the move. My solar panel plugs into redarc rear panel never had an issue yet, and if you read my other threads etc I take heaps of lighting all LED and 12v equipment, never ever ran out of battery and the 4x4 runs the 49 lt Engel for food, Battery wise I have 1 v 110 AH,in 4x4 1 x 100 ah in camper and an 18ah battery pac for remote lighting. plus mate brings a 27 ah battery pac.
Easy to work out what you use, I only use 100watt panel puts back 4,5 ah on a good day , Remember with panels bigger isnt better. 200watt panel wont put 9 ah back in, do your home work. might find a folding 80 watt more efficient

[lorrieandjas]

can't go past rearc aus made affordable. I' Steer clear of the ARB set up looks like you pay more for the sticker than actual product, I'll send you a PM regarding the Solar panel

Thanks threedogs. Will check it out now.

[lorrieandjas]

DONT GO TO ARB. My dad got a dual battery system for his pajero installed by arb with two anderson plugs in the back. They did a shocking job, only ran one lot of wires to the back then piggy backed it when it got there. The dc-dc charger they installed incorrectly for the type of battery dad had, plus they put a horrible little fuse holder in that kept on melting. Dad went back to arb 3 or 4 times before he got sick of it and fixed it himself the lazy bugger.

Ideally if you have the time to learn and setup something yourself it will be far better and cheaper than what arb could ever do, plus you know how everything has bee run so you can fix it in the future.

I vote for the pirahnah model as its made of mill spec components and designed to operate at higher temperatures than the redarc in conjunction with a big heavy marine switch for cranking and winching. The down side off the top of my head is that i believe that the pirahnah doesnt actually have a solar regulator in it, just a feed in.

If you are interested in doing it yourself, then this book is an awesome resource to understand everything http://www.caravanandmotorhomebooks.com/books/motorhome_electrics_caravans_too.htm


No affiliations, just trying to share some of the stuff ive found from researching for my own truck :)

Thanks mate. Will check out that book now.

[BigRAWesty]

X2 on red arc.. If you search around there are specials were they throw in the jumping button (gives ability to crank of 2nd), usually some heavy duty cable and terminal connections for around the $120 mark..

I love the red arc because it's simple.. Clicks on at 13.8V and off at just below 13V.
Seem all sorts of fancy dc chargers used and systems have $1000's sunk into them and they fail when you leave the bitumen due to corrugations, dust or water...

KISS.. Red arc is all you need..


Kallen Westbrook
Owner of
Westy's Accessories (http://www.nissanpatrol.com.au/forums/showthread.php?15134-Westy-s-Accessories.-A-small-back-yard-builder.)

[the evil twin]

Hiya Lorrieandjas,

Just back from some holidays and helping out at the Gascoyne Dash Racing (What a blast). $2200 is a woeful price but some of the gear is a bit expensive.

Most of the replies I totally agree with... however each opinion will differ slightly as each person has different uses or issues IE rear draws so the "drop in" sockets like threedogs has are not useable.

1. I like simple and reliable so a Redarc (or similar) between main and aux is my pref but that won't do the Solar bit. Connect your winch to your main not your Aux and if you do LOTS of winching then get the heavier rated Redarc or whatever. Most people get the 100 Amp which is OK but the heavy prolonged winch currents mean a 150 or 200 amp rated relay is better. Some units are 150 off the shelf and Redarc make a 100 and a 200 amp version.

2. Decide if you want the Solar 'hard' as part of the vehicle wiring for the dual batteries or seperate. I prefer seperate so no single unit getting cooked makes a catastrophe. A great quality dedicated Solar Reg like Steca or similar is cheaper than the vehicle accesory style (Ctek etc). I however use cheap as chips no name Ebay Solar Regs and have yet to have one fail.
My "solar" is a twin folding 50's, chinee MPPT regulator and an Anderson plug. Supercahrge All Rounder Aux in the car and twin 120 Deep Cycles in the Camper but never needed anything like that capacity yet.
I connect it to whatever I want, car, camper, solar with Anderson plugs. I can park in the shade and still get best sun and angles from the panel and this setup runs two 40 litre Engels, a Water Pump, Camp LED lights and phone/cam/lappy recharging no worries at all.

3. Power sockets.
I swear that the Engel fridge socket is the best by a country mile so fit at least one for fridge use and if you have a different brand fridge with a Ciggy plug change it. The rest of mine are Merit Sockets or Anderson and I carry a couple of Merit to Ciggy adapters for accessory/phone/whatevers.
Ciggy plugs just plain suck

4. If you get the Battery Tray and fit it yourself, a good deal on the battery, Ebay for the Panels and Solar Reg, try Sidewinder or other online eleccy dudes for the wire and plugs and run the wiring yourself you can then get an Auto Sparkie to fit off the pins/sockets for under or maybe just on $1000 depending on what Solar gear you get. Check with the Sparkie if you can't fit off yourself (esp the Andersons and battery leads as you want the best crimping you can) as he may do you a good deal on the cable

5. Disclaimer - just like everyone else that is purely my opinions and what works for me and I am set up with fairly similar priorities to your post... IE use the Aux to crank assist every now and then, occasional winching, lots of camping and solar use.

[threedogs]

HI Evil Twin I only use Merit or wire directely where Possible, What sockets of Mine you you happy With, maybe I can clear it up.

[threedogs]

My Engel is pwered from a merit socket wired to the 2Nd AUX battey wired to the back of the centre console via a thermal fuse. With a Cig Lighter as well
IMO cig Lighters have no place in todays modern 4X4. I have cig outlets incase others have and use them instead of merit. I prefer merit
more positve. Always hear horror stories of cig plugs failing. If I had my way I would wire my engel permanently no plugs at all, more plugs conections
the more stuff can and will go wrong

[the evil twin]

HI Evil Twin I only use Merit or wire directely where Possible, What sockets of Mine you you happy With, maybe I can clear it up.

Hiya Cobber... sorry, my bad, I was typing in a rush trying to catch up after so many days away and it didn't come out right.

What I was trying to illustrate was that if someone has a draws then the "drop in" sockets and power panels like you have that fit in that factory spot can't be used. I mentioned you because in your post you were kind enough to include the piccy.

Those drop in Panels etc are quite a nice workable solution for most people albeit some are a tad expensive but I happily wire them in for people.

Totally agree with you on Ciggy plugs and I love the Engel fridge plug because it is screw in so no mid trip fridge disasters and it is only a 10 second job to put the ciggy adapter head back on the fridge lead if you need to run the fridge on someone elses's gear

My rule of thumb when at all feasible is...
Fridge socket - Engel style
General use socket up to 10 Amp - Merit style ( and carry/make a couple of adapters)
General use socket for Solar/Trailer/Power Breakout Box's/etc - Anderson (sml)
Heavy duty/High Power - Anderson (lge)

[BigRAWesty]

You gotta remember the red arc is 100A constant.. It can handle 500+A burst for 5 seconds which is more than enough for cranking a 4.2 diesel..

A 200A red arc is 200 constant and 800a burst..
200A.. That's a lot of draw..

You can always jump the solar onto the 2nd battery via its own inverter. A little more wire but IMO its better to keep things separate and simple


Kallen Westbrook
Owner of
Westy's Accessories (http://www.nissanpatrol.com.au/forums/showthread.php?15134-Westy-s-Accessories.-A-small-back-yard-builder.)

[threedogs]

I don't plug engel in there I plug behing centre console, as you know shorter the better.
I also use a digital tempcontroller, best this I ve ever made temp only varies 2 degrees if that, Your bad ,my bad bad we'er all bad 'all sorted

[the evil twin]

You gotta remember the red arc is 100A constant.. It can handle 500+A burst for 5 seconds which is more than enough for cranking a 4.2 diesel..

A 200A red arc is 200 constant and 800a burst..
200A.. That's a lot of draw..

You can always jump the solar onto the 2nd battery via its own inverter. A little more wire but IMO its better to keep things separate and simple


Kallen Westbrook
Owner of
Westy's Accessories (http://www.nissanpatrol.com.au/forums/showthread.php?15134-Westy-s-Accessories.-A-small-back-yard-builder.)

Hiya Westy...

Eggzackery my point as well so totally agree. When I'm not sure how much winching the OP does I tell people 100 amp is fine for 99% of us BUT if you are a compulsive wincher (E.T. double checks spelling) then they pull past 100 amps pretty quick and the 200 is the weapon of choice to avoid pitted or welded contacts.

I know you and many others will know the following already however for others following the thread.....

Any of the VSR's from any manuf will normally let go as soon as you load the winch as the voltage drops into the toilet and trips the low voltage sense. You need to use the o'ride to hold the VSR in same as for a flat battery if you want to parallel the batteries for load share when winching. The other alternative is not to override and to leave the winch load on the one battery/alternator and then the other is charged up if needed.

Either method works and has arguments for and against so pretty much a personal preference and dependant on circumstances so no real biggee.

[Yendor]

Hi everyone - I know there is a lot of posts on the forum on dual battery setups however wanted some opinions. I have GU 8 Patrol and want to fit a second battery - OK easy enough. The setup I am looking for is as follows:

1. Want to have the dual battery be able to be a "crank assist" battery as well
2. Want it to support a Waeco and some small accessories. Thinking about 30Amp hours per day
3. Have a winch fitted so need to keep that in mind
4. Want to be able to easily use solar panels to recharge when stopped
5. Want to fit rear Anderson (easy enough) and internal power sockets for the fridge and bits and pieces

So the questions I have:

1. What size battery is needed - 100Amp hour?
2. How solid is the ARB setup? They are quoting about $2200 for this type if install
3. Any other things I need to keep in mind?

Thanks - and I know some of this is a duplication of previous posts but each setup is different and I have yet to find a one-size-fits-all answer!

Jas

That's because there's not one.

It all depends on what your individual needs are..... how often you go away, how long the vehicle remains un-started for, how long it is driven for while you are away, the size of your solar panels, the load on the second battery, if the battery is mounted under the bonnet or in the rear of the vehicle....etc

Going by what you have posted, you will need at least a start/deep cycle battery mounted under the bonnet.

Connect your winch to your main/cranking battery.

I wouldn't worry about being able to connect solar panels to your dual battery isolator, most are only able to handle small panels anyway (unless you are planing on mounting a smaller panel permanently on your roof). With the larger panels I would just set up an anderson plug that you could plug the panels (and it's own regulator) into when stopped.

If it was me I would go for the ARB battery tray, the RedArc smart solenoid and a start/deep cycle battery.

Make sure the cable/wiring is of suitable size and a fuse/circuit breakers are used.

If you carry jumper leads, you don't need to worry about connecting the switch that links the two batteries for emergency starting.

[scotty83]

2 x Yendor. This would seem like the most appropriate options for you. The only other thing might be the Redarc BCDC1225. Gives a solar reg with it. Isolators for good for crank but multistage is better for deepcycle batteries from my understanding.

[BigRAWesty]

Hiya Westy...

Eggzackery my point as well so totally agree. When I'm not sure how much winching the OP does I tell people 100 amp is fine for 99% of us BUT if you are a compulsive wincher (E.T. double checks spelling) then they pull past 100 amps pretty quick and the 200 is the weapon of choice to avoid pitted or welded contacts.

I know you and many others will know the following already however for others following the thread.....

Any of the VSR's from any manuf will normally let go as soon as you load the winch as the voltage drops into the toilet and trips the low voltage sense. You need to use the o'ride to hold the VSR in same as for a flat battery if you want to parallel the batteries for load share when winching. The other alternative is not to override and to leave the winch load on the one battery/alternator and then the other is charged up if needed.


I see what your getting at.. And you make a good point.
Would the winch draw be enough to shut off the connection even with the engine running?


Kallen Westbrook
Owner of
Westy's Accessories (http://www.nissanpatrol.com.au/forums/showthread.php?15134-Westy-s-Accessories.-A-small-back-yard-builder.)

[threedogs]

Try and stay away from wet cell batteries if possible, They are a tad messy but more powerful than agm or similar. 110 would be big enough, you need to sit down and write a note of anything 12 v you will be using, you'll be surprised how it will add up. now you added up all watts used, divide that buy 12v. that'll leave the amps your using. then divide by 8 to get the hour rate, at this stage you may have fainted, alls good, your battery will handle this, backed by a decent 12 voly solar panel.,If you have concerns just PM. IMO it's best to let the solar run as much as possible at camp, and please remember leave your start battery for just that starting, you have the camper for anothr drycell battery for lighting duting etc, just make sure your alternator is minimum 100amps, more to it than just buying battery

[harro959]

What threedogs suggests to do with adding up all of what you need power wise is something that is very important to do. A lot of people fit solar for the wrong reasons and also fit the wrong type of stuff for what they want to do. Solar, if correctly setup, is amazing if you want to be camping in an area for more than 2 or 3 days without driving and you dont want to run a generator. Up to that amount of days (from my understanding, please correct if i am wrong) a well setup dual battery system will be able to handle most peoples requirements.


What does everyone think of a system setup as follows:
have a main cranking battery linked to an agm or deep cycle type battery via a voltge sensing relay e.g. http://www.ebay.com.au/itm/PIRANHA-DUAL-BATTERY-ISOLATOR-MANAGEMENT-SYSTEM-12V-DBE140-AMP-CHARGER-/290802563789?pt=AU_Car_Parts_Accessories&hash=item43b52efacd&_uhb=1#ht_1825wt_1156 , or a redarc (thats for you threedogs :)

Then have a marine isolator switch (e.g. http://www.ebay.com.au/itm/12V-24V-BATTERY-ISOLATOR-KILL-SWITCH-KEY-Boat-Marine-Car-4x4-Caravan-RV-/170888654361?pt=AU_Boat_Parts_Accessories&hash=item27c9c1ee19&_uhb=1#ht_5558wt_969 ) joining the aux battery to the main battery to be used for winching or cranking.

Also have a relay attached to the earth lead of the vsr with a switch in the cabin so you can disconnect the vsr from the earth so it wont work.

Then if you need it get a solar setup like evil twin down the track.


What does everyone think???

Stupid question though, wouldnt it be better when winching to have the main battery disconnected from the auxillary so that if you screw up and completely drain the main battery you can still link them to be able to start?? and if you are going for this model, instead of having a permanent link ability in your car you could just get a set of jumper leads which then means you can use them to weld, help other people and restart yourself of your aux.

[MudRunnerTD]

SNIP..


Stupid question though, wouldnt it be better when winching to have the main battery disconnected from the auxillary so that if you screw up and completely drain the main battery you can still link them to be able to start?? and if you are going for this model, instead of having a permanent link ability in your car you could just get a set of jumper leads which then means you can use them to weld, help other people and restart yourself of your aux.

Rule Number 1 when winching! Always have your engine running and increase your revs to attempt to provide drive advantage for your winch should you have any traction. This will also see your Alternator provide charge throughout the winch stage.

Providing the winch with more than 1 battery to winch from will give you a longer winch stage but your winch may get too hot and need a rest anyway. regardless you should not need a jump start after winching unless you turn it off. if your battery gets to low during winching then the winch will simply stop pulling due to not enough power.

Hope that helps

Cheers MR

[harro959]

hhahah, reading that i really screwed that up. I wasnt suggesting winching with the engine off lol. I was just thinking what would happen if you had both batteries linked and nearly fully drained and the car stalled for some reason....

[Rip'n'Shred]

I've got a ARB tray. Fairly cheap at about $118.

I also went with the Autron dual battery management which the solenoid is supposed to be water proof and good for 350amp. The gauge with the system displays both battery voltages and can take an input for amp reading. Comes standard with an override link button.

There are pics in my build up thread.

http://www.nissanpatrol.com.au/forums/showthread.php?p=222810

[the evil twin]

snip...

Stupid question though, wouldnt it be better when winching to have the main battery disconnected from the auxillary so that if you screw up and completely drain the main battery you can still link them to be able to start?? and if you are going for this model, instead of having a permanent link ability in your car you could just get a set of jumper leads which then means you can use them to weld, help other people and restart yourself of your aux.


Not a stupid question at all. As I mentioned in the thread earlier there are always alternative views and at the risk of getting off topic even more...

It is easy to forget that the battery is also part of any electrical circuit. What that means is that any/all of the current flow (other than thru the Alternator circuit) is also flowing thru the Battery. Now, batteries esp in this day and age of "just good enough" engineering hate prolonged high current because batteries have internal resistance and that means heat is generated, sometimes a lot of heat and heat changes the physics of a battery very significantly.

So, a quick hypothetical. Lets say the winch is pulling 250 amps and the Alternator is contributing 50 amps (hypothetically remember) that means the sustained current flow thru the battery is 200 amps. If a second battery is paralled in then the batteries will load share relatively equally but not exactly as even two identical batteries will have slight internal resistance differences. This means 100 amps each. So what does that get us?

The effect of high current draw on batteries isn't linear IE 400 amps isn't twice as bad as 200 amps, it is much worse and 200 amps isn't twice as bad as 100 amps, it is again, worse. The relationship is exponential albeit not savagely so but definitely a consideration depending, I stress DEPENDING on what the user is doing. The effect is also worse in most 'deep cycle' variants as opposed to 'all rounders' and least damaging in 'crankers'.

I always consider reducing the current draw when winching not just for the Winch but also to stop giving the batteries a harder time than needed and quite often use a snatch block because (given the above) it can be quite beneficial to Battery long term capacity and longevity to winch for longer at a reduced current and load.

Bottom line is that there are a lot of variables and no right or wrong way to look at it really. I probably use both methods 50/50

[BigRAWesty]

I'm not sure this theory is 100%, but when you put such a large strain on the main battery your voltage will drop. And it will drop to below the redarc cut off..
Now this is were my brain gives up and I start guessing my theory..
With the engine running the alternator supplies 13-14V at whatever amperage to the main battery. Now it's not enough to cover the winch but helps, but would the redarc still be closed (and allow draw from the secondary) due to the high voltage supplied from the alternator? Or would the drop be enough to open the circuit and disconnect the battery??


Kallen Westbrook
Owner of
Westy's Accessories (http://www.nissanpatrol.com.au/forums/showthread.php?15134-Westy-s-Accessories.-A-small-back-yard-builder.)

[Rustyboner81]

Ive just put in a cheap 2nd battery setup in my girl. Repco hahaha hey stop laughing im poor.
100amp solinoid. Can link to starter battery with 1 button. Yes its repco and yes its a repco deep cycle battery. $400 all up. Its enough to get me out the crap.

[Yendor]

Ive just put in a cheap 2nd battery setup in my girl. Repco hahaha hey stop laughing im poor.
100amp solinoid. Can link to starter battery with 1 button. Yes its repco and yes its a repco deep cycle battery. $400 all up. Its enough to get me out the crap.

Nothing at all wrong with this setup, if it meets your needs.

I have used a similar setup for the last 20 years on 4 different vehicles.

I don't even bother buying the expensive batteries, I just go for the cheaper factory seconds or even secondhand batteries.

My current second battery is one I picked up second hand for a carton of beer.