Simple $75 Dual Battery Setup

You don't have to spend hundreds or thousands of dollars on a dual battery system. If your requirements are straightforward, you can set up a simple system for about $75
Have a Refrigerator? Lights? Lots of accessories? The last thing you want is to kill your cars starting battery. A dual battery setup will run your accessories off a second battery so your car will always start! In this video we install and test a very simple dual battery setup.
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[@davidetzel1194]

I have all but put a duel battery set up out of my mind due to the cost but with this set up and the ability to add and subtract components it’s now number 2 or 3 on the list. It’s great to see both ends of the spectrum on projects for those of us that can only afford so much at one time. Thanks.

[@OverlandBound]

Yup - figured I would get this hooked up and share it before putting in the deluxe version in a few weeks.

[@littlekingcobrasden4217]

​@@OverlandBoundI have a 98 Jeep Grand Cherokee v8 engine. Not really enough room for a 2nd battery, so I'm going to great expense to make room. I've taken the heavy brush guard bumper off my 73 k5 Chevy Blazer, then added overload struts to the Jeep to support the weight of the bumper, and now I'm going to try to get the bumper mounted on the front of the Jeep (the big bumper also has a wench) then I'm going to mount the spare battery next to the wench, inside a marine battery box. I'll also mount a 5 gallon Jerry can on the front of the bumper and somewhere in there I'll try to make room to store the spare tire. I have a spare battery that will work for the second battery on a temporary situation until I can decide what battery I need to get for the second battery and afford to buy it. Some people say that I need a lithium battery, some say I need a marine battery, while others say I need both lithium and marine battery for the second battery. I don't know what to believe?

[@GotScout]

*dual 😏

[@ItsMeGiga]

Edit: all these points are addressed in an earlier post! Excellent build! The only thing I'd like to point out is that when charging directly from the alternator like this both batteries should be the same in capacity and composition (ie lead acid). If you want to use a larger or different composition like I did (agm solar 100ah battery or the newer lifepo4 batteries) you absolutely need a dc to dc charge controller in line. That'll maintain the battery properly and act as a one way so you aren't starting your car from a battery that isn't intended to do a super high current draw like what's needed to start the truck. Also be aware that most starter batteries have a smaller capacity and you don't want to drain it past 50% or else you'll start to damage your battery. Ie a 100ah battery should never be discharged lower than 50ah

[@OverlandBound]

Yup - pinned post mentions this - in my case, both batteries are matching NorthStar AGM.

[@wanderingtrd9382]

This is awesome! In a time with companies inflating prices for everyone wanting to just get safely outdoors and back these videos are essential! Thanks Michael and Corrie!

[@GorsuchCody]

I love channels that share affordable not “cheap” options for us average folks out there. Thanks for all you guys do!

[@themastercarpenter]

very well done video, mic'd up so we can hear you, no annoying music, and straight to the point ! Thanks for the great info! Gonna work on mine soon, since it only takes me 10 minutes as well:)

[@Alan-mw6bs]

Elegant, simple system. You really don't need any more. I've had a similar system in my 11 year old Troopy (VDJ78R) since new with a voltage sensitive relay (VSR) instead of an ignition switch activated one. The VSR has the small advantage of always ensuring that the cranking battery is fully charged before charging the house battery. I have an 80lt fridge, a handful of LED lights and the occasional USB powered device drawing from the house battery which is also augmented by a 200w solar panel. For all practical purposes there seems no need for a state of the art (expensive) battery management system that I can see. I love your videos.

[@OverlandBound]

Awesome and thank you! Ya - that is the next upgrade to this system for sure.

[@rogerbrown5563]

Yes - I was woried about the alternator output of some vehicles being overloaded by recharging both batteries simultaneously - the VSR elliminates this issue, and the risk that a very flat Aux battery will immediately start drawing from the cranking battery when the ignition is on (thus loading the cranking battery just when it's needed for an engine start). A VSR is ESSENTIAL, not just an optional item.

[@tylermiddaugh1515]

@@rogerbrown5563 youve convinced me two switch out my solenoid now! do you have a recommended product?

[@shakenbake0019]

Whats the part number for the solonoid? Will a regular automotive solonoid work?

[@OverlandBound]

Hey all - thanks for watching! Lot's of great comments and questions. Here is a top Q&A from the community: 1. Improvement: Manually switch your solenoid. If the house battery is completely dead - and you turn on the ignition without starting the vehicle, the batteries will equalize - draining your start battery. To avoid this - manually switch your solenoid and turn it on after your engine is started (contributed by Paul Adams). 2. Overlooked: Both batteries should have the same charging profile since there is not battery manager. I have two identical NorthStar AGMs. Same same. 3. Question: Can I use a stock alternator? Sure - However, if you have a weak alternator - it will not be up to the task, and may fail. I am confident in my OEM Land Cruiser alternator (its new), but I will eventually upgrade. 4. What about a "Smart" Alternator? Smart alternators become an issue with DC to DC chargers. They don't see a enough voltage to turn on so you need the small sensing wire to tell the charger to start charging the house battery. (contributed by Hillbillyjeeper WV) 5. Does this setup allow you to jump start your self by connecting the batteries if the starting one dies for some reason? Theoretically yes, but likely your house battery will be more drained. But yes. Also, see note above about Battery Equalization (1) 6. Can I put my house battery in the rear of the truck? Not recommended - you start getting into battery manager territory there - not really intended for this simple setup.

[@mattk.5258]

Note that this won't work if you have a variable voltage alternator. (most newer vehicles), if you do you'll just want to use one of the Redarc dc-dc smart chargers, which has an isolator built in.

[@investing4arellanos]

Do you have a solenoid that you recommend or have specs?

[@mikewhitman745]

Why is it not recommended to put the house battery in the rear of the vehicle? Voltage drop or?? Used to run batteries in the trunk of race cars with no issue, what's the difference besides having two batteries?

[@jamaljamereous6298]

Just get an isolator or separator, im an electrician and nobody ever seems to make a video including these when they are needed for the systems health.

[@weriesblack1375]

Question if having ignition on equalize the 2 batteries why can i just have a manual isolator switch that i turn off to connect the batteries once i started the car then i wont rely on the second battery as a starter or just spend the 150 dollers and buy a charger thats ment for it and forget about the worries of flat batteries

[@JeffPalmer941]

Nice video. a couple things worth mentioning: @9:20 with the relay wired to the ignition, it should be pointed out that if the aux battery is severly discharged (after several days of overlanding for example) then your starting battery is trying to start your vehicle AND balance the charge between the two batteries at once. luckily, with the way you've wired it to the power antenna wire, you can just turn off the stereo, to force the 2 batteries to isolate again. Very clever, even if it wasn't called out in the video.

[@JeffPalmer941]

If you up the budget (by almost double) the solenoid listed here can be replaced with a "cole hersee smart isolator" which includes a logic circuit. It isolates and reconnects based on the voltages present. so it leaves the batteries connected until the two combined drop below (I think 13.7 or .8v) and when it detects 14v (as in, from the alternator) it will wait 2 minutes before reconnecting the 2 batteries. allowing the starting battery to *just* start the vehicle.. and then after it's been running for 2 minutes, will reconnect so the alternator can charge both. I love that you provide "inexpensive" options, to go along with the "cream of the crop" options. I'd consider something like the cole hersee to be the "in between"

[@ApothaconF4i]

Thank you man, this is one of my next projects and this made it _a lot_ more straight forward, also the analog aspect of it is very appealing since swapping a fuse or relay is cheaper then replacing a charge controller

[@paulscomedyclips]

This instantly went into my "Overland to do list" Thanks!!

[@marktaylor2362]

This looks great and in budget. Almost everything else you watch has a $1000 set up. Thank you for this.

[@jimmuehlberg2153]

Nice clean install! I like the simplicity. Since I'm an electrical engineer, I must point out a possible "gotcha". If you drain the house battery, as soon as you turn the ignition on, you will start "charging" the house battery whether or not the engine is running. This will reduce your cranking amps, and if you goof and leave the ignition on without starting, you'll have 2 dead batteries! Solution here is a battery isolator, but that would up your cost and it's solid state, so that goes against your philosophy!

[@weriesblack1375]

I was thinking the same thing having a manual isolator to disconnect at camp and then start the car and once started reconnecting the two to prevent equalizing was my thinking and everyothing running off the home battery with a voltage display did i mis anything. Its manual and a pain yes but its 1 switch haha just dont forget to disconnect it or your in trouble 😂

[@supercoupe1]

Thanks Michael. I saved this video to my overland folder. I'm a new Overland Bound member and this video is helpful and answered a few questions I've had about the dual battery setup.

[@OverlandBound]

Awesome! Glad to hear it!

[@davidbrady9686]

Cant wait to start my set up….need to free up some room first….but with a 1971 Bronco it should be too hard. Love the channel

[@OverlandBound]

Thank you!

[@johnswanson3741]

Old school, dude. Those old Ford rigs, Bronco's, 4x4 pickups were some tough built hombre's.

[@andyaskew1543]

That's a good, simple setup. I have been using a Blue Sea Systems ML-ACR relay with manual control for about 3 years and its worked out great. More expensive but if it will function in a marine environment I know it will survive under my hood.. Has saved me several time from a drained or failed battery...

[@OverlandBound]

Blue Sea makes excellent Overland gear :)

[@marshallnorth3312]

A few years ago I did something similar. Except with 10 guage wire and a 40 amp relay. I had the relay pickup on a switch. Worked great. It was a similar setup to old VW camper busses.

[@daftnord4957]

i like that idea. So you have a switch in your cab to charge when you want? not just whenever you turn the ignition on

[@marshallnorth3312]

@@daftnord4957 yes exactly.

[@13yearsaprepperr.jtilbury.51]

Hi , Instead of the relay why not get a VSR (voltage sensitive relay ) They are $40 on FleeBay when the start battery drops below 12.7vdc it isolates the AUX battery then after you have started your truck the battery VDC will rise to 13.8 and the AUX battery will start to charge , I feel this is the best way as there is no shock to the alternator charging 2 batteries at the same time ,I have been using this setup for 4 years , Works great PS:I know the vid is over a year old but its worth a look , Rob Nowra NSW AU

[@TimsBitsnPieces]

Michael, one comment. I was always taught to run the wires to everything and then fit the fuses, as this stops any short circuits while fitting the wires and joining things up etc. Also, cover all exposed power nuts/bolts in the engine bay with plastic tubing or something similar to stop arcing or contact with spanners or tools when working on the vehicle in the future. When I bought my 80 it had a Redarc SBI12 battery isolator that was not working and I worked out that the previous owner had connected it wrongly, once I changed the wires to the correct places it worked like a dream.

[@OverlandBound]

Great. Good find!

[@radnaabaatard]

Thanks for making an awesome video. Actually, I followed up on your relay panel instruction video and built up a nice and reliable relay panel and fusebox in my Landcruiser 78 troopcarrier. Thank you. BTW, greetings from Mongolia.

[@hillebrandstreet1882]

What a champion I just needed something simple for a long drive and this is perfect excellent video !

[@raygarciaelcubanootr7541]

I guess prices gone up i just ordered all the parts and it didn’t come out to $75.00 bucks it came out to $134.35 video very helpful.Thank You

[@mrbookends]

Stumbled across this video today as I've been contemplating a dual battery setup for my project truck! Subbed and saved - thanks!

[@larryjanson4011]

i have been running a duel batt in my cj-7 for decades. but both of them are connected together for double the usable amps. so i have really unlimited juice for the starter, the winch, and a couple lights. for the winch i use welding cable. and it draws less then the starter motor (smaller wire there). but now in this age sounds like time to install a third batt just for "other" things. including the lights. but yes fuse every wire. coming off a power supply or fuse block, switch, etc. yes cheap, easy analog is best.

[@wyattoneable]

Thanks Michael. The information in the description box helps and that was a cool diagram.

[@Christian76S]

Just one amendment Michael: Place the first fuse closer to the starter battery. Really, I urge you. Lots of metal close to the 4 AWG wire. Imagine the radiator cracking the insulation in an head on accident .. Secondly: get your alternator tested. Unless both batteries were fully charged, it should read 14.4V even when idling ..

[@OverlandBound]

Thanks! For charge rate - both batteries were nearly fully charged.

[@Tyerone1337]

Great video! I didn’t understand how the solenoid worked before watching this video, now I totally get it! Thank you! Great skills

[@snivesz32]

Personally though, I would run different chemistries for the two because i’d prefer to run lithium iron phosphate for the AUX, for the massive available capacity, but it cannot be mounted under hood due to temperatures it sees. So a DC:DC charge controller in the boot with the lithium battery would be my choice.

[@davidbradley1297]

I did basically the same thing on my FJC, I interrupted the negative cable with a continuous duty solenoid, power off the house battery to the solenoid, switch in the cab to the other connection on solenoid, and to ground. I found that the solenoid got hot if connected for a length of time, so I connect them only when aux battery is low and no sunshine for my solar panel to charge aux battery

[@dlofton123]

For those of you wanting to do this keep these things in mind. 1.) Make sure the battery chemistries are the same for both batteries. If you have an AGM battery make sure the AUX battery is also AGM 2.) There is no Battery Management (BMS) meaning your AUX battery will drain and likely be damaged if you are not manually keeping an eye on the voltage.

[@MrCaesar619]

All my questions where answered when you showed the wiring diagram. Thank you 👍

[@knockemkids8083]

We need this class for our schools

[@jackwalsh1468]

Hey Mikey! I enjoyed the video and got a charge out of it, too. Pun intended. Cheers, Mate.

[@petersimon6222]

the best set up i have seen so far thank you

[@themartiandefender2128]

Great video Michael, I’ve only had a basic split charge system on my Defender for the last 13 years and does the trick !

[@matthewspoon9671]

thank you, I'm a poor boy and lucky to have my 2014 stock ram with little to no mechanical experience. looking into these I cant believe the prices been subscribed for a long time will try to scratch money together to join . THANKS AGAIN FOR LOOKING OUT FOR THE ONES WITH LESS KNOWLEDGE AND NO MONEY. From Michigan City, In.

[@deone6434]

Personally I wouldn't put any "non-factory" fuse blocks, breakers, solenoids under the hood. I would mount them on a wood or metal platform then secure them in the cabin somewhere. The only thing under the hood will be the main fuse from Aux battery feed line to the platform inside the vehicle. Mostly for engine heat, water intrusions and dirt build-up.

[@mrcavallos]

excellent video - thanks for giving me the confidence to do this myself and save a bundle

[@DeepBlueandBeyond]

Thank you for this! Question: Would you consider adding a Renogy 40 amp DC to DC Charger to this system? Secondly, probably a stupid question, but now that you have this set up, did you install a panel inside or in the back of the truck where you can plug in your fridge, USB ports, etc?

[@snivesz32]

I like it. One concern is the rate of charge balancing when you have a full starter battery and dead AUX battery; it may exceed 80A and blow the fuse charging, but this can be remedied with a 0.2 Ohm 1000 watt resistor in series with the fuse. The 2nd fuse between the solenoid and the AUX isn’t doing anything. The AUX breaker should be closer to the AUX battery.

[@ThatOneGuyMatt]

This is dope. My grandpas truck is only 2wd so I'm taking alot of influence from you over land guys to build a bad ass fishing, campsite camping and tailgating rig

[@jrvane11]

Great video. Informative and to the point. I recently viewed a product video for a dual battery system that was over $600...without the battery! Not even a consideration for me. But your solution is certainly in the budget.

[@daughertypb3663]

As always, good and informative video. 😊👍

[@tomfrantz]

WAIT! you already linked it THANK YOU!!!!

[@jf3232]

keeping it simple . its about time 👍👍👍

[@seandalejackson2525]

My Man that was awesome. Really appreciate Cha Dude!!! Installing an AuxBeam 8gang and a KeyLine isolator this weekend. Wish me luck.

[@Ryan-yp7zb]

Two questions: 1) The added 100A switch/fuse is downstream of the house battery, yeah? All I'd like to do in my tundra is something similar but I'll house the house battery in the pick up topper, then from there, just a 12v outlet thingy or perhaps an inverter and that's it. 2) How often are you buying/replacing tires?

[@OverlandBound]

Hey there! Yes - downstream from house, before accessory fuse block. Tires - about every 50k

[@LiveOutsideNow]

How will a dead house battery effect the truck battery? Could it struggle to start the truck? I love the simplicity of the idea!

[@OverlandBound]

Your truck would start fine. BUT as Paul noted - the house and start battery would equalize if you left the ignition on and your truck did not start immediately - so its a good idea to have a manual switch to the solenoid - and turn it on after your engine starts to be safe.

[@mithrandir1313]

YOU..... ARE..... AWESOME!!!!!

[@OverlandBound]

You too!! Thank you brother 👊🏼

[@SandipMMane]

If possible, please start selling all products you mentioned in this/similar builts as a package on ebay. This will help people save on shipping cost of multiple items plus duties. Specially for people residing outside US. Thank you.

[@davidhillman1066]

I had no idea it could be that easy! Now I just need to figure out how to make room for another battery in my 02 Astro. Thanks!

[@abedj1220]

Nice video. useful info. All the power plugs in the vehicle run off the original battery. is it worth rewiring the outlets to run off the second isolated battery.

[@davexstuntman]

Nice neat work great video thanks from Down Under 😁👍🍻

[@srira7910]

Awesome production quality video. thanks for your generosity.

[@kbikerider8474]

Better than nice. Well thought out. Thanks.

[@lamhoang1187]

Great set up, thank you so much! But can you make a video how to install a voltmeter for this dual battery system?

[@donthompson2777]

Great video! I have many questions. Does this setup run fine on a stock alternator? Could it do any damage to the alternator by pulling too much? Can the house battery be a deep cycle battery and would that be recommended since you might be running it down and recharging many times? Can the house battery be placed in the rear of the truck? Any issues with distance from the primary battery or alternator? Would you need bigger wires?

[@OverlandBound]

Hi Don. Thank s for watching! 1. Alternator: Sure - it should be in good shape. There is voltage drop to the second battery. You will benefit from an upgraded alternator. My setup runs and charges fine. It is a new OEM alternator. It also depends on the make of car - Land Cruisers are over-built. 2. If your alternator is already in bad shape, or you drive a Yugo, probably, especially if you have a lot of accessories that you run all day, with extended hours of operation. In MOST cases, you should be fine. 3. Deep Cycle - Yes. Your batteries should have the same charging profile - otherwise you will get different charge rates, shorter battery life, and perhaps other long-term issues. Mine are matching Northstar AGMs. 4. Rear of truck - I wouldn't recommend but you could. The farther away it is, the more voltage drop you have, and your alternator will be trying to charge both batteries, so, for me that means inefficient charging on both your house and start battery. If you go this route - do a lot of research on wire gauge and alternator requirements. If you upgraded this proposed simple system - perhaps with a battery manager - you definitely could. 5. Yes. 6. Yes.

[@johnmorgan392]

Love it!!!

[@carolesimpson1474]

Do I need more wire gauge tubing for a 2000 amp Inverter? And also what amp Auxillary Battery should I get? Thank you Great job with presentation. Simple & to the point.👍🖖

[@dlproductions9574]

i assume this would also give you the ability to jump start your own vehicle? unless you have one of those handheld jump rechargeable units that can do it of course

[@OverlandBound]

Yes - I do pack a jump starter since they are so small, and convenient.

[@daftnord4957]

i like this simple and cheap idea instead of a diode or mosfet isolator. So how does this work when the aux(deep cycle) battery is drained, then you turn the key switch on to start the vehicle. Soon as you turn the ignition on(before cranking the engine) will this be affecting the condition of the starting battery to get your engine cranked over?

[@steveffuksake]

Why can't you just put a set of jump leads from the car battery to the leisure battery,and then when you use the leisure battery take of the live jump lead of the leisure battery

[@AH-ro9rr]

Can you make a diagram showing the additional or/or overlooked components please? Great video!

[@doraexplora9046]

That's a starter solenoid from a '60's English car. Originally made by Lucas I think. Commonly found on Jaguars and the like. Lol. Now remarketed for split systems.

[@flockfam3868]

Great vid Mike, exactly what I’ve been looking for!

[@MooseZ71]

Trying to get my setup together now. So why even move to a complicated, and very expensive, "battery management system" if the analog version works perfectly fine and is easier to diagnose and repair? Does it do something else worth the price increase?

[@OverlandBound]

It's the charging profile. A "smart" battery management system allows you to have two different batteries and it will smartly charge them based on their requirements - making sure they don't overcharge, and charge them at the optimal rate. This extends the life of your batteries significantly. Since batteries can be $500 - you want them to last as long as you can. As long as you have the same type of battery on this less expensive setup - you will be OK.

[@TitusJude-l8g]

Tank you for explaining everything so simple❤

[@rollylinogao6895]

Wonderful set up Sir, thanks for sharing your knowledge.

[@Gravel_Rat78]

@Overland Bound, I have the same B&D work table… I love it

[@OverlandBound]

Good stuff right?

[@daleallem]

Thanks! I needed that information. Well done!

[@jimcruz4307]

Wow , excellent briefing on your know how cheap setup. this is probably more reliable than the systems trying to reinvent the wheel. I've seen many videos and have thought about the solenoid. Thank you, sir, for confirming. Question: it should work with a junction box/solar panel added on to the relay?

[@alb2571]

Man I was in from minute 1:30 ! Thanks for sharing all those god tips

[@paulcrouch6928]

Hey Love your channel I am thinking of doing similar I am currently running idc25 to charge second battery using solar when off grid . I have a 110ah agm and would like to use same ah battery as my starter battery as it’s dual purpose How can I use your system but still use solar charging Thanks heaps

[@mikewhitman745]

So my current system is even cheaper. I have a battery in the back hooked up to the stuff it's hooked up to. When the battery starts dying I charge it with a charger off 120, I don't have a huge draw and can run for a couple days with what I use and how I use it. Have been toying with the idea of a solar trickle charger for 30 bucks and just letting it go like that.

[@Dark_Daze]

Can you explain hooking up an inverter to this system after the auxiliary battery and a possible hookup for a 100w solar panel to it as well? This part makes sense to me. I'm very new to all of this. But I would like to see something for everything behind the auxiliary battery if you can please. I would like to have my auxiliary battery and inverter in the bed of my truck with my camper build

[@thomasbrustad5596]

Excellent idea

[@Rubi747HVY]

I'm at that point to ensure my fridge is always on and inverter always charged. Also going with solar panels. Thanks

[@NonnofYobiznes]

Can I use any kind of battery for the secondary? Like a lithium or a deep discharge kind? Thank you.

[@jhartmac100]

Excellent job

[@markhoffman2165]

What type of batteries are you using and what size is the secondary battery? Thanks for this video as I’m in need of a second battery to power my new fridge and saving the money for a Redarc system too.

[@OverlandBound]

I am using two identical NorthStar AGM batteries.

[@pauladams4890]

Not a good idea to have it linked to your ignition... because the batteries will equalise almost immediately when the ignition is switched...if you drain the house battery completely & turn the ignition on without starting immediately...you’ll be stuck. Other factors like a start battery on the way out, or a engine that doesn’t want to start immediately..will also magnify this situation. In my system... I have a manual switch between ignition & solenoid. Which remains off until vehicle is running... then I switch it on. By doing it this way your guarantee your starting ability...

[@OverlandBound]

That's a good point - I have a new engine and a one turn start. I also have a jump starter - but well - that defeats the purpose. Wiring a manual switch to the solenoid is a good idea.

[@pauladams4890]

@@OverlandBound yeah...I found out the hard way.😂 I was stuck on the beach for 2.5 hours.

[@OverlandBound]

Good tip! I planned to wire a manual switch, but this makes it important to call out - added it to a pinned post. Thanks!

[@JeffPalmer941]

@@OverlandBound You effectively already have the "switch" since you used the power antenna lead. When you turn off the stereo, the power to the "antenna" (solenoid) is cut.

[@just_tojo]

so the solenoid is just connected to any 12v source that is only on while the car is running, correct?

[@nautox]

So if your rig is parked on the side of the house for a month, is the battery isolator smart enough to detect a $50 solar panel slapped on the roof rack? Or do you have to move the gator clips every week from one battery to the other to keep them topped off? edit: Great video by the way, If I can find room for a 2nd battery, I'm definitely adding the fuses you recommended!

[@hungphan9343]

Hi Michael! I have box truck with two batteries installed. Can I add 2 more? Thank You!!!

[@miket4685]

Thank you for dumbing it down for me. In this set up, would you be able to start the car with the secondary battery in an event the primary does not crank? If so, how would this be done. Thanks in advance for your response

[@sahaprashant1]

The whole purpose of this setup will be defeated the moment you turn on the ignition. If the aux battery is discharged, the moment you turn the ignition key, the two battery connect and the drained aux battery will drain all the charge from the main battery and you end up with two below par batteries.

[@OverlandBound]

See pinned post - you are correct.

[@Standomness]

Can this be solved by connecting the remote wire to a switch?

[@Mike-ry4ti]

Use a timer with your solenoid swit h wire so the solenoid does not power up until after your engine is started.

[@FaruqGilani]

@Michael Thanks a lot for great solution. I am going to use your solution but will wire solenoid to switch so I have more control. Before I go ahead I see that you have put 80A fuses between the two battery connection, so my concern is what happens if I drain my starter battery all the way then try to start using auxiliary battery . Will the starter not draw lot more current than 80A if so what could be best solution to handle this.

[@bigoper]

Great video! love the notes and diagrams! Care to recommend on a battery?

[@kutapatapu2855]

Thanks for this helpful tip..But do I install the same Amp batries and brands?

[@danc2014]

Where is the starter in the diagram? If the relay switches when the key is in, you have 2 batteries starting and 2 batteries for accessory. You need to switch on the accessory side on after the car is started to have a separate start battery

[@daftnord4957]

i guess the main benefit would be when the vehicle is off you can power things off the 2nd battery. But when you turn the key to start the engine the main battery will drop in voltage to fill the 2nd battery?

[@mansoorahmed3918]

Saved me $1200 :)

[@tomfrantz]

Amazon list please.

[@OVHabitats]

How do I know if My truck has a smart alternator that decreases voltage as needed for the factory system? Would the decreased voltage affect the way this set up will work?

[@OverlandBound]

The way to look at it is the alternator sees both batteries as a single battery for the most part. Through the cables they are linked together and the alternator 'sees' a 12v battery at X% charge.

[@roba6277]

Enjoyed the video. Great instructions! I have an unrelated question. I see you have a VHF/UHF radio antenna on the left-front quarter of your vehicle. I know the Australians in particular have the tendency to locate their radio antennas there too. I don't understand why that is! I'm a ham radio operator and from an efficient RF pattern perspective, that location (in fact any vehicle corner location) is the WORST location for a TRANSMITTING antenna. The best location would actually be in the middle of a metal roof. Please share your thoughts on this. Thank you!

[@steveleston1848]

great video I've read that the wiring going to the starter silanoid needs tobe removed when adding a battery isolator an there should be only one path to the starter? I'm confussed

[@malindaodris1]

Love the video. I've got a Prado 120 series petrol. is it worth adding a DC-DC charger on top of your setup? Don't think my car has a smart alternator. just want to run a fridge.

[@martinroldan6695]

Thank you so much!! Would it be best to use a deep cycle bat or agm??

[@jordanross6286]

awesome vid but i think that when you drain your house battery since batteries are hooked up parallel, then the voltage will equalize, leaving you unable to start your truck on that 9 volts or so. hope you didnt find this out the hard way

[@dattran6372]

can the house battery be overcharged with this setup?

[@jr6546]

Hi just got a truck that has the space and capability for dual battery setup, my question is how to wire accessories and what kind of accessories to the spare battery, my truck already has a factory inverter up to 150 watts. Thank you for sharing your videos

[@brandoncarroll5771]

I turned my 96 Dodge ram into a camper-truck... So I've been wanting to set up the dual battery system. But what extra would I have to add to it to be able to run a tv, and microwave?

[@squatch2461]

Why use 80A fuses instead of circuit breakers? Thanks for the very informative video.