dlichterman
Explorer
If you have an interestate battery near you ask them about blemish/scratch and dent.
How to make a cheap isolated dual-battery setup for $50
- Thread starter evldave
- Start date
If you have an interestate battery near you ask them about blemish/scratch and dent.
coax
Adventurer
Just for reference for folks planning out their systems (and I say this even though this is the $50 dollar dual battery thread...sorry for the deviation), the larger blue sea automatic switch/magnetic latch will do 500A continuous. Warn 15k will only pull 460A at full load according to their specs, and if split between batteries one would be well under the 500A continuous rating of the switch. Depending on the duration of the pull and voltage drop on the batteries, its possible that the in-cab switch would need to be used to over-ride the automatic separation of the batteries. Definitely not a <$50 solution though
SDDiver5
Expedition Leader
How far away from the starting battery can the aux battery be? Is it ok to have the aux battery in the bed/shell and run a power wire either through the cab or under the cab? Or is that distance to far or not safe? I would have the solenoid and the aux battery in the bed mounted in the front driverside corner of the bed under a sleeping platform. I think everything I just typed makes sense....
dlichterman
Explorer
It's fine as long as you have some thick wiring. I ran 4AWG back to the bed along the frame rail(yay zipties!). Are you looking to mount solar as well? Keeps that run short if you mount the panel on top of the shell. I'm in SD as well so if you'd like to meet and look at my truck you are more than welcome to shoot me a PM.
SDDiver5
Expedition Leader
Dude that would be awesome!!
I would like to mount solar but that wont be for 3 or 4 years down the road when I get a new expo vehicle. Hopefully in the next 3-4 weeks I will be doing a dual batt set up so I will for sure PM you. Where in SD if you dont mind me asking?
I would like to mount solar but that wont be for 3 or 4 years down the road when I get a new expo vehicle. Hopefully in the next 3-4 weeks I will be doing a dual batt set up so I will for sure PM you. Where in SD if you dont mind me asking?
dlichterman
Explorer
I'm up in San Marcos.
SDDiver5
Expedition Leader
Sweeet Im in Encinitas
Kevin.Hutch
New member
non hot wire
We used to use the oil pressure switch to delay the solenoid switch on to prevent a dead house battery robbing the start at a critical time.
This would not cut in until after the motor was running.
Kevin
We used to use the oil pressure switch to delay the solenoid switch on to prevent a dead house battery robbing the start at a critical time.
This would not cut in until after the motor was running.
Kevin
Which would of course eliminate the ability to parallel the batteries for starting (dead batt).
Switched power AND a manual switch provides all necessary options while avoided unintentional parallel when shut down. Of course you must remember to parallel them yourownself.
Kevin.Hutch
New member
Cruising options
Typically boats have two way switches installed to allow either or both batteries to be connected and over the years many have dabbled with alternatives to jump starts when too much power is used overnight.
What with all the variables on engine/alternator run time, solar output over the day, battery types and charging regimes, battery selection for start and deep cycle application and battery sizing etc it all comes down to more art than science to get a 8 years out of you batteries.
In the relatively constant world of telephone exchanges 15 to 20 years is common for battery life and it all depends what selection/sizing/abuse you dish up to your batteries it could come down to only one year.
It is hard to simulate an knowledgeable operator that knows when to switch batteries and how all the compromises fit together, but a VSR has proved a good compromise in the rental boat world preferably bidirectional if there are more than one charging source. I got 4 years out of second hand golf buggy batteries.
Kevin
View attachment A Typical BAT DESIGN.pdf
Typically boats have two way switches installed to allow either or both batteries to be connected and over the years many have dabbled with alternatives to jump starts when too much power is used overnight.
What with all the variables on engine/alternator run time, solar output over the day, battery types and charging regimes, battery selection for start and deep cycle application and battery sizing etc it all comes down to more art than science to get a 8 years out of you batteries.
In the relatively constant world of telephone exchanges 15 to 20 years is common for battery life and it all depends what selection/sizing/abuse you dish up to your batteries it could come down to only one year.
It is hard to simulate an knowledgeable operator that knows when to switch batteries and how all the compromises fit together, but a VSR has proved a good compromise in the rental boat world preferably bidirectional if there are more than one charging source. I got 4 years out of second hand golf buggy batteries.
Kevin
View attachment A Typical BAT DESIGN.pdf
So I have a two-step variation on this thread- a dual battery system for about $12 or less.
1. Tap into the trailer battery charge lead at your 7-pin trailer plug (if equipped)
2. Run it to your aux battery.
3. Run your accessory circuit from the aux battery.
The charge lead is already switched to engine-on, and is designed to charge a trailer battery.
The $12 comes from the cost of the wire that you need to tap into that charging circuit.
*Some say* that the trailer battery charging circuit isn't designed to, and won't, charge a fully discharged battery. That may or may not be true; our trailer batteries (2 @ 6v golf cart batteries) get charged pretty well when we are towing our travel trailer from campsite to campsite. But assuming that it's true, do you ever really need to charge a battery from a full discharge? Don't you really just have to top it up between stops?
Anyway, I'm going to try my own Kool-aid and build a setup to power my Edgestar fridge using this type of circuit. I'll use this 26ah battery powered from the trailer battery charge circuit. http://www.amazon.com/gp/product/B002L9AN4G/ref=oh_details_o01_s00_i00?ie=UTF8&psc=1
I'll post up how it works. It obviously won't be useful for self-jump starting, but I'm betting that if the fridge isn't sapping the main battery, there won't be much need.
1. Tap into the trailer battery charge lead at your 7-pin trailer plug (if equipped)
2. Run it to your aux battery.
3. Run your accessory circuit from the aux battery.
The charge lead is already switched to engine-on, and is designed to charge a trailer battery.
The $12 comes from the cost of the wire that you need to tap into that charging circuit.
*Some say* that the trailer battery charging circuit isn't designed to, and won't, charge a fully discharged battery. That may or may not be true; our trailer batteries (2 @ 6v golf cart batteries) get charged pretty well when we are towing our travel trailer from campsite to campsite. But assuming that it's true, do you ever really need to charge a battery from a full discharge? Don't you really just have to top it up between stops?
Anyway, I'm going to try my own Kool-aid and build a setup to power my Edgestar fridge using this type of circuit. I'll use this 26ah battery powered from the trailer battery charge circuit. http://www.amazon.com/gp/product/B002L9AN4G/ref=oh_details_o01_s00_i00?ie=UTF8&psc=1
I'll post up how it works. It obviously won't be useful for self-jump starting, but I'm betting that if the fridge isn't sapping the main battery, there won't be much need.
SSSSTFIRE
Adventurer
Isolator?
If you are using a solenoid as stated in the beginning of the thread and had, for some reason, a dead house battery. Once started, wouldn't the system want to equalize the batteries causing a rapid drain from the start battery, perhaps overloading the system, assuming 4ga wire, 200A solenoid with 120A ANL fuses?
What would be the merits of a battery isolator like this?
Sorry if this has been asked and answered, I missed it.
If you are using a solenoid as stated in the beginning of the thread and had, for some reason, a dead house battery. Once started, wouldn't the system want to equalize the batteries causing a rapid drain from the start battery, perhaps overloading the system, assuming 4ga wire, 200A solenoid with 120A ANL fuses?
What would be the merits of a battery isolator like this?
Sorry if this has been asked and answered, I missed it.
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