Dual Battery Setups! Let's see them! Multiple Batteries Thread!

I use a 3lb hammer, hit it 3 or 4 times. You can tell from the sound and the feel when your done.

 

Yikes when I did my current lug I hit it once with a small hammer

 

I was using HD ring terminals with thick cable.

 

Can i just slap one of these under the hood to make a dual battery system?

I did this to 2 trucks before, and 3 boats. But older models. The fact that no one is doing this on tacoworld makes me fear that you will say it is going to fry my computer. Do I really need all those fancy blinky battery controllers you folks have?

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2004 4x4 4door trdoffroad sr5

 

Half the point of a dual battery system is that when the truck if off it doesn't draw current from the starting battery but only from the house battery. So while that switch will combine two batteries together it's not automatic.

If you want to go the cheaper route you can just wire up a starter solenoid to connect and disconnect your two batteries when the truck is running and not.

 

Fantastic compilation of info... Thank you for updating the OP! I'm considering a dual battery system with internal selectors for individual components (radios, mostly) with solar charging, etc, so this was hugely helpful.

 

I like that it is not automatic

honest. a solenoid is too many moving parts for me. I would rather have something manual that I can switch when the entire system is dead. But a solenoid system might be the best option.

Could i mount a marine switch through the firewall so i can switch from 1 to 2 as I wish? will running the truck and while selecting "both" fry anything? I had this system before and it did not. BUT it was a very old car.

 

I agree with @Zebinator, this is a good thread. It took a few hours to read, but.. great.

 

Of course!

But, as implied above, you, the driver, becomes the isolator - that is, when you turn off the vehicle you want to turn the switch to the off position. Leaving it on will not fry anything; you just run the risk of shortening battery life because the weaker battery always draws power from the stronger battery. If that is not a big concern, you don't need any switch, just wire the batteries together in parallel.

BTW, I have that exact switch controlling my starter. Not only to select which battery cranks the motor, but the knob pops out in the off position, enabling the switch to double as a security device. I believe it can momentarily handle 1200 amps.

 

Is that so... or is it only when you leave it on BOTH?

Check my head for me: With "1" selected battery 2 is not able to drain. and with "2" selected 1 can not drain. It is only when both is selected that they will equilibrate. Right?

 

You could do exactly what you're asking but then what's the point? You have to have the two batteries in parallel for them to charge. You method requires you to connect and disconnect the batteries manually. I give it a week and you're already forgetting to do it. Then when you need the 2nd battery it's dead because you forgot to connect them 3 months ago.

Really a 150A continuous duty solenoid is what you want. They are very simple and cheap compared to the "smart" dual battery systems. Install it, and forget it and when you need it it will be there.

$32 Cole Hersee - 24059-08-BP (24059-BP) 12V Insulated SPST Continuous Duty Solenoid

https://www.amazon.com/Cole-Hersee-...2&sr=8-1-fkmr0&keywords=150am+continuous+duty

 

You could do what you are talking about, but if you just want self jump capabilities you could just get a portable jumper. No need for a second battery if you don't need the extra capacity.

I do not know about using the switch while moving, but I personally wouldn't think there would be an issue. It's essentially what the smart solenoids do.

 

It would work like most boats. 2 vehicles at a camp i worked at had this. It was pretty fool proof. You ran off one battery. Every couple days you switched to the other battery. If you went camping and someone left the dome light on and you got back the car battery 1 was dead but #2 was good. They do not need to be both charged at the same time. Right?

 

Extra capacity is good for winching especially when bringing unbucked firewood to the truck. I want the capacity of the "both" setting. Just not all the time.
The jump capability is of primary concern especially since my truck has an automatic tranny (you can not clutch start it... or even change gears when dead... or even roll up the window when it is dead... pisses me off.).

 

I get the impression from some of the articles i read and videos i watched that the computer controlled systems of a modern truck might get fried as one switches to the "both" setting. Something about an amp or volt surge when one passes the both position of the switch as one moves from 1 to 2.
Here is an example (at 44 sec)

But all of those sources were people trying to sell fancy products. So I greatly appreciate the unbiased opinions here.

 

Only when both batteries are connected together will the weaker one rob from the stronger one. This is not an issue when the motor is running because the alternator is charging both batteries. When the alt is shut off, the weaker battery starts charging from the stronger battery. Your idea of using a switch only to connect the 2nd battery when needed is ideal for your situation.

However, you wouldn't need this particular switch. I would get a simpler on/off switch that sends power from the aux battery to the primary battery. When "on", the aux battery connects to the primary battery and doubles current available to crank the engine. (Well, really, only as much current as can travel through the OEM wiring.) Leave the batteries connected so the alternator charges both batteries. When the aux battery is fully charged, or when you turn off the motor, select "off" on the switch so the batteries are isolated while the motor is off.

If you want to use the switch you have pictured, you will need to rewire the starter and alt wires (the two wires currently on your primary battery + post) to the common connector on the switch, then connect your aux and primary batteries to the switch accordingly.

 

This is more or less what i planed to do:
http://www.pirate4x4.com/tech/billavista/dual_battery/my_dual_battery_setup.htm
that said, i do not want wires in my cab and would rather punch a hole through the firewall and mount the switch at my feet.


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http://www.pirate4x4.com/tech/billavista/dual_battery/Dualbattery5.jpg
VS

https://upload.wikimedia.org/wikipe...achine-OtoGodfrey.com-JMortonPhoto.com-05.jpg

 

Surge protection is overkill in my opinion. I am not using a smart solenoid. I have a DPDT switch in the cabin to control two mechanical solenoids (a 200-amp to isolate the two batteries; and an 85-amp to control power from the aux battery to certain accessories) . I connect the aux battery at highway speeds to begin charging it and have never experienced a surge or any electrical issues. While it may be possible, I've never heard of a battery surging in voltage. The biggest threat is the alternator overcharging, but it's connected to a fuse.

Yes, I have occasionally, forgot to isolate the batteries when I turn off the motor. Never for more than 8 hours, or until I turn the motor on and go to connect the batteries only to see I never disconnected them. Best solution is to re-wire one of the wires on my DPDT switch to an ignition-on source - it's on my to-do list.

 

I had visions of you installing the switch in the engine bay. I think you will find that wiring it in the cabin is quite involved; you will have to drill holes in the firewall to run and manage the thicker battery cables, plus installing that large switch. The wiring for a solenoid runs through the exiting wiring harness - two 14 gauge wires for the on/off switch that controls the solenoid. Maybe none if you locate an ignition-on source in the fuse box. It's doable but I really think you'll be spending more time and money (for the extra wiring) installing your switch in the cabin.

 

@Chuy
YES, you might be right. I already have a growing bank of switches. I just dont want this switch to be dependent on electricity to work. I know of solenoids with manual overrides so it is a likely option.

But note my text in the previous post, that i do not want the '00' 'full juice' wires in the cab like the photo. Most those marine switches are designed to have the knob on one side of the firewall and the wires on the other side. You only drill a little hole for the axle of the switch (sometimes made of a non conducting material). They are a good 2 or 3" deep for that reason. Not unlike race care shutoff switches designed to mount on the firewall with the switch near the drivers foot. I dont mind switches at my foot, i am flexible. I likely will locate it under the hood or do the solenoid trick. A third option is at the firewall but i need to look into it. Not in the cab.

The mod i linked to does not need to have the switch located in the cab.

I posted the photo more for fun... a red neck version of a back to the future delorian.