Dual Battery Setup Help

shit!! hahaha that sucks!

 

Looks like I'm right on par with commandment #5.

 

Thats why I'm spending so much time and effort planning this.

 

And asking the right people.
That's what I do.

 

My next question is, how do I make the house battery accessories only hot when the car is on?

 

Maybe keeping it hot would be good too. While it will be a long time before I have something as large as a fridge, it would be nice to always be able charge phones. Although, next week I'm doing the 100/400w anytime mod, but thats just when the car is on.

 

What are you exactly looking to do with having the aux battery only running with the key on? The reason I ask is that most people want to use the aux battery to power things like a fridge or camping lights. You don't want to have your ignition on just to run things such as that as it is a waste. I have always said that I was not a fan of the IBS and Blue Sea systems because they are not a true isolation system at all. They simply connect the aux battery in parallel to charge it.

 

Never mind. I got my answer. Thanks.

 

Thanks for any help. So trying to do this. Where do I hook up the brown isolation wire from the Blue seas ML ACR (Isolation #1 on Diagram). Do I just remove dash ,look in the steering column in the truck and use a wire tap> Is there a "best"place to tap in the line? I think Im puting the switch on left side of steering wheel in stock switch locations so is the starter switch wiring going that direction since its going hrough the firewall grommet? How do I know which one it is?

Thanks again

 

The isolation wires are actually optional. I didn't use any of them.

 

oh. so from the ml acr to the manual in cab combiner switch all you need is the red to open and close the combination circuit and the yellow to illuminate the switch??

 

Also is there a benefit of the 7622 vs 7620 model. What would be the advantage of the manual lock off that the 7622 offers and the 7620 doesn't??


7622 here:
https://www.bluesea.com/products/76...rging_Relay_with_Manual_Control_-_12V_DC_500A

7620here:
https://www.bluesea.com/products/7620/ML-ACR_Automatic_Charging_Relay_-_12V_DC_500A

Do I really need to lock off the system to do work on the accesories or just disconnect batts old school style??

 

on @Pirhett I couldnt find his dual batt setup?? Is there a link to his setup?

 

Bumping this thread and looking for verifification.

Is it necessary to hook up the brown wire on the blue sea ml acr?

Why would one hook it up or not hook it up, advantages to either setup?

I'm installing in 99 v6 Tacoma if it matters

 

Sorry to sound very noob, but what are the advantages going with a dual battery setup?

 

You're doing the right thing by going through all the research. Wiring is easy, but to get it done right it's expensive and time consuming.

Just remember if you are going to run more than 100A make sure it's well fused and the AWG is sufficient for the runs.

 

Running 1/0, did big 3 upgrade and running high output alternator, I've done my research but the comment I quoted in my earlier post presents an easy solution if I can omit that step.

Need to reiterate my question, is it necessary to run the brown wire off the blue sea 7622 ml acr?

What happens if I don't? What is of added benefit if I do?

 

It is my understanding that the brown wire is not necessary in our application.

It is there for marine applications where starting/cranking power is drawn for extended (longer than 30 second) periods of time in some applications. In those situations, it will protect electrical components in the circuit by isolating them from surges that can occur during heavy amp draw.

 

It's a fair question. There two general camps with a little bit of cross over for some.

Those that need power when the vehicle is off, similar to the needs of an RV, needing to run a fridge, or compressor, or inverter, etc... These folks usually add a deep cycle battery. A sub group are the off-roaders with winches. These folks tend to prefer the AGM batteries - deep cycle qualities but with a high CCA rating. The aux battery is isolated from the primary battery in the event the electrical devices drain the aux battery. This way, your primary battery always has enough juice to start the vehicle.

The second camp are those that simply want a back-up battery in case the primary dies. I'm in this group. I go off-roading solo and if my primary battery dies on me, it may be days, or sometimes weeks, before I see another soul that could jump start me. Yes, there are battery packs, but you have to haul them, and only a very expensive battery pack can start a really dead battery. Any 12-volt battery can be used as an aux battery for these folks. Those that can afford it will go for an AGM battery, but you can throw in a $60 Wallyworld battery if you want.

You can wire the batteries directly in parallel, always pos to pos and neg to neg, if all you want is the same voltage but with more power. This is the cheapest way to set up a dual battery system. However, this also shortens the life span of a battery because the weakest battery is always draining the stronger battery - never the other way around, that's not the way battery chemistry works. To increase longevity, you want the batteries connected when the car is running so that the alternator charges both batteries, but you want a device to isolate the batteries when the car is off so they don't drain each other. This device can be a simple on/off high amp switch that you flip on and off, accordingly; or, a high end electrical isolator that reads the voltage level of both batteries and does all the thinking for you.