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

Are you sure the starter is high enough? From what I remember it needs to be around 12.4 or so for it to automatically charged both.

 

So I'm guessing the answer to my above, is yes.

 

Thanks btw

 

Have you gone through the troubleshooting flow chart?

 

Yes i have gone through the flow chart.

 

Do you have the start isolation # 1 ( brown wire) hooked up ??? Because if you do then i am missing that :/.

 

No I skipped that part.

 

When it comes to wiring I'm retarded and it didn't help that they had like 5 diagrams of different options, could you have wired it according to the engine isolation diagram of something?

 

I will have to check tomorrow. I'm pretty sure I did use the brown wire for something.

 

I'll dig up the alternator bible link for ya soon as I get a chance. Basically, your alternator has to be able to regulate itself to prevent frying components and batteries- so when you turn on a bunch of lights and your seat heaters and bump the stereo, it ramps up the output to make up for the voltage drop you're pulling from your power source.

So
If it were to sense the voltage drop between the hot and ground right at the alternator, it would only see about 12v. Stock, the end of this wire is connected to your stock fuse block harness so it sees the voltage drop between your vehicle components and its output and adjusts up to make the stock fuse block 12v

Now when you have massive dual batteries and an auxiliary fuse block and a winch and lights and air compressor and and and.... All while your alternator is only seeing the voltage drop being used by your stock components, you're probably having a huge voltage drop which will trip breakers and take your batteries forever to charge.

If you relocate the voltage sensing wire to the furthest, highest draw component away from the alternator, that baby will always ramp up and make sure you get your 12-14v at the components you need the most.



Or,
Your blue sea panel is just fucked up.

 

Wow good info. How do I locate the voltage sensing wire? And how do I know where to hook it up to? I added 12v to the bed and back seat for the fridge, air compressors, inverter, lights, etc all draw a good amount, but I don't always have each of them on - so they won't be necessarily drawing the most power at any given time.

 

surely noted.

 

@MJonAgs32
Here's the full text. it took me a couple hours to get through everything and completely learn everything he's teaching you here.

I'll find the specific tacoma voltage sensing wire in a bit. Try and wrap your head around this first it took me a minute

http://billavista.com/tech/Articles/Alternator_Bible/index.html

Here's some excerpts to try and explain:

""
If the battery is fully charged and we have no lights or other electrical accessories operating, very little voltage need be produced by the alternator (there will always be at least some demand due to voltage drop in the system wiring, caused by the resistance of the wire itself - remember Ohm's law!)

However, if we have lights, electric fans, a weak or partially discharged battery, and a big stereo playing, system demand will be high and the alternator will be required to produce much greater output to keep things in balance, charge the battery, and prevent system degradation or malfunction caused by low voltage (e.g. dim lights). We'll look at an example using some real numbers shortly.

Now, the output of any given alternator is primarily determined by the rotational speed (RPM) of the rotor and the strength of the magnetic field produced by the rotor. In turn, the strength of the magnetic field produced by the rotor depends on the amount of current (the field current) supplied through the brushes and slip rings to the rotor windings.

It is this field current that the voltage regulator controls, or regulates, in order to control alternator output voltage across all alternator speeds (RPM).

Today, virtually all alternators used internal solid-state (also known as electronic or transistor) voltage regulators.

The regulator has two inputs and one output. The inputs are the field current supply and the control voltage input, and the output is the field current to the rotor. We will examine the concept of the control voltage input in some detail in the section on wiring. For now, it is sufficient to think of it as a wire from the battery or main electrical distribution block that provides a constant "reading" of system voltage to the regulator.

The regulator uses this control voltage input to control the amount of field current input that is allow to pass through the brushes and slip rings to the rotor windings. If the system voltage drops (e.g. when lights are turned on or engine rpm decreases) the regulator senses this and allows more field current to reach the rotor, which increases the magnetic field strength, which ultimately increases the voltage output of the alternator which brings the system voltage back to the correct level. Conversely, if the system voltage goes up (electrical devices are shut off, or engine rpm increases), the regulator allows less field current through to the rotor windings, and the alternator output voltage is reduced, again bringing the system back into balance. It's a closed-loop feedback system and it works extremely quickly and reliably so that the end result is almost entirely consistent system voltage regardless of electrical load or engine RPM.

The regulator uses transistors to control the field current. A transistor is a device used to amplify and switch electronic signals. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current flowing through another pair of terminals. When system demand causes a voltage drop (the control voltage input is less than nominal) the regulator senses this and a small current is sent to a transistor which amplifies it and sends it to another transistor which acts as a valve in controlling the flow of the field current input to the rotor.""


From our description of how an alternator works, it should be clear that all alternators require a minimum of four "elements" to operate - 1) Field Current, 2) Voltage sensing, 3) Ground, and 4) Output.

"We have already discussed briefly why voltage sensing is required - recall that it is the method by which the voltage regulator senses system voltage and compares the result to its internal setting, and based on the results of that comparison either increases or decreases alternator output. The "internal setting" is built into the voltage regulator and is the system voltage the regulator will try and maintain. Internal settings may differ slightly between voltage regulators but all are about 14.0 volts.

The concept is simple, but there is a nuance that is important. Because voltage is like "electrical pressure", and because there is some resistance in all components in a circuit - even the wires themselves - it should be fairly easy to see that it matters where the "system voltage" is sensed."

"
This is where the concept of REMOTE voltage sensing comes into play. Instead of sensing system voltage at the alternator or close to it (which is like congratulating yourself on a great job regardless of the results!) - we sense system voltage where we need full voltage - in this case at the main distribution point (bus bar).

That way, when the voltage sensing circuit detects 13.0 volts at the main bus bar, it says: " I'm supposed to produce and output sufficient to maintain system voltage at 14.0 volts. I sense system voltage as 13.0 volts. Better increase output to 15.0 volts to bring system voltage up to 14.0 volts."

"Another advantage to this remote voltage sensing, is that it allows the alternator to compensate for increased system demand as more accessories are turned on. That's what it's supposed to do, after all. As more and more devices are switched on, a voltage drop will occur at the main bus bar. With remote voltage sensing, the alternator sees this drop caused by the extra demand, and automatically increases output to compensate. To not use remote voltage sensing, or to simply jumper the wire to the alternator output or some other nearby source would be like hiring a blind sniper - sure you might hit the target, but only by blind luck!"

 

This is kinda the inspiration for my wiring overhaul I'm gonna do soon.

http://www.bodenzord.com/archives/477




And after all this, Here's my wiring diagram. I actually made a big mistake- I have my voltage sensing wire routed all the way back to my bed mounted 12v plug which is protected by a breaker on my sPOD relay block- if I trip the breaker (which I have several times) my alternator will see zero volts and grenade trying to ramp up. I gotta find something that's connected to the battery with the biggest big power draw.

 

Phew my head is spinning after that.

 

the white wire at the alternator in the G2 connector is the voltage sense wire that I wanted to relocate.

 

My head is spinning after that packers pass to win the game just now! holy crap.

take a couple days to read the whole bible it's actually really cool stuff. then again, I read engineering papers for fun and work on galvanic corrosion protection for a living.
I'll try and identify the wire- that writeup doesnt make it all that clear. even without a big 3 upgrade, cutting and relocating the end of it to your aux block will let you pull the full capability of your alternator. the offroad models like mine have a pretty badass one stock. 160 or 180 amps if I'm not mistaken.

 

TDR models have 160 amp.

 

Wow thanks for the info @Spencer. Honestly, I'll probably read it over again and comprehend it at a later time. It's Friday and I'm fried lol.

I thought OEM with the tow package was 130 amp

 

@p1ll1ng for acr write up .