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

Ahh, ok. So really, the starting battery is always hooked to the starter as there is nothing between the two besides the alternator, so a switch would need to be installed to interrupt it. In certain applications the ACR links the batteries and it aids the starter because the first battery is now aided the second. The ACR functions when the engine is running and the charging system is active to link them for charging or determines which gets charged in isolation based on which is in need. It functions when the vehicle is at rest to isolate the batteries and draw power from each particular battery based on what's hooked up to it, so second battery is accessories for most, 1st is stock truck functions such as headlights, starting, etc. You can then force it to link the batteries with the switch on top if you want to use both for some reason. I'm still kind of fuzzy on the off. Does that mean that just the ACR is off? So you still get power from each battery but they are forced into isolation? Will they both charge equally which I take is what a regular solenoid does, neither charge or ? from the ACR at that point?

 

@Laxtoy I'm not sure exactly what your asking, but off means the batteries are disconnected and cannot be connected via the auto mode. So circuits from each battery have power, but the batteries are not connected and they are not charging. When connected, in theory, they receive the same power from the alternator to charge equally.

The ACR is always drawing power from the house battery and since it's connected to the starting battery as well, it monitors the voltage of both.

Essentially the ACR, like you said, connects two separate circuits for charging.

 

Ok, I am new to this thread and have gone through most of the pages. I have recently been researching dual battery set-ups. I was originally thinking of using the IBS system but it seems like there are comparable systems for less.

I was very much attracted to the way that the guy installed two batteries in the rear cab compartments (pictured below) but am confused about the wiring that he did. I thinking of using bluesea battery switches (like the ones pictured) but after reading about the ML-ACR, it seems that that unit would replace any the IBS and any need for switches?

I would like to install two batteries in the rear compartment and keep my original battery location (run 3 batteries). I think I have the voltmeters figured out since the ML-ACR doesn't have any.

I understand that I need to separate the starting battery (engine compartment) from the auxiliary battery but is there any need to separate the two auxiliary batteries from each other?

I plan on installing one of Skygear's Bussman big relay/fuse boxes to the aux batteries.

 

What are you trying to accomplish with two batteries in addition to the starting battery?

 

I plan on accomplishing the same thing as everyone else in this thread. I have many power-draining modifications and more to come but do fully intend to upgrade my alternator and add solar panels.

Do you always answer a question with another question or do you actually have input on the topic?

 

I asked a question to your question because I need more information to give input on the topic. I don't like to assume what you need so I asked. I have a habit of thinking and gathering as much information as possible before assuming I can offer something that resembles help.

So, since you are running a starter battery and two house batteries, I have to assume those two house batteries are connected in parallel since I'm guessing you want the additional capacity and not additional voltage.

When batteries are connected in parallel energy in those batteries wants to be even, so if you have one battery with a high charge and one with a low charge, when they are connected they want to become equal. This is why units like the ML-ACR will not connect two batteries if one is very depleted because when connected it can lower the lower voltage of the starting battery enough to keep your motor from starting.

Now we have two batteries and one ML-ACR, still guessing here, and you have switches to isolate the two house batteries. Are you isolating the batteries to have a backup of a backup? If so, which one is connected to ML-ACR to be charged? Are you needing a high amp draw from the accessories being run from the batteries that you need the extra capacity of two? If so, why would you want to disconnect them?

That's why I asked the question, if you only plan on running things like a fridge, lights, and other items that are "the same thing as everyone else in this thread", why would you complicated the system with two batteries and a bunch of switches if you are getting a controller like the ML-ACR?

If you simply need a bigger amp draw I would get one larger battery over two, but if I were to run two (maybe it's cheaper or fits the space better) I'd run them in parallel without switches.

I hope that's enough of an input to satisfy your posting rules?

 

That time of month?

 

There is something about the way that you worded that question (like many others on this site) that seemed condescending; especially with the lack of input. I apologize if I came off irate.

You are correct in the thinking that I am in search of additional capacity not additional voltage. I understand the logic behind parallel batteries wanting to find an equilibrium. I am partially still trying to understand the setup of the linked image. Why would he switch each battery rather then running them parallel? I have a fridge/freezer, area lights, rock lights, light bar, winch, RTT power, shower water pump, compressor pumps, etc that draw quite a bit from the batteries. These items will be run soully off of the aux (house) batteries. Yes, I am limited in space since I am working with a 27"x11" space inside the cab. Again, yes, I do believe that answers my questions whether I need switches between my two aux batteries.

Thank you for the information regarding my question. I apologize to you again for coming across irate. It is simply because of my intolerance for ignorant, imature people like @nagorb that make me this way.

 

Blame other people for you being a dick, great way to live life.

 

You came off as aggressive from such a simple question that didn't seem to be written in the same manner. But that's ok, we're on the same page now so let's just leave that where it is.

I can't tell from the photo exactly what he's trying to do there. My guess is there is no controller and those switches allow each battery to be manually connected and disconnected to the main battery, maybe in a variety of different combinations.

I'm running almost the same amount of accessories on my setup as you are and so far one battery has been enough. I am about to install a winch, but I may connect that directly to the main battery. On the winch specs it looks like you could have a constant load of around 300amps which means if you try to run that through the ML-ACR it may be too much, not too mention you have to have 0 or 00 gauge wire to really carry those amps effectively. Keeping the winch connected to the main battery allows you to be hooked up directly to the alternator and main battery so you have those large amps on demand.

Another thing I remembered is try to have you starting battery and house battery close in size and type as possible. If you have a small staring battery and too large of a house battery (or group of batteries), you can kill you starting battery even if your house batteries are not fully depleted. It like having a 5 gallon bucket of water and a 1 gallon. If you loose 1/4 of the 5 gallon and try to equalize with the 1 gallon, your 1 gallon bucket will be near empty.

I have a two deep cycles in my truck. A Yellow top for the starting and a Blue for the house. Both are deep cycle so in case they get cycled near empty they won't die right off the bat, and if connected they equalize in a relative manner.

A multiple battery bank is more complicated, but thankfully the marine guys have it all figured out, it just get's expensive.

 

I am definitely following on the type/size of the batteries. I plan on running all Yellowtops and 0 gauge cable. I don't mind leaving the winch on the main battery since I can manually connect the house batteries if needed. I did some research on the yellow vs the blue tops and they were pretty comparable besides the fact that the blue is marketed to the marine consumers and has less of a warranty (24 months compared to the yellowtops 36 months). All of the specs were identical.

I am curious though, why do you say that the ML-ACR would not hold up to the 300 amps when it's continuous rating is 500 amps?

I am building everything around my current setup and will leave it disconnected until I have everything done.

 

I got the blue top over another yellow in the 27 group size because the terminals are reversed and they have the extra stud of + and -. Otherwise they almost the same battery.

The ML-ACR is capable of 500 continuous amps, but read the link below for the cable requirements.

http://assets.bluesea.com/files/resources/instructions/990180180.pdf

You can see that you need 0000 cable to run at those amps. One thing that's not discussed at all is heat resistance. Those ratings are under ideal conditions. A hot cable is going to have more resistance so you need to take that into consideration when placing a cable in the engine bay (meaning it needs to be larger).

On my setup I have 2AWG cable because I only plan on charging the house battery, and if needed to jump the truck I only need 200 amps for a few seconds.

 

@skygear - Can you put this and the other useful info in this thread in the OP? Thanks

 

Yep. Give me a few hours. Working on boxes. Anything else you want in the OP let me know

 

Is someone with a ML ACR 7622 willing to do me a favor?

Will you please measure the voltage of the red "control" wire that comes out of the ml ACR unit in each of the three switch states (latch off, latch on & remote). All start isolation wires, and the remote contura switch should be disconnected. The unit should still be grounded, though.

My unit has never operated correctly in the "auto" state, and it is growing increasingly tiresome to be blown off by the blue sea tech support folks (three separate people so far!) once they realize I've installed the unit correctly. I expected better from them, but I digress.

In all of my testing, the only curious thing is that I am reading 4.25v on the red control wire in all unit states. I'm curious if that is usual. It's been two months since the first blue sea tech (and a month since the second) promised to check in their lab. No response so far.

 

Pm me i will give you my cell and explain what i had to do to get it working

 

I found a metal fabricator on Craigs list for pretty cheel, he does his work at home. And reasonably priced. I suggest you go on Craigs too.

 

Just a question on this dual battery setup. Is there anything stopping anyone from just hooking up the batteries in parallel just to double the amp hours? I just bought this truck and I use it 90% of the time for work. So I have lots of time sitting on ferries listening to music or out in the woods for long periods of time. Besides the convenience of being able to switch to a fully juiced battery if you do indeed kill one.

Thanks,

 

Have to be careful in how you connect them "in parallel". A simple parallel connection doubles the volts output, making it a 24V system, which may blow some/a lot of your systems. You want to either run them with a isolating solenoid or a simple battery isolator. And in those cases the aux battery will not jump the dead primary battery as power does not run back from it to the primary. Each has it's own pros and cons, and requires various changes to the wiring under the hood. Either way gives you what you are looking for in terms of extended radio play time.