How to make a cheap isolated dual-battery setup for $50

patoz

Expedition Leader
Ok so I came here looking for info on making a similar setup to the national luna its system. I've started hearing people having issues with the controllers and the solenoids on those systems and wanted to see if I can replicate the setup using off the shelf parts. I come here to find 97 pages of info. Any of you guys know if you've talked about doing something like this already or is this something new.

What I'm wanting is an automated dual battery monitor and charger. Also the ability to link(jump) the two batteries together using a switch from inside the cabin. I was already prepared to spend the $400 on the NL setup so anything costing the same or less is good with me. Also if its a bit more but adds functionality thats useful is fine too. I will go through this whole thread but can't at the moment.


This is what you'll want...

ML-ACR Automatic Charging Relay with Manual Control - 12V DC 500A


7622.png


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

https://www.amazon.com/Blue-Sea-Sys...rging+Relay+with+Manual+Control+-+12V+DC+500A
 

Redman333

Adventurer

patoz

Expedition Leader
This is all you need to set up and operate a dual battery system in a vehicle, as far as the charging side goes. Adding large amperage fuses mounted in fuse blocks at the positive side of each battery is also recommended. Did you look at the wiring diagram on the Blue Sea page? It's for a boat, but can be easily adapted for a vehicle.

If you are planning on adding a lot of 12VDC accessories, then you may want to add an additional 12V distribution panel with it's own breakers.
 

Redman333

Adventurer
Yes. This BlueSea ACR will operate superbly ! But if you like electro-glitter displays, you might be unhappy with it.
(In fairness, NL can operate without a display.)
That BlueSea gives you override ability to force-combine or force-separate via a remote switch or its yellow knob on the unit.
Also, especially if one charges from solar, BlueSea self consumes very little power compared to that thing from National Luna, and its rated over 5x higher switching capacity.

I actually do like "electro-glitter" however it doesn't come before reliability and function. I really like that you can manually force together or separate.


Sent from my iPhone using Tapatalk
 

Redman333

Adventurer
This is all you need to set up and operate a dual battery system in a vehicle, as far as the charging side goes. Adding large amperage fuses mounted in fuse blocks at the positive side of each battery is also recommended. Did you look at the wiring diagram on the Blue Sea page? It's for a boat, but can be easily adapted for a vehicle.

If you are planning on adding a lot of 12VDC accessories, then you may want to add an additional 12V distribution panel with it's own breakers.

I haven't looked at it but I will try tonight. I'm at work right now and when I get home ill need to prep for my trip to the overland expo so may not have a chance to really look into this until I get back. I do plan on adding a few circuit bit I already have a aux fuse box as well as a aux relay box too. I ran the wires for these with the idea I will have a dual battery setup so all I have to do is connect it to the new battery. I pretty much want all my extra loads on the second battery.


Sent from my iPhone using Tapatalk
 

patoz

Expedition Leader
It sounds like you're on the right track. Installing the Blue Sea ACR is not difficult, but it is a little time consuming to do it right. Definitely, not something you want to do in a rush.

I'm not going to make ExPo East this year, but maybe next year.
 

john61ct

Adventurer
Even a powerful starter doesn't pull that much, these are **very** robust units, just like the remote switched (non-ACR) version.

There is of course a rated duty cycle for everything, but in effect these monsters just don't fail.
 

Redman333

Adventurer
Oops !!
Used the wrong words here. I am quite sure my words "Switching capacity" is not right. That BlueSea is rated 500amps, but I seriously doubt it can SWITCH 500amp, (especially break 500amp DC at least more than a few cycles.) Its rated to CARRY 500amp continuous.
I dont remember seeing a switching value in its 'specs. BlueSeas Engineer might have to answer that one if needed.

I'm trying to think of what situation you'd be in to have to break 500amps anyway. I'd imagine you wouldn't have to do this often if ever.
 

Mad Dog

New member
I know this page is years old & idk if the original member is still active on here but I have a few questions regarding this set up & THANK YOU FOR STARTING IT & Editing it.....Hopefully I don't ask the same question again, I couldn't go thru all 99 pages of replies. 🙄..

I'm not looking for extreme but I just don't want anything to blow up or catch fire or leave me stranded somewhere with my family, so the products I found on Amazon are expensive but I'm not actually going to buy them I just want to know if everything is compatible with one another...

FYI I have 2001 Jeep Cherokee & I've removed the factory air box thing so that's where my second battery will be located.. & I'll be using regular old batteries-i opted to dish out $200 on the optima battery charger instead of one battery...

What did you hook up the "12ga" to the fuses? I'm guessing it's a 12v constant but would you recommend a certain one too connect to?

(I'm looking at a birds eye view of the original post with diagram)
1. Can I upgrade ALL those 4 ga cable to zero?

2. Could I still use the factory wiring going to starting battery in reference to the above question?
3. Would I HAVE to upgrade my alternator?
4. The 80a solenoid, can it be upgraded to one with a max of 500?? (I found Cole Hersee 24213 12V 200A Continuous Solenoid for $60 Amazon-if it were in stock)0F3990F4-2F1D-4A86-AE27-33740E667E50.jpeg942B0438-EFE3-43E8-9A6B-9F645290ACAD.jpeg
5. Also found 200a anl fuse & holder for $13 (if #4 is correct)590E5029-DB6F-4EE1-9209-CB6CA7748D6D.jpeg
6. BONUS😂. Does this look right? Came across when looking for the cables but I've never thought of hooking up to battery
BD64605E-0BDE-4082-B041-D2C3ECFF0E9A.jpeg
Also, I tried looking for where this fits in at with no luck 😳😳69E794DE-BD18-4B86-B5C4-DEF79655A9B1.jpeg

The only reason I'm asking these is because I'm VAUGELY familiar with car audio so I remember using higher gauge cable etc is actually better for speakers etc so they don't get too hot but I've never hooked up anything like dual batteries before.. I was going to save up for those expensive kits but I like this DIY type method instead..


Thanks
 

dlichterman

Explorer
There is never any harm in increasing the wire gauge or a solenoid that can handle more power. But you might want to do the math and figure out how many amps will actually be traveling through to see if it's even worth upgrading as the copper isn't cheap.
 

patoz

Expedition Leader
I know this page is years old & idk if the original member is still active on here but I have a few questions regarding this set up & THANK YOU FOR STARTING IT & Editing it.....Hopefully I don't ask the same question again, I couldn't go thru all 99 pages of replies. ..

The only reason I'm asking these is because I'm VAUGELY familiar with car audio so I remember using higher gauge cable etc is actually better for speakers etc so they don't get too hot but I've never hooked up anything like dual batteries before.. I was going to save up for those expensive kits but I like this DIY type method instead..


Thanks


OK, considering your admitted electrical experience, this is what I would recommend. Go back to post #968 and read forward.

The original post was an excellent solution at the time it was posted and has been for many years. That is exactly what I did back in the late 70's on my 1978 Ford bronco and my 1979 Ford F150 truck. However, this is 2017 and fortunately the manufacturers took the ideas us old guys came up with, perfected them, and put them into production.

Seriously though, the Blue Sea ACR (Automatic Charging Relay) is the way to go. It's simple, foolproof, and the quality is top of the line.

Blue Sea makes several different sizes, but personally I would just go with the ML-ACR Automatic Charging Relay with Manual Control - 12V DC 500A.
It covers just about everything and gives you several options which are very good to have. No point in trying to reinvent the modern wheel!

As far as cost goes, you can get it at Amazon for $191.04. By the time you piece together everything to build you own system, you will be pretty close to this price, and still not know for sure if it's all going to work together as it should.

Good luck with your project and let us know how it works out!
 

Mad Dog

New member
����... Yeah I'll just stick with the original post/diagram ������. ... Thanks for the clarification
 

Glidedon

New member
😳😳... Yeah I'll just stick with the original post/diagram 😅😅😅. ... Thanks for the clarification


I did read all 99 pages plus 100 elsewhere. I installed the Blue Sea ML-ACR. just saying:coffeedrink:
 

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