Dual Battery Setup Help

Equipt

Supporting Sponsor Presenting Sponsor of Overland
Yes, I believe you may start to see some concerns in the readings you get and the activity of the Intelligent Solenoid. Grounding is key to the long term service of the system. The Intelligent Solenoid (IS) constantly monitors the connections and the grounding of their system. That is it's sole purpose, and it does it to a very high degree. Running a single line between the negative terminals is key to maintaining proper grounding connection and sending the right information back to the IS.

What this system does, in essence, is to add a second battery in parallel to the primary battery, and adds an automated switch to control that connection. By connecting the negative on the secondary to a ground point instead of connecting directly to the primary, you are running this charging system through your vehicle. It is now subjecting it to everything else grounding through your vehicle. Frame grounding is not know to be the best grounding solution either. I understand your logic in what you did. But I would suggest putting in the cable between the negative terminals as the instructions state. It will pay off in the long run.

Cheers,
 

Equipt

Supporting Sponsor Presenting Sponsor of Overland
One other thing to note on the NL dual battery systems. It really likes you to put the negative connections on after the positive connections. It cuts down on transient arcing at the moment of contact. That can sometimes take out the inline fuses, which is a real bummer if you don't have another fuse. Positives first, negatives second, little black control wire last.

Thanks,
 

TwoTrack

Buy Once, Cry Once
I just saw that you guys have a x-mas special going on right now (free shipping). Might be time for me to invest...
 

shogun

Adventurer
I used 1AWG cables for all connections on the NL kit. There are some "quirks" to this system (generally good) and the best way to approach it is you are adding a second battery in parallel to the main. Therefore you want it to have pretty much the same load rating and charging. Also, all important connections should be direct (as the previous comments about a pos AND neg direct from the alt).

I did not yet fuse the second battery as in the instructions because it seems a little silly. If you use the aux to jump the main it will probably blow the fuse (and says so in the manual).

I would also mention that my OEM wiring has similarly been upgraded to 1AWG with both pos and neg from alt to main batt.

I highly recommend this guy for custom cables;

http://www.geocities.com/JeepI6Power/index.html

His product is top notch, he's honest, and the 1AWG cables are a pleasure to work with.

From the aux batt to fuse blocks and elsewhere, keep in mind, you really cant oversize the cable. Start thinking 10-8awg for main runs.
 

Equipt

Supporting Sponsor Presenting Sponsor of Overland
I have a couple comments that might help here.

You bring up a good point on the fusing of the secondary battery in the NL set up. It is not for everyone. It is suggested in there as a safety precaution so that an arc or over-current situation doesn't fry your Intelligent Solenoid or controller. In the instructions also have a wiring suggestion for winching that leaves the fuses out, because the full load of a second battery on there would blow them during winching. So your point is understood.

The first time I tried to jump start my own vehicle, I blew the inline fuse. It was from too much amperage through the line, as mentioned in the previous post. What I later realized is that I was supposed to manually override the open connection in the solenoid using the dual battery controller, then wait a minute or so for the current in the 2 batteries to neutralize, then start my truck. It was the waiting that I didn't originally understand. Much like a full cup and an empty cup connected at the bottom by a straw, the liquid will transfer until it is the same in both cups. It's a rough example of what happens with your batteries.

I think the cable in the kit is very good quality, and up to more than the task it's size suggests. But it isn't always the answer for everyone. Alternate cable sources make sense in a lot of situations. What is nice is that we offer the Intelligent Solenoid and the Dual Battery Controller separately, if you want to source your own cable. It can save you a bunch, if your cable runs are fairly short.

cheers,
 

shogun

Adventurer
The first time I tried to jump start my own vehicle, I blew the inline fuse. It was from too much amperage through the line, as mentioned in the previous post. What I later realized is that I was supposed to manually override the open connection in the solenoid using the dual battery controller, then wait a minute or so for the current in the 2 batteries to neutralize, then start my truck. It was the waiting that I didn't originally understand. Much like a full cup and an empty cup connected at the bottom by a straw, the liquid will transfer until it is the same in both cups. It's a rough example of what happens with your batteries.

Yes, the self-jumping situation was a concern until we spoke before I purchased the system. I understand how it is supposed to work now. But, it is an uncertain procedure, how long to wait, what type of battery problem exists? I suspect that if the main battery crumps, the slow charge procedure wont work.

I had an Optima fail this year on a second start, no worky. Damaged cell? All the charging in world wouldnt get it back, and if the slow-charge procedure were used it would simply discharge the aux batt trying to charge the main. If the main was simply discharged, with no other damage, great, but if it failed for other than a simple discharge, I dont want to waste or damage the aux trying to charge the main. As I learn more about this system (just installed last week) perhaps you could see the charge/discharge situation on the display and determine whether to allow it to charge the main or simply abort the procedure and start off the aux immediately?

Thus I would like the capability to start the vehicle via the aux. I just want the dependability when on my own far from a jump start. Thats also why I consider the aux wiring to be like jumper cables, enough load capability to jump/start the vehicle. Like you correctly stated, its an investment.
 

Equipt

Supporting Sponsor Presenting Sponsor of Overland
The way you have yours set up is the right answer for your situation. I agree with your point of being able to start off the aux battery. You would be able to monitor the current transfer from aux to main on the controller, and if that movement was not happening, you could start from your aux setup without the fusing. I would contend that if the main was faulty for some reason, it might not alter the current level in the aux battery. This would be determined on an individual failure basis as to whether it would drain or do nothing. I think you are set up correctly to manage either contingency.

cheers,
 

ntsqd

Heretic Car Camper
snippage......
From the aux batt to fuse blocks and elsewhere, keep in mind, you really cant oversize the cable. Start thinking 10-8awg for main runs.
I have to disagree. You can over-size cables, and doing so results in carrying excess weight that the vehicle will always be carrying. It just reduced the total payload capacity by a couple of pounds/kilos/stone. Not very many of those will add up surprisingly fast!

I use marine amperage vs. distance (include the grounding distance!) tables to size my wires and cables. A little overkill, where appropriate, isn't going to hurt you, but moderation in all things.......
 

TwoTrack

Buy Once, Cry Once
Sorry to bring you guys off topic, but I think that I have figured out my setup. I want to run it by you guys to make sure that it will work or if you guys have any suggestions.

I want to use the Blue Seas Solenoid to connect my batteries. I do not want to set it up to automatically disconnect while starting. I just want to hook it up to a on/off/both switch.

dualbatt.png


What do you think about this setup? Do I need the bus bar? Can I just run a wire from both negative terminals of the batteries? What about the ground wire from the relay? Should I ground it somewhere close by or should I ground it to the second battery?

Another question I have is if I start the truck with the switch in the off position, can I switch it on without damaging anything?

Is there any problem with using this switch/relay combo and not connecting it to the alternator/starting wire?
 

AxeAngel

Expedition Leader
Why not just get the ML series isolator from Blue seas, it integrates the manual switch into one controller.
 

007

Explorer
Paul,

I installed the National Luna kit you sent me last year and have two questions.

1.) If I am running an electric bunk heater off the Aux. battery and I totally flatten it, will the solenoid automatically switch to the main battery and proceed to drain that also? I understand there are alarms once the voltage drops, but is there anything keeping me from draining both batteries aside from the beeping alarm?

2.) I want to add a third battery and a small permanent solar panel to trickle charge everything when the vehicle isn't in use. I also want a portable 60W panel to aggressively recharge the batts, because I use electricity to heat my tent (formerly your 1600 t-top tent :)) and my truck is usually stationary for a few days at a time. Does the NL system pose any challenges to this plan?

Also I would like to thank NL for making such a nice kit, all that double insulated cable was used to mount my aux battery low and centered on the chassis, I used every inch of it! The instructions made it so simple to install and I liked having high quality parts in my hands versus sourcing everything as I was building.

One last comment for anyone: Isn't the idea of grounding your Aux batt. and accessories back to the battery also important to prevent corrosion? I thought I read somewhere that grounding things to the chassis would open up a possibility of electrolysis and metal decay. Please correct me if I am wrong.
 

AxeAngel

Expedition Leader
Price...plus it seems much more complex.

Mine is wired up the nice and simple way with only the isolator connecting the two batteries and the switch/led panel run in the cab.

Not understanding fully why this would be the harder option.

-Sam
 

TwoTrack

Buy Once, Cry Once
Mine is wired up the nice and simple way with only the isolator connecting the two batteries and the switch/led panel run in the cab.

Not understanding fully why this would be the harder option.

-Sam

I just looked at the wiring diagram for it very briefly. I will go back and look at it better when I get the chance. What is the main difference between the ML and the one I have choosen?

Does yours auto disconnect the batteries on startup, and can you turn the system completely off if you wish?
 
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