National Luna Split-Charge System Charging Issues?

[dwh]

Switched over to a 500amp Blue Sea ACR with the remote switch about a month or so ago and haven't had any issues with daily driving. Finally got out of town this past weekend in to the desert, with temps in the high 90's, pulling a trailer over a couple mountain passes and had zero issues with the system and it stayed connected the whole time. Yes the 500amp version is overkill but I after all the problems and time wasted dealing with this issue, I wasn't going to take any chances. Solar charging was great also, when the panel was putting out over 13.7 volts the system connected and charged both batteries and then disconnected when the output of the panel dropped.

Obviously, one weekend in the desert isn't a full test but I am already encouraged by the results. I went this route as I could not figure out any other way to test the NL unit after having replaced the solenoid once already. I will update this thread as time progresses.

Honestly, I think IF the problem is long term voltage loss due to electrolyte stratification, it's going to come back and need that drain/heavy recharge routine again. Even though you changed out the ACR, you still have the same alternator/voltage regulator.

But time will tell.

 

[dstock]

Honestly, I think IF the problem is long term voltage loss due to electrolyte stratification, it's going to come back and need that drain/heavy recharge routine again. Even though you changed out the ACR, you still have the same alternator/voltage regulator.

But time will tell.

While I don't disagree with you, the NL solenoid shutting down for no apparent reason wasn't helping the overall issue. The point of my post was only with regards to the ongoing NL issues.

 

[aviator]

I have been having similar issues with my NL setup on my 80. I have the DHP 34 main and Die Hard aux. some days I go out and it starts up fine, but other days it's too low to crank. If I try to start off the aux batt, it immediately draws that battery down also. Very frustrating indeed!

 

[dstock]

I have been having similar issues with my NL setup on my 80. I have the DHP 34 main and Die Hard aux. some days I go out and it starts up fine, but other days it's too low to crank. If I try to start off the aux batt, it immediately draws that battery down also. Very frustrating indeed!

Sure you are not having starter issues? How old are your batteries?

When my NL unit malfunctioned, it would not join the batteries at all.

 

[RangeBrover]

I read through this thread to chase down an issue that I've been having with my own JK.

For reference my setup is the following:
2014 JKU Rubicon
2 DieHard Platinum Group 34M Batteries
National Luna Dual Battery Monitor

My rig has consistently been suffering from a parasitic draw since installing the National Luna setup, even with all of the accessories disconnected I was having the same issue.

Low and behold, the National Luna display monitor draws 60 milliamps when on and 40 milliamps when turned off. For reference, a standard parasitic draw from a vehicle when turned off is about 10 milliamps.

I should have more details in a few days after we finish sorting out the issue, but I'm happy to answer any questions in the meantime.

 

[Martyn]

We always recommend turning off the display when the vehicle will not be in use for longer than a day. I am more inclined to turn the display off when I stop using the vehicle at the end of the day.

Electrical problems are tricky and without thorough diagnostics it's easy to identify one part as the one causing the failure when it's another. It gets tricky because sometimes you switch out on part and it seems to make the system work as planned, but then the problem returns.

I'm thinking some good basic vehicle electronic classes and recommendations on diagnostic tools and how to use them would be a good idea for Overland Expo or one of the other regional gatherings.

 

[RangeBrover]

Martyn,

Thanks for the reply, and I completely agree with you in regards to classes on vehicle electronics. I know Fred Cook, aka DiploStrat has taught a few in the past, and I've always found his information to be quite informative.

In regards to the National Luna Dual Battery Monitor, the fact that it draws 4 times the normal load (of your typical vehicle when turned off) even with the display off is quite disappointing. Had I have known this, I probably would have gone with a different system.

 

[AndrewP]

And the "smart" solenoid draws close to an amp to keep itself closed (I think Kurt reported 750mA). While that doesn't sound like a lot with the truck running, it's huge when charging with solar power where you may only have 5 amps of charging current and the relay consumes 750mA (15%)alone. Similar products from Blue Sea consume 175mA to keep the relay closed, and can handle more current, and cost less, and have a life time warranty.

 

[dstock]

Just an update for those that care, it's been over a year since I switched away from the NL to a Blue Sea 500 amp ML-ACR for my dual battery charging needs. I've been in all kinds of ambient temps, up to about 115 degrees and the system has worked flawlessly. I still suspect high under hood heat temps and an 80amp solenoid were the issue with the NL system but have no way to prove it.

Highly recommend the Blue Sea ML-ACR model 7622.

 

[dirtlimo]

Not sure this is the right thread but thought I would start here.
Also, it seems my issue is 180 of what you guys see.
I also have a NL charging system with duel batteries and the monitoring panel.
It was installed by Martyn and the gang at AT overland. I am NOT saying they have done anything wrong, but I do want to get as many facts out as I can.

My primary issue right now is I cannot start my Jeep unless I bridge the 2 batteries with the monitoring panel.

All was good for about 6 months until 2 weeks ago on a trip I heard what I believe is the solenoid trying to latch. It sounds like a 10 speed bike in free spin as you roll down a hill. It does this for about 2 mins at a shot about 5 times overall. I see the monitoring panel for both batteries jumping from 14.2 down to 13.5 erratically. After this sequence stops, my dash becomes a Christmas tree with all the ABS,ESP and check engine lights on. I stop and wait for about 5 mis and I then can start the Jeep (batteries bridged) and drive for “some time” before this all starts again.
I read the post about loads and I think all this coincides with the electrical fan starting and stopping based on engine temps. It seems after 8-10 cycles of the fan starting the solenoid clicking starts and this starts all over.

The fan does have a 50amp fuse at the battery and maybe that’s enough to overload the NL system?
After I start the Jeep (bridged) all seems ok, I have full green LEDS on the panel and all seems normal.

When I shut off the Jeep, the panel will go into error and beep after about 3-5 mins. And I cannot restart the jeep. MY OBD port shows 14.3-14.5 on the battery but it will not start without bridging them.
Bad solenoid? Not enough juice from somewhere to get the solenoid latched? Loose connection drawing current?
Thanks Guys.

 

[dirtlimo]

I cannot 100% dispute that this is not the issue. But the OBD states I'm at 14.2-14.5 as does the NL panel which makes me think its ok. Also, both of these batteries had a full charge not 2 months ago. I don't mean a trickle or tender, but a full 7 step with a 35 amp charger.

 

[dstock]

Sounds like a bad starting battery to me..

With the engine off, put a voltmeter on the starting battery after it sits overnight and see what the voltage is, I can't imagine you have 14.5 without the engine running.

 

[dstock]

Since this thread has been brought back from the dead....a little update/thoughts:

In the latest Overland Journal, they have a review of Dual Battery systems including the National Luna. I noticed one of the cons was that the 85amp solenoid may not be enough amps to handle some modern alternators. I suspected this was mine and my friend's issue back when I was running the NL system as our Jeep alternators are rated at 160amps. At the time, life was very busy and the rare weekends we could get away to do some camping I didn't want to spend with continued trouble shooting of the system. Had I had more time to spend getting to the bottom of the problem, I would have requested the 200amp solenoid in an attempt to fix this issue.

The Blue Sea ML-ACR has been functioning very well (500amp..yeah it's overkill) but it always bugged me that the NL problem was left hanging. I still have the system, so maybe at some point as a science experiment, I will swap out the solenoid for the 200amp.

 

[dirtlimo]

Overnight the battery dropped to 12.6 volts. Which I believe is borderline for a bad battery. I still do not think that this is the only issue, as that really does not explain the solenoid going bat s#$t crazy. But its 55 months old and Ill give that a try.

 

[dstock]

Overnight the battery dropped to 12.6 volts. Which I believe is borderline for a bad battery. I still do not think that this is the only issue, as that really does not explain the solenoid going bat s#$t crazy. But its 55 months old and Ill give that a try.

That's not horrible at all. I would also do the same test on the aux battery, so you have a baseline, if it has an issue it could drag the starting battery down with it when connected. After that, I would put both batteries back on the charger get them fully charged and then see what the solenoid does. For sure double check all your connections.