National Luna Split-Charge System Charging Issues?

dstefan

Well-known member
Are all of these National Luna issues solely with their isolator/controller? I ask because I'm considering the National Luna portable power pack. Does anyone know if this uses the same isolator/controller that everyone seems to be having trouble with under their hood? Is anybody here using one of those cabled into the main battery to successfully create a dual system with the PPP Located remotely in the back of the truck or jeep?

This thread has been really helpful to read on general charging and AGM issues. The discussion of auto alternators/voltage regulators inability to fully charge AGM batteries makes me ask if anyone has ever researched or knows of anyone successfully using marine voltage regulators which can supply the requisite multistage charging patterns for deep cycle batteries?

Since I just barely know enough to be dangerous about this stuff I hesitate to recommend anything, but for those like me who don't really understand all of this in depth, I found a really great book called "Managing 12 Volts" by a guy named Harold Barre. It's marine and RV system oriented, not off road. He goes from real basics to real in-depth and is really clear about different battery types and all the voltage and charging needs. He talks a fair amount about the difference between auto charging systems in those from Marine or RVUs that are focused on supplying house batteries for auxiliary (non-starting) power.
 

dwh

Tail-End Charlie
There are some using marine voltage regulators, but for overland trucks, especially newer ones, it's generally a pain to do it.

More common is the use of "battery to battery" chargers, which take whatever voltage the alternator supplies to the chassis, and bumps it up so it can do a proper multi-stage charge on the house battery.

A small B2B pretty popular around here is the CTEK 250S. For more amps, Sterling Power Products. Down under they seem to like the Redarc stuff.

Another option is an aftermarket high amp alternator with integrated multi-diode heavy duty rectifier and a PWM regulator set to an nice high voltage.


But the most common setup is the split-charge relay, or a computer controlled split-charge relay, a.k.a. ACR (automatic connection relay (to electricians) or automatic charge relay (to marketing droids)).

Split-charge relays, either dumb or computer controlled, will generally be enough to get the job done - IF the chassis voltage is high enough AND some hours of absorb charging are provided either from solar or a lot of driving. (Which is also true of a B2B setup.)
 

elcoyote

Supporting Sponsor, Overland Certified OC0004
I had a NLPP in my MJ for several years and now run one in my 2017 Ram without issues.
 

DiploStrat

Expedition Leader
...
Split-charge relays, either dumb or computer controlled, will generally be enough to get the job done - IF the chassis voltage is high enough AND some hours of absorb charging are provided either from solar or a lot of driving. (Which is also true of a B2B setup.)

At the risk of a gross exaggeration:

-- Higher voltage is the secret to faster charge, and,

-- Time is the secret to FULL charge.

They are, of course, related, but, for lead acid, the secret to long life is full charge and the greatest cause of battery death/loss of performance is the failure to fully recharge. In the real world, this almost always requires that the charge be completed by shore power or solar power.

A fast charge from the vehicle alternator gets the battery bank to the point that the solar controller can complete the job. So while it is important that the
vehicle voltage be high enough, it is essential that the shore/solar charger have the correct voltage. Which is why there is not a lot of point in insisting that you need a multi-stage regulator on your vehicle - you need it on your shore and solar chargers.
 

ndamico

Member
here's a update to my issue.


After not receiving a satisfactory response I switch out the NL setup for an IBS setup. I left all wiring intact under the hood and used the same relay I was using with the NL. I only swapped the electronics out. I wanted to let you know that now I have no more heat related charging issues. National luna told me there controller will overheat and stop working at a certain temp, and then start working again after the temp drops slightly. This finally confirms what I have been saying all along. I consider that a design flaw for something that is meant to live under the hood of a vehicle. Anyways I feel I've wasted my money on the NL setup but I'll consider it a lesson learned and at least now I have a system that works as it should.


Paul from equipt1 was very helpful. He did everything he could and is a stand up guy. i wish he would start carrying IBS so i could have purchased the new unit from him.

Long story short- if you run a land rover or anything else that gets pretty hot under the hood you can't run the NL dual battery setup. the only caveat would be if you mounted everything in the cab, but who wants to run a bunch of 4AWG wire into the cab?
 

dstock

Explorer
here's a update to my issue.


After not receiving a satisfactory response I switch out the NL setup for an IBS setup. I left all wiring intact under the hood and used the same relay I was using with the NL. I only swapped the electronics out. I wanted to let you know that now I have no more heat related charging issues. National luna told me there controller will overheat and stop working at a certain temp, and then start working again after the temp drops slightly. This finally confirms what I have been saying all along. I consider that a design flaw for something that is meant to live under the hood of a vehicle. Anyways I feel I've wasted my money on the NL setup but I'll consider it a lesson learned and at least now I have a system that works as it should.


Paul from equipt1 was very helpful. He did everything he could and is a stand up guy. i wish he would start carrying IBS so i could have purchased the new unit from him.

Long story short- if you run a land rover or anything else that gets pretty hot under the hood you can't run the NL dual battery setup. the only caveat would be if you mounted everything in the cab, but who wants to run a bunch of 4AWG wire into the cab?

Well at least finally NL admitted there is a heat issue, which is what I also suspected all along. I'm not happy about the wasted $$ either, nor the time it took me sort through it all. I still have the system sitting in a box but don't feel good about selling it to anyone.

Agreed, Paul is stand up guy and did what he could to help.

Thanks for the update.
 

BWilliams

Observer
IBS publishes operating temps for their dual battery system relay. They are -40 to 176 degrees Fahrenheit. So, be careful where you mount it under the hood. I have had an IBS DBS relay go bad under the hood of my 80 that was temperature caused.

The strange thing is that the RBM module that works with the DBS module has higher temp tolerances.
 

pluton

Adventurer
Are all of these National Luna issues solely with their isolator/controller? I ask because I'm considering the National Luna portable power pack. Does anyone know if this uses the same isolator/controller that everyone seems to be having trouble with under their hood? Is anybody here using one of those cabled into the main battery to successfully create a dual system with the PPP Located remotely in the back of the truck or jeep?

Yes, that's what I do.
Got the NL PPP in the spring of '13. For me, it's a temp install only during trips, no room in vehicle to leave it in all the time. Use it no more than 4 or 5 weeks a year. Most of my trips are 3 to 5 days. The NL PPP has worked fine so far, no problems yet. Still has the same DieHard Plat group 34 I put into it in 2013. I use it to run an Engel MT45.
What I have in case of NL PPP failure:
A heavy gauge 3' jumper with 50A Anderson connector on one end and simple ring connectors on the other end. The Anderson end mates with the NL supplied cable coming from the car batt to the NL PPP. The simple ring connectors on the other end connect with the house battery while still in the PPP case. What I'll do---if the NL PPP fails---is take the NL PPP controller out of the system and have two car batts joined in parallel. If I was really scared of draining all battery power by accident, I'd bring a third battery to swap in or one of those mini jump start things.
 

Boltripper

Member
Same problem here with the NL setup and my 1997 80 Series.

Called and spoke with NL last month and they didn't mention the temp issue, but said my alternator was probably decreasing voltage in the heat. I confirmed that was not the issue.

Glad to see my initial thought that this was heat related was spot on.... Its been doing that for a few years now, but today started not disengaging after the truck was shut off and keeping the unit (both batteries) connected until I started the truck again... Its obvious that the solenoid is shot.

Now what to replace it with??


Thanks,

John
 

tomrupp

New member
1984 FJ60 here. Mine also stopped activating the timer and putting both batteries in a parallel connection. I read this thread, particularly Paul's contributions. I disconnected all battery posts. Reconnected positives first, then the negatives, saving the main battery negative for last where the sensor wire goes from the negative post to the intelligent solenoid assembly....thus rebooting the system.... As advertised, the green light flashed once and now after driving for 5 minutes the solenoid kicks on, or I can force it with the dual battery controller. I had been doing some under hood wrenching and I always disconnect the batteries and cover the posts to guard against me inadvertently shorting something out with a tool carelessly laid aside. I did not realize until after reading this thread that you should hook up positives prior to negatives, saving the sensor for last. My problem certainly wasn't heat related as the vehicle was cold and outside temperatures are only 40 degrees. Plus the 60 series does not run hot unless you have other cooling issues. I also did not realize it is advised to power down the LEDs on the battery controller/monitor is the vehicle is to sit for more than a few days. I don't drive the 60 much so I am doing it now. My NL system has been in for at least 5 years and has worked flawlessly until just the other day.
THX, Tom
 

Boltripper

Member
Tom,

Glad to see yours was an easy fix.

I spoken with Paul as well and hes always been helpful. I decided to go with a new 200 amp solenoid and swapped my original 85 amp out. All working great again.

I know plenty of people have been running the 85 amp without issue, but just wonder what the 100 Series Alternator puts out.. While I have an 80 series, Its got the 4.7L V8 and 100 Series Alternator. I've never shut down the LED's but after reading this I think its a good idea when leaving the truck for several days. I really love the Split Charger, but the draw is an issue.

Best regards,

John
 
Id like to chime in here a bit in regards to my National Luna Portable Power Pack and my 2018 Chevrolet ZR2 diesel truck. I have been running the National Luna PPP for years in my other build. I decided to pull the PPP over to my new truck and went down the rabbit hole today researching people installing dual battery setups on their newer GM vehicles. Well I did find something interesting and did email Paul about it at @Equipt I am still waiting for a response to see what he says regarding the potential issue.

GM has something called "electric power management system (EPM)" which reduces the voltage going to the main battery based on algorithms in the battery sensor estimating battery temp and state of charge. The National Luna solenoid separates the batteries again when it senses voltage of less than 12.7V which is exactly what happens with the EPM. It is a “design feature” GM introduced to help with fuel economy.

I had a guy on the Zr2 forums mention he was having major issues getting his auxiliary battery charged up properly using his NL setup because of this EPM system present in GM vehicles.

Here is the post I am referring to regarding the National Luna charging issues:
"I have installed a second battery in the bed of my truck and am using the National Luna dual battery management system with a smart solenoid to send power to the auxiliary battery after about 5 minutes of charging just the main battery. However, the 2nd battery, and Odyssey AGM 205AH, does not fully recharge. Watching the volt meter on the display at some point when the Electric Power Management (EPM) system in the ZR2 sense the main battery is fully charged it drops the voltage from 13.7 or so down to 12.5 which is not enough to fully charge the AGM deep cycle battery. Odyssey tells me I need 14.7V. At 12.5V neither of the batteries is being charged.

Thoughts?
 

DiploStrat

Expedition Leader
With the HUGE caveats that I had a 2013, not a 2018 Chevrolet, I would offer some comments:

-- For a relay based system (aka "split charge") to work, the resistance between the primary and secondary battery has to be low enough that the alternator/regulator "sees" the second battery. If the resistance is too high, then the alternator will charge the primary battery and effectively ignore the secondary battery.

-- Most intelligent relays open when the voltage of either battery drops to around 12.7v for a period of time. 12.7v is nominal "full." When the voltage is higher, typically 13.2v or more, then the relay closes. If the alternator/regulator/vehicle computer system intentionally drops the voltage below 12.7v, then, depending on the exact settings, you may have a problem.

-- Typically, the trick is that the second battery, connected by a low resistance path, shows the charging system that there is something that is below 13v and the charging system responds by ramping up the amps.

-- Battery to Battery chargers, aka B2B/DC-DC/etc. typically incorporate a front end with a similar logic. This is to prevent them ever drawing the starter battery below a "full" charge of 12.7v. Again, if your vehicle is set up to go below "full" charge, you may have a problem.

Sterling Power has a line of B2B which are specifically designed to deal with low voltage starting battery systems. You might want to give them a call. https://www.sterling-power-usa.com


Again, I don not have one of these beasts so I cannot offer any real world experience.

Good luck!
 

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