National Luna Split-Charge System Charging Issues?

Equipt

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Hi Harley.

If GM has a scenario in place to drop the voltage to 12.5V, then yes it will drop out the contact on the solenoid on the PPP until the charge voltage again goes above 13.1V.

The one situation that I can envision you charge being relatively fine is that when the batteries are connected after the initial 5 minute timer, the batteries are connected in parallel and are, in essence, one bigger battery. If the total voltage of the connected batteries are below the GM prescribed charge level, they would charge together until they both reach that charge level. At which point the would isolate.

There is not a permanent way to alter this connection/isolation voltage on the Intelligent Solenoid or Portable Power Pack. Alternate 110V or solar charging would be a good supplement plan. The GM alternator is not going to get you to the prescribed 14.65V anyway.

Cheers.
 
Hi Harley.

If GM has a scenario in place to drop the voltage to 12.5V, then yes it will drop out the contact on the solenoid on the PPP until the charge voltage again goes above 13.1V.

The one situation that I can envision you charge being relatively fine is that when the batteries are connected after the initial 5 minute timer, the batteries are connected in parallel and are, in essence, one bigger battery. If the total voltage of the connected batteries are below the GM prescribed charge level, they would charge together until they both reach that charge level. At which point the would isolate.

There is not a permanent way to alter this connection/isolation voltage on the Intelligent Solenoid or Portable Power Pack. Alternate 110V or solar charging would be a good supplement plan. The GM alternator is not going to get you to the prescribed 14.65V anyway.

Cheers.
Thanks Paul. Your service is always top notch even if it isn't the best news. I really appreciate your response!
 
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!
Very good points there..I appreciate your feedback. Im just going to roll with it and go ahead with the PPP install on the new truck and see how it goes. The good thing is most of the time I do run solar at camp so charging up the PPP shouldn't be an issue based on the weather. I just hope that once the 5 minute time period is passed for the PPP is able to charge via the GM power management system since the batteries are joined in parallel.
 

DiploStrat

Expedition Leader
The key thing is to be sure that the wiring from the starter battery to the camper battery is large enough. (Low resistance) As long as the camper battery can draw down the starter battery, the vehicle's charging system will respond.

Now, wether it will respond with a sufficiently high charging voltage is another matter. My 2013 Silverado 3500 was superb, running up to 15.5v in cold weather. Can't speak to your 2018.

Edited to add: If the National Luna has a full, five minute delay, this might cause problems as five wall clock minutes might well be enough to recharge the starter battery and then allow the voltage drop, if indeed there is one, to kick in. As noted, most intelligent relays open when the voltage hits 12.7v or so, as this is "full charge" for a lead acid battery.

Sterling Power has a line of B2B that claim to address these issues directly.
 
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BTW I just did a 4 hour drive and monitored the output of my starter battery as well as monitoring the National Luna auxiliary battery setup as well. As I was driving after five minutes the batteries joined together and I was getting 13.7-13.9 volts the entire trip. Not once did my battery drop to any number in the 12s. I spoke with National Luna regarding this.

If your main voltage remains stable between 13.7V and 14V then you should have no problem. We typically see 13.9V from most vehicles and this works out fine.
Voltages above 14V are not that common since this can potentially over-charge batteries that are in a hot environment. You might see a higher voltage when your vehicle is cold but this tends not to last long. The Portable Power Pack triggers at 13.2V and only disconnects at 12.7V so it should have no problem within the range you mentioned.



So I am NOT seeing the same issue the guy on the other forum is seeing using the National Luna portable power pack on my newer GM vehicle. Mine is a Zr2 with a diesel not sure if that has anything to do with it? I believe other guy with the charging issues has a GMC Canyon.
 

DiploStrat

Expedition Leader
BTW ...I spoke with National Luna regarding this.

If your main voltage remains stable between 13.7V and 14V then you should have no problem. We typically see 13.9V from most vehicles and this works out fine.
Voltages above 14V are not that common since this can potentially over-charge batteries that are in a hot environment. You might see a higher voltage when your vehicle is cold but this tends not to last long. The Portable Power Pack triggers at 13.2V and only disconnects at 12.7V so it should have no problem within the range you mentioned.

...
Some of us would quibble with National Luna about the 13.9v. Ideally, you would like to see lead acid batter reach somewhere in the neighborhood of 14.4v before dropping and holding to a float of around 13.Xv. (13.9v is the default for many alternators [including GM] unless overridden by the external regulator or the vehicle's computer.)

Ironically, many South Africans will swear that the CTEK D250S is far superior to the National Luna Split charge relay. They are "correct" but not for the reasons that they suspect. The CTEK D250S is a nice unit that runs at 14.4v, but it only puts out 20A. However, on a Toyota or other vehicle which only charges at 13.9v, this is far superior.


But this is not a fault with the National Luna or any other relay based system, but rather a question of you vehicle's charging system. On my 2013 Chevrolet, which runs at 14v, a split charge relay, with 0000 AWG cabling can charge at over 100A. The practical limitation is that battery voltage; once that begins to rise, then the charge rate will drop, no matter how big your alternator. So the real question is whether your vehicle will produce a sustained voltage of over 14v. If it won't, then a battery to battery charger (aka B2B) may be the easiest answer. I rather like REDARC products but Sterling Power offers more and bigger options with more adjustability.

Ideally, when under charge, you would like to see a voltage of around 14.4v at the starter battery terminals.

And finally, it bears repeating that you are unlikely to ever drive long enough to fully recharge a large camper battery bank, topping up with solar or shore power may be essential.

 

kb1ejh

Member
I had the NL PPP in my 2009 Silverado and had no problems. In the Spring I ditched the truck and got a 2018 K3500. Installed the NL split charge with a spare group 48 under the hood. The GM has the fuel efficient power management BS that drops the alternator when the batter is charged like the others have said. I have the 200amp alternator with the plow package. Still drops out and won't charge the battery through the NL due to the low output once the starter battery is topped off. The work-around I found was just turn the head lights on and then it runs fine. When I tow and use the tow/haul it also brings up the volts. It's just something to learn to live with on the newer vehicles. Was simpler back in the day without all of the "management"...
The NL split charge does get flaky once in a while, disconnects and won't manually reconnect at all when it's hot once in a while. Shutting the truck off than restarting it after a bit resets it. Strange, but not worth worrying about. It still works overall.
 
I did a test..so the other day I was driving with fully charged aux battery so I never saw it go over 13.9v. So with that said I kept the fridge going in my truck overnight along with some LED lights to deplete the battery. The next morning I drove just over an hour and on my drive I noticed my voltage stayed at around 14.4 V jumping up to 15v at times. I assume the NL was seeing the aux battery depleted once the system joined the batteries together as I was driving. This confirms I do not have the GM power management issue as I had stated before. The guy who had this issue had a GMC canyon I have a 2018 Colorado Zr2 diesel not sure if that makes a difference but I know the diesels come with larger AGM starter batteries.

And BTW I do use a high quality Odyssey battery charger to charge up my Group 31 Odyssey AGM battery as well as solar. I was never super concerned with other charging methods or "killing" the battery but my main focus was getting my truck to properly charge my aux battery without the need for other power sources. Sometimes there is no sun so solar is useless and I camp off grid so being close to any kind of other power sources is very unlikely. So it was crucial I figure out charging the NL using my vehicle's alternator.
 
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I had the NL PPP in my 2009 Silverado and had no problems. In the Spring I ditched the truck and got a 2018 K3500. Installed the NL split charge with a spare group 48 under the hood. The GM has the fuel efficient power management BS that drops the alternator when the batter is charged like the others have said. I have the 200amp alternator with the plow package. Still drops out and won't charge the battery through the NL due to the low output once the starter battery is topped off. The work-around I found was just turn the head lights on and then it runs fine. When I tow and use the tow/haul it also brings up the volts. It's just something to learn to live with on the newer vehicles. Was simpler back in the day without all of the "management"...
The NL split charge does get flaky once in a while, disconnects and won't manually reconnect at all when it's hot once in a while. Shutting the truck off than restarting it after a bit resets it. Strange, but not worth worrying about. It still works overall.
Have you tried using the NL controller to force join the batteries together it times out after five minutes but your aux battery should now be "seen" by the power management system and it should continue to charge both batteries properly as you drive.
 

kb1ejh

Member
Have you tried using the NL controller to force join the batteries together it times out after five minutes but your aux battery should now be "seen" by the power management system and it should continue to charge both batteries properly as you drive.
When it does the "heat disconnect" it will not join the batteries, the solenoid is most likely overheated. It works later fine. As for the 5 min disconnect, I am familiar with that from running the PPP. The aux battery has had more capacity than the main so the BMS does not see it as the Aux is supplying the main and the alternator just doesn't put out power. I suppose if I drained the battery more than the main it may. Perhaps it's my OCD trying to keep everything 100% charged that prevents me from deep testing it.
 

kb1ejh

Member
I still like the NL battery systems. The split charge and the PPP along with the remote monitor/controller. Dead starter battery? Just hit the connect button. I don't think anything is 100% reliable any more, BlueSea or NL or any other, but overall I have been happy with the NL products for what I need it for and what it does. If I needed to do it again I'd still call Paul at Equip and order another NL product.
 

dstock

Explorer
I still like the NL battery systems. The split charge and the PPP along with the remote monitor/controller. Dead starter battery? Just hit the connect button. I don't think anything is 100% reliable any more, BlueSea or NL or any other, but overall I have been happy with the NL products for what I need it for and what it does. If I needed to do it again I'd still call Paul at Equip and order another NL product.
The Blue Sea works the same way, dead starter battery, hit the connect button, and mine has been 100% reliable unlike the NL system. The failure due to heat is unacceptable for those of us who live in the south west. I don't understand why anyone would want to pay so much for marginal performance but that's just me.

Paul at Equip is a great guy and did his best to help me with my situation, it's not his fault the product has flaws.
 
The Blue Sea works the same way, dead starter battery, hit the connect button, and mine has been 100% reliable unlike the NL system. The failure due to heat is unacceptable for those of us who live in the south west. I don't understand why anyone would want to pay so much for marginal performance but that's just me.

Paul at Equip is a great guy and did his best to help me with my situation, it's not his fault the product has flaws.
I did not know Blue sea made such an item. I absolutely love their fuse blocks and usb/12v power outlets. I will def keep this in consideration if I ever have future problems with my NL setup.
 

CabinCruiser

New member
I just want to throw a shout out to Paul at @Equipt as I've had few problems with my National Luna Split Charger System. I somehow lost the display of the main battery on the display/controller. After speaking with Paul initially, we thought it might be the display unit itself. I sent it back to Paul and he had tried it in a couple of his vehicles. The unit worked fine for him so he sent it back to me. After reinstalling and checking a few of the circuits and my wiring with my Fluke multi-meter, I determined that I had no voltage coming out from the top two wires in the connector on the Intelligent Solenoid. This lead me to believe that there was a problem with the circuitry in the control board. I spoke with Paul about this and he suggested that we replace it, so he sent out a new one.

I received the new one last week and brought the FJ into the shop this morning. I took the label/sticker from the circuit board to replace it. Low and behold I see some corrosion in the bottom of the box, flipped over the circuit board, and sure enough. It was at this point that I determined that water intrusion had shocked the system and burned out the board. Paul and I spoke about how the unit is designed to be mounted in an upright position, such as the literature from National Luna recommended. I will have to do this at a later time, as I just don't have time to relocate my compressor at this time. I decided on keeping the location for right now and sealing up the unit from water damage until I get that accomplished. I used a clear silicone sealer from VersaChem to seal all of the seams, wiring ports, housing screws, and around the perimeter of the new label/sticker.

I'll update later, but don't expect any issues. My advice to anyone using this system is to mount it upright so at least if it does encounter water intrusion, it will be able to drain out where the wiring comes in. Thanks a bunch, Paul! You're customer service is top notch! (y)(y)

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