National Luna Split-Charge System Charging Issues?
- Thread starter dstock
- Start date
dirtlimo
Observer
So today I isolated each battery and put them back on the 20 amp charger. Both batteries took a while to pass the "absorption" stage, like 2 hrs. That had me thinking that the alternator is not doing its job. But when I tried to start the Jeep the same issue occurs. It will not unless I bridge both batteries. The charger "states" that they are both passing the "test" segment which really kind of confuses me. They are getting and holding a charge yet one battery cannot start the Jeep. I did not try swapping batteries as I ran out of time. I have a battery to pick up on Monday and will swap it out soon. Black wire from the NL looks fine, i see no obvious issues.Thanks for the help guys
Hi,
ive been having this issue for over 2 years. finally took the time to figure it out last weekend. here is a copy of my email to Paul and NL. its the electronics in the solenoid controller that can't handle the under hood heat. hopefully they have upgraded electronics as I'd rather not have to buy another system.
Im hoping by putting both of you together in this email you can help. I have been dealing with this problem for over a year now. I contacted my US distributor and he sent me a new control board last year. I replaced it and have the same result. This is installed in a 1995 range rover classic with dual northstar AGM batteries. As with most older rovers, it makes a good amount of heat under the hood. At the suggestion of Paul I purchased a larger 200Amp solenoid as he felt that might be the problem. This made no difference. The symptoms rarely happen in winter but now that summer is here I can make it happen at will. Here is the scenario:
1) Drive truck down trails (dirt roads, etc) at slow speed when its hot out. Running the air conditioner will make it happen more frequently
2) After say 10 minutes or so the second battery will drop off charge. It will show full yellow on the display (but not green). The main battery will still show 3 green dots of charge.
3) If I pull onto a main road where I can get more vehicle speed (airflow) and drive for 10 minute or so I will hear the solenoid click and the aux battery will start charging again and show 3 green dots just like the main battery
4) If I come to a stop and idle, or start to drive slow (rock crawl, dirt trail, etc) It will stay connected for a few minutes and then drop off again. Pushing the button to manually bridge the 2 batteries does NOT bridge them together.
Last weekend it was very hot and my aux battery was starting to drain because the luna controller would not keep the batteries bridged as we were mostly on slow, dirt roads. I pulled out my multimeter and checked the voltage of the relay control wires of the luna controller when it was hot and I got ZERO volts. If I let the vehicle cool down and then check it (manual bridge button active for example) I get 12v. In desperation I ran a 12v feed directly to the control input of the solenoid. Now, no matter how hot it gets outside my batteries will stay bridged. This proves that the problem is the controller overheating and failing to deliver a 12v signal to my solenoid.
While my aux battery charges now this situation is far from ideal as I have to manually disconnect the solenoid power to break the bridge and my luna display has no control function and is just a voltage indicator now.
Do you have a solution for this? When I originally asked about the controllers overheating I was told that was impossible. Well its possible and it happens to both the boards I have. It has even happened to other people I know.
Please advise as this has been a thorn in my side for 2 years now.
Thank you!
ive been having this issue for over 2 years. finally took the time to figure it out last weekend. here is a copy of my email to Paul and NL. its the electronics in the solenoid controller that can't handle the under hood heat. hopefully they have upgraded electronics as I'd rather not have to buy another system.
Im hoping by putting both of you together in this email you can help. I have been dealing with this problem for over a year now. I contacted my US distributor and he sent me a new control board last year. I replaced it and have the same result. This is installed in a 1995 range rover classic with dual northstar AGM batteries. As with most older rovers, it makes a good amount of heat under the hood. At the suggestion of Paul I purchased a larger 200Amp solenoid as he felt that might be the problem. This made no difference. The symptoms rarely happen in winter but now that summer is here I can make it happen at will. Here is the scenario:
1) Drive truck down trails (dirt roads, etc) at slow speed when its hot out. Running the air conditioner will make it happen more frequently
2) After say 10 minutes or so the second battery will drop off charge. It will show full yellow on the display (but not green). The main battery will still show 3 green dots of charge.
3) If I pull onto a main road where I can get more vehicle speed (airflow) and drive for 10 minute or so I will hear the solenoid click and the aux battery will start charging again and show 3 green dots just like the main battery
4) If I come to a stop and idle, or start to drive slow (rock crawl, dirt trail, etc) It will stay connected for a few minutes and then drop off again. Pushing the button to manually bridge the 2 batteries does NOT bridge them together.
Last weekend it was very hot and my aux battery was starting to drain because the luna controller would not keep the batteries bridged as we were mostly on slow, dirt roads. I pulled out my multimeter and checked the voltage of the relay control wires of the luna controller when it was hot and I got ZERO volts. If I let the vehicle cool down and then check it (manual bridge button active for example) I get 12v. In desperation I ran a 12v feed directly to the control input of the solenoid. Now, no matter how hot it gets outside my batteries will stay bridged. This proves that the problem is the controller overheating and failing to deliver a 12v signal to my solenoid.
While my aux battery charges now this situation is far from ideal as I have to manually disconnect the solenoid power to break the bridge and my luna display has no control function and is just a voltage indicator now.
Do you have a solution for this? When I originally asked about the controllers overheating I was told that was impossible. Well its possible and it happens to both the boards I have. It has even happened to other people I know.
Please advise as this has been a thorn in my side for 2 years now.
Thank you!
vtsoundman
OverAnalyzer
I've read about a number posts talking about NL systems with random/ weird gremlins. Shame on NL -> An 85A bridging solenoid/contactor is simply ridiculous - modern vehicle alternators can output 80-100A at idle and 150-200A while cruising down the road. A discharged battery can & will max out an alternator's current. Closing a discharged battery into a charged battery can result in massive surge currents that will fry an 85A solenoid - especially the Group 31 low resistance AGMs, that so many like to use. It may not happen on the first use, but it may eventually cause issues.
Intermittent vs Continuous ratings are dependent upon the temp / ambient temp of the device. Underhood temps of vehicles - Jeeps in particular - are extremely high -> shame on NL for designing a controller that is not rated appropriate. I don't buy the QC parts issue since it seems to be somewhat endemic to the issues on the various forums. I'd say it is an engineering design quality issue.
So it is simple:
1. Best : Separate the batteries completely via DC/DC charger (CTEK or similar). (But keep any CTEK like device out of the engine compartment for longevity). Use a high current relay NO/NC to switch the Aux loads to the main alternator system while the vehicle is underway. This will accelerate the aux battery charging. Con: More expensive. CTEK requires another unit to charge at >20A while driving. Other options available for higher current, but also more expensive. Harder to bridge/jump the main battery. But how often is that really an issue.
2. 2nd best: Use a Blue Sea ACR -> Simple & Automatic. Easy to bridge both batteries. Cons: Subject to power flow between batteries; potential non optimal charging for both aux & house batteries. Pros: Never fails, always works.
3. 3rd best : Use a manual solenoid/switch arrangement as suggested in the huge "$50" thread.
Intermittent vs Continuous ratings are dependent upon the temp / ambient temp of the device. Underhood temps of vehicles - Jeeps in particular - are extremely high -> shame on NL for designing a controller that is not rated appropriate. I don't buy the QC parts issue since it seems to be somewhat endemic to the issues on the various forums. I'd say it is an engineering design quality issue.
So it is simple:
1. Best : Separate the batteries completely via DC/DC charger (CTEK or similar). (But keep any CTEK like device out of the engine compartment for longevity). Use a high current relay NO/NC to switch the Aux loads to the main alternator system while the vehicle is underway. This will accelerate the aux battery charging. Con: More expensive. CTEK requires another unit to charge at >20A while driving. Other options available for higher current, but also more expensive. Harder to bridge/jump the main battery. But how often is that really an issue.
2. 2nd best: Use a Blue Sea ACR -> Simple & Automatic. Easy to bridge both batteries. Cons: Subject to power flow between batteries; potential non optimal charging for both aux & house batteries. Pros: Never fails, always works.
3. 3rd best : Use a manual solenoid/switch arrangement as suggested in the huge "$50" thread.
dwh
Tail-End Charlie
DiploStrat
Expedition Leader
dwh Beat me to it.
To be a bit pedantic:
-- You are not going to see a surge. You might see heat and resistance if the contacts are too small.
-- B2B (CTEK, Sterling, Redarc) are great products IF, and only if, your vehicle's charging voltage is too low. There are also alternatives to simply raise the charging voltage.
-- The main advantage of an intelligent/voltage sensing relay over a key controlled relay is that it senses on both sides and thus shares solar or shore power with the starter battery. Also avoids possibility of damage to the ECU, a specific issue with Chevrolets.
The "secrets" of charging a lead acid, rpt, lead acid, battery are:
-- The proper, higher voltage, and,
-- A full and complete charge. That means a LONG absorb stage.
Things that help:
-- A charge source running at the correct, temperature compensated, voltage,
-- Short, properly sized wire runs, to lower resistance, and,
-- Long drives or solar/shore power to complete the charge.
At the end of the day, the real issue is that the voltage of a lead acid battery rises relatively rapidly and thus even with the biggest alternator and the fattest wire, the charge rate is going to drop long before the charge is complete.
To be a bit pedantic:
-- You are not going to see a surge. You might see heat and resistance if the contacts are too small.
-- B2B (CTEK, Sterling, Redarc) are great products IF, and only if, your vehicle's charging voltage is too low. There are also alternatives to simply raise the charging voltage.
-- The main advantage of an intelligent/voltage sensing relay over a key controlled relay is that it senses on both sides and thus shares solar or shore power with the starter battery. Also avoids possibility of damage to the ECU, a specific issue with Chevrolets.
The "secrets" of charging a lead acid, rpt, lead acid, battery are:
-- The proper, higher voltage, and,
-- A full and complete charge. That means a LONG absorb stage.
Things that help:
-- A charge source running at the correct, temperature compensated, voltage,
-- Short, properly sized wire runs, to lower resistance, and,
-- Long drives or solar/shore power to complete the charge.
At the end of the day, the real issue is that the voltage of a lead acid battery rises relatively rapidly and thus even with the biggest alternator and the fattest wire, the charge rate is going to drop long before the charge is complete.
vtsoundman
OverAnalyzer
dwh link deals with a 'surge current' myths. I agree with all of your points except the one about surge currents. I agree that surge current during a close is not a serious issue in and of itself, but arcing leads to component failure especially if the control system is not behaving as expected.
QUOTE=dwh;2323226]http://www.smartgauge.co.uk/nosurge2.html[/QUOTE]
Interesting theory and mostly sound - in practice there is a slightly different story. There is some credence to the conclusions when considered in a vacuum or simply connection two batteries together.
I designed battery based UPS systems for a number of years that were used in both high volume consumer applications as well as hi-rel life saving equipment. One thing in common was a used a multi-stage connector that permitted some connections to be time based - that is to say, some connections made prior to others. The first connections were always ground/chassis ground & battery negative, secondary was a terminal with a resistor in series with the positive terminal of the battery pack, tertiary was the high current positive terminals. The series resistor did two things: prevent battery surge current and prevent damage to the connectors from due to make/break arcing. The damage to the connector was the primary issue. The surge current was secondary. High current contactors in some of the aux/additional runtime battery modules also had a similar circuit using relays if a timed connector was not feasible or permitted. A small relay with a series resistance would serve to equalize the batteries eliminating damage to contacts from arcing & surge currents that were exacerbated when a lead acid battery has surface charge. These surge currents can vary with chemistry and charge. If a solenoid or contact does not have a wiping action, which most inexpensive automotive solenoids do not, damage due to arcing whether from surge currents during connection or arcing during a break from inductive loads can be an issue. There is also quite a bit of capacitance used in modern vehicle systems that excerbates in-rush/surge currents even more. One way to overcome this is to oversize the contactor/solenoid increasing surface area. An 85A continuous contactor with a intermittent duty less than 2x cont rating is not the way to do it.
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DiploStrat
Expedition Leader
Since I don't/didn't do this for a living, I'm not going to argue. I would suspect that the systems you worked on were considerably more complex, especially if they were not true UPS, but rather fast acting transfer switches.
Beyond that, if you drill down into the SmartGuage site, you will note that they make most of your points in advertising why their 200A relay is better than most "high power" relays that you find being sold.
The CTEK D250S/Smartpass combo works, even (or especially) on a 13.9v Toyota, Mercedes, or what ever, because:
-- At the start of the charge cycle the battery voltage is well below 13.9v so the practical difference between 13.9v and the common 14.4v is less important.
-- As the battery charges and the voltage rises, the amp flow/charge rate drops, and once it drops below 20A, the D250S earns its keep during the absorb stage by assuring a 14.4v charge.
Sadly, the 14.4v is not adjustable and thus the CTEK combo is less than optimal for use with certain flooded lead acid batteries, such as Trojans, which want an absorb voltage of around 14.7v
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dwh
Tail-End Charlie
Or certain AGMs, such as Odysseys, which also want an absorb voltage of around 14.7v.
vtsoundman
OverAnalyzer
@dwh & @ DiploStrat - great conversation.
I've toyed with the idea of cracking opening the CTEK unit and seeing if I can modify the voltage sense a bit to raise it. If it is well designed, there is not a separate voltage sense return outside of the control loop and modifying the resistor divider will also increase the lower voltage/all the other points as well. I've sent an email to their PM hoping for a response - we will see if I get a response about being able to modify the voltage.
I've noticed my Jeep's voltage regulation doesn't seem to track with battery charging current all that well (expected value) which reinforces others' observations that Chrysler algorithm isn't the greatest. On a positive note, I regularly see 14.4 for long period of time, but also see the voltage drop while the current into the battery is quite high...I am hoping my Sam's Club East Penn AGM Group 31 DC/Starting Combo battery won't be killed too fast - the added capacity for the price (they screwed up the pricing on it!) was worth it...I'm happy if I get 3 years out of it given how much it runs one of my loads. I got 7 yrs out of my Group 34 Diehard AGM Platinum, on buddy's battery lab tester , it was down to 60% capacity when I yanked it (increased series resistance too!).
DiploStrat
Expedition Leader
Do it the easy way
Two thoughts:
-- Don't bother. Contact Sterling Power USA and take a look at their line: http://www.sterling-power-usa.com Almost all of their B2B are very adjustable. (N.B. Often available at Defender at better prices: http://www.defender.com) (Sorry Charlie!)
-- GM has various sub routines which go so far as to actually shut off the alternator at times. As a practical matter, however, this never happens when you have a low resistance path to a (relatively) large camper battery(s) because it takes hours to get them to full charge. You may also have some version of the EURO 6+ set up with alternator braking, etc. Rumor has it that some Ford F150 trucks have this.
Final thought: Some folks obsess with trying to assure that their vehicle alternator will drop to a true float. As a practical matter, this is almost irrelevant; you simply won't drive that long. A true float is, however, very important for solar and shore chargers.
Good luck!
Two thoughts:
-- Don't bother. Contact Sterling Power USA and take a look at their line: http://www.sterling-power-usa.com Almost all of their B2B are very adjustable. (N.B. Often available at Defender at better prices: http://www.defender.com) (Sorry Charlie!)
-- GM has various sub routines which go so far as to actually shut off the alternator at times. As a practical matter, however, this never happens when you have a low resistance path to a (relatively) large camper battery(s) because it takes hours to get them to full charge. You may also have some version of the EURO 6+ set up with alternator braking, etc. Rumor has it that some Ford F150 trucks have this.
Final thought: Some folks obsess with trying to assure that their vehicle alternator will drop to a true float. As a practical matter, this is almost irrelevant; you simply won't drive that long. A true float is, however, very important for solar and shore chargers.
Good luck!
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DiploStrat
Expedition Leader
You are Correct ...
but, as you noted, single sense units are rare. And, in any case the single sense only works when the relay is open, once it is closed it is effectively double sense.
but, as you noted, single sense units are rare. And, in any case the single sense only works when the relay is open, once it is closed it is effectively double sense.
vtsoundman
OverAnalyzer
Youre good.
PTC resistors
. Loop control could easily detect the voltage drop upon current draw and flag the failure. sent via the cone of silence
enzo
Explorer
I've had issues with the NL system in my LC for years. If I let my car warm up and the solenoid clicks on after 5 minutes , it clicks off once I put it in reverse. My main battery is an Autozone brand that the PO installed and my aux is a diehard platinum marine battery. The only thing hooked up to the aux battery is an ARB fridge.