National Luna Battery Monitor
National Luna Battery Monitor
Not Compatible With the Intelligent Solenoid
This monitor is not compatible with the National Luna Intelligent Solenoid or the Portable Power Pack. If you run an Intelligent Solenoid, you need the National Luna Dual Battery Controller instead, which is a different product. This monitor works with any standard multiple-battery 12Vdc or 24Vdc setup. If you are unsure what your system uses, call us at 844-200-3979 before ordering.
A dual battery setup without a monitor is guesswork. You know roughly how long your fridge has been running and you hope the aux battery has something left. This monitor removes the guessing. It gives you an immediate, at-a-glance readout of your battery capacity on a simple 14-stage color display, and it warns you audibly and visually before you run into trouble at either end: excessive discharge or over-charge.
It is programmed specifically for the non-linear discharge characteristics of lead-acid batteries, which is what makes the reading actually useful rather than a raw voltage number you have to interpret yourself. Power draw is minimal, and a sleep mode turns the display off entirely when you do not need it. Install is simple, the unit is polarity protected against wiring mistakes, and every version ships with 3.5 meters of cable. Available as a single or dual battery monitor, in surface or recessed mount. Backed by a 3 year comprehensive warranty.
Choose Your Configuration
Two decisions at checkout. Both are straightforward once you know what you are looking at.
1. Single or Dual
Single Battery Monitor
One battery display. Choose this if you are monitoring a single 12V battery, or if you only care about the state of your auxiliary battery and are happy to leave the starter battery unmonitored.
Dual Battery Monitor
Two individual battery displays side by side. Choose this for a dual battery setup where you want to see both starter and auxiliary at once. This is the right pick for most overlanding builds running a fridge off a second battery.
2. Surface or Recessed Mount
Surface Mount
Sits on top of the surface using the supplied mounting plate. No cutting required. Best for retrofitting into an existing dash, a drawer system face, or anywhere you do not want to cut a hole. Measures 3.5" L x 2" W x 1" D.
Recessed Mount
Flush-mount design that sits inside a cut-out for a clean, factory-look finish. Best for custom panels, drawer systems, and camper builds where you are building the panel anyway. Measures 4.75" L x 2.5" W x 1" D.
Quick answer: Running a fridge off a second battery? Dual. Retrofitting into an existing dash or panel you do not want to cut? Surface. Building a custom panel or drawer face from scratch? Recessed.
What the Alarms Actually Do
Excessive Discharge Warning: Triggers when DC voltage drops below 11.4V. This is the one that saves you. Deep-cycling a lead-acid battery below that threshold repeatedly is how batteries die early, and it is also the point where you should be thinking about starting the engine rather than running the fridge another hour.
Over-Charge Warning: Triggers when DC voltage climbs above 14.65V. Over-charging cooks a battery just as effectively as over-discharging, and it usually points to a charging system fault you want to know about immediately rather than after the battery is ruined.
Audible and Visual: Both alarms are visual on the display and audible. The audible alarm can be muted when you do not want it going off in the middle of the night, and the display has a sleep mode that turns it off entirely while continuing to draw only 8mA.
Specifications
| Compatibility | Any multiple battery 12Vdc or 24Vdc configuration. Not compatible with Intelligent Solenoid or Portable Power Pack |
| Display | 14-stage color display, digital |
| Display Range | 11.4V to 14.2V |
| Power Supply | 8Vdc to 15Vdc |
| Low-Voltage Warning | DC voltage below 11.4V |
| Over-Charge Warning | DC voltage above 14.65V |
| Alarms | Audible (can be muted) and visual |
| Battery Programming | Non-linear lead-acid battery characteristics |
| Power Consumption | 8mA sleep mode, 34mA average, 40mA max |
| Cable | 3.5m (11' 6") 4-core cable |
| Protection | Polarity protected |
| Surface Mount Dimensions | 3.5" L x 2" W x 1" D (mounting plate supplied) |
| Recessed Mount Dimensions | 4.75" L x 2.5" W x 1" D (flush panel mount) |
| Weight | Approximately 4.5 oz |
| Warranty | 3 year comprehensive |
Stock Codes by Variant
| Single / Surface | BMS-10101 |
| Single / Recessed | BMS-10111 |
| Dual / Surface | BMS-10201 |
| Dual / Recessed | BMS-10211 |
Pros
- 14-stage color display gives an at-a-glance read instead of a raw voltage number to interpret
- Programmed for non-linear lead-acid discharge, so the reading reflects actual usable capacity
- Audible and visual alarms for both excessive discharge and over-charge
- Sleep mode drops draw to 8mA when you do not need the display
- Polarity protected against wiring mistakes during install
- Four configurations covering single or dual batteries in surface or recessed mount
- 3.5m of cable supplied, enough to reach most dash or panel locations from the battery
- 3 year comprehensive warranty
Cons
- Not compatible with the National Luna Intelligent Solenoid or Portable Power Pack. Those systems require the Dual Battery Controller instead
- Programmed for lead-acid battery characteristics. If you run lithium, the capacity curve will not match your battery's actual behavior
- Recessed mount requires cutting a panel opening, so it is a harder retrofit than the surface version
Frequently Asked Questions
Will this work with my Intelligent Solenoid?
No. The battery monitor is not compatible with the National Luna Intelligent Solenoid or the Portable Power Pack. If you run an Intelligent Solenoid and want dash-mounted status readout, you need the National Luna Dual Battery Controller, which is a separate product that also adds a manual override function. This monitor is for standard multiple-battery 12Vdc or 24Vdc systems without a solenoid. Call us at 844-200-3979 if you are not sure which one your build needs.
Single or dual: which do I need?
Dual gives you two individual battery displays so you can see your starter and auxiliary batteries at the same time. That is what most overlanding builds want, because knowing the aux battery is at 40% is only half the picture if you also need the truck to start. Single monitors one battery. Choose it if you only run one battery, or if you genuinely only care about the aux side.
Surface or recessed mount?
Surface mount uses a supplied mounting plate and sits on top of whatever you attach it to, requiring no cutting. It measures 3.5" x 2" x 1" and is the easier retrofit into an existing dash or panel. Recessed mount is a flush design that sits inside a cut-out for a cleaner factory-look finish. It measures 4.75" x 2.5" x 1" and is the better choice when you are building a custom panel or drawer face anyway.
Does it drain my battery?
Barely. The monitor draws 34mA on average and 40mA at maximum while the display is on. Switch it into sleep mode and that drops to 8mA, which is negligible even over weeks of the vehicle sitting. For context, that is a fraction of what most vehicle parasitic draws already pull.
Does it work with lithium batteries?
The monitor is specifically programmed for the non-linear discharge characteristics of lead-acid batteries, including AGM and gel. Lithium batteries hold a much flatter voltage curve through their discharge, so a monitor calibrated for lead-acid will not translate voltage into an accurate state of charge on lithium. It will still show you voltage, but the capacity reading will not reflect what your lithium battery actually has left. If your build runs lithium, call us at 844-200-3979 and we will point you at a better fit.
Complete Your Power System
Questions About Your Dual Battery Setup?
We will confirm compatibility with your system and help you pick the right monitor and mount.
844-200-3979
