Volt Meter

BurbMan wrote:
I added an eBay voltmeter when I installed the inverter and transfer switch.



I only have two 6v batteries and I use the same chart above that RoyB uses to get an idea of what the charge level is in the batteries. When charging I can also tell if the PD converter is in boost mode by looking at the voltage in the system. Not very scientific but gets me in the ballpark of where the batteries are.

I added a small on/off slide switch below the meter, even though the meter is very low draw it is very bright at night and a problem for anyone sleeping on the pull out couch.

Exactly what I am going to do. And it will satisfy my needs.

ROYB.. THANK you for the JPG (Battery SOC chart). That was much needed in this thread.

I want to monitor a whole bunch of voltages here.. Most of them are AC but converting AC to DC... not a problem (I design stuff to do that and I might add when I design it it works very well)

So i'm going to order a bunch of those Radio City panels.

I could also use a good slip on current monitor system but that will take a bit more design work.. I'm not sure I can find cores of the kind I need for 50 amps.

I added an eBay voltmeter when I installed the inverter and transfer switch.



I only have two 6v batteries and I use the same chart above that RoyB uses to get an idea of what the charge level is in the batteries. When charging I can also tell if the PD converter is in boost mode by looking at the voltage in the system. Not very scientific but gets me in the ballpark of where the batteries are.

I added a small on/off slide switch below the meter, even though the meter is very low draw it is very bright at night and a problem for anyone sleeping on the pull out couch.

TEDDYU - My meters like yours just monitors the DC VOLT LEVELS.. I use this DC VOLTS VERSES BATTERY SOC chart to get me in the ball park of the battery state of charge...

Granted it is not an absolute battery state of charge indication but gets you in the ball park.. This is what I look for when using my batteries when camping off the power grid. If I see around 12.0VDC on my meters I know I am very close to being around 50% charge state and need to start re-charging right away so that I won't do internal harm to my batteries.



I designed for all of my DC loads for the 120VAC item using an Inverter and direct connected 12VDC items we wanted to have ON for one day. Then installed a battery bank to provide this. For us we get away with a 255AH capacity 12VDC battery bank. Then hopefully my batteries will not drop below 12.0VDC by 8AM each morning when I am usually allowed to run my 2KW Generator to safely re-charge my batteries back up to their 90% charge state. Then I can do all of this all over again for the next day/night battery run.

This has been my successful method for the past five years or so now surviving the off the power grid operations of my OFF-ROAD POPUP setup.

Roy Ken

I always thought this voltminder meter unit was great. easy to mount on the wall and runs from 12VDC... This has alarm mode which is great to have. I had one installed in my previous F150 truck... Don't know if they are still available or not - Was not expensive as I recall $30...



Alot of RV FOLKS like this Bogart TRIMETRIC TM-2025-RV meter panel. Great for one Battery zone to monitor... Has many different monitor things and alarms - Kinda expensive however $150...


Roy Ken

Like the OP, I wanted to monitor the voltage of my batteries. I don't have a remote monitoring panel so I bought simple two-wire, 3 digit voltmeters on e-bay. Also bought the bezels for the units - got 3 displays and 5 bezels for under $10. Installed one set in the electrical compartment to monitor the converter output (it is next to my PI EMS-LCHW50). Installed the second unit in the dash to monitor the coach batteries. The dash mounted monitor has an added benefit of monitoring the BIRD functionality (including the alternator output). I agree it does't determine battery state of charge, but just knowing the alternator is charging the coach batteries while on the road gives me peace of mind. When the engine is off, the dash unit monitors the coach batteries and the converter output. I like knowing what's happening when the coach is in motion since DCV is important for the AC units, furnace, refeer, and the inverter. JM2¢...

This is my setup for monitoring my two group BATTERy BANK...



This allows me to monitor both 12VDC levels of each group and also measure the input/output DC current being used when in operation. In my case I am looking for the battery banks to not go below the 12.0VDC level before 8AM the next morning so that I can fire up my 2KW generator and recharge my batteries.

This is my BATTERY MONITOR PANEL and location inside my OFF-ROAD POPUP.. I actually glued the small LCD meter units to the back of the three switch plate panel and all is installed in a standard three position PVC electrical box. All cabling in enclosed in 3/4-inch PVC flexible conduit going back to the battery switch locations. The LCD meters are very bright when on and I have a ON/OFF switch for each meter panel.


I used small LCD meters available from SURE ELECTRONICS ebay/china models ME-SP230 and ME-SP038 but unfortunately they are no longer available. The inexpensive 12VDC meters are available at many providers but the current meter is not. SURE ELECTRONICS no longer provides this current meter model anymore. I had less than $60 invested in the LCD meter panels

This might give you some ideas on your project...

Roy Ken

Before I got the victron I used one of these. Inova dig meter

In both of my trailers I mounted a free Harbor Freight digital VOM on the wall. I cut the probes off and wired directly into the 12v system. I use the original meter's on-off switch.

Total cost; $0

Check these out,, If they ask where you heard of them give Credit to the American Radio Relay League (ARRL) newsletter.

Digital Volt Meters at Radio City