Battery monitor - with lead acid batteries

[buffalojeep]

On the battery monitor that indicates F, 2/3, 1/3, E, when using lead acid batteries does E mean complete discharge or does it mean around 12V which should be around the max discharge not to damage the batteries.

I the long run I will get a better monitor that gives me actual voltage, but just wondering on the factory ones.

Thanks

[twinboat]

E is for empty, 10.5 volts. Run them down to 1/4 , you'll be fine.

The 50% thing is just for longest service life/cost number, your not doing any damage.

Run them down to 10% and you will loose an extra day of life each time.

You want then to really last, only run them down to 90%.

Here is a chart.

[MSHappyCampers]

Hi ! Welcome to IRV2! We're sure glad you joined the gang!

Looks like twinboat answered your question. Noticed you are kinda new on the forum and wanted to say hello.

Good luck, happy trails, and God bless!

[Mark_K5LXP]

I'm not sure that question can be answered without a direct measurement. What corresponds to Full through Empty on mine or anyone else's might be different than yours.

A free harbor freight voltmeter connected to your battery bank could be a very enlightening exercise. Once you get a feel for what *your* status panel is displaying, you won't have to wonder.

Mark B.
Albuquerque, NM

[Fritz.]

Originally Posted by buffalojeep

On the battery monitor that indicates F, 2/3, 1/3, E, when using lead acid batteries does E mean complete discharge or does it mean around 12V which should be around the max discharge not to damage the batteries.

I the long run I will get a better monitor that gives me actual voltage, but just wondering on the factory ones.

Thanks

Do you have a 12v volt outlet inside the rig, like for a cigarette lighter plug you'd plug a 12v tv into? You can put a voltage display into those to monitor voltage.

Voltage isn't the best way to monitor battery level though.

[theoldwizard]

Get a Victron BMV-700 !

[powercat_ras]

I supplemented with a Victron BMV-700 Battery Monitor, $ 104, and can see exactly how much charge and how much current is flowing in and out at all times.

The thresholds vary slightly from panel to panel but they indicate based on the voltage seen at the monitor panel...

The % values are only accurate with little or no load on the batteries without charging taking place. If there is a large load on the batteries like from the inverter the voltages shown below will not be an accurate indication of the stored charge remaining. If batteries are being charged, you will see the top LED no matter how little stored charge remains in the batteries.


Top LED at >= 12.5 to 12.6 V
2/3 at >=12.2 V to 12.3 V
1/3 at >= 11.7 to 11.8 V

Battery almost totally discharged is <= 10.5 Volts

However, I suspect that the bottom red LED may light even at voltages less than 10.5

The main value of the bottom LED is to clue you in that you have operated the battery disconnect switch when you are not on generator or shore power.