Battery Monitor Panel Accuracy

[raspivey]

Just a quick question:

How accurate are the level indicators on the stock panels? For instance, when the panel indicates 50% or 75% battery, roughly what voltage should the batteries be at?

I'll find out for sure in a few weeks when I dry camp for the first time in this trailer, but I was just curious if anyone knew off the top of their head. My last trailer didn't have an indicator and I just used a multimeter to watch them. Until I get around to installing a panel inside, that's what I'll still do. I'm hoping that it's scaled to around 12.2V at empty. I wouldn't even start to check them until 50% if that were the case.

[Iwannacamp]

My old battery days... A battery(lead acid) is supposed to be fully charged at 12.6v. This also has to do with specific gravity. My assumption is if it's "normal" then it would be charged. A 12v reading should be 50%

[raspivey]

I just re-read my post. Mine generally read about 12.9-ish when fully charged. I never run them below 12.3V as 12.2 is around 50% charged most of the time. What I was really curious about was, for instance, if the lights on my panel inside show 50%...is that about 12.2V, or are they scaled differently? Like I said, I'll find out for sure (at least on my unit) in a few weeks. I figured somebody here would have experimented a little.

[BarryD0706]

Originally Posted by Iwannacamp

My old battery days... A battery(lead acid) is supposed to be fully charged at 12.6v. This also has to do with specific gravity. My assumption is if it's "normal" then it would be charged. A 12v reading should be 50%

See picture:

[Herk7769]

Originally Posted by BarryD0706

See picture:
Attachment 40421

I have this exact graphic next to my TM-2025 battery monitor!

[BarryD0706]

Originally Posted by herk7769

I have this exact graphic next to my TM-2025 battery monitor!

So let's ask the same question of you that the OP is asking for the cheapie monitors: Does your "% Full" read relative to 50%-SOC or relative to 0%-SOC?

[Herk7769]

Originally Posted by BarryD0706

So let's ask the same question of you that the OP is asking for the cheapie monitors: Does your "% Full" read relative to 50%-SOC or relative to 0%-SOC?

That one is easy! It is in the monitor manual. Look to the right on the graphic of a typical panel. the lights to not read like the tanks.

They read "C", "G", "F", and "L"

All four lights mean: CHARGING - Voltage above the fully charged voltage

three lights mean: GOOD - Voltage above 50% discharged - use ok

TWO lights means FAIR - VOLTAGE VERY LOW (less than 50%) - MUST BE RECHARGED to avoid battery damage.

ONE light means LOW Voltage above 6 volts (enough to power the light) and damage IS occurring.

NO LIGHTS - Battery removed or too dead to recharge.

[raspivey]

Originally Posted by BarryD0706

So let's ask the same question of you that the OP is asking for the cheapie monitors: Does your "% Full" read relative to 50%-SOC or relative to 0%-SOC?

I wasn't very clear about this but, yes, this is exactly what I was getting at.

Originally Posted by herk7769

That one is easy! It is in the monitor manual. Look to the right on the graphic of a typical panel. the lights to not read like the tanks.

They read "C", "G", "F", and "L"

I don't have a stand alone panel...it's integrated into the switch panel and shares lights with the tank levels. All that's marked on it are E, 1/3, 2/3, and F ( I think...I'll go check in a little while). I'm double checking all of my manuals, but I don't remember ever seeing one for the panel.

I always meant to put a Trimetric unit on my last trailer and never got around to it. It's definitely on the list for this one, just probably not until after the first of the year.

[Herk7769]

I think you will find the battery legend is as I described.
However if it is not so marked, I would assume the lights still represent the voltage values I listed.

[raspivey]

It is...I finally managed to go look at it. From the experience I have with 12V, that panel is completely useless to me. Full may not be full and good, well....isn't. Once it comes off of full it could be anywhere between 50 - 90%. Kind of defeats the purpose. I may just go ahead and order a 2025 tonight, it'll beat the constant multimeter checking (I'm kind of paranoid with my batteries).

[Herk7769]

Originally Posted by raspivey

It is...I finally managed to go look at it. From the experience I have with 12V, that panel is completely useless to me. Full may not be full and good, well....isn't. Once it comes off of full it could be anywhere between 50 - 90%. Kind of defeats the purpose. I may just go ahead and order a 2025 tonight, it'll beat the constant multimeter checking (I'm kind of paranoid with my batteries).

Don't even get me started about the holding tanks...
F - is not full (about 7/8)
2/3 - is about 1/2
1/3 - not empty (1 flush can turn this on).
E - empty

[raspivey]

Hey, I'm still happier than with the popup. Beats the heck out of no holding tanks (besides the cassette toilet) and a water tank with no way of telling whats left in it until it runs out.