Voltage monitor question

[hausmutti]

I have a vintage tt (88 fleetwood prowler 15 ft) and it has a panel with lights for checking the status of the battery and tanks.  But, no display showing the actual voltage left in the battery.  There is a 12V outlet in the trailer.  Would this show how much voltage is in the battery without having to take off the case cover and using a volt meter every time?  Currently, I'm just recharging my battery at home but I have a renogy suitcase and plan to get a honda generator if I take her on the road.  thanks 

https://www.amazon.com/dp/B01JA627K...sZ&pd_rd_r=JZGFRFZBAK6ZQ7M7Q4DR&pd_rd_w=NbIij

 

[tx2sturgis]

Yep, that will do it. It will indicate voltage at the socket, which might vary a bit from the battery voltage at the terminals.

I use a similar one in my van, just be sure that it is making good contact, and it's probably not super accurate, but it will give you a good indication of whether the battery is charging.

 

[hausmutti]

Yep, that will do it.

I use a similar one in my van, just be sure that it is making good contact, and it's probably not super accurate, but it will give you a good indication of whether the battery is charging.

What I want to do is to be able to see how much voltage is left so I don't run it down too much. Of course, that also means I have to remember what number I'm looking for

 

[highdesertranger]

x2 on what Texas said. it will read voltage at the socket which will be less then battery voltage. but with some comparison numbers of actual battery voltage it will be a good measurement of battery voltage. highdesertranger

 

[John61CT]

Just realize that voltage - no matter how accurately measured - is a very rough indicator of State of Charge, AH left in the bank.

If you have just been running heavy loads, V will be much lower, if you've had a high amp charge running V will appear much lower.

You need to let the batt sit isolated 24+ hours, really 72, no charge no loads, to get an accurate measure.

But it's good enough for most, if your use patterns are consistent.

Just don't use it to measure 100% Full for the purpose of stopping charging, need an ammmeter on the batt to get that accurately via trailing amps.

But then many don't bother with precision for that either, if your bank is cheap you don't mind replacing it more often never mind.

 

[tx2sturgis]

We can assume that with a vintage travel trailer that the built-in converter is doing the charging and the OP just wants a simple monitor of the battery voltage.

If and when the OP upgrades to an expensive battery bank and aftermarket charging components, that they will also upgrade the way they monitor the batteries.

For now, one of these is fine.

 

[highdesertranger]

yep everyone can't buy a Rolls Royce right off the bat, some people have to start with a Pinto. we need to understand that. highdesertranger

 

[jimindenver]

You can learn a lot about your usage and battery via voltage over time. It is not perfect but neither is a monitor that has no idea how many amp hours are in the battery to begin with. In either case you learn to deal with what you have.

 

[Weight]

If there is no load on the circuit, a volt meter will read the same voltage regardless of how far it is from the battery terminal. If any load is involved, there will be voltage drop.

 

[deadwood]

I agree that voltage alone won't tell you what exactly is going on with the battery but it is a good gauge to use. I have one built into my rocker panel switches and every time I open the door I see it. When I check it against the battery with my volt meter it is pretty much right on the money. Over time you will get used to how your batteries are working and the voltage monitor gives you a good idea.

You will notice that when something is running that the voltage will drop a little. Or when you are charging the voltage will go up. For me I know that my Fullriver batteries want to be bulk charged at 14.7 volt. My controller is set to get them there. So when I see the voltage gets up there I know that the battery is getting close to full because it needs that high voltage to push the last few amps in there.

Knowing the voltage gives you good information. As you get to know your battery bank it will give you a better idea of where you stand. Voltage alone is not the only answer but it is a good tool to add into your bag of tricks.

 

[DLTooley]

I use voltage after disconnecting loads, in the morning, for a few minutes. It will read a bit lower than actual, but that's the way you want to have your margin of error. There are a variety of ways of measuring amps. I don't think we've agreed on a standard, affordable, way to do it.