Best way to monitor battery-Centurian 3000 30amp converter

[redbarron55]

I like the trimetric, but it is a little pricey if you don't have a solar system.
I talked with the guy about the charging controller if it could be used with a regular battery converter that might be regulated to a higher voltage to mimic a solar setup.
He said is should work just fine, but he had not tried it.
The cheap (less than $20.00) system I use does not read the daily useage, but would have to be reset since the power is a total number.
I have used it writing down a beginning and end number to get a daily useage number.
As Carol has said once you have everything setup you really don't need to check all the time.
A good digital multimeter is a necessity and since I am a professional electric guy I have several, but I can appreciate a cheap power meter for my curious mind.
We don't (yet) boondock so the system is good for our needs.
I want to install a solar system for the Scam so that we can park it and not worry about power to keep the battery up.
Since we are in the deep South the heat and humidity are high enough to rule out too much boondocking in the summer months.
I haven't yet focused on adding solar, but as an electrical guy I am definitely interested!
Carol seems to have a pretty good grasp of electrical maintenance and I agree with her that a multimeter will do much of what you need to do.
The power meter does one thing really well and that is measure the current even at high levels (100 amps) that the multimeter would have a problem with.
The current is what does the work in the circuit so its fairly important and will also let you know it you have an unknown drain on the system.
Turn on a light and see how much current it adds to the total.
For a little time and less than $20.00 you can learn a lot about your system, if you want to know.
Voltage tells you 1/2 of the answer. With the addition of current you know three things, voltage, current, and power.

[gordon2]

Originally Posted by redbarron55

..
I talked with the guy about the charging controller if it could be used with a regular battery converter that might be regulated to a higher voltage to mimic a solar setup.
He said is should work just fine, but he had not tried it...

I have given this just enough thought to be dangerous and started a new thread for discussion on the matter.

[Carol H]

Originally Posted by gordon2

If you battery is in use or has been recently (charging, discharging, etc) then the voltage reading alone will be of limited help in knowing the state of charge of the battery. In fact, if you go by voltage reading while the battery is under even a fairly moderate load, then the voltage reading is about useless.

Yes, you can let it sit for some time while fully disconnected and then get a fairly good idea of the state of charge from the voltage reading,

Thats why there is a lot to be said for simplicity, especially when it comes to most of the older Boler's & Scamp's.

Unlike newer or larger trailers where there is more often than not going to be some load from something running all the time, the old Boler's and Scamp's if unplugged do not normally have any load on the battery - that is until you run the water pump, lights and furnace. The older 3 way fridges when on propane had/have little to no measurable power requirement.

So by simple not running any lights or water pump for an hour while off the grid, which is probable going to happen frequently throughout any given day anyways, one can get a fairly accurate reading on the state of the trailers battery.

Now with my newer larger trailer there is indeed a constant draw on the battery by various items when off the grid making things more difficult in regards to determining the actual state of the battery.

Having more than once while camping off the grid with the new to me trailer that has a number of power eating items that are constantly on, yearned for the return of my simple Scamp system.

[The Minimalist]

Well guys, I think it's pretty well established that determining the state of a battery when is in use or being charged or both simultaneously is tantamount to nailing jelly to a tree.

What I wanted was a fair assessment of what was going on at a given time; both what was coming out of the battery and what was going in, as well as the immediate charge state. I'm totally solar, so things are simplified somewhat.

I built a simple switch box with a surplus volt/amp meter, which is connected to two homemade shunts, one on the charging circuit and one on the power leg. I can tell at the flip of a switch my charge rate and my discharge rate, as well as the battery charge level.

As stated before, all of these readings are in flux; as clouds pass, lights are turned on, water pump is used, etc.

Understand, I'm not keeping a chart of all this, but it has given me a good idea of how my system is working, and that's the real benefit. I'm know my system much better and know what to expect in various camp settings.

Since my CO/LPG detector is on all the time, I get the best battery status reading first thing in the morning before anything is turned on.

By the way, I use my amps out reading to set the Fantastic Fan at the lowest amp draw and best air flow using my PWM fan controller. Most of the time it functions well at about .5A.

[gordon2]

Originally Posted by The Minimalist

...
What I wanted was a fair assessment of what was going on at a given time; both what was coming out of the battery and what was going in, as well as the immediate charge state. I'm totally solar, so things are simplified somewhat.

I built a simple switch box with a surplus volt/amp meter, which is connected to two homemade shunts, one on the charging circuit and one on the power leg. I can tell at the flip of a switch my charge rate and my discharge rate, as well as the battery charge level.

Once again I need to challenge your choice of usernames..

Minimalist? Then why TWO shunts?

I will admit that there is some benefit.. you can monitor the power draw separately from the charging - something I have to do a little math to figure with my single shunt. But you are the only person I have ever seen to use two shunts to monitor your system. Perhaps the name is an inside joke because you are nothing but a minimalist...

Originally Posted by The Minimalist

...
By the way, I use my amps out reading to set the Fantastic Fan at the lowest amp draw and best air flow using my PWM fan controller. Most of the time it functions well at about .5A.

My brother! I only yesterday converted my Fantastic Fan to a PWM contoller.. a write up I plan to do when it passes the first real world camping trip. So follow me if you want to hear all about it!