TC off the grid, and solar question

[towpro]

when we get the new camper, we might try doing 2-5 nights without electric this fall out at the beach.
Sure I will have a generator but I only want to use it if AC is needed.

So looking at what many on this forum have printed about there system, but this brings up a question. The solar charge co9ntrollers are a little different.
Some have Load terminals
Some have 2 battery outputs.

Does the 2 battery outputs treat each battery different? or is it just a convention way to wire 2 batteries.

The ones with Load terminals: If its a 30A controller, I assume that means don't put more than 30A solar charge load through it, but does it also mean the load side is only good for 30A? (I understand you don't wire the on-board AC/DC charger through this).

TC content:
How much current does a TC run for just day to day living (no AC inverter for microwave).
Refreg on propane, hot water on propane, couple LED lights, maybe heater starts, will the load ever go over 30A?
The only High current stuff I might run is a small inverter to run a Satellite receiver.

[towpro]

Thanks everyone. when I get around to looking at purchasing equipment, I will provide my thoughts and ask for your additional recommendations.
There was enough knowledge transfer so far that I get a better idea how these things are laid out.

[Tamnative]

trail-explorer wrote:
To fully understand your questions, and how to give an accurate answer, we really need to know what controller(s) you are talking about.

They are talking about solar controllers for the solar panels that he is/has installed.

[wintersun]

A panel usually provides 6 amps of output so a 30 amp controller can handle up to 5 panels. These controllers are made for home use and not for RV's so they are more than enough for a camper.

Batteries will be wired so as to accept 14 volts from the controller. Only one set of wires will be going from the controller to the batteries. As the lowest voltage will be the outputs from the controller it is best to place it as close to the batteries as practical.

Big difference in controllers is that some provide for a remote digital control and monitor (like the IPNremote from Blue Sky) and some require 12ga wires from the panels as they are designed for residential and commercial use where there are many more panels and 20x the output voltage from each string. The Blue Sky controllers are an exception as they will take much larger gauge wires without the need for jumpers.

For a camper that will be used for 3-4 days of boondocking you should be able to get by with 2 batteries and 220 AH at 12 volts of battery bank. That provides 110 AH of draw down before you get them to 50% DOD. If on day 4 you are driving home and the batteries are at 50% and charging that is good enough and you do not need a generator or solar panel(s).

The biggest problem I found with my camper was that the Lance battery charge level monitor was off by 20% so the batteries would show as being at 100% when they really were only at 80% charge level. If I was not adding the Blue Sky IPNremote I would have installed a Trimetric digital charge meter.

[2oldman]

towpro wrote:
don't own anything yet, I am looking at controllers,

Ok, then share what you're looking at.

[towpro]

don't own anything yet, I am looking at controllers, trying to decipher the differences I see in the hookups of the different ones.

as an engineer, I study every angle of the puzzle before proceeding.

[trail-explorer]

To fully understand your questions, and how to give an accurate answer, we really need to know what controller(s) you are talking about.

[trail-explorer]

pianotuna wrote:
No. You connect the battery terminals of the controller.

This is an incomplete phrase and doesn't make sense.


Connect the battery terminals of the controller to what?

DId you mean to say this?: You connect the battery terminals of the controller to the battery bank

[AnEv942]

towpro wrote:

...as I read the manuals it "sounds" like this "load terminal" is setup to help stop you from cycling your batteries down to far but cutting off the load at a pre set voltage on the batteries. ...

I use the 'load' terminal to power a separate 7.5 amp fused 12v circuit (during the day). It what I use for charging RC stuff. I used the load output due, as you read, it cuts off power (to load terminals) if batteries fall too low and Im not attending. Though the LVD is unadjustable 11.4v on ours- still its not flat-lining the batteries.. for me 12.2 is when I start turning stuff off.

[AnEv942]

towpro wrote:
The original question:
Do I wire camper load (and not camper changer) to load terminal? or leave them empty? I expect by using load terminals I can view current amperage usage the RV is using on a display. And If its a 20A controller, that that mean the current between battery and Load is limited to 20A?.

NO. All you are adding is solar output TO the batteries.
Generally on a camper the load terminals are not used, leave them empty.
Your loads (camper) will still be connected to battery thru converter/fuse panel. As earlier mentioned, solar is basically a battery charger. There are uses for the load-but not as far as setting it up.

Yes the load terminals are generally limited/rated at what ever the controller is rated at (some less)-however many are NOT intended to be used for high loads. Anything that has potential to exceed (inverter etc) can damage controller if connected to the load. Ignore the load terminals

As to reading-it shows voltage and amp output of panel. I can see the battery voltage, I can see, during the day if panle is at full output, up to its capacity what camper is using.
Not the controllers function-its showing what panel is putting back, say I turn on a light- panel will show 1.5 amp rise (if it can). But its not really measuring draw. Kinda relative for getting idea of amp use but its not a system meter- If I turn on something that draws more than panel output it will only show max of panel.

If it is a controller with 2 separate battery connections (2 batteries) does it treat each battery different?
example, every 25 days it does a charge to knock sulfation off the plates, but a single 100w panel might not have enough current to run de-sulfation mode on 2 batteries at the same time

Well its going to do what it can do...100w is small.
But the 2 sets of battery connections- Im unsure. My first thought is your describing output terminals to battery, second set of battery terminals are for the input or sense wire that controller uses for measuring battery? not an out put. Im sure there are controllers that are able to wire two battery banks.

[2oldman]

towpro wrote:
as I read the manuals it "sounds" like this "load terminal" is setup to help stop you from cycling your batteries down too far ..

Not sure that's correct. We don't know what controller you have. And this should be in Tech.

[towpro]

pianotuna wrote:
Hi towpro,

I tried to answer, but you did not understand.

your right. I did not know what "turn a light on" meant.

as I read the manuals it "sounds" like this "load terminal" is setup to help stop you from cycling your batteries down to far but cutting off the load at a pre set voltage on the batteries. in fact one said something about "if this light flashes, your current on load was over 2X capacity, reboot panel 4 times". (it really said reboot 4x)

I also see there is battery monitors like bogart TM-2030 that use a shunt to show current in ether direction.

I like stuff I can "LOOK AT" to show me its working. Sure solar is cool, but all it really is, is a battery charger and all the solar controller is going to show you is what the charging current is at this point of time (as well as probably voltage).

[pianotuna]

No. You connect the battery bank to the battery terminals of the controller.

deltabravo wrote:
You connect the load side of the solar controller to your batteries with new wiring that you run between the controller and the batteries.

Yes. The "feed" for the camper is left on the battery bank.

deltabravo wrote:
You don't rewire the camper and put all the loads to the solar controller, you just leave those wires as is and run new wire.

[deltabravo]

towpro wrote:
The original question:
Do I wire camper load (and not camper changer) to load terminal? or leave them empty? I expect by using load terminals I can view current amperage usage the RV is using on a display. And If its a 20A controller, that that mean the current between battery and Load is limited to 20A?

You connect the load side of the solar controller to your batteries with new wiring that you run between the controller and the batteries.

You don't rewire the camper and put all the loads to the solar controller, you just leave those wires as is and run new wire.
Load and the charger already present in your camper are hooked tot he battery - nothing changes there.

As far as what the meter on the solar controller is telling you, it will depend on what brand and model solar controller you are talking about, but generally speaking, it tells you what amount of current the solar is putting out to the batteries, because all it is doing is monitoring solar current. It doesn't monitor the amount of amperage that your camper is using. If you want to monitor what the camper is using, then you need another meter - like a Xantrex LinkLite of LinPro

towpro wrote:
If it is a controller with 2 separate battery connections (2 batteries) does it treat each battery different?
example, every 25 days it does a charge to knock sulfation off the plates, but a single 100w panel might not have enough current to run de-sulfation mode on 2 batteries at the same time.

I haven't seen a controller that had two output isolated from each other - they are parallel to each other, meaning they are "connected" internally (in the controller).

But, what make and model of controller are you referring to? Knowing that details, we can give a proper answer.

[pianotuna]

Hi towpro,

I tried to answer, but you did not understand.

The load terminals would not be used for battery charging. They could, in theory, be used to operate a light from dusk to dawn. I don't know of any RV'er who has bothered to use them.

You do NOT wire the load to anything. You use the battery terminal. In my controller there is just one battery connection.

Your second question would have to be asked about a specific controller--and probably emailing the maker would be your best bet for an answer.

My Blue Sky 3024di does have load output. It can provide up to 2 amps to charge a chassis battery, or to operate a light, or to operate a relay. I chose to do nothing with it. The next iteration is the 3024iL. The load can be up to 20 amps for that. That could, in theory, be used as a diversion load after the main battery bank is fully charged. They want $70 smackers to upgrade my di version, so it is NOT going to happen.

towpro wrote:
The original question:
Do I wire camper load (and not camper changer) to load terminal? or leave them empty? I expect by using load terminals I can view current amperage usage the RV is using on a display. And If its a 20A controller, that that mean the current between battery and Load is limited to 20A?

If it is a controller with 2 separate battery connections (2 batteries) does it treat each battery different?
example, every 25 days it does a charge to knock sulfation off the plates, but a single 100w panel might not have enough current to run de-sulfation mode on 2 batteries at the same time.