New PopUp Camper solar install quesitons

Eckenwiler

System:
Tracer 20amp Charge Controller with MT50 Remote
100amp solar panel
12V Sealed Deep Cycle battery

Here are my 2 questions:
1.  Multimeter reads 12.75 on the battery when it is not connected to solar charge controller.  As soon as I connect the charge controller (with solar panel connected)-- the multimeter reads 14.4.  Is this normal or is something wrong?  I would have assumed the battery would slowly charge and change over time (or is the reading I am getting actually the Voltage directly coming from the solar panel through the battery)?

2.  My MT50 remote will not get past the first screen saying "Connecting".  I bought the remote controller and Charge Controller from the same company as a package deal so it doesn't seem to be the 2 can't communicate due to software differences.   Is it possible to be a faulty remote?

TIA- Mike

Photowhit

System voltage and resting voltage are different things. At rest 12.7 would be nearly fully charged with an AGM battery at rest, so whe you connect it to a system it will be near the absorb stage of charging with the charge controller limiting how high the voltage will go.

Here are the stages of charging for flooded lead acid batteries, very similar for AGM/sealed batteries;

The voltage you are seeing is the system voltage and not the battery voltage. If you are connected to charging or a load it will effect the system voltage.

During charging, there are basically 3 stages of charging, Bulk, Absorb, and Float.

BULK;

First thing when charging starts you will be in bulk, the voltage rises from what ever the system voltage was to a set point, around 14.5 volts. At that point the Charge controller stops the voltage from rising. Higher voltage can damage sealed batteries.

ABSORB;

Once the battery hits the preset point the charge controller keeps it at that point. Your batteries are roughly 80% full. Flooded batteries will start accepting less current at 80-85% full AGM/Sealed may go a little longer before accepting less current.

On many controllers you can set this point, Some will have different presets for Flooded, and sealed batteries, or flooded, AGM, and sealed batteries. 

The charge controller has a couple ways to know when to switch to float, Most inexpensive Charge controller are just timed for 1.5-2 hours. Some will also see less current flowing through the charge controller and shut it down when minimal current is flowing through the controller. On more expensive charge controller. You can set battery capacity to give the Controller a better idea of when to stop. you can also set a longer Absorb time. Or set 'end amps' a amount of amps flowing through the charge controller to stop Absorb and switch to the final stage.

FLOAT;

Once the Controller has determined the battery is fully charged it reduces the voltage to a point where very little current is flowing to the battery. This will prevent the battery from over charging and heating up.

While in 'Float' the charge controller watch for voltage drop, which would indicate a load. If the voltage begins to drop the charge controller will allow as much current to flow from the panels/array to compensate and maintain the voltage. If the voltage can be maintained, the load will in essence be running directly off the array/solar. If the voltage drops below the preset float voltage, the controller may start a whole new cycle if it stays there for a period of time.

The system voltage drop you see at night when the sun goes down is the charge controller moving into a resting mode with no energy to contribute to the system.

The morning voltage may reflect a load present that is effecting the voltage level. With sealed batteries, you would want to disconnect the battery from the system and allow it to 'rest' for a while to get an accurate idea of it's SOC (State Of Charge) from the voltage.

mike95490

Be aware, that a 100w panel will not produce a lot of power.  you could run a string of 12V LED holiday lights all night, or some other  light loads.   The next day, you have to have not used so much power, that you cannot fully recharge the battery.

Eckenwiler

mike95490 said:

Be aware, that a 100w panel will not produce a lot of power.  you could run a string of 12V LED holiday lights all night, or some other  light loads.   The next day, you have to have not used so much power, that you cannot fully recharge the battery.

I’m mostly adding this solar system to keep my battery relatively charged when only running the heater fan at night and occasional LED lights.  I don’t run any higher load accessories unless hooking shore power to a generator. 

Eckenwiler

Still trying to figure out the MT50 remote. I bought it with the controller as a set from the same manufacturer so it should be compatible.  The light indicating it’s connected does not come on and the screen just lights up and says “connecting” but never goes beyond that. I bought another one— same thing is happening.  Not sure what to do other than replace the controller as well.  Any ideas?

Photowhit

Might be a process type thing, might connect it, then turn on the unit...

mike95490

Is the cable good ?  ( not crushed somewhere )
 connected properly at both ends ?

Eckenwiler

Photowhit said:

Might be a process type thing, might connect it, then turn on the unit...

Photowhit said:

Might be a process type thing, might connect it, then turn on the unit...

I’ll give that a try- would be surprised if that works but easy enough to give it a shot. 

Eckenwiler

mike95490 said:

Is the cable good ?  ( not crushed somewhere )
 connected properly at both ends ?

Brand new cable- no damage.  Connected properly.  Only one way to connect them but I did even try reversing ends with no difference. 

Eckenwiler

Purchased a new MPPT and MT50 from a different company through Amazon.  Everything worked perfectly once I swapped the MPPT out to the new one so it appears the MPPT was faulty and not sending a communication signal to the MT50.  I had tried to email the Chinese company EpicSolar to ask if they could provide troubleshooting tips and never received a response.