I recently picked up a 2018 Tab 400 and the solar system isn't charging the battery past about (11.8-12.2)V. The previous owner had it on shore power and the battery was above 12.8V. I'm only getting 0.6A to 1.5A out of the 2 rooftop panels in bright (but not direct) winter sun conditions. I think these Grape Solar panels are 100W each? I'm guessing the panels are done?
Also curious why my multimeter measures 21V from the wires on the roof, but 12V at the charge controller. Same amperes. Any insight?
Any tips how to deal with panel replacements if you can't weight the roof? I can't reach them from a ladder! I have no idea how I'll re-seal the roof vent too.
Thanks for any tips! As a first-time RV owner, catching up with all the maintenance the previous owner neglected is a bit overwhelming.
Comments
How/where and under what trailer 12VDC loading conditions are you measuring the voltage?
Same question for solar panel amps - - - Current Clamp Meter ? or - - -
On Shore Power the WFCO Power Center charging function generally causes a Battery Voltage readings of 13.2 to 14.4 V with ~ 13.6 most typical. These voltages reflect which charging stage the Power Center is in. A shore power battery voltage of 12.8 may suggest the Power Center Charger/Convertor is not operating. Have you confirmed the "on shore power" trailer 12VDC value at your location?
How/where are you measuring the 21Volts.
Same question for the "12V at controller".
Observations:
If your rig has Grape Solar 100W panels.
The panel maximum Open Circuit Voltage is 21 VDC.
Open Circuit meaning No Load, solar panel wires not connected to anything.
If the Panel Voltage is measured connected to the controller I would expect a lower voltage.
Next, if the 12V at the controller is on the controller output terminals to the battery.
I would expect the voltage to be higher.
The 12V suggests you are just reading the battery voltage.
So, maybe your controller has failed; based on the input and output side voltages reported.
TV: '17 Colorado V6 Z71 4x4, Tow Package, GM Brake Controller
Adventures: 54 Nights: 341 Towing Miles 43,780
Indirect sun light or partial shade reduce panel output significantly. The curved flexible panels aren't helping either.
What is the solar controller ? I'm guessing it's the PWM type as the current doesn't change from the panels to the battery. PWM "averages" the output voltage by switching the input voltage on and off rapidly.
The goal being to reduce the electrical load to just the solar controller. This will get you the most realistic 'displayed voltage' value.
Typical trailer wiring directly connects the Solar panels & controller to the battery bypassing the Cut-Off Switch:
" The main function of a solar charge controller is to ensure the amount of power that is sent to the battery is enough to charge it, but not so much that it increases the battery voltage above a safe level.
Say you have a single 100-watt solar panel and a 12-volt battery. Remember a 12-volt battery is actually able to charge up to about 12.9 volts.
The 100-watt solar panel can put out a maximum of 21 volts, which is a little too high for the battery to accept safely. Leaving it connected to the battery too long could result in a dangerous situation . . . a charge (solar) controller in between the solar panel and the battery to limit the voltage available to the battery. "
TV: '17 Colorado V6 Z71 4x4, Tow Package, GM Brake Controller
Adventures: 54 Nights: 341 Towing Miles 43,780
No on second question. WFCO Power Center only monitors/controls the 12VDC level when Shore Power is used.
The WFCO Power Center has three functions:
++ 120VAC Distribution Panel, the circuit breakers
++ 120VAC-to-12VDC Convertor & battery charger
++ 12VDC Distribution Panel, the fuses
Here is another reference diagram:
TV: '17 Colorado V6 Z71 4x4, Tow Package, GM Brake Controller
Adventures: 54 Nights: 341 Towing Miles 43,780
Am assuming:
++ The "My Renogy charge controller" means the Charge Controller included with the Portable
Solar Panel connected to the 7-Pin.
Normally a Renogy error code b01 means 'Battery Not Connected'.
Seems like your custom wiring harness has an issue; open, wire connection error.
And/Or the trailer Battery Cut-Off switch is in the OFF position.
A sketch of how you believe you have the system wired with Renogy model/part numbers might be helpful to understand your set-up and data points.
TV: '17 Colorado V6 Z71 4x4, Tow Package, GM Brake Controller
Adventures: 54 Nights: 341 Towing Miles 43,780
TV: 2005 Toyota Sienna LE (3.3L V6)
RV: 2018 T@B 320S, >100 mods
And BTW - Nice Video Link.
It sure seems you have an Open Circuit.
If this were my rig, I'd triple check all the connections for Correct Placement and good electrical contact.
With the Solar Panel disconnected; What Voltage do you read at the 7-pin mc4 Connectors?
type-o on figure ~ 12 VDC not VDVC
If by chance the mc4 measurement is Bad and the Trailer 7-Pin is Good
then your adapter is not wired as you intended.
If both measurement locations are Bad; then cut-off switch, junction box, bad in-line fuse, broken wires are the most likely source of your Open Circuit.
TV: '17 Colorado V6 Z71 4x4, Tow Package, GM Brake Controller
Adventures: 54 Nights: 341 Towing Miles 43,780
It turns out that my RF brake controller was causing the open circuit. If I bypass the brake controller everything works great.
Cheers