Solar Panel & Controller Choices?

1bentbike

We have 2 series 24-12volt batteries wired in parallel. What solar panels and controllers are people using. Would like to add an inverter to supply all AC plugs in the trailer which would require a smart converter charger and a transfer switch. any suggestions.

jkjenn

There are a lot of decent panels on the market, today. I recently bought 4 Renogy Mini-Eclipse 50w panels and am using a Victron SmartSolar 100/15 solar controller. Early tests are promising.  I also use a Victron battery monitor. Bother the monitor and controller are bluetooth enabled and have a good app for monitoring your battery and solar .

rajamar

+1 on the Victron controllers. After a lot of research we used a SmartSolar 75/15 and an older (non-Eclipse) style 100 W Renogy suitcase folding panel. The SmartSolar Victron controllers have built-in bluetooth while the BlueSolar line is bluetooth capable, but require a separate plugin bluetooth transmitter.

BrianZ

I just got the same controller, @rajamar, and awaiting delivery of a 100W Renogy Eclipse.  Trying to figure out whether the load terminals are optional, but having trouble reading the microscopic print in the tiny manual. 😳  

Sharon_is_SAM

@BrianZ, the load terminals are typically optional on charge controllers.

rajamar

BrianZ said:

I just got the same controller, @rajamar, and awaiting delivery of a 100W Renogy Eclipse.  Trying to figure out whether the load terminals are optional, but having trouble reading the microscopic print in the tiny manual. 😳  

For easier reading you can get the manual .pdf here:
https://www.victronenergy.com/solar-charge-controllers/smartsolar-mppt-75-10-75-15-100-15-100-20#manuals

While there you should also grab the "Which solar charge controller: PWM or MPPT?" white paper - excellent technical info.

Regarding the load terminals: I couldn't figure that out either, so I set up all my SAE-connector pigtails to use the load terminals in the circuit if I wanted to.

I had some trouble getting the Android bluetooth app connected and called Alan at baymarinesupply.com . Bay Marine Supply is an authorized Victron dealer and Alan fields technical support questions. He's extremely knowledgeable and helpful. After getting the bluetooth issue squared away I asked about the load terminals and how to use them in our application. Basically he said don't bother - they're intended for remote locations where there are multiple battery banks and load switching devices. The SmartSolar controllers monitor battery voltage and have programmable low voltage disconnect and reconnect thresholds - default disconnect at 11.1V, reconnect at 13.1V.

That being said I had already wired mine so we have the option to use them, but I haven't used them yet.

They can shut off the load to protect the battery, but there are limitations to what can be on the load side - no inverters. 

I have not written up my solar project yet, but here is the way I wired it up: 


NOTE: just noticed by both the red and green asterisks I forgot to specify that 5 has to be connected to 6 for the electrons to get in from the panel.

BrianZ

Thanks you all for the great responses - very helpful!  Now I have plenty to keep me moving forward.  I'll probably skip the load connections, certainly for now anyway, until I get up & running.  I have quite a library of PDFs now!

Sharon_is_SAM

@rajamar, curious why you put your battery cut off switch on the negative lead off your battery?

jkjenn

Another tip on the Victron solar Bluetooth setup is that the default pin is 00 00 00.

rajamar

Sharon_is_SAM said:

@rajamar, curious why you put your battery cut off switch on the negative lead off your battery?

Mostly based on this thread: https://tab-rv.vanillacommunity.com/discussion/745/battery-disconnect-switch

and this video:

https://youtu.be/NPI3f3edL9U

I also did some Googling and found that the question is discussed/debated on several RV and automotive forums. The general consensus is that while it will work on either terminal, many disconnect at the positive side because that is the way RV manufacturers do it.

See:
https://www.heartlandowners.org/showthread.php/22139-Battery-Disconnect-Switch-Positive-or-Negative 
and:
http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/20705627/print/true.cfm