Portable solar panel causing drop in output from main system?

[American-Thunder]

Hey guys/gals,

I have an odd thing that is happening on a new to me travel trailer I purchased. I installed 4 180w panels into a Victron 100/30 MPPT controller feeding 400AH of Lifepo4 batteries and I am seeing in the neighborhood of 20-25A on a sunny day here in AZ in the winter.

I had a portable 200W renogy setup with a Renogy Voyager 20A PWM charge controller that I use on a cargo trailer conversion I thought I would take along on on our maiden voyage if I needed extra juice while boondocking in the new trailer. The trailer came "pre-wired" with a zamp solar plug that goes directly to the batteries so I figured I would use this to connect to the trailer.

Here is the problem....According to my Victron Smart Shunt as soon as I attach said portable panel the Amps flowing into the battery drops from 25-30 to less than half that output. I double checked that polarity is right (zamp seems to be reversed) but for some reason the pwm charger seems to be messing with the Victron? I can watch it via bluetooth and the amps ramp up then drop in half ramp up and drop in half over and over with a clear blue sky. I even replaced the charge controller on the portable just to make sure it wasn't defective. If I unplug the portable it goes back to normal. What am I missing here? PWM fighting with the MPPT? Instead of more juice I'm getting less and I've not seen this before.

Thanks in advance for any suggestions!

 

[chrisski]

I recommend hooking to the battery itself.

I have 3 MPPTs and am fine. Others use MPPT and PWM.

I’m not a big believer trailer builds are quality.

You could also change the PWM settings to a lower voltage. I don’t think this will work, but it’s worth a try. If there is no way to input a voltage, Usually FLA setting is the highest and lithium or gels is the lowest. If they are fighting each other, than lowering the voltage on the PWM may help.

Edit: also check the polarity. Could be reversed at the panel or factory wiring.

 

[American-Thunder]

Thanks for the response. Yeah I am not a big believer either which is why I wired straight from the Panels-MPPT-Batteries and bypassed all the factory stuff when I installed my roof system. The unit came with one of them fancy Zamp 30A PWM controllers inside and the SAE plugs on the roof but I couldn't resist using the existing plug on the side. ?

I tried changing the PWM and that didn't seem to make any difference. The portable doesn't really seem to be needed but I sure would like to have the "insurance" if needed. Thought about removing the existing PWN controller, putting the portable in series, and sending it into another MPPT controller in the cargo area since that's where the plug is but maybe that's the lazy mans way out and it still may not work due to factory wiring.

Edit: Yea I checked the factory wiring before I installed and it is reversed from a standard SAE plug so I just reversed my output from the charge controller.

 

[12VoltInstalls]

recommend hooking to the battery itself

I was going to ask if OP had tried….

According to my Victron Smart Shunt as soon as I attach said portable panel the Amps flowing into the battery drops from 25-30 to less than half that output

….running both solar SCC outputs directly to the battery. The zamp fitting is suspect to me too

pre-wired" with a zamp solar plug that goes directly to the batteries so I figured I would use this to connect to the trailer

 

[American-Thunder]

Thanks guys. I think I will try the direct to the batteries through the door approach and see that it does. Since all of my batteries/charge controller/inverter are on the camp side under the stove and in a cabinet I wasn't thrilled about installing another plug and having a wire running over to the panels to trip over after a few barley pops. That said if it works I can figure something out to make it a clean install. Thanks again!

 

[chrisski]

Thanks guys. I think I will try the direct to the batteries through the door approach and see that it does. Since all of my batteries/charge controller/inverter are on the camp side under the stove and in a cabinet I wasn't thrilled about installing another plug and having a wire running over to the panels to trip over after a few barley pops. That said if it works I can figure something out to make it a clean install. Thanks again!

Clean installs are hard.

I am helping with an install. The battery is under the trailer on a frame. Very hard to install solar, cleanly. This battery needs to be taken out from underneath. This also makes inverter installation difficult.

On my RV, I had to run conduit through the roof for the wires. I then painted the conduit to match the wall.

For my portable panels, there is a 3” hole in the bottom of the battery tray.

 

[littleharbor2]

I am helping with an install. The battery is under the trailer on a frame. Very hard to install solar, cleanly. This battery needs to be taken out from underneath. This also makes inverter installation difficult.

Sounds like this would be for sealed batteries only. Maintaining a flooded battery sounds impossible. Personally, I can't remember the last time I used flooded batteries but still why would they mount the batteries this way?

 

[chrisski]

Sounds like this would be for sealed batteries only. Maintaining a flooded battery sounds impossible. Personally, I can't remember the last time I used flooded batteries but still why would they mount the batteries this way?

These under frame house batteries are sealed. There is space to add a second battery. I can only think the factory built the under frame battery to save space. Maintaining a flooded battery would be impossible.