Connecting solar panels to Converter

RJsfishin wrote:
I wonder why none of the RV MFGs know that.

They know, it's just cheaper to use less wiring.

Quote:

All battery charge sources (charge controller, converter, alternator) should all terminate at the battery with separate cables
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I wonder why none of the RV MFGs know that.

How much voltage drop is there between the controller and the batteries? That's the question that needs to be answered.

You should only wire the controller to the converter if voltage drop to the batteries would be within acceptable limits. So you need to find out exactly what size those wires are and how long the run is, and put those numbers in a voltage drop calculator. Your batteries will charge either way, but if voltage drop is too high they won't charge fully. Besides losing battery capacity you will also lose battery life, unless you periodically use some other method to get the batteries fully charged.

If your controller allows you to bump up set point voltage then that could compensate for too much voltage drop, but many controllers do not allow that adjustment.

So it makes sense to minimize voltage drop. You've got to run the numbers or you just won't know how bad it is (or isn't). Run the numbers, then decide based on the outcome whether or not you want to leave it that way.

Everything is connected and working as it should. The only odd thing I noticed is that I cant put the converter into the lowest setting using the button on the remote, I only get med or high. My guess is because the solar controllers float setting is higher than the float setting on the converter. I think the PD9100 series is 13.2.or 3 and the solar controller is 13.6. Maybe at night when the panels aren't producing it might drop to there. Other than that it seems to be working as intended. I also noticed that when I unplug the converter and or shut the main off the remote light still flashes. I measured the amps coming in and got 10.5 which seems right given the flat mounting and the winter sun I'm getting.

Thanks again for the input!

Hi,

I prefer to use a buss bar instead of having several connections on the battery connector.

sdmotor wrote:
Is it possible to connect the output from my charge controller to converter instead of direct to the batteries? I have the PD 9100 series that has two sets of pos and neg terminals on it.

Yes, It will work just fine.
I installed 500 watts of solar and put the charge controller in the same compartment as my PD9180. I wired the charge controller into the second set of terminals, as you purposed. It's a no brainier, if the wiring will handle the PD9180, it will handle the solar. In my case voltage drop is not an issue. My charge controller has a separate voltage sense lead.

Richard

That would work in an emergency but not recommended for normal operation.

All battery charge sources (charge controller, converter, alternator) should all terminate at the battery with separate cables. As part of their routine, the charge controller and converter monitor battery voltage. These smart chargers can react to what voltage they see at their battery cable connection. If you turn on the generator for 5 minutes to operate the microwave, the charge controller that's connected to the converter will not see battery voltage but the sum of V_bat and V_cable_drop.

Both chargers could drop down to a lower charging mode.

Sal.

sdmotor wrote:
Not to be cheap but I'm trying to keep wire runs to a minimum.

The wires from converter to battery (via DC dist panel) can easily handle the solar amps, where say it is a 55amp converter and solar can do max 15 amps. But there is still the voltage drop issue for the solar controller.

If the controller "sees" 14.4v when the batteries are only at 14.3, and the controller's set point to start controlling is 14.4, then the batteries will only ever get to 14.3.

You can beat that by either reducing the voltage drop with a wiring change, or just crank up the controller's set point to 14.5.

Changing the set point leaves a possible issue that the battery still won't get to 14.4 if it takes too long to get up that last 0.1v that day before dark, but that is just in theory. In real life once the batteries are up into the 14s voltage rises fast.

Wires from the converter don't have to be big.
Wires from the controller to the converter only have to be big enuff to handle the amperage of the solar.....for that distance, no matter where the batteries are. Then the wires from the converter have to be big enuff to handle the amperage output of the converter to (normally) the 12v distribution center, no matter where the batteries are..
Then the wires from the 12v distribution center have to be big enuff to handle the converter's output to the batteries, no matter where the batteries are.

The one down side may be voltage drop, this depends on wire gauge and run length. Voltage coming from the panel is higher than from the controller to the 12V system. If you have big honking wire from the battery to the PD not a problem, but they are not really built for big wire.