Solar 101a

[GallenH]

This is a dumb question but:

Let's suppose you have a 100w solar panel on your roof going to a controller and then to the house battery. Your house battery is also connected to the engine alternator. When you're driving down the road, is your battery receiving charge from both?

Alternate scenerio with same components but a B2B charger which accepts inputs from both the alternator and the solar panels. Is the battery getting charged by both or (via the ignition wire) only by the alternator when the engine is on and only by the solar with the engine off?

thx.glenn

[MsNomer]

B2B's with both inputs usually accept one at a time, which is one of the disadvantages of these combo units. Our B2B and separate charge controller can both feed the batteries at the same time.

[GallenH]

thx.ms. So do you have a B2B between your alternator and house battery? Or is that B2B cin between your chassis battery and your house battery? Or is that basically the same?

Then you have an independent solar controller going to the house battery as well, correct?

thx.glenn

[dmb496]

Our 2020 Galleria has 300 watts of solar panels, and a dedicated alternator for charging the lithium batteries. Both sources of power feed the batteries at the same time.

[Davydd]

Originally Posted by dmb496

Our 2020 Galleria has 300 watts of solar panels, and a dedicated alternator for charging the lithium batteries. Both sources of power feed the batteries at the same time.

Ditto we our previous van with 460 watts of solar and a second alternator.

[engnrsrule]

I was under the impression that coach batteries could not simultaneously receive multiple charging streams from different sources. From my Road Trek Manual:

"The auxiliary battery is automatically charged through the battery separator by the engine’s alternator while the engine is running.This battery is also automatically charged by the inverter / charger when:
1. The battery disconnect switch on the monitor panel is set to the “ON” position prior to connection to an outside electrical power source, (shore/generator power).
2. The breakers in the distribution panel, are in the “ON” position.
3. Or while the generator is in operation, (if so equipped).

A disconnect switch, located on the monitor panel, provides a disconnect for the auxiliary battery from the 12V system while your vehicle is not in use."

It is not clear to me whether the battery separator functions as a multistage charger to the coach batteries. I know my on-board charger (both original TrippLite and a subsequent upgrade) are multistage. If the Solar controller output is going to an input on the B2B, I would expect it is prioritizing from among power sources available. I do know that charging off the alternator when running is at least as fast as or faster than shore tie or generator (when the 110v charger is engaged). That is also considering that when rolling I am running fridge on 12v too. Use propane when boondocking; 110v when on shore tie.

I do not have a solar system per se, but do utilize a 6W solar panel to help boost my coach batteries when boondocking. That panel adjusts its charging rate based on battery need to avoid overcharging.

[TomF]

Originally Posted by GallenH

This is a dumb question but:

Let's suppose you have a 100w solar panel on your roof going to a controller and then to the house battery. Your house battery is also connected to the engine alternator. When you're driving down the road, is your battery receiving charge from both?

Alternate scenerio with same components but a B2B charger which accepts inputs from both the alternator and the solar panels. Is the battery getting charged by both or (via the ignition wire) only by the alternator when the engine is on and only by the solar with the engine off?

thx.glenn

I installed a 100w Flex panel on the roof of my RT. It is connected through an MPPT controller to the house battery. It charges any time there is enough sunlight, whether the engine is running or not. The battery will charge fine with either or both sources of charge.

[Rlum]

Originally Posted by TomF

I installed a 100w Flex panel on the roof of my RT. It is connected through an MPPT controller to the house battery. It charges any time there is enough sunlight, whether the engine is running or not. The battery will charge fine with either or both sources of charge.

I know on my 2016 PW. The alternator and solar will work concurrently. If I want quicker charging. I will sometimes turn on gas generator. Since it goes thru the inverter/converter. The house battery will receive charging from three sources. The most is from the alternator and least is the solar. I found this is the fastest way to charge when batteries are low.