Charging Batteries from Solar ONLY? (2775RB FT Newbie)

K

KevinYrRoundOhio

Member
I have a 2019 Wilderness 2775RB and I have just gone full time. I have a newbie question that I am pretty certain has a very simple answer, thus I am about to embarrass myself. Be nice to the new guy! Here goes:

I am taking my first baby step toward eventual off-grid living. I just purchased a 200 ah AGM battery and 200 watt solar panels w/30a charge controller. I went with this small of a setup so I can begin to learn a bit more hands-on, and I plan on expanding as time goes on.

For now I want to remain connected to shore power in order to still use the appliances that are too much to run off of my SMALL beginner solar setup. BUT, I don't want my battery to draw ANY power from shore power. In other words, I want to know that 100% of my 12V AC power is ONLY coming from the sun. Even when the battery starts running "low" (yes I know to not drop below 50% w/AGM) during cloudy days I do not want it to start charging from shore power. This is to ensure I am able to perform true power audits in order to determine exactly what I need down the road. Make sense? How do I do this?

I am guessing the answer lies somewhere in the 12v fusebox, which I am SUPER confused about (the factory-installed charge controller is also IN the fusebox? what?). If this is the case, tell me everything you know and I promise to send you cookies.

Cheers
 
danemayer

danemayer

Well-known member
Hi Kevin,

When on shore power, 120V AC is supplied to your Power Converter. The Power Converter changes the 120V AC into 12V DC. The 12V DC is routed to the fuse box to power your lights and other interior 12V DC devices. It also goes to the battery to keep it charged.

The easiest way to be sure that your 12V DC system is not getting any help from shore power is to locate the 120V AC circuit breaker for the Power Converter and turn it off.

Our Electrical user guide has drawings and photos that you may find helpful. It's in this folder.
 
Oregon_Camper

Oregon_Camper

Well-known member
A typical 200W panel designed to charge a 12v battery would have a maximum power point of around 9A at 21v. If you are loading the panel more with the battery so you would not be operating at maximum power point. Perhaps you might get 4A at 14.5v.

A 200Ah battery (100Ah usable) should be bulk charged at ~5A.

At that rate, it will take 20 hours of direct (straight over head) sunshine in summer. Unless you have panels tilted and can follow the suns path, (otherwise you'll be "off axis") you would be looking at >3 days to charge the battery from 50% DoD...assuming no other draw to battery.

Don't let this discourage you. You are doing exactly what you should be doing...starting small and LEARNING.

A battery monitor kit will go a LONG way to help you understand battery amp consumption. I installed a Victron BMV-712 this summer and it is very helpful for me to see amps being used and amps coming in. It will show you your current SOC and provide valuable information. You can read it via the display or connect to it via Bluetooth to Windows/Mac/Tablet/Smartphone and see a LOT more information.

Link to Victron BMV-712 on Amazon - $206
 
porthole

porthole

Retired
KevinYrRoundOhio said:


In other words, I want to know that 100% of my 12V AC power is ONLY coming from the sun.
Click to expand...


The Bogart Trimetric and Victron BMV are both great battery monitors with the Victron being blue tooth a plus, even without the paid endorsement.

Bogart Tri-metric battery monitors


Amazon Victron BMV 712


Well that worked ��

In the interest of full disclosure I have corrected the incorrect order of the Victron item’s acronym letter order, too many years of EMS items I guess.
The link is still correctly linked to an unaffiliated web URL.
 
Last edited:
porthole

porthole

Retired
Oregon_Camper said:
Opps...looks like someone needs new glasses, and its not me. The model number is BMV-712 not BVM-712.
Click to expand...

So thankful you pointed that out. Misinformation never helps anyone.

KevinYrRoundOhio said:


In other words, I want to know that 100% of my 12V AC power is ONLY coming from the sun.
Click to expand...


The Bogart Trimetric and Victron BMV are both great battery monitors with the Victron being blue tooth a plus, even without the paid endorsement.

Bogart Tri-metric battery monitors


Amazon Victron BMV 712


Well that worked 😜

In the interest of full disclosure I have corrected the incorrect order of the Victron item’s acronym letter order, too many years of EMS items I guess.
The link is still correctly linked to an unaffiliated web URL.
 
K

KevinYrRoundOhio

Member
danemayer said:
Hi Kevin,

When on shore power, 120V AC is supplied to your Power Converter. The Power Converter changes the 120V AC into 12V DC. The 12V DC is routed to the fuse box to power your lights and other interior 12V DC devices. It also goes to the battery to keep it charged.

The easiest way to be sure that your 12V DC system is not getting any help from shore power is to locate the 120V AC circuit breaker for the Power Converter and turn it off.

Our Electrical user guide has drawings and photos that you may find helpful. It's in this folder.
Click to expand...

Ok so I figured out which break runs to the converter and I flipped that off. Unfortunately that same breaker supplies power to a bunch of 120v outlets too. So now I’m trying to figure out how to ONLY shut the converter off or just stop sending power to the converter?
 
travelin2

travelin2

Pennsylvania Chapter Leaders-retired
KevinYrRoundOhio said:
Ok so I figured out which break runs to the converter and I flipped that off. Unfortunately that same breaker supplies power to a bunch of 120v outlets too. So now I’m trying to figure out how to ONLY shut the converter off or just stop sending power to the converter?
Click to expand...

Unplug it


Sent from my iPhone using Tapatalk
 
danemayer

danemayer

Well-known member
So, a 2775RB Wilderness is a lightweight travel trailer. It's possible the Power Converter function is built into your power distribution box. In that case, you may not have a simple way to shut it off or unplug just the Converter portion.

It may be the best you can do is use one of the suggested monitors while unplugged from shore power.
 
K

KevinYrRoundOhio

Member
LBR said:
If that neutral wire in lower left is from the converter, then why not disconnect it for a test-run...would be effectively the ssme as pulling the plug from a receptical, correct?
Click to expand...

The green one? It’s running from the converter to the neutral hot ground. Can I just unscrew it or something there and still leave the black wire and white wire connected?
 
K

KevinYrRoundOhio

Member
LBR said:
Sorry, I meant the common...white.
Click to expand...

Ok so if I just shut off the main breaker I can then unscrew the white wire running from the converter to the neutral terminal bar, disconnect it, turn the main breaker back on, and then the converter will no longer be working?
 
danemayer

danemayer

Well-known member
Looking at the 120V AC circuit breakers in your photo, it looks like the 20 amp breaker, 2nd from the top, might have the wire that powers the Power Converter. I can't tell for sure, but it doesn't look like more than 1 wire in that breaker. If so, turning that off should turn off the Power Converter.

Is that the one you turned off earlier?
 
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