Disconnect Battery Cable

[GrandDesignNewbie]

I have a 2023 Grand Design 2600RB that has a 165W solar panel on the roof. The trailer is under a storage building and has little chance of the panel receiving any sunlight.
I have a 7.5W solar panel that I can hook up to my battery that should receive 3 to 4 hours sunlight per day. Do I need to disconnect my battery cable to protect the electronics?

[TucsonJim]

Welcome. 7.5 watts at 12 volts will yield about 2/3 of an amp. If you yield this for three hours, you'll gather about 1.9 amps. But due to inefficiencies of solar panels, realistically, you're looking at about 1 to 1.2 amps of charging. The parasitic loads from the trailer run for 24 hours a day. So I would not plan for that small panel to keep up with the loads on your RV. I'd disconnect the battery to protect it when not in use.

Jin

[howson]

I have a 2023 Grand Design 2600RB that has a 165W solar panel on the roof. The trailer is under a storage building and has little chance of the panel receiving any sunlight.
I have a 7.5W solar panel that I can hook up to my battery that should receive 3 to 4 hours sunlight per day. Do I need to disconnect my battery cable to protect the electronics?

Changed the title of your thread to reflect the contents. Helps others find the information when they have a similar question.

Hope you understand -- welcome to the forum.

Howard (Moderator)

[GrandDesignNewbie]

Are there any concerns with installing a battery disconnect at the battery? That way I won't need to disconnect the battery cable each time I leave in the RV.

[Jlawles2]

No. Many members here have added a disconnect switch. If you have solar that complicates things a little.

I personally have added a disconnect on the negative battery lead of my 303. Removed the one from the battery, attached it to one side of the switch and added a new piece from the switch to the battery.

While in there working on negative cables, if you do any boon docking are have interest in keeping track of battery levels you can add a shunt and monitor. https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 You will either need a weather proof box or somewhere to mount the shunt safe and dry.

Something like https://www.amazon.com/Zulkit-Dustpr...al%2C92&sr=1-4 with glands (assorted pack but you can order by wire size) https://www.amazon.com/QILIPSU-Strai...zcF9hdGY&psc=1 to keep everything dry. Then mount the gauge inside the pass through or wherever convent.

Remember a wet cell battery is technically at 0% charge at 50% of the amp rating they give.

[GrandDesignNewbie]

Thanks Joseph,
My docking station has gauges that show current draw, battery voltage and % of battery power available. Pretty cool.
The solar panel charges the battery even when the battery disconnect switch is disconnected but I guess its controller would shut down when the battery cable is disconnected or a battery disconnect is used.
Richard

[Jlawles2]

That's the issue, some of the controllers do not shut down and disconnecting the battery when the controller has solar power input can lead to damage of the controller. People are adding solar input disconnects so they can disconnect the panels first from the controller, then power down by disconnecting the batteries.

Tag Howard (howson) he has a lot of information I believe and can point you in the proper direction.

[TribForce]

Here is the solar disconnect that I am using.
https://shop.explorist.life/shop/all...or-disconnect/

[HVAC21]

The solar system have caused me concern with how/what to do to winterize the AGM batteries. At first I pulled the 2 battery's and purchased trickle chargers. After more online research, I added a battery disconnect switch, put the battery's back in the RV, connected everything but left the negative off (raped in elec tape) at the battery's. We might get down to zero a couple nights per year. OR should i leave everything connected? Solar panels get sun most of the day. What to do?

[TedS]

The batteries need to stay charged. Either use your trickle charger or let the solar panels keep up the charge.

[TribForce]

With AGMs and flooded led acid batteries I don't think you need to worry about charging at freezing temps. If they were mine I would disconnect any loads, plug in a smart trickle charger and forget about them.