New to Solar. Conect directly to battery ????

For whatever it's worth, we boondock a lot and have a 120 watt folding portable panel. It has a built in controller -- the panel puts out almost 14 volts in bright sun. We hook it right to the battery (group 31) with alligator clips.

The panel supplies all of our power almost all the time. We've been using it this way for many years with great results.

We have a portable panel (not rooftop) because we usually park the trailer in the shade. We use a long ten gauge cable so we can park the panel in the sun without a lot of voltage drop due to the long cable run.

The twelve gauge cord that came with the unit did cause a measurable voltage drop because of the resistance in the thinner wire. So we replaced it with ten gauge.

The panel is a "no name" Chinese imitation of a Renogy briefcase unit.

Dusty R,

My panels are from 2005. They still work well. They have paid for themselves several times over.

I've read that Michigan ranks 47th in the 48 continental states for available sunshine. With this in mind, how well do solar panels pay?

The most important thing about solar is to be flexible with your listening.....There are those that say, "you're wasting time not having tilting panels".......Or, here's an old favorite"PWM controllers vs MPPT controllers, PWM's are useless".........If you're buying new, I fully recommend a MPPT. If you want to and have the coin, tilting panels will aways give you the most harvest. But I've had panels screwed to the roof and a PWM charging four six volt batteries for 6 years and never want for power and never need the emergency genny I have on board. I think the most important thing is to have the controller as close to the batteries as possible to minimize charge voltage loss.

Solar panels are not voltage regulated in another forum someone is comlaining his batteries were overcharged to the point of failure. Turns out his charge controller is shorted or miswired and the panels are kicking out 17+ volts.

I have 5volt panel or so it says. Hits 12 in partial shade.

With regard to the need for a controller, years ago I remember West Marine opined a 1/60 ratio. If the amp output of your solar was less than 1/60th of your battery amp hour rating, a controller wasn’t needed. This was way back when lead-acid was just about the only show in town, and panels were modest in their output. Probably no longer applies. Not applicable to lifepo4!

Another factor is where you like to camp.
State parks and Federal campsites love trees. Solar hates trees and shade.
If you like open fields go for it.

An excellent component to add to your RV/TT is a battery monitor. There are very suitable ones for $20-50 that will give you some indication as to HOW your power gets used, what each device in your RV uses for power, and a whole host of other great things. There are also more expensive battery monitors that interface through your phone. Just depends how fancy you want to be.

Here's a link to a newbie solar install I did about 3 years ago. Lots of info, pics, steps. Was very inexpensive and it still is working great!
https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/30217540.cfm

WARNING: Solar is addictive...

Stay charged!
Chris

Hi TenOC,

You can use minimal solar of about 15 watts per 100 amp-hours with no controller. Of course that is only good for maintenance between trips.

I'd recommend over sizing the charge controller. That way it is quite cheap to add more panels.

This series of articles may help:

https://freecampsites.net/adding-solar/

Make your own folding panels hinges and metal screws are cheap.

May I suggest adding a dc to DC charger? Mine works like a charm while I trundle down the road.

Welcome to the wonderful world or solar and free power!

TenOC wrote:
I want to add a portable solar panel such as Harbor Freight Underbolt Solar100 Watt Solar Panel Briefcase
Harbor Freight 100 watt

For $10 more you get a Charge Controller (which you must have): Thunderbolt Solar