Desert Snow

No worries. I appreciate the response!

Desert Snow

Thanks. I just did some reading on running batteries in parallel and serial and combined with your response this all makes sense now.

The solar unit I ordered does come with the charge controller. I'm not accustomed to using one and I believe there are required settings for charging in parallel. I'll be sure to read the manual and pose questions for confirmation I'm not going to destroy anything.

Gotcha in regards to going 1-2 steps up for the wiring gauge. I'll use that chart you gave me to figure it out. Here's possibly an odd question: Are there concerns with going TOO big if it's practical for growth/expansion later down the line?

14Sport

There are no concerns with going with larger wire beyond cost and fitment. Smaller wire is always a cause for concern.

And yes you want your fuse to blow first, protecting all the other components and reducing the risk of fire. So it should be sized accordingly. Just large enough to handle the load without blowing. That way when a short occurs and the load increases it cuts off power quickly. A 55A fuse would allow a substantial amount of current before cutting off. Potentially a fire threat. The main purpose of the master fuse is to reduce the length of the unprotected lead wire. The shorter the better. The fuse size is determined from maximum load of all accessories being on at the same time.

And the 18" lead wire should be sleeved and secured to prevent chafing. That is going to be the most dangerous wire you install in your circuits, treat it with the respect it deserves.

As to wire sizing, if you ground your accessories to the chassis then the length of the positive wire is what you need to use in determining wire size. However, if you choose to ground back to the battery then you have to use the combined length of the circuit (both your positive and negative wire) in your size determination.

This is the wire size calculator I use...

Wire Size Calculator

Since it sounds like you have some but not a lot of wiring experience, make sure you read through the notes on the bottom of the page. You can also change the voltage drop in the calculator to 5% to get sizing that matches the chart posted earlier. I leave the calculator at 2% drop as a built-in safety factor and because I have read that some devices perform poorly if the voltage drops off too much. For example lights that are less bright than advertised.

Good luck.

countrydude1992

The only thing that would make it "too big" is taking it beyond what your fuse panel is rated for. For example, I have a Blue Seas fuse block rates for 100 amps total, so if it's 10 feet away from the battery, I'm looking at 4 gauge wire to safely handle the possible load of the panel. Since that's all the panel can do, I have no reason to go bigger than that. I could use 0 gauge wire if I want but since the panel can't handle over 100 amps, why go bigger?

However, if you have a small fuse panel now but might want to swap it for a bigger one in the future, or add a distribution block and put in a second panel, all of that needs to be accounted for. You can never go too big, as long as your fuse is just big enough to handle your devices. Even if you have huge wire, you still only want that 20 amp fuse for now.

Desert Snow

This is great stuff. I'm glad I read through those notes.

In regards to operating temperatures and wire type I'm thinking I should use GXL wire considering I'm in the low lying desert and may occasionally have this trailer in direct summer sun at the lake with outside temperatures hitting 110 during the day.

Thanks for the great information. I'm beginning to get a little more comfortable with this project.

Desert Snow

Gotcha. Considering my lead to the fuse box is 18" I suppose upgrading to a bigger gauge would be a simple task, but I would rather plan properly from the get go.

I also chose a Blue Seas panel, which has a rating of 30A per circuit x 6 available circuits. Does this mean it rates at 180A (of which I have no plan on coming close to)? This is the link to the exact item I purchased:

Blue Sea Systems ST Blade Fuse Block - 6 Circuits with Cover https://www.amazon.com/dp/B000K2MBPA..._0qXzvb0WJJNH8

Thanks!

countrydude1992

This specific panel is only rated up to 100 amps total. Each individual circuit can handle up to 30 amps, but not all the circuits at 30 amps at the same time. So since you're capable of 100 amps, I would go with 4 gauge just because you never know for sure when you're done adding stuff! Once you realize how simple it is, it gets addicting. Who knows, you may want to add a stereo system or a power inverter or something else with a high amp draw. Or just a big handful of LED strips or a charger for a MagLite or some red campsite lighting. There are just so many options for 12v accessories.

Desert Snow

How did you determine it was a max 100A? Formula or just going to the mfg site? I didn't see it in the description.

I'm already considering adding led rock lights and even a small amp to connect to an iPad, but I was concerned of draining the batteries since I'm at 75ah each (150ah combined).

So, since i only have 6 circuits I can combine appliances onto a single circuit as long as I consider the total amps drawn with all those devices and then also adjust the wire gauge too, right? For instance, I can have two led floods drawing 1.25A each on less than 20' of 16AWG wire with a 3A fuse? Am I getting this right?

countrydude1992

Yes you are exactly right. You can wire quite a few LEDs together on the same circuit as long as the fuse and wiring are sufficient.

As for amps/speakers and stuff, look into the Kicker Powersport line. Great quality, made for anything that gets dirty and wet, and has very little amp draw. I've used a few of these products and have nothing but good things to say.

And I'm just going by the mfg site for the amp rating.

Desert Snow

One question I have is related to grounding. The fuse block does not have a ground connection, so I assume the approach is simply run all grounds from the appliances, lights, etc to the switch and then from the switch to the same location on the trailer frame?

And, then the same from the negative terminal of the battery to the frame.