Planning to convert a 6x12 cargo trailer.

[flboy]

I understand. I did use Chassis return for my system. All DC circuits return through the Chassis. If the frame is welded as it is and good connections are made with washers that bite into the steel, it will be and is very reliable. The other way works fine too just more cost and wire management.


I chose Chassis return ( which is not ground technically) as it saves alot on wiring which is expensive. I have alot of circuitry and just the actual wires themselves would take too much space in the chases and to manage in the electrical area. Automobiles use Chassis return for this reason also. Ground is often a term misused in this application. I do it myself all the time.

To be clear however, the chassis is not ground like "earth ground". It is just the return to negative side of battery in DC applications.

In 110vac applications, the neutral is the return and "safety " ground should be grounded to earth. The purpose is for safety when bonded properly to the neutral.That connection is made through the shore power panel at the campground where it is bonded to nuetral. Your AC safety ground should connect to your Chassis in the CTC so it never can become hot due to a wire shorting. The connection of AC ground to Chassis in the trailer is to ensure the Chassis stays at Zero volts AC and GFCI breakers pop as they are suppose to so nobody gets hurt.I use GFCI throughout the CTC for all outlets. I treat it as an outside appliance that could get wet.


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[rebelrider.mike]

I tend to think of ground and DC negative as two separate things. Though in vehicle wiring, they're basically the same. Here is an updated diagram based on what I've learned:


I think that's going to be all for my grounding research. In other news, I got my solar panels! I made a short video of my solar plan and unboxing and testing a few of the panels.


This weekend is the last cargo run before the trailer gets gutted and rebuilt. From there, progress will only be limited by funding, weather, and how much energy I have between this and other projects.

[flboy]

Never a good Idea to switch neutral wires to appliances. Please don't do that. All the neutrals should tie together. Only hot wires should go through the switches. If you were to have a contactor open up on the nuetral path, you could become the return.


You will notice that in electrical panels or junction boxes, all nuetrals are connected together.

Why not just put a transfer switch between the Inverter output and the Shore Power input and then feed the AC through the breaker box for distribution?

[rebelrider.mike]

You make some very good points. But first, I've noticed that when I moved my inverter in the diagram, I forgot to also move the AC leads. They should be shown coming out the little outlet on the right of the inverter, not randomly out the bottom. I don't think that has any bearing on what you said though.

I'm actually looking into automatic transfer switches. Turns out there are some out there that are specifically designed to switch between grid AC and an inverter. I will keep researching.

[flboy]

How's this build going? Any updates. Probably getting close to done by now?

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[rebelrider.mike]

The rain hasn't let up here, so all the stuff I planned to start around mid April is still waiting. Unfortunately, that includes the trailer. My son and I have been working on cleaning out our old carport so we have at least a little shelter to work under.

The good news is that despite all the rain, the trailer interior remains bone-dry.

[Staryder61]

The rain hasn't let up here, so all the stuff I planned to start around mid April is still waiting. Unfortunately, that includes the trailer. My son and I have been working on cleaning out our old carport so we have at least a little shelter to work under.

The good news is that despite all the rain, the trailer interior remains bone-dry.

Mike. dry is good..
I used to have an old carport, wow, the rain that leaked through that thing.. I'd take it now for some shade..
I welcome some rain down here, send us some..

[rebelrider.mike]

Here it is July, and it's still raining where I live. But I did get a box built for my battery.





We're still cleaning out the carport so I have room to empty out the trailer. Can't really work on it until it's empty. I'm hoping this week I'll be able to start moving things.

[featherliteCT1]

rebelrider.mike,
I really enjoyed watching your video and found the content very interesting.

I hope you continue to update us on what you are doing and how things are working out with your electrical system.

[JasenC]

Ah yes, dealing with all the stuff, I was doing that in the garage a month ago.

Yes, keep us updated

[rebelrider.mike]

Finally got the trailer cleared out! Now I can start dismantling the inside.

[rebelrider.mike]

Since my cells have a self-discharge going on, and they seem to discharge at different rates, I got one of those "active" balance boards to keep the battery top balanced.

20220802_161131.jpg (265.15 KiB) Viewed 2499 times

There's a spot on the board where a switch can be added. Otherwise the board is balancing all the time. No point in trying to balance the cells when they're under 3.4V each. So I found a programmable switch that turns on or off depending on voltage. There's a threshold separating the on and off function so it's not getting triggered a bunch while the cells are right at 3.4V. It even shuts off the display after a while so as to not use extra power.

Without the switch and balance board, it takes about 20mA to keep the battery at full voltage, and the difference between cells is always more than 100mV. With the switch and balance board, the battery takes 30mA to stay topped up, and the difference is only 12mV. I ran an air conditioner and a mini fridge for a few days, along with a power supply to simulate a bit of solar input. The battery periodically got low enough in voltage for the switch to shut off the balance board. With the fridge and A/C compressor cycled off, there was enough power to recharge the battery, and the balance board kept everything within 50mV as far as I saw.

[JasenC]

Looks like you scavenged parts from my Grandfathers RCA console TV.

Just seems odd seeing stuff like that these days

[rebelrider.mike]

Hey all, it's been a while.

Sadly, my father passed away October of 2022. Between him and my grandfather's passing the year before, things have sucked and priorities have shifted. I still have the trailer, and the battery I've been working on, and all the plans. So at some point I'll continue to work on building my camper. Hopefully I'll make some progress in 2024.

I haven't completely ignored the project though. Since January, I've been doing a self-discharge test of the battery without the balancer and BMS connected to see if the voltage would drop slower. With the balancer and BMS connected, the battery started to reach its discharged voltage in about 5 months. With everything disconnected, It's been 11 months and the battery is still at nominal voltage. There are 2 series that are lower than the rest, but not by enough to cause concern. I suspect the BMS's Bluetooth is what is making the difference. Either way though, the battery should be fine. If I were to store the trailer and not use it, the solar panels would continue to keep the battery charged even during months of poor sunlight.

My little Ford Ranger has developed a transmission issue, and it looks like it's towing days are over. In a completely unexpected turn of events, I ended up inheriting my dad's Chevy Silverado which can tow over 7,000 lbs. So it looks like I won't have to worry about trailer weight anymore. Still, I'd like to keep the trailer as light as I can. I'm envisioning spending $100 on gasoline every 300 miles. We'll just have to budget accordingly.

Anyway, I'm starting to work on various projects again. Hopefully I'll have something interesting to share soon.

[flboy]

Good to hear from you. Best wishes for 2024. I am sorry to hear about your losses. My condolences.