M116A3 Build

[bdosborn]

That's one area where Victron needs to get its act together, Venus OS really needs a backup routine.
Bruce

[lfhoward]

Sort of an aside that will interest anyone running a homemade LiFePO4 battery. I was with the trailer today when the charge hit 100%, and the battery’s delta was only 0.007 volts (7 millivolts). Pretty happy with that! I top balanced them a year and a half ago. Delta is the difference between the highest and lowest cells in the battery.

[bdosborn]

I haven't been charging mine to 100% except when we are using the van:

I've noticed two things with cell balance:

The balance is better when we've been using the van and there have been some charge/discharge cycles. It slowly creeps back up when it's sitting in the driveway.
The cell balance will go out of wack (delta~20mV) when a cold front comes through. It's usually back in balance the next morning.

Bruce

[lfhoward]

That’s really interesting that storm systems affect the voltage! Next time one comes through I’ll have to check to see if it happens with mine too.

My BMS is not connected to the Venus Raspberry Pi yet, but once it is, I will be able to check the delta remotely and maybe even graph it over time. My ruuvi tag shows big drops in barometric pressure with big storms, so it would be easy to see a correlation.

[lfhoward]

Happy Easter everyone, to everyone who celebrates it!

This afternoon's task was to get the touchscreen installed in its permanent location.

That meant running cables under the bed/bench.



And cutting a hole.





The touchscreen fits!



It doesn't take up too much space in the closet.



Some photos of it in place, and working:





In this close up, I like how I can easily get the indoor and outdoor temperature, battery and CPU temperature, and propane level.



The upper left white square will have the shore charger via the smart shunt, and the upper right will have the 800 VA inverter, as soon as I get them installed.

The next task will be to address the wiring. Since I added many features bit by bit since building the trailer in 2015-16, the wiring is looking like a plate of spaghetti. It needs to be rerun and reorganized inside of flexible conduit to make it neat and tidy. Also all the 120VAC wiring needs to be redone because I used solid copper house wire (Romex) at the time, not knowing any better. For anyone reading this, vibration can cause solid copper wire to crack and burn down your trailer. I ordered some 12 gauge stranded wire that is certified for 120VAC marine applications. All the Romex has to go.

[bdosborn]

Nice! Can you rotate the screen via software so you can install it with the hdmi connection on either side? It would be nice if there was a bezel so you could cover up the cutout...
Bruce
P.S. Finally picked a location for a touch screen in the van...

[lfhoward]

Nice! Can you rotate the screen via software so you can install it with the hdmi connection on either side? It would be nice if there was a bezel so you could cover up the cutout...
Bruce
P.S. Finally picked a location for a touch screen in the van...

Hi Bruce,
Yes, the software has the ability to flip the readout 180° if you wanted your HDMI cable on the other side.

A bezel would be really nice. Something silver to match the rest!

[featherliteCT1]

Looks great to me!

[lfhoward]

This week I had an issue with my trailer’s internet that began during a big thunderstorm on Sunday. The cellular connection apparently went out momentarily, but when it returned (when phones worked again) the Sixfab Raspberry Pi did not connect back to the internet like it should have. Thus, I could not monitor the battery and solar status via the Victron VRM for 4 days until I could get to the trailer and manually reboot the Raspberry Pi. After doing that, communication worked again.

This was not cool, because I was 5 states away from the trailer and didn’t know what was going on with it until I returned. I didn’t know if the trailer had been struck by lightning or burned down or was stolen … yup, I have good imagination …

Today I found a raspberry pi script that pings Google’s IP address to see if there is internet, and reboots the pi if not. This would have saved the day when my pi didn’t come back online as expected, and I was not there. I programmed the crontab (the pi’s scheduled events list) to run the script at noon and midnight going forward, so the most the pi could be offline is 12 hours. I could have made the pi check for internet more frequently, but I didn’t want the pi rebooting every hour for a week the next time I camped off grid. I figure 2 reboots a day in that situation will not hurt anything.

[bdosborn]

That's a nice little mod! You never see on a YouTube video; the sneaky little tweaks you have to do for your particular situation. I guess you don't know you need it till you have a problem. You'll be able to troubleshoot most problems when you're out in the boonies since you built everything yourself. I just have to shake my head on some of the posts I see from kids that buy a school bus for their dream RV and have never turned a wrench before.

I pulled the trigger on the Waveshare monitor; I got a discounted one that's on back-order so it won't be here for weeks.

Bruce

[lfhoward]

I think you’ll really like having the waveshare touchscreen. It can be set to go dark after a minute or so, so it conserves power and won’t keep you awake at night. I love having the data and the settings at my fingertips without having to pair my phone or use cellular data.

I think it’s true about the building it yourself part. I feel I can fix or mod most things as the need arises. I am working on writing up a trailer manual of sorts so that my family will be able to understand how everything works, in case they ever have to tow the trailer or camp without me. Also, writing things down is useful for my future self, because I won’t remember all the circuitry or programming 10 years from now. I have also found that my photo documentation on this thread has come in super handy already! For example, where is the 1x2 pine skeleton positioned inside that wall, or where do these wires go? LOL. Good to be able to go back and look.

[featherliteCT1]

I am working on writing up a trailer manual of sorts.

In the near future I hope to start researching in earnest how to set up a raspberry pi to monitor my system. Of course, your posts will help me ... especially if you post your "manual".

[bdosborn]

I won’t remember all the circuitry or programming 10 years from now.

I'll be very surprised if you're not on your second or third trailer by then.
Bruce

[rjgimp]

Nice! Can you rotate the screen via software so you can install it with the hdmi connection on either side? It would be nice if there was a bezel so you could cover up the cutout...
Bruce
P.S. Finally picked a location for a touch screen in the van...

Hi Bruce,
Yes, the software has the ability to flip the readout 180° if you wanted your HDMI cable on the other side.

A bezel would be really nice. Something silver to match the rest!

3-D print one, schmaybe...?

[lfhoward]

The trailer passed PA inspection again today. Here is a good photo from last year.



I also topped off the propane tank at the local depot, and then drove to a CAT scale located at a truck stop. I had never weighed the trailer before, and I think it is about time!

First weigh, with the whole rig:



Because I am not a truck, the labels are not right. My entire Jeep is the steer axle, and the trailer is the drive axle.

Re-weigh, this time only with the trailer, unhitched from the Jeep:



These two weighs give me a lot of good info:

First, the trailer:

The trailer weighs 2800 lbs loaded up for camping, with full propane. I thought it was between 2500 and 3000, so I wasn't far off.
The tongue weight is 300 lbs. This is about perfect, as 10% of the trailer weight is the ideal.
The trailer's GVWR (according to the tag on the tongue) is 3160 lbs, so I am in spec.


(picture is of a tag from a M116A3 trailer like mine, found on another forum)

Second, the Jeep:

The Jeep weighs 5460 lbs with me sitting in it and the trailer hitched up, carrying a load of heavy tools in the back.
This is under the Jeep's GVWR of 5675 lbs, which is good news. My lifted Jeep has beefier springs than the stock version, so it can probably handle more weight. I don't plan to overload it, though. It does make me hesitate on eventually getting a steel winch bumper (wanted one for a long time), because that would replace some weight for cargo. Hmmm...
The towing capacity of the Jeep is 5000 lbs with 500 lbs of tongue weight, and the trailer is well under that.
The bottom line is our rig is within safety margins, which makes me and my wife feel good. It is definitely not as light as most trailers on here. The flatbed military trailer itself was 800 lbs according to the tag, before I built anything on it. I think it would be interesting to weigh the trailer empty at some point. I think I probably have 500 lbs of stuff in it right now, which means I added about 1500 lbs with the build itself.