M116A3 Build

...ask your questions in the appropriate forums BUT document your build here...preferably in a single thread...dates for updates, are appreciated....

Re: M116A3 Build

Postby bdosborn » Wed Aug 11, 2021 8:54 pm

John61CT wrote:LFP cells should not just sit at high SoC when in storage mode, being Floated shortens longevity no matter the voltage.


How much capacity do I lose a year at 3.35V/cell? Nobody seems to be able to answer that question. I use maybe a dozen partial cycles to 80% SOC a year so they are going to age out well before they cycle out. I do a full discharge test every year, on year 2 they were still at full capacity. That reminds me, I need to do a year 3 test. I'm gambling that the convenience of leaving it on the charger outweighs any lost capacity.

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Re: M116A3 Build

Postby lfhoward » Thu Aug 12, 2021 9:39 am

bdosborn wrote:
John61CT wrote:LFP cells should not just sit at high SoC when in storage mode, being Floated shortens longevity no matter the voltage.


How much capacity do I lose a year at 3.35V/cell? Nobody seems to be able to answer that question. I use maybe a dozen partial cycles to 80% SOC a year so they are going to age out well before they cycle out. I do a full discharge test every year, on year 2 they were still at full capacity. That reminds me, I need to do a year 3 test. I'm gambling that the convenience of leaving it on the charger outweighs any lost capacity.

Bruce

It's nice to hear you still pull full capacity after 2 years. :thumbsup: I'd be interested in your 3 year results if and when you run another capacity test.
My off-road camper build on an M116A3 military chassis:
http://www.tnttt.com/viewtopic.php?f=50&t=62581
Tow vehicle: 2008 Jeep Liberty with a 4 inch lift.
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Re: M116A3 Build

Postby John61CT » Thu Aug 12, 2021 12:47 pm

bdosborn wrote:How much capacity do I lose a year at 3.35V/cell? Nobody seems to be able to answer that question
Too many variables, very expensive lab testing, incentives of funding sources are skewed.

But if all the factors are coddled, at least two decades' lifespan is possible. You certainly should not see SoH% declining much during the first one in a non propulsion context.

If the use case requires "abuse" then fair enough, so be it. But your selected infrastructure should let you choose.

Are you getting a substantial benefit from floating?

Are you getting a substantial benefit from sitting at that high a SoC%?

Obviously this is not a moral issue, each owner sets their own priorities...
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Re: M116A3 Build

Postby lfhoward » Tue Aug 17, 2021 12:03 pm

Sitting in the Jeep on the way to camp! Of course it’s raining! :rainy:

I wondered how the new solar panel was doing charging in the rain, and so I remembered the BMS and battery monitor both have bluetooth! The BMS had the strongest signal since it’s in the front of the trailer.

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Not bad for a cloudy rainy day. The battery should be charged up to 100% by the time we reach our campsite. :D
My off-road camper build on an M116A3 military chassis:
http://www.tnttt.com/viewtopic.php?f=50&t=62581
Tow vehicle: 2008 Jeep Liberty with a 4 inch lift.
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Re: M116A3 Build

Postby lfhoward » Tue Nov 23, 2021 12:12 pm

Wow, It's been a while since I logged on! Here are some new developments about my M116A3 build.

Battery Update:

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I would like to report that the 156 Ah LiFePO4 battery has been running like a champ for the last few months, in case anyone is reading this and thinking about building their own. I have done several long camping trips with the new battery, including one to the West Virginia mountains and one to Minnesota, and had no issues. We are starting to get freezing temperatures now in the Philadelphia region, but I haven't camped yet in a situation where the battery heater would be required. I can confirm that the Victron charge controllers will not push a charge to the battery if the temperature is below their set threshold (which I set to 38 degrees to be on the safe side). [I have the BMS set to not allow charging below 36 degrees as second safety net.] Since the trailer is just sitting idle outdoors right now, there is no need to run the battery heater, because the daytime temperatures allow charging after mid morning or so. But, I did try the battery heater out in the early morning, and it does work. The two beehive heaters draw about 2.4 amps when on, which would be below 39 degrees. If I were camping in the cold, they would allow the battery to warm up before the sun came up, maximizing charging. They'd also get some secondary help from the Propex heater in the trailer! When I do my first below freezing camping trip this winter, I'll report back on how well the battery heating system works.

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The key of course is to allow the solar panels to harvest more Ah from the sun than the battery heaters would burn keeping the battery warm.

Accessibility Mods:

Up to recently, my wife and I have been using a step ladder to get in and out of the trailer, which did the job but was not ideal. For one, I had to put a dirty wet ladder inside the trailer when packing up in the rain. For another, it wasn't always stable depending on what ground we camped on. After having the ladder tip over and landing on my backside, I decided to get some real stairs. I would never want this to happen to my wife!

These stairs are by a company called EasyHitchStep, which is out of South Carolina. They are designed for pickup truck campers, and go into the receiver hitch on the truck.
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The beautiful thing about them is that they fold up and can remain on the back of the trailer while traveling from place to place. Of course, being in a receiver hitch, the stairs can be manually removed and stowed inside if I need extra ground clearance for driving off-road with my trailer.
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To be able to use these stairs, I had a local Jeep shop [Locked & Loaded 4x4] weld in and support a receiver hitch on the back of my trailer frame. If you're in the Philly metro area and need a great metal fabricator, send me a message and I'd be happy to refer you.
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Finally, I installed a grab handle on the trailer to allow safer stair climbing!
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Kitchen Mods:

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Our kitchen is on the passengers side of the trailer, under our Shademaker awning. In inclement weather, we can put sides on our awning room and run a Little Buddy heater to keep things warm in there. This fall, we decided to upgrade our stove. We had been running a Coleman 2 burner stove which we got almost 20 years ago as a wedding present. The stove served us well over the years, but it wasn't the fastest thing in the world. Now that we have a propane tank on the trailer itself, we have the potential to run a better stove. I was able to find this 20,000 BTU Camp Chef Everest stove online for cheap. It was new and never used, but dented. I did a little body work on it, and it is as good as new.

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I bought a Buddy heater propane hose to connect it to the trailer's LPG tank. The Buddy brand propane hose does not have problems with oily residue developing inside, and so does not require an in-line filter. It keeps the stove burners running efficiently and clean.

Also on the kitchen side of the trailer I installed a waterproof Blue Sea 12 volt power outlet. We had always had a 110 AC outlet there, but it required us to run our inverter when not connected to shore power. The 12 volt will provide all sorts of flexibility in the kitchen.
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First, it powers an LED light strip. We never had a light on the kitchen side of the trailer (if building a camper from scratch again, I would add one), so we either used flashlights, phones, or our 20 year old Coleman lantern. Now, we have dimmable LED lighting! The light strip is by a company called TuffStuff, and has both adjustable velcro straps and clips. It connects easily under our awning, as it was designed to be used inside roof top tents.
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Second, using a 12 volt splitter, I can run other kitchen gadgets without unplugging the light. I can put our 12 volt fridge under the table in the kitchen instead of keeping it under the bed in the trailer. (Of course in bear country I would not leave it outdoors.) Keeping the fridge in the kitchen is so much more convenient for meal prep and morning coffee! Another important use I got out of the kitchen 12 volt socket was running a heated sleeping bag liner. I came down with a sinus infection on our last trip and snored like a buffalo. The solution to keeping my wife sane and letting her sleep was to move me to a cot and sleeping bag inside the kitchen tent. I was nice and toasty warm.

Future Mods:

As you well know, a trailer project is never really "done"! My ideas for future fun mods center around the solar/battery system in the trailer. I have been super happy with my Victron 75/15 solar charge controllers and their BMV712 battery monitor. The Victron devices have allowed me to keep tabs on what is happening with the LiFePO4 battery, and made it easy for my wife and I to manage our power consumption on our camping trips. They run on a Bluetooth network and talk to each other, and there is a Victron smartphone app that makes it easy to check and set all the parameters. Of course I have to be "in range" of bluetooth to use the app. Sometimes that means standing right next to the trailer. Since my camper is not parked at home, I have to make periodic visits to it to keep tabs on battery status when we are not camping. Here is the solution!

I can monitor battery and charging using Victron's VRM system, from anywhere in the world. The Victron devices just have to be connected to the Internet! A way to do that is to connect them to Victron's Cerbo GX device, which is fairly expensive. A better way is to clone a GX device on a tiny microcomputer called a Raspberry Pi!

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The Rpi is small enough to fit in my hand like a deck of cards! It also has a super low power draw.

The directions for setting up an RPi as a GX device and connecting the Victron controllers to it are elegantly described here:
https://off-grid-garage.com/victron-connect-through-raspberry-pi/
I have learned so much from the Off Grid Garage's YouTube channel and highly recommend it. Fair warning, you will get hooked.

I am super excited to be able to keep tabs on my trailer's charging system from afar. The Raspberry Pi running the Victron GX software has to be connected to Wifi for this to work, however. The place I park my trailer doesn't have Wifi, so part 2 is getting 24/7 internet in the trailer. Raspberry Pi's can be programmed to run just about any project, which includes being a cellular modem. I ordered a cellular "hat" kit to go on a second RPi from https://sixfab.com/ that essentially turns it into a hotspot device. The cool things about the Sixfab hotspot that make it better than a hotspot device from a regular carrier is that 1) they have a "SuperSim" card that can connect to more than one carrier, making it more likely you'll have connectivity wherever you go, and 2) there are places on the chip to connect cellular and GPS antennas, which increases usable range to cell towers. The Sixfab kit itself is not too expensive, but if you want to use it as a wifi hotspot to watch Netflix and not just for battery monitoring, high GB of service can get expensive quickly. Luckily the SuperSim card can be swapped out with sim cards from AT&T or T-Mobile, which offer high GB data plans at more affordable prices. I may eventually do that. In the short term, though, I can have my Victron GX RPi connect to my Sixfab hotspot RPi and access the internet for $9 a month (500 MB).

That's it for now! Happy to answer any questions about these things. I'll post up my process of programming the two Raspberry Pi's and installing them in my camper, in case anyone else is inspired to do that too. This will probably happen in the new year. Happy Thanksgiving, everyone!
My off-road camper build on an M116A3 military chassis:
http://www.tnttt.com/viewtopic.php?f=50&t=62581
Tow vehicle: 2008 Jeep Liberty with a 4 inch lift.
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Re: M116A3 Build

Postby bdosborn » Tue Nov 23, 2021 3:46 pm

You know that the Venus Pi can do GPS locating with a cheap USB GPS antenna? Now with your cellular hat you can set up a Geo fence and have it email you if your trailer moves. Been running the Venus software on a Pi for a couple of years now. I like it so much I sprang for the Cerbo GX for the van.
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Re: M116A3 Build

Postby lfhoward » Tue Nov 23, 2021 4:30 pm

bdosborn wrote:You know that the Venus Pi can do GPS locating with a cheap USB GPS antenna? Now with your cellular hat you can set up a Geo fence and have it email you if your trailer moves. Been running the Venus software on a Pi for a couple of years now. I like it so much I sprang for the Cerbo GX for the van.
Bruce

That’s awesome. I would love to have that security feature to see where the trailer is when I’m at home and to be alerted if anyone steals it. Ordering a cheap USB GPS antenna compatible with the Raspberry Pi.

Also, I’m glad to hear you also have both the Venus OS and a Cerbo GX, and like what they can do! This is my first Pi and am looking forward to playing around with it and setting it up.
My off-road camper build on an M116A3 military chassis:
http://www.tnttt.com/viewtopic.php?f=50&t=62581
Tow vehicle: 2008 Jeep Liberty with a 4 inch lift.
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Re: M116A3 Build

Postby featherliteCT1 » Tue Nov 23, 2021 7:01 pm

lfhoward,
1. I love your set up! :thumbsup:

2. I have been watching “off grid garage” every night for several months now. Andy is a hoot and soooo knowledgeable. I too am hooked.

3. My Bogart battery monitor can be accessed with a wifi device I use. Like yours, I have to be close to the trailer to get a signal. The manual says that the wifi unit can be set to “station mode” to join an existing “access point”, to allow monitoring the system remotely. I have no clue how to do that. I am basically electronically illiterate.

4. I am hoping that you will keep posting about how you are configuring your system and that Bruce will keep dialoging with you; all in the hope that I will learn more about this stuff.

Thank you for posting!
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Re: M116A3 Build

Postby bdosborn » Tue Nov 23, 2021 7:41 pm

Make sure and turn on "has DC loads". it's under settings>system setup. The default is off and its the value I want to see the most in the main interface page:
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The rest of the settings are pretty intuitive. Here's the page where I found Raspberry Pi setup info (if you didn't know about it already):
https://github.com/victronenergy/venus/wiki/raspberrypi-install-venus-image

I don't have a Victron inverter in the trailer but the van will be getting a 2000W Multiplus Compact. Looking forward to having AC info showing on the Cerbo.

Bruce
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Re: M116A3 Build

Postby lfhoward » Fri Nov 26, 2021 2:55 pm

The parts for the Raspberry Pi project are starting to trickle in. They are Christmas presents so no playing around with them early!

For the Victron Pi: (from Andy’s Off Grid Garage instructions)
Raspberry Pi 3b+ for the Victron Software - it doesn’t play nice with Pi 4’s yet.
The kit includes a 32 GB SD card, Pi enclosure, and AC power brick.
1 USB GPS antenna
I have 2 solar charge controllers and a battery monitor to connect, so I got:
3 USB to TTL serial cables
3 JST PH to male cables
1 USB extension cord (battery monitor is at the other end of the trailer)

Raspberry Pi 4b for the Sixfab mobile hotspot
The kit includes a 32 GB SD card and AC power brick.
1 Sixfab 4G mobile hotspot kit - includes everything you need including the hat, modem, sim card, and 4G antennas
1 Sixfab Pi enclosure - includes cooling fan; enclosure is large enough to contain antennas and cords.

To run the Pi’s in the camper:
2, 12 volt to 5 volt, 3 Amp buck converters with micro USB end
1 micro USB to USB 3 adapter (the 4 uses a USB 3 power input)
1 micro SD card to SD adapter for flashing the OS’s to the SD cards

I am thinking about how best to connect Pi power circuits. 2.5 amps at 5 volts is like 1 amp at 12.5 volts, so they don’t draw that much power. And that 1 amp would be the Pi’s processors running full out, which they won’t need to do. I am betting most of the time draw for both together will be well under an amp, maybe half an amp.

I don't have any free circuits left in my fuse panel. I could either tap into my LED lighting circuit, or join the lights and fantastic fan together onto the same circuit to free up a dedicated place for the Pi’s. What are the pros and cons? Of course the 5 volt converters will be installed at the end of the lines, just before the Pi’s.
My off-road camper build on an M116A3 military chassis:
http://www.tnttt.com/viewtopic.php?f=50&t=62581
Tow vehicle: 2008 Jeep Liberty with a 4 inch lift.
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Re: M116A3 Build

Postby bdosborn » Fri Nov 26, 2021 3:45 pm

The Venus software will log readings to a USB flash drive so you don't lose your PV data when you're out of cellar range. The Venus software doesn't leave much storage on the SD card after installation, but a USB flash drive has plenty of storage ( I think I used a 32Gb I had laying around). It will upload the info to the VRM website when it reconnects to a network. Pretty handy as its out in the boonies when you want to know the most about how your system is performing. It will also connect to a cellphone WiFi hotspot. You'll need to configure the USB for storage in the Venus software but that's about all you need to do.

Bruce

P.S. My Pi runs flawlessly off this:
https://www.amazon.com/gp/product/B00O6R9PCC/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
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Re: M116A3 Build

Postby lfhoward » Sun Nov 28, 2021 3:19 pm

The two Raspberry Pi’s are up and running, successful proof of concept.
Pi 3b+ running Victron’s VRM via Venus OS
Pi 4b running Sixfab’s cellular hotspot
The first successfully connecting to the second’s wifi network
Total amp draw about 0.6 together after booting up
All put back in their boxes for Christmas…
;)
My off-road camper build on an M116A3 military chassis:
http://www.tnttt.com/viewtopic.php?f=50&t=62581
Tow vehicle: 2008 Jeep Liberty with a 4 inch lift.
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Re: M116A3 Build

Postby lfhoward » Sun Nov 28, 2021 10:04 pm

I’ve been thinking about rewiring some circuits now that I will be installing the Raspberry Pi’s for Victron VRM monitoring & mobile hotspot service. I have two circuits that run from the load terminals on the Victron solar charge controllers, because of lack of space in the main fuse box. (They have in-line fuses so it’s ok). One is the Propex heater (5 amp fuse) and the other is the new 12 volt kitchen power outlet (15 amp). I want to replace these circuits on the Victron devices with the battery heater circuit and Raspberry Pi circuit, and move the Propex heater and kitchen power outlet circuits to the main fuse box.

The rationale for having the battery heater powered through one of my Victron controllers is that this setup will give me the option of remotely turning the battery heater on and off from anywhere using the VRM software, which would be a fantastic ability. The charge controller’s load terminal can be programmed to turn on the battery heater one hour before sunrise, or be controlled manually. (Once the load terminal turns ON, the heater has its own thermostat that is set to bring the battery up to 42°F if it starts below 39°.) This would be handy on a clear cold morning, where I could make sure the solar system could take advantage of the clear day without having to drive out to where the trailer is parked to turn the battery heater on manually. Likewise, if it’s dark and cloudy out, I can make sure the battery heater doesn’t waste energy that the solar cannot recoup, and stays off.

The rationale for having the Raspberry Pi’s powered via a Victron charge controller load output circuit is similar: so that I can control the use of electricity. If the Pi’s were draining the battery more than the solar could compensate for (thinking this could happen during a long stretch of cold temperatures and winter cloudiness), I would have several options to reduce power draw. It seems from preliminary tests on my workbench that both Pi’s use about 0.6 amps together. Thus, they consume about 15 amp hours in a 24 hour period being constantly on. The battery heater burns 2.4 amps when on. During short winter days it is conceivable that the sun may not completely offset these draws, at least not every day. With the VRM, I would have control of that Pi circuit: I could turn it off completely (resulting in having to manually turn it back on later), which would be a way of eliminating all battery draw from the Pi’s. Better still, I could program to load output to be on for only an hour at certain times of day, like at sunset, using the streetlight function. At that time the modem could send compiled data to the VRM, and I could log on to change the settings if I wanted to. Or I could have the Victron controller turn off the Pi circuit below a certain voltage threshold to protect the battery, and turn back on once the sun came back. The Victron charge controller is pretty flexible in its programming, and I would have control of its behavior from my phone.

It’s pretty cool what the VRM will allow me to do from afar. VRM is not only a battery and solar monitoring system, because it also allows for direct control of all the Victron devices in the network. The possibilities are fun to imagine.
My off-road camper build on an M116A3 military chassis:
http://www.tnttt.com/viewtopic.php?f=50&t=62581
Tow vehicle: 2008 Jeep Liberty with a 4 inch lift.
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Re: M116A3 Build

Postby lfhoward » Sun Nov 28, 2021 10:12 pm

bdosborn wrote:The Venus software will log readings to a USB flash drive so you don't lose your PV data when you're out of cellar range. The Venus software doesn't leave much storage on the SD card after installation, but a USB flash drive has plenty of storage ( I think I used a 32Gb I had laying around). It will upload the info to the VRM website when it reconnects to a network. Pretty handy as its out in the boonies when you want to know the most about how your system is performing. It will also connect to a cellphone WiFi hotspot. You'll need to configure the USB for storage in the Venus software but that's about all you need to do.

Bruce

P.S. My Pi runs flawlessly off this:
https://www.amazon.com/gp/product/B00O6R9PCC/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Bruce, the Venus OS takes up about 1.8 GB of space, and I have a 32 GB SD card. I’m a little disappointed that the VRM tells me there is only about 300 MB of space set aside on the SD card for logging offline. I will be using all four of the USB ports on the Pi (2 charge controllers, 1 battery monitor, and 1 GPS antenna), so I wish the Venus OS would be smart enough to use the extra space I have on the SD card for offline logging. (Yes I could get a USB splitter and add a thumb drive but it’s not an elegant solution). Have you heard of anyone being able to use a large SD card (like my 32 GB one) for the purpose? I am not a programmer but I can run code if I can find the right SSH commands.
My off-road camper build on an M116A3 military chassis:
http://www.tnttt.com/viewtopic.php?f=50&t=62581
Tow vehicle: 2008 Jeep Liberty with a 4 inch lift.
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Re: M116A3 Build

Postby bdosborn » Sun Nov 28, 2021 10:59 pm

I don't think there's a way around the SD card limit. It's probably bad form to write data on your OS disk, you might fill it up and that's why they limit it so much. But, I've never looked into it.

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