Tesla powered Tiffin Motorhome

[linuxkidd]

Hey all,
I thought I'd drop in to post about my installs. I have three separate ones, so I'll put those into three separate posts since they all differ a bit.

My first big install was on my 2016 Tiffin Allegro Bus 45OP.

Before Shots:


After Shots:


High level parts list:

• 18 x 100w Renogy Mono solar panels
  • Had to go with the small panels to fit around all the stuff on the roof)
• 2 x Magnum Energy MSH-4024M Hybrid Charger/Inverters
  • I wanted hybrid so I could use the batteries to offset lower current shore power connections.. and more...
• 1 x Magnum Energy PT-100 Solar Charge Controller
  • Since I was using Magnum for the inverters, it made sense to stay with the brand to centralize control and config
• 4 x 4.5kWh Tesla Battery Modules
  • Best power density for the $, but you need to understand the environmental limitations and have safety measures in place.
• 2 x Victron Energy Orion 24/12-70 DC-DC converters
  • I didn't want to convert the whole coach to 24v, so I opted to use these converters to give a combined 140amp @ 13.2v to run the rest of the coach.
• 2 x Victron Energy DC-Links IN units, modified to hold fuses for each Tesla module input ( 300 amp per ), and each major load output.

I'm using some open source arduino code that I modified to tap into the Tesla BMB to read parallel group voltages, positive/negative terminal temperatures, and be able to use the built-in balance resistors if any cell balancing is required. So far, even under heavy charge or discharge load, the entire bank is never more than 0.02vdc out from highest to lowest cell pack, so I've not had any need to use the balancing capability.

I wrote my own system monitoring software in NodeRED and automated alerting to low battery state, temperature extremes, etc via PushOver.

My Power Monitoring Interface:



Unexpected operation
One mode of operation I had not thought of or planned for that I've seen occur is very.. very cool. Consider a scenario where Leg 1 needs more than the configured power limit ( 24 amps in the above screen shot ). However, Leg 2 is only using a few amps. This dual-hybrid inverter config allows the Leg 2 inverter to provide DC charge current that the Leg 1 inverter uses in a hybrid support mode to supply the coach AC loads on Leg 1 that are in excess of the 24 amp cap!

One more thing...
Oh, that "and more" from above regarding the Hybrid inverters. TL;DR; I can run my coach and charge my EV from the same 50 amp shore power connection without tripping the breaker!

With this setup, I can configure the inverters to limit their shore amps to say.. 24 amps per leg ( as seen in the screenshot above ) -- then the excess power needs of the coach are supplied by the Tesla modules. And use the rest to charge my Tesla Model X. I use an OpenEVSE which provides an MQTT topic monitoring for available current ( intended use is for solar power production following of your EV charge current ). I publish for this topic based on the power available from the 50 amp shore power connection to my coach, that my coach isn't using so the EV can use the 'spare' shore current. Note that AC breakers ( at least in the US ) are only rated to 80% of their listed capacity for long duration high current load, thus the system is only allowed to pull 40 amps from the shore connection, between the coach and the EVSE.

More details?
I have a full write up of the install, my reasons for picking what I did, settings I'm using, etc.. on my blog post:

MOD: TESLA Powered Tiffin!

That is not a typo… our RV is now powered by TESLA! Well, Tesla battery modules that is! Oh, and the Sun! Yes, the Sun, too! WARNING — This post is full of technical content. Here&#8217…

turtleherding.com

Hope someone finds this useful. All questions / comments are more than welcome!

Michael J. Kidd
aka linuxkidd

 

[Craig]

Very nice. I perused your magnasine code a bit hope you don't mind if I use it as a reference for some of my projects.

 

[linuxkidd]

Hi Craig,
Sure thing... it's actually a fork of someone else's code. I need to update my repo as I've expanded the code to work with the PT100. I also found some anomalies in the protocol on the Hybrid inverters vs the non-hybrid -- specifically, there are some fields missing in the main 'inverter' portion of the packet, so it makes decoding of the remaining data shift to the left 2 bytes.

Ultimately, I need to put some time into detecting which shift pattern is in the protocol received and adjust the decoding as needed... I also need to finish the PT100 decoding stuff ( I added code for the real-time portion, but mostly ignore the historical data fields that are used to show previous days data on the remote ).. then, I'll publish it.. lol.

I've also updated the code to be python3 compatible since python 2.x is EOL.

Thanks,
LK

 

[Picasso]

I love Tiffin had an 04 Alergo Bus from them for a few years, I put 700ah thunderskys in it. The Tiffin factory tour is one that you will never get in america. 1 hour tour and the rest of the time you can just walk around the factory. Woodshop started on fire few days after we took off. I noted lack of dust control. Good company that mostly stands behind its product. Even if it is just a couch on plywood.

 

[linuxkidd]

Ya, we chose a Tiffin based on their reputation of customer service and the ability for me to be on-site during the build. We have videos covering the build process on YouTube. Here's the playlist if you're interested.

Tiffin has had to change their policies a bit since then.. they no longer allow you to be on-site during the build and after someone drove through a service bay, they now have the service area fenced off and secured after hours. Stupid people ruin it for the rest of us..

LK