Apologies for the length, but I wanted to ensure I provide adequate context. I am working on a food truck that will operate all its equipment from a battery-based system. Below, I have outlined the system specifications, the proposed setup, and a few technical questions
System Overview:
We are aiming to run the entire food truck operation electrically, with a 48V / 80kWh battery system, which must be fully charged daily. A 3kW solar array is available, but it alone cannot meet the daily charging requirements, hence the need to integrate a Level 2 EV charger for supplemental charging.
System Components and Configuration:
Battery Configuration:
Five (5) 48V x 16kWh batteries
Each battery lands on a Victron Lynx Distributor, aggregating to power a 15kVA Victron Quattro inverter/charger
The Quattro’s maximum DC input current is 350A @ 48VDC
Charging Source:
A ChargePoint Level 2 EV charger providing 50A @ 220V
Capable of charging the battery system from 10% to 90% in approximately 7 hours
Grounding:
The neutral-to-ground bond will be disabled on the Quattro to allow for external bonding control
Load Requirements:
Peak 120A @ 240V if I started everything at the same time but continues is about 60V @220V.
Peak 50A @ 120V and that’s if all my coolers compressors kicked on at the same time.
Proposed Setup:
Input Side:
The Level 2 charger will supply 50A @ 220V via two hot wires and one ground wire to a J1772 Type 1 Socket Inlet (preferred).
An optional secondary shore power inlet (also 50A @ 220V) may be installed.
Both inlets will exclude a neutral conductor for safety considerations.
An Automatic Transfer Switch (ATS) will manage the switch between shore power and EV charger input.
Output Side:
Each of the Quattro’s AC outputs will connect to a 100A Victron Autotransformer.
Configuration: 2 x 100A @ 220V and 2 x 32A @ 120V
both autotransformers outputs will feed into the main AC breaker panel.
Technical Questions:
Input Side Safety:
Is this input configuration (two hot wires and ground only, without neutral) safe and compliant, particularly with the use of a J1772 inlet and ATS?
Equipment Grounding:
Given the high voltage and current in the system, is it safe and advisable to bond equipment enclosures (such as inverter housings, breaker panels, transformer casings) to the vehicle chassis?
Neutral Bonding Strategy:
Since the grid input does not supply a neutral, and the only neutral exists on the output side of the autotransformers, do I still need to establish a neutral-to-ground bond in the AC breaker panel?
If so, what are the implications of bonding in the panel while the system is charging or in passthrough mode? Is there a risk of back-feeding or ground loop issues?
Autotransformer Isolation:
What is the recommended method to **wire the two autotransformers outputs ** to the AC breaker panel in such a way that, if one transformer shuts down or fails, power from the other transformer does not back-feed into the inactive unit?
Thank you very much for your time and assistance.
Hi. Please accept my feedback in the positive manner I intend. I’m not trying to crap all over your design.
I do not recommend much of what you are thinking, but this forum isn’t the place for system design. As Ludo said, you’ve presented us numbers that don’t jive with what you say you need. And understand that if you want to use an autotransformer to converter 230V to 120V, you will NOT get 100A of conversion capacity. You will get at most 28A and you will very quickly overheat the AT’s. Trust me on this if you’re not clear as to why.
Instead of thinking of loads in terms of voltage and circuit amperage requirements, you are better off thinking in terms of watts and watt-hours on the AC side and you will want actual running and surge power values, not the minimum circuit rating. You may likely find that if a piece of equipment requires a 20A circuit, for example, that maybe the equipment has a running power of far less than 20A x 120V would indicate.
In the end, you should consider working with a trustworthy Victron installer or distributor to help you design this properly. If you are the installer, then work with a Victron distributor that can assist with the design and selling you the products. Ideally they would provide a detailed wiring diagram for you to use.
If you don’t have a local Victron distributor that is highly technical, then give us a call. But if you have someone local to you, that’s the better avenue.
You are right I might of exaggerate the numbers to show that my goal is to not have any bottle necks. My peak load at startup is about 120A @220v peak if I started everything at the same time but then it drops to 60A as consistent load. And that’s with all heavy equipment running at the same time, which realistically does not happen often. My main issue is that there not much documentation for the auto transformer.
Thanks Ed but the 100A is a pass through 220v there is no conversion there. there is no load on the transformer. It’s only converting 20A or so to split phase.
I think I found solution for the way to wire the auto transformers. if we are trying to power 220v load there is no reason to even send it to the transformer in the 1st place instead we can send it to a dedicated 220v only breaker panel straight from the quattro using one of the AC out . and we then can use the second AC out from the quattro to go through one auto transformer and create a split phase then a separate breaker for the 120v load and with a bit of load managements that could work. I have 2 * 15A coolers, led lights and a pc. what do you guys think ??
** follow up, I found out that the Victron Quattro 2nd AC out is only available when connected to the grid So I setup all the AC output to go to a 200Amp 230V only Breaker panel to power all my 230V load and then I also added a 50Amp breaker to feed the autotransformer 230 AC in. I was able then to step that down to 2* 110V lines going to a 100 Amps 110 V sub-panel. and for safety I am also going to use all GFCI breakers as well. I am also going to bond ground and Neutral in the transformer only when I am not in the pass through mode using the relay in the quattro.