First Electric Car - Finding a Level2 220V charger for setup for my Off-Grid House

rpvietzke · November 2022

My wife purchased a Hyundai Kona Electric, which is a great little car. At our main on-grid home, I ran a couple of #4 AWG to the garage and we can charge at 8Kw+/hr. The little car gets topped off in a few hours... But that is a 50Amp dedicated 220V line and it draws 45A the whole time it is charging.

At my off grid house, I run a 24V schneider CSW4024 system with 6.5Kw of panels on the roof and 3x 3.8kw lithium ion batteries. I have a Generac EcoGen 6.5Kw generator setup at 220V for the dark months. The "main breakers" are 25A-2P on the generac itself and that is what I have setup on the load side of the 4K CSW4024 too. (My normal loads are never even close to 4000W.

So I am trying to figure out some level of basic charging at my off-grid location. It doesn't need to be as fast as home, but I'd like to be able to put some charge on the car, either when the sun is out and sometimes off the generator. I've thought about an A/B transfer switch right in front of an EV charger so I could alternate power between "generator direct" and "inverter", but really that is not the main issue. The main issue is finding a 220V charger that can be set to a low draw like 8-16A per leg.

In looking at 220V chargers, there are lots out there that do 32A-50A at 220V. The one at my main house lets you set the draw level in that range via a web app. But for my off grid location, I probably need to set it down to something more like 8-16A on each 220V leg so that my little 4000W inverter can still do some other loads when charging the car. Something in that range would be fine when the sun is out and should also mean I never trip a breaker when the generator is running and charging both my house batteries and the car.

Anyone know a solution they like (brand suggestions for a level2 charger welcome) that let you set the draw down this low, or is there a different way to think about this?

Rob

Photowhit · November 2022

You have a 3500 watt inverter in the CSW4024, Not sure I'd bother with a level 2 charger, a 16 amp 120 volt level 1 charger is about 1900 watts. At that level you can still run your fridge and such at the off grid place without worrying much about the system. Since you are using lithium batteries, you could start charginging early on sunny days and run it a bit longer allowing your batteries to catchup the next day.

rpvietzke · November 2022

In further searching, I have found a 220V charger that has settings at 8/10/13/16 Amps. This is a nice option as it would let me split the load evenly on both legs of both the inverter and the Genset. On a bright sunny day or when running the generator, that would be 3.8KW at 220V, not the 1900W typical of a 15Amp 120V charger...

Still curious what folks think about just running this all off the load-side of the Inverter, perhaps with "generator assist" or one of the AC-Assist modes of the inverter enabled, or if it might make sense to have two power sources, one pre-inverter direct from the generator for the winter (so you would never draw on the batteries) and one inverter-powered for the summer when there is likely excess solar... Is it worth it to add all that complexity?

BB. · November 2022

Rob, what are your expectations for running the off grid home and charging of the EV?

https://www.hyundaiusa.com/us/en/vehicles/kona-electric/compare-specs

Battery system capacity 64.0 kWh

Level II, Standard (7.2kW onboard charger) (10-100%) 9 hrs 15 min

I am for keeping it simple... A dedicated charger for the Inverter side and a second charger for the Genset (winter) option sounds like fewer headaches overall.

You have something like 10 kWH of lithium batteries and a car with a 64kWH battery bank... There is probably little need to fast charge from your solar system when it could empty your solar bank and only put 1/6th charge on your EV.

A guess at your solar harvest for a fixed array somewhere around Hartford Connecticut:

http://www.solarelectricityhandbook.com/solar-irradiance.html

Hartford
Average Solar Insolation figures

Measured in kWh/m2/day onto a solar panel set at a 48° angle:
(For best year-round performance)

Jan	Feb	Mar	Apr	May	Jun
3.29	4.05	4.62	4.65	4.85	5.07
Jul	Aug	Sep	Oct	Nov	Dec
5.01	4.92	4.73	4.17	3.21	3.00

Say at least 4 hours of sun per day:

6,500 Watt array * 0.61 off grid lithium AC solar eff * 4 hours per day = 15860 WH of 120/240 VAC energy per day (15.9 kWH per day)

I would stick with a low power charger for the solar (maybe 1-2 kWatt max) for long term solar charging. It will take at least a day of "summerish" sun to recharge 25% of the EV battery bank... Probably enough for a daily around town driver.

Reserve the genset if you want fast charging/winter charging. Perhaps even a "cheap" 9-10 kWatt noise maker for fast winter charging (if you will need that--Say drive up, empty battery, and need to turn around and head back home for an emergency)...

Yes, generator assist is pretty nice... But what happens if the genset runs out of fuel/low oil shutdown/etc... This is going to stress or shutdown your solar--And now you are "dead in two ways"--Genset and possible solar.

I would avoid a "large" fast charger on your solar system... You run the risk of draining your battery bank quickly, and only have a 1/4 charge... And the stress/management of the solar power system with a relatively large EV load that would could still take a few days to fully charge an empty EV battery pack--You may end up "breaking" the solar system and spend a large amount of time and $$$ on repairs. More than a genset + gallons of backup fuel would cost.

Your thoughts?

-Bill

Photowhit · November 2022

I bet @Dave Angelini would know if running a 120 volt high wattage off one leg would be an issue for the Schneider inverter.
From my feebly mind, I think it is an issue with Magnum inverters but not Schneider inverters, but I can't recall why...

solar_dave · November 2022

clipper creek make nice chargers
https://store.clippercreek.com/residential/level-1-12-amp-ev-charging-station-acs-15

for a level1 @ 12amps

BB. · November 2022

Takes a lot of reading:

https://www.solar-electric.com/lib/wind-sun/Conext-SW-120-manual.pdf

Page 6-2 or 114 (pdf):

Image: https://us.v-cdn.net/6024911/uploads/editor/uc/tjohap088o3p.png

2,550 Watts max / 120 VAC = 21 amps @ 120 VAC

-Bill

Dave Angelini · November 2022

The CSW will only put out 1/2 charge with 1 leg used. (1/2 of 45adc on the 4048) As shown by Bill. It does work well. The problem with this thread is that a CSW is a small cabin inverter/charger. The OP will probably make it through warranty and then the CSW will fail from being over heated and over worked. It is a poor choice for a large load like an electric car charger.

Like running an electric range or dryer loads, it is the wrong choice. An XW that is designed to properly cool and defend itself from high duty cycle loads is what should have been used, in my opinion.

rpvietzke · November 2022

Thanks all. This is great input. The “total continuous output” of 2550 is certainly a little less than I had thought it would be.

So for now, my likely path is to wire the charger off my pre-inverter generator panel. This way I can get a reasonable 3.8kw charge in those situations where I need to charge at the house. I would love to have a way to harness the solar instead in the summer, but can do that with the super slow charger until some other upgrade…

Best,

Rob

rpvietzke · December 2022

Here is what I ended up doing: I purchased a 220V level-2 charger that I can set to 8-10-13-16A. I did end up running this off a feed from my CSW 4024. At 10A / 220V= 2200W, which should be well under the inverter continuous load limit and it allows me to harness solar for occasional runs in the summer.

For the winter, I put a manual spring-loaded timer switch (6 hours max) next to the plug outside to start the generator. This will allow the 10A/220V to flow from the generator via the pass-through relay in the inverter and shouldn't be too taxing on either those contacts or the generator.

I did seriously think about putting this on the "generator only" panel, but thought that would be complicated because the inverter tends to want to top off the batteries at high current whenever the generator starts. By wiring this through the inverter, the inverter gets to judge the total load and adjust the charge-rate to the batteries when the generator starts.

This certainly won't charge the battery in the car quickly or to the top, but it should add the miles we need to get around. Not perfect, but given this will only get used a few times a year, I think/hope it is the right choice.

Rob

Dave Angelini · December 2022

Two kinds of people, those who want solar and those who want more. 😉

rpvietzke · December 2022

That's spot on. I want both, of course. And cheap. not a good combination!

JRHill · December 2022

Just saw a feature one the news: Driving in,, and I quote, VERY RURAL area with an EV.

If you can guess, it was down the interstate in Cali. The next was down the interstate in TX. Both between big cities on the interstate.

To me, Very rural is where I live. Get it? Friggin city people think VERY RURAL is between metro areas a few hours apart on the interstate? Its not 2 to 5 hours out on two lane roads.

We will have to ditch our rigs due to climate change. Right.

We have a problem here....

Dave Angelini · December 2022

We landed a man on the moon a long time back. Electric cars are way down the list from getting into another world war, a crazy southern border, and uninformed people who just want to be entertained.

So many problems and so little aged wine and spirits in the cellar. You might as well have a good time!

Just so I do not derail further, an electric car in an offgrid home needs at least 10KW of solar and a failsafe to protect the battery.

In my opinion. Cheers!

JRHill · December 2022

WA Gov Inslee just negated fossil fuel CARS by 2035. Gee, go figure, right after Cali. Details to follow, but how does a farm rig fuel?

Using Dave's numbers we can't get 10kW.

It's all about city people.

oilpond · December 2022

Not sure but wouldnt waste my expensive lithium and just go some portable crap see8ng its going to sit for weeks.

JRHill · December 2022

I would consider a hybrid of suitable ground clearance, 4wd and a suspension and steering that can handle our year around environment. And wouldn't it be cool if its generation capabilities could be paired to an off grid situation if needed? That rig will be a long time coming to market. That Ford with the power taps was a step in the direction but it wasn't a hybrid. Sure haven't heard much of that rig lalely.

Dave Angelini · December 2022

Me too JR. It just needs to make sense. The quote you used from me was 10 + KW of solar.

An offgrid home has to power the home and anything else is gravy. I know several in Alaska that are well over 20KW just for the home.

First Electric Car - Finding a Level2 220V charger for setup for my Off-Grid House

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Hartford
Average Solar Insolation figures

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First Electric Car - Finding a Level2 220V charger for setup for my Off-Grid House

Comments

HartfordAverage Solar Insolation figures

Categories

Hartford
Average Solar Insolation figures