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Forum Index : EV's : EV's Off grid charging?

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Godoh
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Joined: 26/09/2020
Location: Australia
Posts: 387
Posted: 09:19am 20 Jul 2023
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We are toying with the idea of having an EV.
We live totally off grid at the moment with around 5kw of solar panels.
We would add more panels to the system but are wondering what the simplest way would be to charge an EV off a solar system.
eg.
Could it be charged straight of DC from the panels?
Would we need a battery bank and inverter to even out the load variations from the solar panels?

We would probably drive around 150 to 200 klm a week.
From what I have read on the forum this would mean we would need enough panels to supply around 15 to 20 kwh to the batteries.
Of course there are cloudy days to take into account.
I am just looking at possibilities at the moment, and interested in the simplest system possible.
I would prefer a very simple car too, but the commercial varieties seem overly complicated to me.
over to you folk
Pete
 
Revlac

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Joined: 31/12/2016
Location: Australia
Posts: 964
Posted: 10:09am 20 Jul 2023
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  Quote  Could it be charged straight of DC from the panels?

Usually No For the commercial varieties, Have a read over on the AEVA https://forums.aeva.asn.au/index.php?sid=5ef8c9eedf7ea1b1836b32701da4ffd0  or just ask them.
For a home built conversion, DIY home DC charging would be preferable.
Edited 2023-07-20 20:21 by Revlac
Cheers Aaron
Off The Grid
 
Godoh
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Joined: 26/09/2020
Location: Australia
Posts: 387
Posted: 04:05am 21 Jul 2023
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Thanks for the response and link Aaron. I will check it out.
Pete
 
Revlac

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Joined: 31/12/2016
Location: Australia
Posts: 964
Posted: 08:31am 21 Jul 2023
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I was also toying with the EV idea, travel is about 100km a week lately with the occasional 250km or so round trip to go to the doctor and some other places.
Also have to include that the return trip to home should still have enough power in reserve (without the need for a charge) for an Emergency trip to the Hospital if needed, Don't think it won't happen because getting older it happens, would not like to be the one with a flat battery in an emergency.
Its very quick and easy to drop 10L of fuel into an ICE vehicle from a fuel can and be on your way, an EV electric charge stop along the way (if even possible) is not going to be quick.

The conclusion was, it made no economical sense to go with a NEW EV or the cost of building one at this point in time, far better cost savings and environmental savings to be had by adding solar and storage to a house.
It may be a different story for those who do a lot more regular travelling.

Also I would not want to end up developing the mental insanity and paranoia that some EV owners get, not all of them just some, while others are very helpful to answer any questions, pros or cons about EV's.

Had a friend over today and his son had a late model hybrid for work, while I could never afford such a thing it is a better more practical solution at this point in time.
I should have asked him if it was a plug in hybrid.
Cheers Aaron
Off The Grid
 
Murphy's friend

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Joined: 04/10/2019
Location: Australia
Posts: 602
Posted: 08:44am 21 Jul 2023
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Pete, in your situation I would only consider a plug in hybrid car from what's available today.
These you usually can slow charge from a power point. Your solar & battery capacity obviously has to be able to supply this charge, especially if the charging time goes beyond sunshine hours.
 
Godoh
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Joined: 26/09/2020
Location: Australia
Posts: 387
Posted: 08:53am 21 Jul 2023
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Thanks yes it does sound like a plug in hybrid would be a good way to go. Being stuck on the mountain with a flat battery in an EV may not be good as Aaron says.
I will have a look at the PHEV range
thanks
Pete
 
Davo99
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Joined: 03/06/2019
Location: Australia
Posts: 1578
Posted: 11:07am 23 Jul 2023
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5 KW is a VERY modest amount of panels to live off!
I'd be doubling that before you even thought of an EV.
You may be able to charge in town while you do the shopping but I'd still put up more panels just for peace of mind.

For the limited amount of Miles you do, I cannot see how an EV would make any sense financially.
 
Godoh
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Joined: 26/09/2020
Location: Australia
Posts: 387
Posted: 08:07am 24 Jul 2023
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Hi Davo, we live a very modest life. Our power usage is only around 1.5kwh a day.
We don't run our batteries down below 70% full charge, so have three days of storage before they have to be topped up.
So far the sun appears or the clouds lighten enough to keep the batteries up fine.
I only use heavy loads like power tools when the weather permits and I know that the batteries will be topped up before sun down.
We are just trying to get away from fossil fuel usage. So far we have ditched gas, so now are trying to ditch petrol where possible.
Considering how complicated car manufacturers want to make their machines these days, we may have to make our own EV.
I definitely don't want heated seats, apple or google play, radar sensors, or any other rubbish. I just want a simple car, so far it does not look like any manufacturers are doing that.
Cheers
Pete
 
Trev

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Joined: 15/07/2006
Location: Australia
Posts: 639
Posted: 10:16am 02 Aug 2023
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Pete,
Commercial EV will be very hard to charge direct from solar. Most are running 300 plus volts. The bigger, heavier vehicles are much higher. F150, Rivian and Cyber Truck all run 800v. An inverter to run a wall outlet charger will be the only option.

You also need to consider how much power you will use and have to put back in. See the thread on EV consumption https://www.thebackshed.com/forum/ViewTopic.php?FID=15&TID=15357

My EV's are 144v nominal.
In EV Hilux I have the main pack in 3 sections of 48v nominal. Each of the 3 sections are connected in series to make the 144v.

I have 3 separate solar systems of 48v nominal. Approx 4kW each.

On one side of the changeover switch, all 3 solar systems are connected in parallel when charging my house batteries.

When charging EV Hilux, the other side of the changeover switch connect each solar system to it's own section of the main pack. The voltage of each pack can get out of balance, but when all done they are all the same voltage. They don't reach full at the same time. Charging in good sun, this can charge around 100km range in a couple of hours.

Ok so then to charge T-Rev direct from the solar....... I connect the 3 solar systems to EV Hilux and connect the 2 vehicle packs together in parallel.

I can also charge either EV Hilux or T-Rev from the wall outlet powered from the inverter, connected to the house solar battery.

Another possibility, if your driving distance is not to high, you can charge an EV at a public outlet, each time your out shopping. I have heard a number of people doing this. They never charge at home. There are still some shopping centers offer free charging.
Trev @ drivebynature.com
 
Godoh
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Joined: 26/09/2020
Location: Australia
Posts: 387
Posted: 10:32pm 02 Aug 2023
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Hi Trev, thanks for the explanation of how you charge your vehicles.
It gives me a bit to think about.
Splitting the cars batteries sounds like a great way to go.
Thanks again'
Pete
 
pollenface

Regular Member

Joined: 01/09/2020
Location: Australia
Posts: 41
Posted: 05:51am 20 Feb 2024
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I occasionally charge my MG ZS EV from a 6000w inverter @ 1.5-1.8kw during strong sunlight. I have roughly 5.5kw of solar split between 4 victron mppts and 5kwh worth of usable lead-acid batteries.

I don't have a lot of battery storage (yet) but also have grid-tied solar available which does most of the work. Charging usually draws about 15-20kwh from the AC side so I imagine 20-25kwh worth of LFP storage in the off-grid system would be great!
Edited 2024-02-20 15:54 by pollenface
Off grid man caver
 
Godoh
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Joined: 26/09/2020
Location: Australia
Posts: 387
Posted: 07:28am 20 Feb 2024
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Hi Pollenface, just wondering what sort of inverter you are using, and what battery voltage?
I have a 24 volt bank, and now that I have added more solar panels I have around 10kw of panels.
They are split into 8 banks so I have 8 controllers and a 14.4kw battery bank.
So plenty of solar to charge the car on sunny days, and still enough on cloudy days to keep the house running and put some into the car if necessary.
Some more information on what gear you have would be great
Pete
 
pollenface

Regular Member

Joined: 01/09/2020
Location: Australia
Posts: 41
Posted: 01:46pm 21 Feb 2024
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Hi mate, the inverter is a high-frequency Xijia/CNSwipower 48v model. It's a good quality Chinese one with built in soft start, probably overkill but it does run my 2.5hp belt-driven air compressor. I've added an extra fan to the rear (with a small buck converter) to run a quiet fan 24/7 to help keep the unit cool & quiet in summer.

I have a mixture of Victron 100/20s and 150/35s and a few different 1-1.5kw matched panel kits which I've picked up 2nd hand from people upgrading their grid-tied systems. Each panel group to it's own controller.

I just need to get my batteries up to speed now, hoping to build a 15kwh lifepo4 bank within the next 12-18months.
Edited 2024-02-21 23:52 by pollenface
Off grid man caver
 
Godoh
Guru

Joined: 26/09/2020
Location: Australia
Posts: 387
Posted: 08:24pm 21 Feb 2024
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Thanks, good to hear that your HF inverter is doing such a good job.
I bought some 2.8mm enamelled wire yesterday to begin winding a bigger transformer for my car charging inverter.
Going to be hot here ( for us) so will make a start on the high voltage side today.
Pete
 
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