Off-Grid EV Charging
Several of us have been discussing methods of charging our electric cars if the power grid quit working. Our PV systems using Enphase Microinverters will not work if they are not supplied with 240 vac. With a Net-Metering agreement with our electric provider, we can get paid at a wholesale rate for excess production, but with an Off-Grid PV installation, any excess power simply goes to waste. With that in mind, perhaps a small Off-Grid PV system with enough output to charge a car using the 115 vac cable that comes with most EVs. Dozens of email have been exchanged, and I'll post them here to document the "journey".
Old style is the M215 Microinverter, with or without the Integrated
Ground (IG). These are being sold for less than $40, and seem to be
brand new. (I got some for $36, delivered.) Look for used solar
panels with 245 watt rating. Very cheap, and work well with the M215.
They cannot be shipped UPS, and must come via Motor Freight, or you
can find them on Craigslist in Austin now and then.
> Can you expand on this. (Inverter Generator) The best description of how these work is on a Scooter Store webpage: https://www.scooterwholesales.
Please scroll down to where it says, "How does this work". "In
contrast with the traditional generators that run at a constant
RPM/speed, DG-3000 portable inverter generators are equipped with
microprocessor controlled Intelligent Throttle Technology which
automatically adjusts the engine speed to precisely match the load.
So, if the generator is not powering many appliances, it runs at a
lower engine speed. This allows the generator to run quieter while
increasing fuel efficiency, increasing engine life and extending
running time between refueling. Once the load is increased, this
inverter generator increases the speed and RPM automatically to meet
the demands of the load. The variable speed feature of the DG-3000
inverter generators provides many advantages, some of which include:
Increased Life Span Due to Decreased Engine-Wear.
Lighter Weight and Compact
Fuel Efficient and Economical to Operate
Quiet Operation
Environmentally Friendly"
I'm not recommending their generator, but they have the best
description. Everybody makes and sells this type of generator in
2019.
Yes, I read the Austin-San Antonio Tesla Forum, and even the postings
on Facebook.
Regarding Batteries. Been there, done that using 6 volt golf cart
batteries, truck batteries, and marine deep cycle trolling motor
batteries. I would recommend some like the Thundersky Winston 200Ah
3.2V LiFePO4 Lithium Battery Cell WB-LYP200AH
They look like this:
https://www.ebay.com/itm/Thund
Willie has a couple hundred of them that he used in his DIY Electric Cars.
They need either a BMS or a very watchful operator. There are some
YouTube videos worth looking at, especially this one:
https://youtu.be/E4pN4DVPOcY
There are charge controllers that are specifically for LiFePO4 batteries.
Another neighbor, here in Dale is charging his batteries with single
cell chargers. One automatic charger for each battery. He also has a
Tesla and a Nissan Leaf. He was the subject of a 3 page article in
the CoOp Newsletter:
http://austinfarm.us/homegrown
Gene wrote up a proposal on how he might charge his car with a few solar panels and a single battery, but he has marked it as "copyrighted by him", so I'll not show it here.
Gene wrote, " Any comments on this design?"
I would label the box connected to the panels as a charge controller,
rather than an inverter.
With solar panels being so cheap, I would recommend an array capable
of producing a minimum of at least 2000 watts for a period of 5 hours
per day (when the sun shines)
Why use such a small battery? It should be able to smooth out the
fluctuations in solar power caused by those big fluffy clouds we see
so often. Why not use some of the excess power stored in the battery
to allow some charging past 4 P.M.?
One thing that worries me about level 1 charging is the fact that I
can hear the pumps running the coolant inside the battery. Perhaps
level 2 charging would minimize the amount of wear and tear on the
pumps?
>With solar panels being so cheap, I would recommend an array capable
>of producing a minimum of at least 2000 watts for a period of 5 hours
>per day (when the sun shines)
Good suggestion but the panels need to match the level 1 max charging
I have in mind. Level 2 charger could be made for panels up to 10 kW
using the same concept but my daily car driving doesn't use that much
energy. Also I don't have room for 10 kW of panels. The Tesla
proposal for 5 kW used two of my roof sections. Im thinking one roof
section can handle the 2 kW fine and its easier to install. And this
is going to be an off the grid system. I don't want AE involved in this.
>Why use such a small battery? It should be able to smooth out the
>fluctuations in solar power caused by those big fluffy clouds we see
>so often.
The arrangement allows the car itself to track the solar
fluctuations. By using a small battery the cost is minimized. Being
a small battery means it has to be in float operation most of the
time. A larger battery could be installed but its extra energy would
only be used to store extra energy the EV cannot take. That requires
moving more load to it. However with 10 kW and level 2 and extra
batteries I could move my pool pumping load which is 240 volt over to
that larger system. I'll consider that as a second phase if all
works well with the first phase. The objective right now is to get
the car off fossil fuels. It's a marketing thing.
> Why not use some of the excess power stored in the battery
>to allow some charging past 4 P.M.?
There is no need to have power stored for use after 4 PM because its
already stored in the car as extra miles.
>One thing that worries me about level 1 charging is the fact that I
>can hear the pumps running the coolant inside the battery. Perhaps
>level 2 charging would minimize the amount of wear and tear on the
>pumps?
I have noticed when those things are running there is little charging
on the EV battery as you have noticed with level 1. However you can
close the Tesla door and step away from the car and when all that AC
and other loads stop running the level 1 charging resumes. I'm
assuming the sentry is turned off also being parked in your
garage. The charging level is easy to monitor.
https://www.solaredge.com/us/p
It came from this list of 2018 top solar inverter products listed
here: https://www.solarpowerworldonl
On June 29th, I wrote this to Gene and Willie:
As you know, my most recent solar experiences have been limited to
grid-tie with Enphase Microinverters, so thinking about a set-up for
off-grid charging your Model 3 is a bit of a "mind exercise".
My very first solar setup was with some golf cart batteries, a charge
controller, and a crude inverter with the idea of using it for
basement lighting in the workshop, to offset power pulled from the
grid. It worked for a while, but I never recovered even a fraction of
the initial cash outlay.
However, now I realize my system will not work if the grid goes down,
so I've been looking into your request for an inexpensive scheme to
charge your car and run a refrigerator. (Who knows, I might need to
do the same?)
How about this? Nine of Willie's used 245 watt panels, set up as
three series strings of three, feeding into a MidNite Solar Classic
150-SL MPPT PV Charge Controller available from Northern Arizona Wind
and Sun for $599. Then, the Outback Power VFX3524M 3500 Watt Sine
Wave Inverter available for $1780. (This is for a 24 volt battery.)
I'll leave it to you to find enough batteries to do the job.
Study this YouTube video and the links in the description.
https://www.youtube.com/watch?
Also, it might be helpful to call Northern Arizona Wind and Solar on
their help line at 800-383-0195 and ask them for recommendations.
Also check out the instruction and installation manuals available on
Wholesale Solar's site.
https://www.wholesalesolar.com
In fact, you might ask these professionals for a quote.
On June 30th, I wrote this:
I've been looking at MPPSolar.com products which incorporate a charge
controller, battery charger, and Inverter all in one package for a
very reasonable price. (Made in Taiwan, though.) I decided the
PIP-5048 MG would be best, outputting 240 vac and using lots more
panels, and (if required) a 48 volt battery.
Then I found this guy (Aviad Offer) charging his Bolt the MPP product
using output from only 4 solar panels (255 watt) and a 24 volt battery
pack, plus he incorporates a web interface to show what is happening
with the power flow.
https://youtu.be/FqyARTCtGxs
It seems to be exactly what Gene was talking about. Also, with enough
panels, I think I read that batteries aren't even necessary with some
versions of the MPP. Plus that, the grid isn't required either.
Data sheet here: https://www.mppsolar.com/v3/ca
Then, as Mr. Offer's addiction grew, he added many more solar panels,
and 3 more MPP units, plus a Juicebox 40 (This is the one I have.)
Now he can do some serious charging!
He switched the batteries over to Chevy Volt packs, but needed just a
little more, so he added 300 18650 batteries (all in parallel as a 1S
configuration). Adding the pack of 1S batteries in series with the 24
volt configuration of the Volt batteries allows them to be charged to
a higher voltage with the MPP units.
The Juicebox through the API can change the current pushed to the car,
so on overcast days, the lower current going to the car matches the
reduced current coming from the solar panels.
He has also added his house AC to the off-grid system so he can use
the solar power when both the Bolt and the Volt batteries are charged.
https://youtu.be/-A8rjNvvyvs
Finally, the information about How to turn Chevy Volt 6s (22v) to 7s
(24v) for MPPsolar Hybrid Inverters (Or any inverter)
https://youtu.be/EkpraWsZ-tk
When making the pack with the 300 18650 cells, he put fuses on each battery.
Really good information, IMHO.
On July 1, 2019 PIP-5048MG
It is shown on Aliexpress for $642 + $115.79 shipping.
https://www.aliexpress.com/ite
I've never purchased anything from AliExpress.
Here is the data on the used solar panels from Santansolar in Gilbert, Arizona. Before Freight charges, the panels are $49.49 if bought as a pallet full.
August 9, 2019
The two pallets of 25 panels each have been delivered and distributed between four people.
I spent days and days scanning eBay and YouTube for possible solutions, wavering back and forth between very high quality charge controllers, pure sine wave inverters, etc, and decided on the MPP Solar Hybrid LV2424 that will include the MPPT charge controller, a 2400 watt pure sine wave inverter, and software monitoring, so excess power can be fed into the grid via a 120 volt extension cord. This will require a 24 volt battery in the system, and once the battery is full, excess power not needed by a load (such as charging an Electric Car) will be fed into the grid using my existing net-metering Distributed Generation agreement with the local power company.
The PV into this unit cannot exceed 2000 watts, so four strings of two panels will be combined and fed into the unit. (8 X 245 = 1960 watts)
Old style is the M215 Microinverter, with or without the Integrated
Ground (IG). These are being sold for less than $40, and seem to be
brand new. (I got some for $36, delivered.) Look for used solar
panels with 245 watt rating. Very cheap, and work well with the M215.
They cannot be shipped UPS, and must come via Motor Freight, or you
can find them on Craigslist in Austin now and then.
> Can you expand on this. (Inverter Generator) The best description of how these work is on a Scooter Store webpage: https://www.scooterwholesales.
Please scroll down to where it says, "How does this work". "In
contrast with the traditional generators that run at a constant
RPM/speed, DG-3000 portable inverter generators are equipped with
microprocessor controlled Intelligent Throttle Technology which
automatically adjusts the engine speed to precisely match the load.
So, if the generator is not powering many appliances, it runs at a
lower engine speed. This allows the generator to run quieter while
increasing fuel efficiency, increasing engine life and extending
running time between refueling. Once the load is increased, this
inverter generator increases the speed and RPM automatically to meet
the demands of the load. The variable speed feature of the DG-3000
inverter generators provides many advantages, some of which include:
Increased Life Span Due to Decreased Engine-Wear.
Lighter Weight and Compact
Fuel Efficient and Economical to Operate
Quiet Operation
Environmentally Friendly"
I'm not recommending their generator, but they have the best
description. Everybody makes and sells this type of generator in
2019.
Yes, I read the Austin-San Antonio Tesla Forum, and even the postings
on Facebook.
Regarding Batteries. Been there, done that using 6 volt golf cart
batteries, truck batteries, and marine deep cycle trolling motor
batteries. I would recommend some like the Thundersky Winston 200Ah
3.2V LiFePO4 Lithium Battery Cell WB-LYP200AH
They look like this:
https://www.ebay.com/itm/Thund
Willie has a couple hundred of them that he used in his DIY Electric Cars.
They need either a BMS or a very watchful operator. There are some
YouTube videos worth looking at, especially this one:
https://youtu.be/E4pN4DVPOcY
There are charge controllers that are specifically for LiFePO4 batteries.
Another neighbor, here in Dale is charging his batteries with single
cell chargers. One automatic charger for each battery. He also has a
Tesla and a Nissan Leaf. He was the subject of a 3 page article in
the CoOp Newsletter:
http://austinfarm.us/homegrown
Gene wrote up a proposal on how he might charge his car with a few solar panels and a single battery, but he has marked it as "copyrighted by him", so I'll not show it here.
Gene wrote, " Any comments on this design?"
I would label the box connected to the panels as a charge controller,
rather than an inverter.
With solar panels being so cheap, I would recommend an array capable
of producing a minimum of at least 2000 watts for a period of 5 hours
per day (when the sun shines)
Why use such a small battery? It should be able to smooth out the
fluctuations in solar power caused by those big fluffy clouds we see
so often. Why not use some of the excess power stored in the battery
to allow some charging past 4 P.M.?
One thing that worries me about level 1 charging is the fact that I
can hear the pumps running the coolant inside the battery. Perhaps
level 2 charging would minimize the amount of wear and tear on the
pumps?
>With solar panels being so cheap, I would recommend an array capable
>of producing a minimum of at least 2000 watts for a period of 5 hours
>per day (when the sun shines)
Good suggestion but the panels need to match the level 1 max charging
I have in mind. Level 2 charger could be made for panels up to 10 kW
using the same concept but my daily car driving doesn't use that much
energy. Also I don't have room for 10 kW of panels. The Tesla
proposal for 5 kW used two of my roof sections. Im thinking one roof
section can handle the 2 kW fine and its easier to install. And this
is going to be an off the grid system. I don't want AE involved in this.
>Why use such a small battery? It should be able to smooth out the
>fluctuations in solar power caused by those big fluffy clouds we see
>so often.
The arrangement allows the car itself to track the solar
fluctuations. By using a small battery the cost is minimized. Being
a small battery means it has to be in float operation most of the
time. A larger battery could be installed but its extra energy would
only be used to store extra energy the EV cannot take. That requires
moving more load to it. However with 10 kW and level 2 and extra
batteries I could move my pool pumping load which is 240 volt over to
that larger system. I'll consider that as a second phase if all
works well with the first phase. The objective right now is to get
the car off fossil fuels. It's a marketing thing.
> Why not use some of the excess power stored in the battery
>to allow some charging past 4 P.M.?
There is no need to have power stored for use after 4 PM because its
already stored in the car as extra miles.
>One thing that worries me about level 1 charging is the fact that I
>can hear the pumps running the coolant inside the battery. Perhaps
>level 2 charging would minimize the amount of wear and tear on the
>pumps?
I have noticed when those things are running there is little charging
on the EV battery as you have noticed with level 1. However you can
close the Tesla door and step away from the car and when all that AC
and other loads stop running the level 1 charging resumes. I'm
assuming the sentry is turned off also being parked in your
garage. The charging level is easy to monitor.
| |||
It came from this list of 2018 top solar inverter products listed
here: https://www.solarpowerworldonl
On June 29th, I wrote this to Gene and Willie:
As you know, my most recent solar experiences have been limited to
grid-tie with Enphase Microinverters, so thinking about a set-up for
off-grid charging your Model 3 is a bit of a "mind exercise".
My very first solar setup was with some golf cart batteries, a charge
controller, and a crude inverter with the idea of using it for
basement lighting in the workshop, to offset power pulled from the
grid. It worked for a while, but I never recovered even a fraction of
the initial cash outlay.
However, now I realize my system will not work if the grid goes down,
so I've been looking into your request for an inexpensive scheme to
charge your car and run a refrigerator. (Who knows, I might need to
do the same?)
How about this? Nine of Willie's used 245 watt panels, set up as
three series strings of three, feeding into a MidNite Solar Classic
150-SL MPPT PV Charge Controller available from Northern Arizona Wind
and Sun for $599. Then, the Outback Power VFX3524M 3500 Watt Sine
Wave Inverter available for $1780. (This is for a 24 volt battery.)
I'll leave it to you to find enough batteries to do the job.
Study this YouTube video and the links in the description.
https://www.youtube.com/watch?
Also, it might be helpful to call Northern Arizona Wind and Solar on
their help line at 800-383-0195 and ask them for recommendations.
Also check out the instruction and installation manuals available on
Wholesale Solar's site.
https://www.wholesalesolar.com
In fact, you might ask these professionals for a quote.
On June 30th, I wrote this:
I've been looking at MPPSolar.com products which incorporate a charge
controller, battery charger, and Inverter all in one package for a
very reasonable price. (Made in Taiwan, though.) I decided the
PIP-5048 MG would be best, outputting 240 vac and using lots more
panels, and (if required) a 48 volt battery.
Then I found this guy (Aviad Offer) charging his Bolt the MPP product
using output from only 4 solar panels (255 watt) and a 24 volt battery
pack, plus he incorporates a web interface to show what is happening
with the power flow.
https://youtu.be/FqyARTCtGxs
It seems to be exactly what Gene was talking about. Also, with enough
panels, I think I read that batteries aren't even necessary with some
versions of the MPP. Plus that, the grid isn't required either.
Data sheet here: https://www.mppsolar.com/v3/ca
Then, as Mr. Offer's addiction grew, he added many more solar panels,
and 3 more MPP units, plus a Juicebox 40 (This is the one I have.)
Now he can do some serious charging!
He switched the batteries over to Chevy Volt packs, but needed just a
little more, so he added 300 18650 batteries (all in parallel as a 1S
configuration). Adding the pack of 1S batteries in series with the 24
volt configuration of the Volt batteries allows them to be charged to
a higher voltage with the MPP units.
The Juicebox through the API can change the current pushed to the car,
so on overcast days, the lower current going to the car matches the
reduced current coming from the solar panels.
He has also added his house AC to the off-grid system so he can use
the solar power when both the Bolt and the Volt batteries are charged.
https://youtu.be/-A8rjNvvyvs
Finally, the information about How to turn Chevy Volt 6s (22v) to 7s
(24v) for MPPsolar Hybrid Inverters (Or any inverter)
https://youtu.be/EkpraWsZ-tk
When making the pack with the 300 18650 cells, he put fuses on each battery.
Really good information, IMHO.
On July 1, 2019 PIP-5048MG
It is shown on Aliexpress for $642 + $115.79 shipping.
https://www.aliexpress.com/ite
I've never purchased anything from AliExpress.
Here is the data on the used solar panels from Santansolar in Gilbert, Arizona. Before Freight charges, the panels are $49.49 if bought as a pallet full.
Description:
This listing is for a 245W 60 Cell Poly solar panel. These are used panels.Panels have developed snail trails (see pictures). Does not affect output. Mfg labels have been removed. Panels have been tested and have good output. These would need to be for off grid applications.Features:
- 60 Cell Polycrystalline
- Weather resistant. Certified for salt mist and ammonia resistance
- Anti-Reflection surface treatment
Specifications:
- Rated Power: 245W
- Open circuit voltage (VOC): 37.5 V
- Max power voltage (VMP): 30.2 V
- Short circuit current (ISC): 8.68 A
- Max power current: 8.13 A
- Power Tolerance 0/+3%
- Maximum system voltage: 600V (UL)
- Fuse Rating: 15 A
- IP65 Junction Box w/MC4 Compatible Connectors
- Frame: Anodized aluminum alloy
- Weight: 41 lbs
- Dimensions: 1650 × 992 × 35mm (64.95 × 39.05 × 1.37 inches)
August 9, 2019
The two pallets of 25 panels each have been delivered and distributed between four people.
I spent days and days scanning eBay and YouTube for possible solutions, wavering back and forth between very high quality charge controllers, pure sine wave inverters, etc, and decided on the MPP Solar Hybrid LV2424 that will include the MPPT charge controller, a 2400 watt pure sine wave inverter, and software monitoring, so excess power can be fed into the grid via a 120 volt extension cord. This will require a 24 volt battery in the system, and once the battery is full, excess power not needed by a load (such as charging an Electric Car) will be fed into the grid using my existing net-metering Distributed Generation agreement with the local power company.
The PV into this unit cannot exceed 2000 watts, so four strings of two panels will be combined and fed into the unit. (8 X 245 = 1960 watts)
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