Of grid solar charging

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MikeDabrowski2017

Well-known member
Joined
Aug 18, 2017
Messages
53
Location
North East Ct
Most EV owners want to charge as fast as possible
But in my situation I need to control the rate.

I have a battery based micro grid solar system in my home
My outback radian inverter can output a max of 9kw continuous at 240vac
The 45kwh 48v battery bank and 7.5kw solar array
Will fully charge the solar storage bank by noon this time of year so the remainder of the day my excess output was wasted , so the Bolt is a perfect place to dump those electrons
I bought a clipper creek 24 A evse which works fine.
Problem is the solar array with midnight solar mppt charge controllers can at best provide 100-110A of current to charge the solar batteries
The inverter draws 145A from the batteries so to charge the Bolt I cannot maintain the batteries SOC

To solve this problem I just got a juicebox pro 40
This evse is supposed to allow setting the charge current from 6A to 40A
I just got it today so I may not be using it correctly but
It seems to default to 32 A even if I set the max charge rate to 6 A?
Will play with it over the weekend to better understand if I am using it correctly
Anyone else with the juicebox pro 40?
Mike
 
I have neither product, Mike.

However, the EVSE that came with your Bolt is rated for 100 to 268 VAC.

It is internally (automatically) switchable to work in foreign countries.

It will run on 208 or 240 VAC and will be limited to 12 amps. From you car's dashboard, you can limit charge rate to 8 amps.

So you have options with your OEM equipment.

-John
(Former MIMA owner.). :D
 
Correct me if I am wrong, but I thought the switchable 8 amp vs 12 amp setting only applies to when you are charging at 120v?

I used the 12 amp setting with the GM OEM 120v charger until I upgraded my garage to 240v and put into use a Clipper Creek LCS-25p that has been collecting dust since my Chevy Volt days.
 
The juicebox pro40
Can be set to any charge rate with the phone app
So in theory my phone could adjust the rate based on the solar availability
The car accepts that rate and will charge accordingly
Only issue is that the rate of charging seems to be negotiated when the evse is attached and will not change rates until the evse is physically disconnected then re connected
Never easy
As the days get shorter I will not have much excess solar so this may not be something I will not be concerned with until next spring
 
I'm just getting ready to setup an off-grid system and I'm using the OpenEVSE which has the same feature of charge rate control. The car will respond to any charge rate change command from the EVSE and can be varied throughout the charge cycle and/or paused. This is required by the J1772 charger standard so that multiple chargers sharing the same circuit can automatically adjust output depending on how many EVSE are in use at a given time and/or grid conditions in larger installations.

I'm going to use the OpenEVSE in combination with an EmonPi energy monitoring unit to automate opportunity charging when the state of charge in my storage batteries is high and the solar output is in excess of current demand, (and I have inverter output headroom) as a diversion load. I'm not sure if the JuiceBox has an API or if it is open source so you can integrate it with your solar in a similar fashion, but I think setting up an EV this way is a great opportunity to maximize off grid solar harvest throughout the year. :)

I look forward to seeing or hearing more about how your setup works!
 
BoltHighTension said:
I'm just getting ready to setup an off-grid system and I'm using the OpenEVSE which has the same feature of charge rate control. The car will respond to any charge rate change command from the EVSE and can be varied throughout the charge cycle and/or paused. This is required by the J1772 charger standard so that multiple chargers sharing the same circuit can automatically adjust output depending on how many EVSE are in use at a given time and/or grid conditions in larger installations.

I'm going to use the OpenEVSE in combination with an EmonPi energy monitoring unit to automate opportunity charging when the state of charge in my storage batteries is high and the solar output is in excess of current demand, (and I have inverter output headroom) as a diversion load. I'm not sure if the JuiceBox has an API or if it is open source so you can integrate it with your solar in a similar fashion, but I think setting up an EV this way is a great opportunity to maximize off grid solar harvest throughout the year. :)

I look forward to seeing or hearing more about how your setup works!

That's a great thought, but I have a major issue with it - for the vast majority of days, I am not home during peak production. I work during the day, so my car is not at home / available to absorb the excess production. Do you work nights? Is there some other circumstance that I'm missing that would allow you to do this?

I'm very interested in learning about your project even if it wouldn't help me. Could you share some of these details with us?
 
The commute the car is used on is only about 50 miles round trip and the work schedule is a rotating afternoons/days/every other weekend mishmash of terrible corporate planning - so it affords more opportunity to be home for more sunlight hours than a 9-5 might. On afternoon days we can keep charging until after 1pm, and day shift we can charge at the tail end of 4pm, which is really only useful late spring to early fall. The every other weekend shift deal means full daytime charge opportunity is only spaced a maximum of 3 days apart with some weekdays off sprinkled in.

If our commute was shorter, standard "weekends" off schedule might work ok since we currently need to charge about once every 4 or 5 days. The major downside is you only get one "chance" per week and if the weather is bad, it doesn't work out on that schedule. The program that interfaces with the API will just dump sunlight into the car battery whenever it is hooked up to the plug and conditions are optimal with some power to spare. I was thinking about using cloud forecasts to further optimize the charge timing algorithm over time.

tl;dr: Having an oddball schedule gives us a few more opportunities during the week to work around the weather. Having a BIG battery on site to dump power into is great bonus for off grid installs.
 
You work the crazy hours of a nurse! I don't know how you folks do it. If I didn't have a regular schedule, I think it would wear me out in a month flat. More power to you, if you can.

So yeah, that makes sense. Certainly wouldn't benefit everybody, but if you work out a method that allows you to harvest more sunlight, that's great!
 
The other thing I forgot to mention is we are going LiFePO4 for our storage bank, so we can be more flexible with SoC there as well, which gives more flexibility to the overall system - plus the round trip efficiency in and back out of the storage battery is better overall for when we need to tap the house bank off hours.
 
Setting the charging rate with JuiceBox is confusing. You can use load groups, but I haven't figured out yet how exactly those allocate the amperage. Basically you can set the wire rating, the charging rate on the EVSE and the load group. Once you set some parameter the others are effected until you reset everything. Confusing interface.

Note the Bolt will only charge a minimum of 8A, I found it wouldn't charge on any setting less than that. So 8A@120V/960W
 
Happy to see I’m not alone in feeling that the huge 60kwh battery in the Bolt may make a great place to dump excess solar production.
We are going through a spell of weather that
Is mostly cloudy so my 7500w solar array is struggling to keep my 48kwh lead acid storagebank filled
Each day so EV charging is not on the table right now
I can switch to grid supplied power any time and have been using the grid to charge the Bolt .

I have been collecting plug in hybrid battery packs from Ford energi plug in vehicles
The packs use lithium Nickle manganese cobalt oxide NMG type chemistry and the cells are 27 AH
Each rack of 21 batteries can be reconfigured as 1
567AH cell by putting the cells in parallel
Have 16 racks to make a 48V battery
To add to my lead acid solar storage bank.
Hope to get this additional 27kwh of storage on line
soon and hopefully some sunny days to charge it all up
At that point I should be able to charge the Bolt off stored solar energy and still run the house and shop
Off grid.
Too many projects not enough time.
 
MikeDabrowski2017 said:
Too many projects not enough time.

I feel this way simply keeping up a 60-year-old house. I envy the time (and skill!) you have to undertake those projects. Before I traded in my Leaf, I toyed with the idea of keeping it and playing around with the battery. But in the end I decided not to.

Keep pushing the envelope!
 
MikeDabrowski2017 said:
Happy to see I’m not alone in feeling that the huge 60kwh battery in the Bolt may make a great place to dump excess solar production.
We are going through a spell of weather that

Hope to get this additional 27kwh of storage on line
soon and hopefully some sunny days to charge it all up
At that point I should be able to charge the Bolt off stored solar energy and still run the house and shop
Off grid.
Too many projects not enough time.

My 2012 Leaf is set up to direct solar charge (off-grid) with this setup:
1. OpenEVSE (OE) charge controller that accepts simple commands to adjust the amperes.
2 Arduino controller that sends these simple commands based on solar energy production.
3. Sensor monitors the amperes out of my Midnite 250KS CC into my 48 VDC FLA battery pack that is used to calculate the solar energy to the battery system. Sensor Also monitors the battery pack voltage to cut off the OE to prevent too low SOC on the battery pack.
4. Sensor information is used by the arduino to send required ampere setting to OE to "match" (open loop) solar energy going to battery pack.
5. Goal is to maintain 90% plus SOC in battery pack - and keep them in MPPT mode. I can quickly "float" at end of run.
6. I use an 48 VDC based APC UPS for the inverter that outputs 208 VAC to the OE, maybe not the best, but cheap and works great.
6. This installation is in a rural environment that does not have a "sustainable" internet (have to hot spot to get any and SLOW), so limited options on getting solar data => system must be stand-alone

Eventual goal is to purchase a new/used Bolt and use bi-directional CCS/PLC based protocols to drive-in, hook up the CCS and charge/discharge the Bolt's energy for off-grid, emergency use. Why? - the OE level II system is very inefficient - and admittedly a kludge.

I am very interested in information on off-grid solar charging, especially at the 400 VDC bus level. Also,of course interested in any information about GM's CCS protocols that could allow bi-directional energy along a 400 VDC bus :idea: .
 
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