Want grid connected solar without storage to be able to charge EV

[DaveCA]

I live in CA and am looking at getting solar panels but given storage's expense, I plan to skip getting battery backup for now. Pretty much everyone has said that means I have to get a system that would automatically turn off if the grid goes down -- my panels go down with the grid. Adding a battery so I could draw on panels and battery when grid was down would cost >$5,000. A lot more than I want to pay. I don't really need power storage, I can deal with getting power only during daylight hours and I am not much of a do it yourselfer.

What I want

1. is a (cheap) way to at least charge my EV's battery from the panels when the grid is down. I figure voltage and wattage fluctuations from panels shouldn't be a problem for charging EV batteries but maybe I am wrong
2. to know why some sort of big capacitor or small battery with rapid charge and discharge couldn't be attached to system so during daylight hours the panels could buffer into battery to provide enough stability to run things like refrigerator without really storing much energy. Think like < 10 Wh storage (maybe < 1 Wh).

Any suggestions or explanations greatly appreciated.

 

[Supervstech]

Let’s start with some realistic math.
What ev do you have? What KWh is the battery pack? How do you charge it now? How fast does it charge?

 

[DaveCA]

Tesla Y, 75kWh. No hurry, currently I typically use less than 10 kWh/day on the battery those 10 kWh could be put in over 5 hrs so 2kW through the system, maybe 3 peak. The solar systems I am looking at will generate way more power than that. I am just looking at something to keep car charged and maybe run refrigerator, wifi, and charge up laptops and tablets when the sun is shining.

 

[time2roll]

I think you want a "Secure Power Supply" grid-tie inverter.

This will operate as a normal grid-tie inverter and shut down when the grid goes down. However you can use your level 1 charge connector to charge the EV from a single outlet to be used when the grid is down. You may not get 10 kWh per day but it will certainly extend the range if you can get a few miles each day.

SMA Sunny Boy SB3.0-US-41 to SB7.7-US-41 Grid-Tie Inverters

"SMA’s unique Secure Power Supply feature has been improved, and now can supply up to 2,000 W (15 A / 120 VAC) of power to a protected outlet during a grid outage, which provides a single ‘protected’ outlet useful for recharging portable devices or a small UPS directly from the PV array. "

http://www.solarhome.org/SMASB3.0-USSunnyBoy3000WGridTieInverter.aspx

 

[Lvivlviv]

I have Tesla Y and charge it with my solar.

 

[solar8484]

I have Tesla Y and charge it with my solar.

Yes, you are charging with solar but also with batteries which the OP does not want.

 

[solar8484]

I live in CA and am looking at getting solar panels but given storage's expense, I plan to skip getting battery backup for now. Pretty much everyone has said that means I have to get a system that would automatically turn off if the grid goes down -- my panels go down with the grid. Adding a battery so I could draw on panels and battery when grid was down would cost >$5,000. A lot more than I want to pay. I don't really need power storage, I can deal with getting power only during daylight hours and I am not much of a do it yourselfer.

What I want

1. is a (cheap) way to at least charge my EV's battery from the panels when the grid is down. I figure voltage and wattage fluctuations from panels shouldn't be a problem for charging EV batteries but maybe I am wrong
2. to know why some sort of big capacitor or small battery with rapid charge and discharge couldn't be attached to system so during daylight hours the panels could buffer into battery to provide enough stability to run things like refrigerator without really storing much energy. Think like < 10 Wh storage (maybe < 1 Wh).

Any suggestions or explanations greatly appreciated.

What is "cheap" for you?

 

[Scorch]

I'm considering doing something similar, but not grid tied. Thinking about building a carport next to my off-grid cabin and mounting a bunch of used solar panels .... maybe 10kw or so. Would be great if there is a small inverter out there that could feed nothing but a 220 NEMA 14-50 outlet and just feed the Tesla whatever power it creates. Does anyone know if that is possible or if it could damage the battery having big swings in voltage? Might not be too much more to just add a couple kwh of battery to smooth things out. Any suggestions are appreciated.

 

[solar8484]

I'm considering doing something similar, but not grid tied. Thinking about building a carport next to my off-grid cabin and mounting a bunch of used solar panels .... maybe 10kw or so. Would be great if there is a small inverter out there that could feed nothing but a 220 NEMA 14-50 outlet and just feed the Tesla whatever power it creates. Does anyone know if that is possible or if it could damage the battery having big swings in voltage? Might not be too much more to just add a couple kwh of battery to smooth things out. Any suggestions are appreciated.

Unfortunately, it's not that simple. If EV charging current is set at a given level and your off-grid solar system is not producing enough then the EV will likely go in to cycling charging off then on a few times before stopping permanently. Even if you set the charging current to minimum (5A for Tesla's) there could be clouds, passing bird flocks or planes that disrupt charging. Tesla's would require you to manually unplug then replug the charging connector to reset. To be practical in general, you need to have a system that can automatically adjust the charging current level to available solar power. Otherwise, you have to do it manually which is likely only usable in limited situations.

 

[mrzed001]

The problem you face is that the sun shines at 8-16:00, but in this time most people are at work and not home ... so is there Tesla
If charging when the sun shines is ok then 2 solution:
1, a Grid-tie system: you need paperwork, local utility to allow it .... it is different anywhere
2, an Off-grid system: no paperwork, no utility, and you do not need a battery.

There are batteryless Off-grid inverters.
You connect the solar panels to the inverter and you got power as long the sun is up.
This 6kW inverters are cheap like $950. The solar panels cost waaaaay more.

Also you can mix solar with utility power. You can charge the Tesla like with 5kW and 4kW comes from solar and 1kW from utility.
So you use as much less from utility as much your solar array produces.