Solar Charging

[Sandroad]

Here are a couple of photos of my solar charging station for our Clarity PHEV. One photo shows a ground mounted solar panel array. There are two arrays with six panels each, for a total of 12 panels. At 250 watts for each panel, we have 3000 watts of production capacity. The other photo is of the charging station showing the charge controller, inverter, master switch panel, and AC outlets. The inverter can output a maximum 4Kw. Directly below the charging station (but not pictured) are eight deep cycle lead-acid AGM batteries with a total usable capacity of approximately 7.2Kwh, so the car can be charged approximately 50% using the storage batteries going through the inverter. This is an off-the grid system not connected to the utility. It has both level 1 and level 2 charging capabilities, but using the level 2 capability requires full sun on both panel arrays, as well as additional stored power from the deep cycle batteries. The pre-built charging station from Northern Arizona Wind and Sun was $3800. The batteries and wiring were $1800, and the two solar arrays were $1300 each. So the total investment was $6900. We use the Clarity for all local driving and occasional longer trips. So far, our miles are courtesy of the sun, with a very rare resort to to a few Kw from utility power on weeks with extended cloud cover. The charging station has many different ways of tracking power production/usage and after a few months of use, we’ll report back on that data.

 

[loomis2]

How big are those arrays? And where are you? I notice the snow in the photo. Also, how much does this save you each year?

 

[Sandroad]

We live in the Lansing, Michigan area. We had some snow around through most of April. The arrays (2 of them) are roughly 15X6 feet each, with each panel being roughly 3X5 feet. We don't have enough data yet to give you firm answer on the savings, so I won't speculate on that. We're dealing with major shading issues for the solar arrays, so production will be well below theoretical. And, we didn't do this for financial reasons, we did it for fun, to learn new stuff, and reduce our carbon footprint.

 

[vicw]

That's very impressive. I wish I had the space to try that, for the same reasons as you described. Is all of the electronics in your second picture related to the solar power management? Maybe you could share a rundown on the general setup, and what the components are doing.

 

[GetClarity]

It's to bad you/we have to convert to AC for the Clarity to convert back to DC. Especially since grid-tie PV panels could produce the high voltage DC the Clarity is probably using.

The value proposition isn't all about direct dollar savings, as you suggest. Good job getting it done.

 

[Sandroad]

That's very impressive. I wish I had the space to try that, for the same reasons as you described. Is all of the electronics in your second picture related to the solar power management? Maybe you could share a rundown on the general setup, and what the components are doing.

Yes, all the electronics are related to the power flow/management. As an overview:

The box on the right is the Magnum Power Track charge controller. It's a 3 stage charger that takes the DC output of the solar panels and charges the storage batteries. The box on top is the Magnum MagnaSine inverter that takes the DC power in the batteries and inverts it to AC power. The AC power from the inverter then goes to the grey boxes on the left, which are the AC breakers and receptacles to plug the car into. Below the inverter the box with the meter on it is the switch box that has all the wiring to/from the panels, to/from the inverter, to/from the batteries and to/from the AC breakers. The meter also has data storage, so I'm looking forward to doing a data dump after a few more Clarity charge cycles.

And in response to @GetClarity , yes, there is a lot of conversion going on, not just DC-AC-DC, but also DC-DC voltage conversion and also from electrical to chemical to electrical to chemical to electrical by the time the power gets from the solar cells to the Clarity motor! Someday when I feel like being depressed, I'll figure our the total losses in the system

 

[Pushmi-Pullyu]

Solar panels on a frame on the ground makes so much more sense to me! If you put them on your roof, then you can either have shade trees keeping direct sunlight off the house, or power from solar panels... but not both! Also, when it snows, it's far easier to brush the snow off when the panels are near ground level.

But I suppose shading the house is far less important in Michigan, where you don't need to run a central A/C to cool the house for that many weeks per year. Here in Kansas, we need to run the A/C for about 5 months a year, so shade trees above the roof help a lot!

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[jdonalds]

Our system has 20 panels of 365W each. The system peaks about 6,500kW mid-day. It is supplying both the house needs (no A/C yet but that will come soon) and charging the car. The system is also returning more than 10kW/day to the grid.

I'm not sure the solar will be able to provide all of that when the hot weather starts. We have about 6 weeks of 100-105 with occasional 110-112 up to 5pm. The temp never drops below 80F overnight during those weeks. The solar system will produce less then. The A/C will run 24 hours a day. And the Clarity won't be as efficient at those temps. My hope is we can bank enough grid power to break even over the whole year.

 

[GetClarity]

I doubt the Clarity can be tricked in to being a 240VAC source without hacking, but it would be great if a grid-tie inverter could recognize it as a grid source and supply current to the Clarity HV battery. You could get by with as little as 6 panels, 6 optimizers (solar DC-DC converters), and a SolarEdge inverter. Of course the vehicle would have to be home during the sunny part of the day to get use of the arrangement.

 

[vicw]

Yes, all the electronics are related to the power flow/management. As an overview:

The box on the right is the Magnum Power Track charge controller. It's a 3 stage charger that takes the DC output of the solar panels and charges the storage batteries. The box on top is the Magnum MagnaSine inverter that takes the DC power in the batteries and inverts it to AC power. The AC power from the inverter then goes to the grey boxes on the left, which are the AC breakers and receptacles to plug the car into. Below the inverter the box with the meter on it is the switch box that has all the wiring to/from the panels, to/from the inverter, to/from the batteries and to/from the AC breakers. The meter also has data storage, so I'm looking forward to doing a data dump after a few more Clarity charge cycles.

And in response to @GetClarity , yes, there is a lot of conversion going on, not just DC-AC-DC, but also DC-DC voltage conversion and also from electrical to chemical to electrical to chemical to electrical by the time the power gets from the solar cells to the Clarity motor! Someday when I feel like being depressed, I'll figure our the total losses in the system

Thanks, Sanroad.I think I understand the layout now, except for those two round things mounted to the sides of the Meter and the Switch Box areas.

 

[Sandroad]

Lightning (surge) arrestors from Midnight Solar. One is for the DC and one is for the AC circuits. Good surge protection and excellent grounding is needed in off-the-grid solar systems. I learned the hard way on that topic.

 

[vicw]

Lightning (surge) arrestors from Midnight Solar. One is for the DC and one is for the AC circuits. Good surge protection and excellent grounding is needed in off-the-grid solar systems. I learned the hard way on that topic.

Aha!. That makes sense. Having that exterior wiring exposure to lightning damage must increase the risk substantially.

We are in the Southeast, and have had our share of lightning-caused damage to electronics. My next door neighbor and I had damage from a single strike to a tree between us that caused about $13k damage a few years ago. I do have a full house surge suppressor, but whenever we have a threat of lightning now, I pop the breakers for the 240 V charger, and keep the car disconnected from it, until the threat passes.