using Clarity as battery back for for solar system

  • Thread starter Thread starter glockgirl
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glockgirl

glockgirl

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hi,
has anyone thought of or tried to use the 17 kw battery pack as battery back up for metering house solar system? i leave in FL and thinking of getting solar installed on roof, but also want the battery back up option as well. with sell back option, if the storm knock out the power, solar stops working, to prevent electricity going back to power company as they try and restore power and work on damaged power lines. its big safety issue.
is there a way to set solar system to pull from clarity to power the house? use the solar panels to recharge the clarity during the day?
adding house battery pack would set me back another 10K in addition to solar panel set price. (the new ford truck has that option as one of its selling points)
 
Some have used the Clarity as a power source during a grid outage, but only for a select few items (not whole house). This was done with an inverter on the 12V battery, but is limited to maybe 1.5 kW. There is a thread about this here:
https://www.insideevsforum.com/community/index.php?threads/successful-clarity-back-up-power.7363/

For your desire, it would be probably be necessary to access the HV battery direct, and the Clarity has no native provision for that.

There are others here who know a lot more about solar than I do. You can certainly set up a solar sytem that can operate while the grid is down, and perhaps charge the Clarity (maybe this would require a 'small' house battery pack), but since the Clarity is not architected to be able to provide power to a 'house', this doesn't really address your wishes completely.
 
That’ll be a can of worms and would likely void the battery warranty.

Have your installer provide an estimate for FLA batteries. We’ve had Rolls-Surrette L16’s for nearly 10 years. They provide us approximately 10kWh’s of back up power. Cost would probably be around $3000 which would be eligible for the 26% Fed credit. Unless you’re in an off-grid situation where you are cycling the battery on a daily basis, lithium isn’t worth the investment.
 
glockgirl said:
but also want the battery back up option as well. with sell back option, if the storm knock out the power, solar stops working
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Selling power from the panels will not be significantly impacted from the addition of batteries. There will be some loss through inefficiencies as the panels will send power through a charge controller and then to the batteries. See photo below of our monitoring system.

During a power outage the panels will be isolated from the grid. They will continue to provide power to the batteries and inverter, which power specific circuits in the house.

To my knowledge, the energy stored in the batteries cannot be sold to the power company. My preference is to keep them charged so that we have the energy available when needed. It is possible to open the main breaker, which simulates a power outage. This puts the house on battery back up power and we would, at that point, no longer be consuming power from the grid. We do that periodically to test the system and measure battery performance.

Someone on a TOU plan might opt to go “off-grid” when rates are high and use their stored energy. However, they might also be sacrificing the selling of high priced electricity to the grid at the same time. Not all power companies pay the going rate for grid-tied solar energy, so you’d need to know the price at which you’re selling as well as the price you’re being charged to determine if doing the switcheroo makes sense. You’d also have to decide if depleting your batteries at any given time is a risk you are willing to take. 9290A09C-910C-42E5-B48C-45E3FE883A49.webp
 
Frankly, a gasoline powered generator would be the cheapest way to provide backup power to your home. You can pick up a 7500 watt generator for less than $1000 from Tractor Supply that will provide enough power to run 10 circuits in your home. I bought a 10 circuit transfer switch for $300 from Amazon, paid an electrician to wire it up to my main electrical panel. I have a single power cable that connects from the generator to a power inlet on the exterior wall of my home and provides power to the 10 circuits on the transfer switch.
 
Not everyone wants the cheapest option. If you’re going to get one of those clatter traps, at least get one that operates on propane.
 
Yep, it's dual fuel... gasoline and propane. And it doesn't risk damaging a 17Kw battery that would void the warranty and leave the owner footing a bill in the thousands of dollars.
 
toolman3640 said:
Not in the US but they are testing a V2G (Honda Power Manager) prototype in Europe. https://insideevs.com/news/371233/honda-charging-solutions-home-public-v2g/. For solar charging the car the Enphase IQ8 solar backup configured system will power four circuits if power is lost via the panels.
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V2G and V2H can both be accomplished. It’s just a matter of gaining access to the battery and inverting that DC voltage to AC voltage that is compatible with the grid and/or house.

The Clarity lacks that capability. Charging batteries from solar panels, however, is relatively straightforward.
 
@Landshark
Landshark said:
To my knowledge, the energy stored in the batteries cannot be sold to the power company.
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I too have solar but without a battery backup. The decision of a battery backup should be weighed against the likelihood of frequent power failures. From a cost perspective, anything that is not being immediately used by the house is sold back to the power company and we essentially "buy it back" from them when the panels are not generating. Interestingly, the rate the power company pays us for the solar power is slightly higher than what we would pay for that power if we were using their electricity without generating our own (due to a tiered system which charges more per kWh as usage goes up). So, to me it actually makes sense to sell it back to the power company than to store it.
 
Rajiv Vaidyanathan said:
@Landshark

I too have solar but without a battery backup. The decision of a battery backup should be weighed against the likelihood of frequent power failures. From a cost perspective, anything that is not being immediately used by the house is sold back to the power company and we essentially "buy it back" from them when the panels are not generating. Interestingly, the rate the power company pays us for the solar power is slightly higher than what we would pay for that power if we were using their electricity without generating our own (due to a tiered system which charges more per kWh as usage goes up). So, to me it actually makes sense to sell it back to the power company than to store it.
Click to expand...

To be clear, unless we have a power outage, or I am conducting a test of the back up system, the energy in the batteries is not being used and replaced on a daily basis. They are maintained in the float stage at full charge. Put differently, the first X kWh’s of solar generation each day are not being stored in the batteries. We’re selling everything we don’t use, just like you. The only difference is that I usually don’t know about a power outage until my neighbor calls and tells me the power is out.
 
Here’s a YTD report. We were out of town for January-February, so usage was low. The online data recording was down for a few days here and there, as well. It is cloudy right now, hence the low output. The upgraded system, from 2.85kW to 4.56kW came online last September. We expect to sell enough electricity to cover 7-8 months of usage. There is room to increase the array to 6.8kW, which would probably cover the entire year. 38B9594E-B8EF-4BBD-AB45-AA6969DB037F.webp
 
toolman3640 said:
New product from DCBEL offers renewable energy ecosystem.
Charge your electric vehicle with solar energy and transform its battery into a backup power source with dcbel r16. Connecting your home, solar panels, EV charger and the grid. https://www.dcbel.energy/technology
Click to expand...
hi,
just looked at website and it looks very promising. the cost isn't that bad either, $5K.
i'm waiting to find out what state of FL is going to do about solar. They talking about decreasing the "sell back" rates over 20 years. they trying to end the subsidies for industry as whole. if they pass that bill, it will be less advantages to get it to solar set up then now. but maybe that will drive the price of solar panels and install to more reasonable rates. wait and see
 
glockgirl said:
hi,
just looked at website and it looks very promising. the cost isn't that bad either, $5K.
i'm waiting to find out what state of FL is going to do about solar. They talking about decreasing the "sell back" rates over 20 years. they trying to end the subsidies for industry as whole. if they pass that bill, it will be less advantages to get it to solar set up then now. but maybe that will drive the price of solar panels and install to more reasonable rates. wait and see
Click to expand...

I’d recommend that you decide sooner rather than later. Not sure how any State could disallow the Fed credit, which is 26% this year and 22% next year, before being phased out in 2024. Things may change, but right now, it’s a bird in the hand.

The disincentivizing has begun. TOU plans and rates paid for solar generated power, in some areas, are being designed to hose those of us who played along and did the right thing. In California they are considering a $40-48 monthly fee on homes with solar installations.

The latest gripe is that we aren’t paying for infrastructure while simultaneously oppressing the poor. Who knew that going green would be so bad?
 
Also, keep in mind that the DCBEL inverter, or any inverter for that matter, will only be able to output the amount of energy that is being input from the solar panels. A 10K watt array, at high noon, would peak at roughly 10,000 watts. Or the equivalent of a 40A Level 2 device. It will not be capable of DC fast charging at 150-250kW’s.
 
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