Solving high electricity usage and cost using solar + batteries to store off peak power

Mikeyboy01443

I have looked briefly at V2H but from what i understand it's still quite niche...
I may consider it when my leaf is old and only worth a few grand,  i would not want to be using v2h  otherwise as this will just be eating into your battery life...

michaels

Mikeyboy01443 said:

I have looked briefly at V2H but from what i understand it's still quite niche...
I may consider it when my leaf is old and only worth a few grand,  i would not want to be using v2h  otherwise as this will just be eating into your battery life...

Studies show that batteries are not harmed, V2G/H only uses battery between say 20% and 90% (configurable) and charge and discharge rates are order of magnitude lower than fast charging and ordinary driving.  Can also avoid temp extremes too if that is thought to be a concern.  SO basically nothing that will show up in battery longevity.

Mikeyboy01443

But every battery will have a finite amount of charges / discharges, no? Obviously depending how it is used can affect that lifespan...
My 2014 leaf is still on full bars, i know someone who had a 2016 leaf which had lost 2 bars by the time they got rid of it, go figure...
I do a fair amount of rapid charging too.
Either way its not something i would consider until my leaf was ready for the scrappy... also aren't the V2H chargers considerably more expensive than regular chargers? 

QrizB

Mikeyboy01443 said:

But every battery will have a finite amount of charges / discharges, no?

Typically somewhere between 5000 and 10000, so 13 to 27 years of daily cycles.

elrao

michaels said:

Have you had any more solar quotes, we got ours 6 years ago and it cost just over £4k for 4kwp of panels with solar edge inverter so your quot sounds expensive.

Our usage is lower but we are looking to add a heat pump and off peak hot water tank heating and use our EV for V2H which will hopefully allow a shift from gas at 13p/unit (come October) to electricity at 4.5p per unit overnight.

No

Was a lot lower without the solar edge and the zappi charger.  About £14k for 16 panels, string inverter and 19KwH of batteries.

Compared to various advertised packaged and was favourable 

Martyn1981

Mikeyboy01443 said:

But every battery will have a finite amount of charges / discharges, no? Obviously depending how it is used can affect that lifespan...
My 2014 leaf is still on full bars, i know someone who had a 2016 leaf which had lost 2 bars by the time they got rid of it, go figure...
I do a fair amount of rapid charging too.
Either way its not something i would consider until my leaf was ready for the scrappy... also aren't the V2H chargers considerably more expensive than regular chargers? 

Hi, you'd think there would be a negative impact, but actually the studies on Leaf's used for V2G seem to show that the SOH actually improves. Something about the small and low power charge/discharges helping to rebalance the battery.

If you think about it, a 24kWh battery Leaf at full power (pedal to the floor) is pulling 80kW, a massive hit on the battery, as is even a charge rate of 50kW, but a few kW's of charge or discharge is quite gentle.

I had similar concerns as you, but no longer. As Michaels says these are small cycles, and avoid the low/high charge/discharge levels, not full cycles, and also not at extreme temps due to the low power levels.

Yes, the V2H/G chargers are much more expensive, but can provide a good source of income for fleet operators who have a lot of vans, buses (etc) parked up during peak demand periods when the wholesale grid price of leccy is typically higher.

Mikeyboy01443

That's good to know, i have registered my interest with indra for a trial so who knows i may end up getting one installed

silverwhistle

elrao said:

Working out the costs on a dual-rate tariff proved more complex, as while I would save £700 on charging the EV during the off-peak hours, I  would be paying a premium for the majority of my electricity. 

You say 'majority' of your electricity, but what impact will having solar have on your purchased electricity? As you say, it's complex as we all have individual situations, but my day time use is covered by solar and with some adjustments I don't use too much peak. I'd be the first to admit that being single means _I_ am in full charge!:-)

elrao

I mean that probably 46KwH of the 50KwH I use (exl. EV) would be "peak" during the summer months (off peak is 0030 to 0430). Meaning I'd be paying 35p for those KwH on a dual rate tariff.  So I'd be paying more (a premium) for those units compared to being in a standard tariff.

elrao

To clarify, about 25-30KwH per day (all year) would need to be bought from the grid.  That's the amount I'd need over the solar, majority would be peak.

That's maybe 10,000KwH at an extra 7p per KwH