Creative Solutions to Voltage Drop
Sorry for the long post, just want to provide full context. tl;dr is I’m wondering if I can mitigate voltage drop on long undersized mains with a battery system like a PowerWall.
Okay, so I’ve got a farm property that was built in the late 70’s and the house is about 1000 feet from the meter. The mains are direct buried aluminum that are a bit undersized (appear to be about 4/0 or 250 MCM.) The house was set up for 100 amp service but rarely saw anywhere near that as it had propane for heat, hot water, and cooking appliances. Well we upgraded the water heater to a hybrid unit and installed an induction range and electric oven. We also put in a four head mini-split system and charge an EV as our primary vehicle. Suffice to say we are at times pulling significantly more amperage than before. I’ve got a Sense energy monitor and have noticed that fairly regularly we’ll see each leg’s voltage drop down to about 110v from its average of closer to 120v (220v across the legs.) I’ve verified this with a quality Fluke multimeter.
So what to do about this situation?
A) Fixing this by trenching and putting in properly sized new mains is exorbitantly expensive (my electrician estimated it would be north of $100k in copper alone before materials and labor.)
B) I’ve spoken to PG&E and running a new poles and meters would be I think $40k-60k or more though they are cagey on the numbers until after they complete engineering, which requires a few thousand dollar non-refundable deposit.
C) One electrician suggested a step up transformer near the meter and matched step down close to the house. Raising the voltage and thereby lowering the amperage would either require smaller replacement mains or we might be able to get by with our current ones. It looks like the transformers aren’t that expensive (maybe $15k in parts) but there is some inefficiency and ongoing energy loss by using them.
D) Here’s the creative one I’m wondering about. The voltage drop happens due to high amperage going through the mains. So what if I could shave off the peaks in that demand and average the amperage out to a lower level. Looks like the PowerWall 3 handles up to 11.5 kW of discharge so a couple of those could cover my peaks. If the house is drawing those down then my thought is that directly reduces the amperage pulled through the mains. They recharge at about 20-30 amps and so would effectively shave the peak usage and spread it over a longer period of time which would limit the voltage drop. Plus I’d have the benefits of battery storage and time shifting electricity usage, which PG&E seems to be incentivizing with its latest rate structures. And at a price point that would likely be similar to the transformers.
I’m on a 15 acre avocado farm with essentially limitless space for more solar panels (currently I have a dated system from about 20 years ago that outputs a peak 2.5 kW but I plan to add more.)
All thoughts and discussion welcome. Anyone seen a setup like I’m describing work or am I missing something obvious?