I thought I’d add my 2 DIY science cents to @Selfmadestrom’s showcasing a great use of solar heating a pool (and more).
As far as DIY goes, I remember there’s something about electricity, and water:
They don’t mix well.
Big reveal!
Or perhaps, they mix a bit too well.
Ask Dall-E (Edge’s AI) to illustrate an accident about to happen:
Not kidding, while a heatpump like the one Erik showcases is safe by design, my heating rods (from Aliexpress) might be a bit more questionable in this regard:
“Honey - Get the popcorn: There’s a forum guy about to take a dive in a pool full of 230V boiling rods. The show is likely to be entertaining.”
Disclaimer: No racoons were harmed for the writing of this post.
Joke aside, my wife shared some recent use of our generators in a more down-to-earth manner.
I’ll take a different angle on our use of Bluettis in this post, and showcase how they can help dealing with peak demand pricing for #LifeWithBluetti especially in combo with a full-blown ESS home solution.
What is peak demand pricing?
As a good-bye gift from our so-called ecologist party, our electricity bill isn’t just based on average consumption but also on the highest peak of usage during a month.
For example, instead of being charged for the average draw of 2kW (total consumption divided by the duration of the period in hours), you’ll pay for each kWh during that period based on the price tier applicable to the 15kW peak consumption.
This pricing model can make your energy costs skyrocket and make you wonder why battery systems are quickly becoming popular in Belgium.
Overview of my setup
Bluetti’s AC300 was the game changer I needed to set in motion the entire solarization of my buillding: two joint houses and my company’s office, totaling 25.000kWh of annual consumption. Everything electric, from heating to cooking, including hot water & all.
Probably adding an electric car to the mix next year will add another 5kWh to 7.5kWh to the mix.
So back in summer 2022, after AC300 was an eye opener, I decided to go all-in solar and designed what seemed to be the best available at that moment - a Victron & Pylontech setup.
Notice my OCD with cable management:
Forgive me, Bluetti.
But in my defense, I ordered the components on that last week of August 2022, litterally days before EP600 was announced/revealed at IFA Berlin (first week of September 2022).
So technically, Bluetti, it’s your fault for not announcing it 10 days earlier.
Just kidding.
Even though the amount of wiring helped me satisfy my OCD for a while, I must say I wished I could go back in time, and get two EP600 with a nice stack of B500 instead of this DIY setup (just make a guess: how long did it take me to assemble that thing?)
Anyhow, the spec of that setup:
- Top row: 3x 5200W charge controllers (connected to a total of 20KWp panels)
- Middle row: 3x 4 kW AC charger/inverters
- Bottom row: 16x 3.5kWh LFP batteries
Technically, this is close to 2xEP600 & 11x B500, but with much, much more wires, and installation complexity. Next oportunity I have to install a system of that size, I’ll definitely go for Bluetti.
Why Bluetti over Victron?
ESS component prices in the EU are impaired by a large profit margin imposed by the official importers for both Victron & Pylontech. On top of that, online retailers refuse to offer any form of support in case something goes wrong. They just ghost you, plain & simple. In spite of EU laws, they just play possum, and instruct you to deal directly with the brand (that is not on the EU territory).
A malfunction in one of the batteries blew the motherboard of all 16 batteries. That took me 9 months to solve, as I was in direct contact with the headquarters (in China). Support was surpisingly good, and honest, but extremely long. Much better than the kind of cold shoulder I got from online retailers I got the pieces from.
Caveat: with no batteries, the whole system stays offline. So, that’s 20kWp down the drain for 9 months.
Caveat #2: with multiple brands involved, and multiple online vendors to source all the pieces, you can imagine the fingerpointing game. Blame-game, Mexican standoff style. Good scenario for a Tarintino movie if he ever plans to make a cinema adaptation of my little mishap with Victron & Pylontech.
I kept hoping I’d be just get overly impulsive, tear everything down, and replace these blue boxes and 19" batteries with EP600 & B500.
Didn’t happen, and that’s probably better for my finances as there’s no reselling used solar stuff on ebay for a reasonable price.
Finally managed to fix the batteries (replacing PCBs & all), but lesson learned: source everything from the same vendor, minimize wiring, and ideally, source everything from the same brand.
Hello, Bluetti.
So now what, AC500 & co?
This post’s title is all about peak demand pricing. As explained above, a single, short lived, consumption spike can almost increase your energy bill two-fold for an entire billing period. As if you would pay your 5G data subscription based on the peak data consumption of the month. Absurd? No, Belgian (rymes with “dystopian”, anyone?)
Oh, and last but not least: my Victron / Pylon system was considered “too powerful” by the grid operator to inject in the grid. Old, old grid can’t take 12kW from a single house, while it can take 9kW from each of my 3 neighbors. Go wonder why. I must have skipped the class about the 1st and 2nd law of thermodynamics, this explains that.
So once the batteries hit 100%, my system goes idle.
In summer, that means idling from 11am or 12pm on until I install a grid-bound inverter of 9kW for the sole purpose of injecting surplus in the grid (more wires for my OCD, good). Luckily, there is still room for that above the diff box (see picture above, check the white box on the left).
Jesus, not kidding, regulations in this country drive me nuts.
So not only I can’t inject surplus, but I need to keep my consumption below 4kW to 4.4kW per phase (Multiplus II 5000 spikes to 4.4kW AC out for short durations).
That’s right, even though the total output power of my system is somewhere between the nominal 12kW and peak 13.2kW, the phases are fed separately and don’t pool their power.
@BLUETTI_CARE does EP600 pool its 6kW across the 3 phases, or is it 2kW per phase?
See it in action, from two weeks ago on a sunny day (summer didn’t start yet… still chilly like it’s April, or late September):
Luckily, surplus goes in the battery on that picture. But 15% later, as described, the system won’t produce those extra 2271W. And that, while the grid (red box: “réseau”) pulls about 1kW on L3 to compensate for the 5000W pulled by L3 (see green box on the right). L1 and L2 still have about 1500-1700W of available power, but as explained, that extra power can’t jump from one phase to the other.
Another lesson learned I guess.
Sooo… AC500?
Well, AC500 and its 3 B300S acts as a buffer:
This is the utility room between the two houses where the grid meets some of the electric shenanigans of the building. Main setup is right underneath, in the basement.
AC500 is set to charge slowly (5A to 10A depending on the solar conditions), so it doesn’t hog the bandwidth of the inverter feeding that phase:
AC500 boosts the capability of Live3 by 5kW, which means about 9kW of peak power before the grid starts to kick in. This way, it made sense to hook the heavy consumers onto AC500: boiler, laundry, iron, etc.
It also adds a second layer of UPS-ness to the entire building, keeping the internet router & main network switch up&running even in case the primary solar generator fails (who knows, it’s not a Bluetti after all). I have server runnings 24/7/365 in the company’s offices and can’t afford an interruption of service due to a brownout, or sudden voltage drop (these seem more & more frequent, thanks to EVs hogging the grid).
The Customized UPS function allows scheduled charing during “off-peak”, in this case cheap energy means daytime energy thanks to the main solar generator:
Smart plugs
This is probably another inexpensive way to help with the energy management in a house.
They allow planning & scheduling when the heavy loads kick-in, and manually start some “energy dumps”:
Multi-outlet smart plugs can even manage their sockets separately, so we have about 16 separate circuits with their own schedules and/or activation on demand.
AC500 has two smart strips, for example:
Storage heater
Notice that “accumulator” (EN: “storage heater”) has no schedule (clock icon is greyed out), this means I activate it on demand. That’s for Sept-April. The storage heater is a 4.5kW beast, capable of storing up to 15kWh of electricity under the form of heat.
With the 56kWh of batteries in the main solar generator plus AC500’s 9kWh, the 15kWh of thermal storage in the heater, the 6kWh of hot water stored in the boiler, we start to near the 100kWh of energy storage (there is another B300, an AC200L following the same trickle feed & scheduling patterns, a second boiler for the other house, its own storage heater and we easily reach that figure - plus a few smaller Bluettis).
Other solutions when grid injection is not an option
So while @Selfmadestrom uses the proper way (aka heatpump) to warm up his pool, I’m precisely doing what he avoids here:
So while the picture makes it hard to read, this thermometer shows a steady increase of 1.5°C per hour. We should reach 34°C by the end of the afternoon.
While I have an appointement later todaywith the heat pump sales/tech rep, that’s only going to be an air-air unit for the house - houses actually, one unit per house.
Next summer, based on the progress I make in the meantime, and better assesment of the need (if still be after testing the 3 heating rods), I’ll possibly go for this heatpump:
1.2kW consumed, up to 7kW thermal. Could even work on a smaller Bluetti (AC240L, I’m looking at you) so it’d derive some of the consumption directly from garden panels and use the AC pass-through for the rest.
Another option to “dump” the extra power is… an electric car.
I’m quite reluctant given the NMC battery technology in use there. LFP isn’t car friendly due to lower energy density. The problems of NMC are higher flammability, higher risk of fire, high temperature of operation, less cycles, but that’s the tradeof for a better capacity-to-weight ratio compared to our Bluetti (and Pylon, oops) batteries.
Quick word about a recent comment I got from the car salesman (I was inquiring about the Ioniq5 N):
NMC batteries are guaranteed 8 years and/or 600cycles before dropping below 80% capacity. Why would you need heavier batteries? With 600 cycles, even at 400km per cycle, that’s 240.000km.
Dumb answer: “Because a guy on the internet told me LFP batteries are better”
No, seriously. I want clean chemistry in “my” car, not nickel-manganese-cobalt nonesense.
Moreover, Asian cars have the vehicle-to-load capability, which is technically a 3.5kW inverter ready for action. Since I like to drive a battery around in my “mobile toolshed”, this sort of feature matters to me.
And having a mobile 3.5kW AC out + its mobile 85kWh battery is actually very appealing, like a mobile powerstation. Too bad it’s NMC, not LFP.
Mobile toolshed:
I’m probably starting to rant here.
But hey - car manufacturers need to answer the marketing call of “more miles per charge” like Intel & AMD were competing for more GHz in the early 2000s. Turned out to bloat the Pentium 4, and completely drop the architecture (and move back to a Pentium 3 arc, that still inspires nowadays Core i3-5-7-9 architectures, so LFP all the way. Please.)
In my opinion, V2L (and then next, V2H & V2G: home & grid) is the future of home energy.
There, LFP makes more sense than ever, as the car AND the house work in tandem.
Too bad the future isn’t now already in that regard. Ioniq 5 N seems such a fun car:
It’s like a Bluetti on wheels, and on steroids (650HP, drift mode, fake engine sounds, all the substance my inner machild wants for his 40th birthday later this year… yes, I know… 1st world problems).
Well, I hope this was… erm, instructive.
Sorry for the last minute rant, and a wishing a good day to all!
however, if it gets me an AC50B… well… won’t say no 
