PC Pro - UK 2021-12)

willingtoclimbupandswapthe
dodgyinvertersforacoupleofspares
thatI’vemanagedtosourceviaeBay.
Soweremicroinvertersabad
choice?Notatall–I’ddothesame
againifIwasinstallingtoday,albeit
choosinginvertersfromamore
establishedplayersuchasEnphaseor
SolarEdge.Theadvantagesfar
outweighthedownsides.

FITforpurpose
Ifyouhaveasolarpanelsystem
installedtoday,you’llbeabletoselect
anexporttarifffrommostofthebig
energysupplycompanies,whichpays
youforanyexcessenergythatyou
generatebutdon’tuse,andsoendup
exportingtotheNationalGrid.The
priceyou’repaidwillalmostcertainly
belessthantheunitpriceyoupayfor
importedelectricity(elseyoucould
setupa nice littlescamimportingand
thendirectlyexportingfora profit), so
there’sa realincentivetoutiliseas
muchofyourgeneratedpowerasyou
canonsite,andminimiseanyexport.
Inmycasethisisdoublyso,
becauseI’monanolderandnolonger
availablefeed-intariff(FIT),andthis
onlymetersthesolargeneration,not
theamountI actuallyexport.Andit
assumes I’llconsumehalf andexport
theotherhalf,soifI canusealmostall
oftheenergyI generate,I’montoa
winner,financially.
Someargue thatsuchactions are
cheating,orgamingthesystem,and
aren’t“green”,butI disagree.Yes,
utilisingasmuchofmygenerated
electricityaspossibledoesreducemy
overallfuelcosts,butyoucertainly
can’taccuseitofnotbeinggreen.If I
runmywashingmachineonself-
generatedelectricityitmeansthere’s
lessdemandon power stations,and
feweroftheinherentlossesinvolved
intransmittingthepowerfromthe
powerstationtomyhouse.
Thesegreencredentialsare
improvedevenfurtherif I usemy
generatedpowertochargemyplug-in
hybridcar.Thatreducesthe
extraction,refining,transportation
andcombustionofthatnasty
hydrocarbonfuelwecallpetrol.So
yes,thecostsavingsarea bigfactor,
butyoucan’targue thatitisn’talso
environmentallyfriendly.
HowdoI usemysurplus energy?
Well,partlyitinvolves usingsome
thingsthatonlyswitchon when the

ABOVEEddicomes

fromthesamestable

asZappi

BELOWMyenergi’s

ZappiV2canfollow

yoursolargeneration

sunisout.Anexampleofthisisthe

dehumidifierinmygarage.Itdoesn’t

needtoruncontinuously,butit’s

goodto haveitkickinnowandagain

tostop thingsgoingrusty.SoI haveit

ona smart plugthatonlyswitcheson

whenI’mgeneratinglotsofpower

fromtheroof.It’sgood,butcrude–I

can’tturnthedehumidifier“halfon”

whena cloudreduces thesunlight.

Thenthere’sthecarcharger. The

veryfirstcarchargerswerepretty

dumbdevices,justlikea poweroutlet.

Thencamesmart chargersthathad

thingsliketimersandappcontrol, but

again theyweren’tmuchsmarterthan

theplugcontrollingmygarage

dehumidifier.ButthemodelI choseis

areallysmartcharger, anditcan be

settofollowthegenerationfrommy

solarpanels. So if a cloudgoesover

thechargeratetomycar

I should have mentionedthat

chargerisa ZappiV2from

Myenergi, an innovative

Britishcompany,whose

productsaremanufactured

hereintheUK.

Theoneproblemwith

power-trackingcar

chargersisthat theCCS2

spechasa lower limit of

1.4kW(CCSstands for

combinedcharging system

andisusedby many cars

thesedays).Thismeansyou

can’ttechnicallythrow,say,

500Watthecar.Thecarcan

requestlowercharging

rates,butnothingbelow

1.4kWcanbeinitiatedby

thechargeritself.

Sowhathappensifit’s

a dull dayandmysolar

panelsareonly generating

1.3kW?Well,theZappi

willignoreit,butobviously

I’drathernotexport this

generationifitcanbeused

onsite.Thisiswherethe

waterpre-heattankI

mentioned last monthcomes

in.Youmightrememberthat

itsits justbefore my combi

boiler,reducingtheamount

ofworkithastodowhen

heatinghotwater.

Thetankcontains an

immersionheater – a bog

standardone, nothingspecial.

Butrather than connectingit

directly to themains,I havea

devicecalledEddithatisalso

madebyMyenergi – in fact,it

talkstotheZappicar charger

viaa 868MHzwireless

interface,and theysharedata

sotheycanprioritiseloads.

TheEddihasa puresinewave

output,butthepowerismodulatedto

usewhat’savailable.Soifthere’s

1.3kWavailableitwilldumpthatinto

thetank,andthesameif there’sonly

100W– I don’twastea drop.Butifthe

generated powerthen rises about

1.4kWthesystemswitchesto

chargingthecar.Ifthetotalsolar

generationismorethanthe carcan

handle,then both Zappi andEddi

sharethepowerbetweentheir

respectiveloads.Itallworks pretty

well,withonlythe occasionalhiccup.

There’sanapp too(you’llneed

tobuy an optionalhub),butI’ve

foundthat to be slightlylessreliable

thantherestoftheecosystem.I think

Myenergineedstopay moreattention

toitscloudinfrastructure,butI

seemto be sayingthata lotrecently,

allkindsofhardware as

asapps.

Exportcontrol

There’sa problemwithmy

setup,though.I don’tuse

mycareveryday,soitcan

oftensitfora weekonmy

drive,fullycharged.And

ona sunnydaymypre-heat

tankcanreachits75°C

maximumtemperature at

around11am,sofortherest

ofthedayI’mexporting

generated power again.

OratleastI was,untila

fewmonthsbackwhenI

addedthefinalpieceofmy

greenenergyjigsaw: battery

storage.Youhavealmost

certainlyheardofTesla’s

werwallproduct;well,my

tupdoesmuchthesame

exceptit’snowherenear

ty,isfarmoreflexible,

costsa fractionoftheprice.

“Afewmonths

back,Iadded

thefinalpieceof

mygreenenergy

jigsaw:battery

storage”