Ditching gas, going electric immersion only, a wee project

Solarchaser

OK then, figures. 
I have 3 sources of figures, and they don't completely agree.
I have the myenergi zappi and eddi
I have the lux acs3600
I have a smart meter

I have to go with the smart meter being the truth and while the other two give me useful info, it's from CT clamps which have an inheritance tolerance. 

So in this case what I'm going to do is lay out what my octopus bills have said for the last year vs the previous year, so midway through May 21 to May 22 vs midway through May 22 to May 23.

Why these particular months, well because I've always been billed mid month, but my other data sources come from 1st of the month essentially,  so I asked octopus to change it to 1st month from June, and so the data would be skewed if I did it till today.

So ignoring cost completely and just going by kwh usage I'll list below, note there was a couple of months where I got a 2 month bill one year and two individual month bills the other, so I figure rather than halfing the 2 month bills, id just put them in, but add the opposite bills months together.
So one bill is from dec21 to Feb 22, and so to compare I've added dec22 to Jan 22 and Jan 22 to Feb 22 together for comparison.

The left hand column is combination of gas and electric, right hand is after the switch to electric only.

So the raw numbers:-
July 21 =101kwh July 22 = 59kwh (58%)
Aug 21 = 206kwh  Aug 22 = 78kwh (38%)
Oct 21 = 957kwh  Oct 22 = 963kwh (101%)
Nov 21 =1326kwh  Nov 22 = 1327 (100%)

At this point I finally had the eddi running and monitoring temperature, until then I was relying on switching on timers and hoping it was sunny, and trusting in tank thermostats.

Dec21 = 2213kwh  Dec22 = 1939kwh (88%)
Feb22 = 4489kwh  Feb23 = 4139kwh (92%)
Mar22 = 1762kwh  Mar23 =1786kwh (101%)
Apr22 = 1487kwh  Apr23 = 1406kwh (95%)
May22 =755kwh  May23 = 843kwh (112%)
June22 = 399kwh  June 23 = 170kwh (43%)

This averages out to around 83% which is different to what I said right?

Why?
Well, at the start of the year my source of free charging, literally at the end of my street was stopped, and so now I charge the Tesla from the zappi, for the last two years I charged...  well this is the problem, I dont really know, I *think* I'd only really charge the Tesla from zappi if it was a sunny day and I was exporting, but how do you put a percentage on that? More than 20%? Less than 10%?
This year its 85% at least on zappi.
A big failing of myenergi is that you can only see this months and last months data, and while day to day the eddi will tell you how much green (solar) its used, the zappi doesn't, so how do you know how much is from the grid and how much is solar?

I can confidently say that before mid April, nothing would have been from solar, and since then I'd honestly be stunned if it was more than 20% total.... however in certain months the zappi uses more than the entire house, and so in those months it must be... say 50% solar??

So now my excuses are up, what's the figures for zappi?

Jan 286kwh
Feb 274kwh
Mar 409kwh
Apr 315kwh
May 335kwh
June 271kwh (so halfing that to 135 as bills are mid month)

So if I take mid Feb 4139 and take off zappi Jan and half Feb I'm at 4139-423 =3716kwh which gives me 82%
Mid March 1786 - half of Feb and March = 1445 so 82%
Mid April 1406 - half of April and March = 1044 so 70%
Mid May 843 - half of May and half of April = 518 so 68% but at least some of that is solar so not fair.
If I take it as half its then 90%
Mid June 170kwh half of May and June is already more than the consumption at 303kwh, half of that is 151, so yeah, maybe.

So do the figures help... hmm if I could remove more data from the figures to separate them to solar and grid I'd be able to give a better answer, but I can't.

This is why i said I'm 15-20% better off, trying to find a middle ground between both sets of figures really.

I think it's clear because of my larger solar array, I get much better use of the solar power in the brighter months and so the cost of heating water is really negligible, as the vast majority would have been export and because I'm on fit, I wouldn't be paid for that anyway (my idea has always been self consumption rather than earning from export)

I also think adding a roll of insulation in mid winter made a big difference to the heatloss, and I think that £25 roll of insulation is the difference between October and November's almost parity with the gas figures and December onwards saving, though the zappi controlling things definitely made a difference. 

That's alot of figures and alot of back and forth while typing, so if you notice something stupid, feel free to point it out.

michaels

Solarchaser said:

It's been a wee while since I've been on the forum, I'm not gonna do a very wordy post unless folk want individual detail.

Short version is my electric consumption for the year, vs my electric and gas consumption for the previous year is around 15-20% less for the heating cost.
That is I've assumed the same electrical consumption for not heating, and so removed it from the calculations, and so using purely what's left against the gas consumption over previous years I'm 15% better some months and 20% better other months.

I noted when I was away for a week, the tanks used roughly 8kwh a day, that is 8kwh were expended each day through the eddi to maintain an 84C temperature across both tanks.

So there is work to be done with boxing them in as I've mentioned in previous posts... just need to get round to actually doing it.

Is that 15-20% less energy input?

Solarchaser

QrizB said:

chris_n said:

Solarchaser said:

It's been a wee while since I've been on the forum, I'm not gonna do a very wordy post unless folk want individual detail.

Need more detail pleeeeeze. ;-)

I'd also appreciate a few more details, please, if you don't mind.

Did it work as planned?

Did you need to change or adapt anything on the fly?

Do you have any thoughts on future modifications or improvements?

Did it work as planned, that is a really good question. 
When you start out on these things, you want to gather as much info about who else has done it and how did it work, where are the pitfalls etc.
Either I'm a Google idiot, or no-one had done this before, which seems kinda ridiculous in this day and age, so I assume others have done it, but the algorithms are keeping me from seeing details, either I'm using the wrong words or whatever.

I couldn't find anyone who had done the same thing, and thats always a bit of a worry.
If I was a plumbing and heating engineer I'd crack on, but I'm not, and when I asked in various forums for help, people tended to not answer the questions I asked, told me it was a stupid idea, or told me I should do something else.

I think I've lined up enough excuses there, right?

So did it work as planned... yeah I think so.
It provided hot water and it heated the house.
Was it as efficient as the gas boiler, yeah I honestly think it was.
It had hidden costs, but you could argue those were choices not costs.
I got rid of my electric showers and fitted mixers, and for me personally, that was awesome, rainfall showers are great imo, much more power and more refreshing. 
The hot water arrives at the taps quicker and when it gets there, it's there at the same temperature all the time and with roughly 3 times the pressure.
I've fitted an outside hot tap as well as a cold which was great for the 3 days of summer we had, both for filling the kids pool, and for washing the pool after use etc.

The heating worked as I hoped, but... in the dead of winter the tanks were not enough, as I've probably covered in previous pages, I based my calculations on averages which really was daft looking back, so doing it again I'd have stuck with my original (well about plan F) plan of using 2 x 500L tanks instead of a 300 and 500l and I think that would have seen us through much better.

I also failed to add in what the showers were using energy wise, as when switching to thermostatic showers the energy used from showers needed to come from the tanks, and there were a few occasions where the kids or wife said the showers weren't hot enough in the evening, because the heating was drawing the heat out of the tanks. 


Did I have to change anything on the fly, yeah I had really underestimated how much thermosyphon would happen, and so early on had quite a bit of heat lost in the tank system itself with just heating up its own pipes and the central heating pump I was using as a destratification pump, simple one way valves really solved this issue, but yeah I really was not expecting it to be as much of a heat loser as it was.

I was surprised to find the pressure dropping in the small tank, even though the large tank was fine, and I understand it, kinda but not fully.
A 1 way valve and a motorised valve stop fluid going from the large tank to the smaller except during destratification, but I still don't really understand why it loses all its pressure when they are both at the same temperature. 

I put expansion vessels at the top of the tanks thinking that air would expand in there first, however when the air is done, its very hot water that goes in, so that wasn't the cleverest, so I will be moving them to the lowest part of the tanks instead and will attempt to bleed off all the air when refilling.
It was to try and reduce any air /hammer when the destratification pump was running, and it probably did, but I'll be leeching heat away in the expansion tanks too, so needs improvement. 

Onto the monumental F up.
From when the tanks were first fitted the wife noted the downstairs hot tap seemed very stiff In the morning. 
Loosening off during the day.
I logically thought it must be the fact it's always had a bar or combi pressure and now its 3 bar of pressure causing stiffness... looking back it was a warning that should have rang an alarm bell.. but trying not to be too hard on myself (so the wife tells me) I had asked for help from heating engineers and didn't really get any, so I was flying a little blind.
All the other taps in the house were fine.

I mentioned earlier about being surprised by thermosyphon,  and this was true of the hot water circuit too, I noted the cold water supply pipe to the tanks and the hot water supply to the mixer valve were warm if not hot to the touch, so I added two one way valves to that circuit to reduce heat loss.

All seemed OK, until around late March time when intermittently the hot water flow would fall to a dribble.
I'd bought the mixer from ebay and assumed early failure, so bought another and replaced the original, all good for a week and then the fault came back, strange!
I traced the problem to the first one way valve in the circuit which seemed to have blown its back section out and it was floating back and forward in the water flow occasionally completely occluding flow to the coil and so giving no hot water. Looking back that should have been a belisha beacon with a klaxon to me but it was the only single check valve I'd fitted, I didn't like how freely it moved and thought it felt a bit cheap, so replaced it with the double check valves I'd fitted in all other parts of the system including the heating system to stop hot water getting to the heating pump, which had worked really well.

I had a full bore valve fitted to the cold water supply to the coil and another to the cold water supply to the mixer, but when I went to replace the mixer I had to wait for the whole hot water system to drain, so I decided to fit another full bore valve just after the mixer to aid in its removal at any future date.
But.... I couldn't find my bahco shifter (adjustable spanner to non Scots) so had to make do with a b&q silver one which was alot larger and less precise, the area was really tight too, so I wasn't totally happy with it, but tested the pressure after fitting, all good and no leaks.
When I find my bahco ill tighten it a bit more to be certain.....

Solarchaser

This is the start of April, I've taken a week off to go biking type trips with the family, try and lose some of this middle age spread perhaps, or at least not always have the family remember dad as always fixing something, always under the house with the tanks etc etc, never spending time with them.

So It's a really nice sunny day, but cool, so the panels are running a treat, the eddi is diverting sun like a dream, nearly 20kwh into the tanks over the day, both tanks are approaching 83C, and I'm halfway through a wee cycling jaunt an hour from the car and 2 hours from home and I check the app to see this:-



For those who haven't guessed, this was that newest valve I'd fitted that I wasn't quite sure was fully tight, deciding to let go.
3 bar of water emptying itself into the kitchen and livingroom for 3 hours before I got home to shut it off.

It's a terrible feeling knowing you have damaged all of this stuff and there's no-one to blame but you!😔

Anyway... why? Why had this happened now?
Was the valve not tight enough... well yeah it wasn't as tight as I'd have liked, that is part of it, bit the real reason is that by fitting one way valves to the water in and out of the tanks I had created a pressure circuit, and by then heating the tanks, I had created a serious increase in the pressure to the circuit but given it nowhere to go, and so it increased with the tank temperature increasing until the pressure was sufficient to separate the not tight enough valve.

In the other circuits I'd fitted the one way valves I had already considered this, thought about how the pressure would push out through the one way valves, into the circuit and be compensated with the expansion tanks on the circuit, but there was no expansion tank on the circuit... on the to do list.

The warning signs were there, the stiff taps, the one way valve which had exploded, but I just never pieced that evidence together.... not until afterwards.

That was 4 months ago, and there is an expansion tank where one of the one way valves used to be.
It's not ideal, but I've kinda scunnered myself off going under to redo it.

For those of a curious mind, kitchen and livingroom flooring, carpets, skirting and facings (Architraves for non Scots) were all ruined, and its still not all fixed.

Sounds terrible.... however, I was already planning to replace the kitchen flooring, and had already gathered skirting and facings to replace both rooms, carpet was a bummer as I liked it, and the wife wanted flooring everywhere.... I flooded the place, so I lose my vote, and we now have flooring everywhere. 
Plus sides, I wanted to replace the 60 year old floor boards in the livingroom,  I got to do it.
I wanted to extend my poor man's underfloor heating, and got to do it from above, rather than below which was way nicer, and I guess the wife got rid of the carpet she didn't want.

So the lesson, use bahco spanners, and fit expansion vessels to a circuit when you close it up.

Solarchaser

Just as an aside, I thought I'd put up my combined figures for energy in the last five years, it was quite surprising to me.

2018 = 19214kwh (13486 gas)
I then fitted the second solar array start of 2019 and increased insulation in loft 
2019 = 16007kwh (12342 gas)
Replaced gas oven with electric start of 2020
2020 = 15245kwh (10945 gas)
Fitted underfloor insulation 
2021 = 13593kwh (9735 gas)
Half way through 2022 removed gas
2022 = 13050kwh (4554 gas)

Heedtheadvice

Great summary. Good detail you have remembered too.

Don't be too hard on yourself, very many positives there. I'm impressed ( suppose though that does not mean much :-(   )

I have read it all...oh dear now I am a masochist or something.

Very clever of your wife to stuff a killie pie into the works to get her own way on the flooring but spoiling your one day off is a bit much....

Solarchaser

Solarchaser said:

OK then, figures. 
I have 3 sources of figures, and they don't completely agree.
I have the myenergi zappi and eddi
I have the lux acs3600
I have a smart meter

I have to go with the smart meter being the truth and while the other two give me useful info, it's from CT clamps which have an inheritance tolerance. 

So in this case what I'm going to do is lay out what my octopus bills have said for the last year vs the previous year, so midway through May 21 to May 22 vs midway through May 22 to May 23.

Why these particular months, well because I've always been billed mid month, but my other data sources come from 1st of the month essentially,  so I asked octopus to change it to 1st month from June, and so the data would be skewed if I did it till today.

So ignoring cost completely and just going by kwh usage I'll list below, note there was a couple of months where I got a 2 month bill one year and two individual month bills the other, so I figure rather than halfing the 2 month bills, id just put them in, but add the opposite bills months together.
So one bill is from dec21 to Feb 22, and so to compare I've added dec22 to Jan 22 and Jan 22 to Feb 22 together for comparison.

The left hand column is combination of gas and electric, right hand is after the switch to electric only.

So the raw numbers:-
July 21 =101kwh July 22 = 59kwh (58%)
Aug 21 = 206kwh  Aug 22 = 78kwh (38%)
Oct 21 = 957kwh  Oct 22 = 963kwh (101%)
Nov 21 =1326kwh  Nov 22 = 1327 (100%)

At this point I finally had the eddi running and monitoring temperature, until then I was relying on switching on timers and hoping it was sunny, and trusting in tank thermostats.

Dec21 = 2213kwh  Dec22 = 1939kwh (88%)
Feb22 = 4489kwh  Feb23 = 4139kwh (92%)
Mar22 = 1762kwh  Mar23 =1786kwh (101%)
Apr22 = 1487kwh  Apr23 = 1406kwh (95%)
May22 =755kwh  May23 = 843kwh (112%)
June22 = 399kwh  June 23 = 170kwh (43%)

This averages out to around 83% which is different to what I said right?

Why?
Well, at the start of the year my source of free charging, literally at the end of my street was stopped, and so now I charge the Tesla from the zappi, for the last two years I charged...  well this is the problem, I dont really know, I *think* I'd only really charge the Tesla from zappi if it was a sunny day and I was exporting, but how do you put a percentage on that? More than 20%? Less than 10%?
This year its 85% at least on zappi.
A big failing of myenergi is that you can only see this months and last months data, and while day to day the eddi will tell you how much green (solar) its used, the zappi doesn't, so how do you know how much is from the grid and how much is solar?

I can confidently say that before mid April, nothing would have been from solar, and since then I'd honestly be stunned if it was more than 20% total.... however in certain months the zappi uses more than the entire house, and so in those months it must be... say 50% solar??

So now my excuses are up, what's the figures for zappi?

Jan 286kwh
Feb 274kwh
Mar 409kwh
Apr 315kwh
May 335kwh
June 271kwh (so halfing that to 135 as bills are mid month)

So if I take mid Feb 4139 and take off zappi Jan and half Feb I'm at 4139-423 =3716kwh which gives me 82%
Mid March 1786 - half of Feb and March = 1445 so 82%
Mid April 1406 - half of April and March = 1044 so 70%
Mid May 843 - half of May and half of April = 518 so 68% but at least some of that is solar so not fair.
If I take it as half its then 90%
Mid June 170kwh half of May and June is already more than the consumption at 303kwh, half of that is 151, so yeah, maybe.

So do the figures help... hmm if I could remove more data from the figures to separate them to solar and grid I'd be able to give a better answer, but I can't.

This is why i said I'm 15-20% better off, trying to find a middle ground between both sets of figures really.

I think it's clear because of my larger solar array, I get much better use of the solar power in the brighter months and so the cost of heating water is really negligible, as the vast majority would have been export and because I'm on fit, I wouldn't be paid for that anyway (my idea has always been self consumption rather than earning from export)

I also think adding a roll of insulation in mid winter made a big difference to the heatloss, and I think that £25 roll of insulation is the difference between October and November's almost parity with the gas figures and December onwards saving, though the zappi controlling things definitely made a difference. 

That's alot of figures and alot of back and forth while typing, so if you notice something stupid, feel free to point it out.

Aaaaaargh darn it.
I've made a total rear end of that post.
Sorry guys.
I started talking about not using anything after May because I changed the billing and then used July.
What a muppet.
I also mixed halfway through the month figures with start of month figures.
I have a spreadsheet of what I've been billed which is mid month and another with meter readings that i take at the start of each month and I've mixed the data up, it was that last month being 43% that caught my eye as I was sure most figures were between 70-110% when I'd done it before except September when I was fighting with timers and thermostats. 

I'm a bit surprised you guys didn't point out my stupidity, I'll blame the kids talking to me, calls from work and as many other reasons I can find 😳😳😳

OK I'll try this again and this time I'll only use the smart meter figures and not a mix of those and billing data 🤬

It should at least be easier to spot a mistake.

The gas was removed mid June 22, but so I don't faff it up again I'm going to do start of July21 to start of July23 with smart meter readings only.

July 21 3562 gas852  July 22 7118
Aug 21 3606 gas861 Aug 22 7189
Sep 21 3776 gas871 sep22 7295
Oct 21 3969 gas881 oct22 7708
Nov 21 4420 gas939 Nov 22 8807
Dec 21 5085 gas1043 Dec 22 10376
Jan 22 5771 gas1181 Jan 23 12603
Feb 22  6375 gas1329 Feb 23 14871
Mar 22 6791 gas1464 Mar 23 16769
Apr 22 6933 gas1600 Apr 23 18576
May 22 7004 gas1696 May 23 19658
Jun 22 7071 gas1743 Jun 23 20132
July 22 7118 gas1753 Jul 23 20229

For gas conversion I've found they give a large equation,  but if its a modern meter then it's basically x11, older ones are x7 or even x4.

Anyway.
Total for the year ending July 22
7118 - 3562 = 3556kwh
gas 1753 - 852 = (x11) =9911
Total with gas = 13467kwh
Total for year ending July 23
20229 - 7118 = 13111kwh so 97%
This includes 1890kwh of zappi car charging

So end of month by month
July 44 + 99gas =143 vs 71 = 50%
Aug 170 + 110gas = 280 vs 106 = 37%
Sep 193 + 110gas =303 vs 413 = 136%
Oct 451 + 638gas = 1089 vs 1099 = 101%
Nov 665 + 1144gas =1809 vs 1569 = 86%
Dec 686 + 1518gas =2204 vs 2227 = 101%
Jan 604 + 1628gas = 2232 vs 2268 = 102% (88% cc)
Feb 416 + 1485gas = 1901 vs 1898 = 99% (85% cc)
Mar 142 + 1496gas = 1638 vs 1807 = 110% (85% cc)
Apr 71 + 1056gas = 1127 vs 1082 = 96% (68% cc)
May 67 + 517gas = 584 vs 474 = 81% (27% cc)
June 47 + 110gas = 157 vs 97 = 62% (-110% cc)

Cc is if I include all the car charging in the cost, which makes June a minus number amusingly.

Please feel free to sense check these numbers, all numbers are here, I just wonder if I've made a calculation mistake 🙈

1961Nick

Solarchaser said:

OK then, figures. 
I have 3 sources of figures, and they don't completely agree.
I have the myenergi zappi and eddi
I have the lux acs3600
I have a smart meter

I have to go with the smart meter being the truth and while the other two give me useful info, it's from CT clamps which have an inheritance tolerance. 

So in this case what I'm going to do is lay out what my octopus bills have said for the last year vs the previous year, so midway through May 21 to May 22 vs midway through May 22 to May 23.

Why these particular months, well because I've always been billed mid month, but my other data sources come from 1st of the month essentially,  so I asked octopus to change it to 1st month from June, and so the data would be skewed if I did it till today.

So ignoring cost completely and just going by kwh usage I'll list below, note there was a couple of months where I got a 2 month bill one year and two individual month bills the other, so I figure rather than halfing the 2 month bills, id just put them in, but add the opposite bills months together.
So one bill is from dec21 to Feb 22, and so to compare I've added dec22 to Jan 22 and Jan 22 to Feb 22 together for comparison.

The left hand column is combination of gas and electric, right hand is after the switch to electric only.

So the raw numbers:-
July 21 =101kwh July 22 = 59kwh (58%)
Aug 21 = 206kwh  Aug 22 = 78kwh (38%)
Oct 21 = 957kwh  Oct 22 = 963kwh (101%)
Nov 21 =1326kwh  Nov 22 = 1327 (100%)

At this point I finally had the eddi running and monitoring temperature, until then I was relying on switching on timers and hoping it was sunny, and trusting in tank thermostats.

Dec21 = 2213kwh  Dec22 = 1939kwh (88%)
Feb22 = 4489kwh  Feb23 = 4139kwh (92%)
Mar22 = 1762kwh  Mar23 =1786kwh (101%)
Apr22 = 1487kwh  Apr23 = 1406kwh (95%)
May22 =755kwh  May23 = 843kwh (112%)
June22 = 399kwh  June 23 = 170kwh (43%)

This averages out to around 83% which is different to what I said right?

Why?
Well, at the start of the year my source of free charging, literally at the end of my street was stopped, and so now I charge the Tesla from the zappi, for the last two years I charged...  well this is the problem, I dont really know, I *think* I'd only really charge the Tesla from zappi if it was a sunny day and I was exporting, but how do you put a percentage on that? More than 20%? Less than 10%?
This year its 85% at least on zappi.
A big failing of myenergi is that you can only see this months and last months data, and while day to day the eddi will tell you how much green (solar) its used, the zappi doesn't, so how do you know how much is from the grid and how much is solar?

I can confidently say that before mid April, nothing would have been from solar, and since then I'd honestly be stunned if it was more than 20% total.... however in certain months the zappi uses more than the entire house, and so in those months it must be... say 50% solar??

So now my excuses are up, what's the figures for zappi?

Jan 286kwh
Feb 274kwh
Mar 409kwh
Apr 315kwh
May 335kwh
June 271kwh (so halfing that to 135 as bills are mid month)

So if I take mid Feb 4139 and take off zappi Jan and half Feb I'm at 4139-423 =3716kwh which gives me 82%
Mid March 1786 - half of Feb and March = 1445 so 82%
Mid April 1406 - half of April and March = 1044 so 70%
Mid May 843 - half of May and half of April = 518 so 68% but at least some of that is solar so not fair.
If I take it as half its then 90%
Mid June 170kwh half of May and June is already more than the consumption at 303kwh, half of that is 151, so yeah, maybe.

So do the figures help... hmm if I could remove more data from the figures to separate them to solar and grid I'd be able to give a better answer, but I can't.

This is why i said I'm 15-20% better off, trying to find a middle ground between both sets of figures really.

I think it's clear because of my larger solar array, I get much better use of the solar power in the brighter months and so the cost of heating water is really negligible, as the vast majority would have been export and because I'm on fit, I wouldn't be paid for that anyway (my idea has always been self consumption rather than earning from export)

I also think adding a roll of insulation in mid winter made a big difference to the heatloss, and I think that £25 roll of insulation is the difference between October and November's almost parity with the gas figures and December onwards saving, though the zappi controlling things definitely made a difference. 

That's alot of figures and alot of back and forth while typing, so if you notice something stupid, feel free to point it out.

The Tesla app may give you an insight into how much solar you're using to charge your car - The Time-of-use at home breakdown on mine is showing 95% Off-Peak & 5% Peak for the past year's 2634kWh. The 'Peak' 5% is actually surplus solar - 132kWh.

Solarchaser

Hi Nick, apologies for massive delay in response.
I dont see that option anywhere in my Tesla app, and I've been through every section (I think).

However the charging is a mix of the Tesla and the wife's leaf, so that wouldn't necessarily give me accurate information 

1961Nick

Solarchaser said:

Hi Nick, apologies for massive delay in response.
I dont see that option anywhere in my Tesla app, and I've been through every section (I think).

However the charging is a mix of the Tesla and the wife's leaf, so that wouldn't necessarily give me accurate information 

Charge Stats & then scroll down. You can select past month or past year for the 'at home' charging breakdown