Solar - 8kW Hybrid Inverter w/10kWh (upgraded to 20kWh in Sept. 2022) ESS/battery (not DIY)

[MJCM]

@KhunLA

 

If we would have your system at our House we would be approx minus 500 on the PEA meter every month

 

[KhunLA]

1 minute ago, MJCM said:

@KhunLA

 

If we would have your system at our House we would be approx minus 500 on the PEA meter every month

If we did 40kwh a day, then a PEA bill would be ฿6800 a month ????

 

Without the car, we're only using 15-20kWh a day, 450-600 for the month.  The scooter doesn't use much, and inverter ACs are way too efficient.  Starting to use the house ACs more, as warming up quickly down here/PKK.  Out of the house  most of the morning yesterday. 

 

March & April will add a bit of kWh with ACs running non stop, but don't think much more.  If run overnight past midnight, another 4kWh a day.

[MJCM]

What I meant was that you produced 600kW with your Panels this month and we used less then 100kW so if we had your system, that would leave OUR PEA meter at Minus 500 ???? (if exporting that is)

[KhunLA]

Just now, MJCM said:

What I meant was that you produced 600kW with your Panels this month and we used less then 100kW so if we had your system, that would leave OUR PEA meter at Minus 500 ???? (if exporting that is)

They wouldn't notice that ... ????

[MJCM]

4 minutes ago, KhunLA said:

They wouldn't notice that ... ????

55555555555555555

 

I suspect that would be another visit from the PEA for us

[MJCM]

10 minutes ago, KhunLA said:

If we did 40kwh a day, then a PEA bill would be ฿6800 a month ????

With Ft standing at 0,9343 that would be 7100+

 

Avg Cost per kWh				฿                5,57
Total Energy Costs				฿        5.433,81
Standard Service Charge				฿              38,22
VAT 7%				฿            466,76
Extra Charge or Ft Charge				฿        1.195,90
Total Amount to be Paid				฿        7.134,70

 

Units Used 1280,

[KhunLA]

Think I'm getting a peek at how much energy we'll be using come March, April and half of May, before rainy season hits.   Yesterday was another high kWh use day, as topped up the car & scooter, along with ACs going all day and most of the evening.

 

Sunday broke 41kWh, and Monday, actually broke 40kWh.

Sunday: 41 - 19.9 (car) = 21+kWh for house load

Monday 40 - 13.4 (car) - 3 (scooter) = 23+kWh for house load.

 

Only difference, less for EVs, but more for ACs, since turning on earlier, and temps higher:

What is missing, is any other appliances being used.   I didn't do any baking, rare, as usually baking something, bread or pastries, which is 1 hr of electric, at 2kWh.

 

Mrs. out playing in garden, so not sewing, washing clothes or ironing, which are motors & heating elements and sometimes she's running those for anywhere from 2-6 hrs.

 

If we were to top up the car everyday, that would probably be about 5kWh, and only 30-35 kms a day.  Myself & dog can put those on easily cruising around, hit the park, surf, search for critters to photograph.

 

All fairly minimal use, so 20-25-30kWh a day, come hot season won't be much of a stretch.  We averaged about 15kWh a day to run house, since installation, without the EVs.   But little to no AC use till just recently.

 

Since long rainy season, overcast, nice temps, then a nice cool season.  Now that seem to be over, and expecting 30sC till the rains start.

 

20 or 25kWh a day, for minimal use, house, ACs & EVs, and we'll be matching or exceeding our PEA usage from the rental, of 600-700kWh a month, which we based the size of the system on.

 

May not have overestimated after all.  Definitely think 10kWh ESS will not be enough in hot season, as 14 hrs of AC+ overnight is about 7kWh or more.   Really don't want to take ESS down to 30% or lower.  So with 20kWh ESSs, we'll easily stay above 50%.

 

Just 13 days of February, and broke 300kWh, and just now using the ACs all day.  300 ÷ 13 = 23 a day X 30 = 692kWh monthly. 

 

[KhunLA]

Normal daytime use, 0000/midnight to 1630, still producing what we're consuming.

 

No extras today, no EVs charging.  Using: 2 frigs, 2 ACs (9 & 24BTUs), 65" TV on most of the day, and laptop to that, TV as my monitor.  Just now, wife threw in a load of wash (?) in , and jumped in shower (3.5kWh (5mins).  I already showered (3.5kWh (10mins).

 

I baked bread, 2.2kWh for 30mins, and that's it for the day, for electric use, aside from morning coffee, <0.5kWh.

 

Produced 23.4kWh and consumed 18.4kWh, up to now.  See what happens, consumed now till midnight.

 

Heading out for a munch, then after dinner, wee bit of torrents before sleep.  AC's will be off in about 15 mins.

 

[KhunLA]

A few final numbers added to yesterday for 24 hr period.

18.4kWh while still producing matching consumption

23.4kwh consumed for 24 hr day ... 'on the meter'

 

 

Driving EVs during that period, normal daily driving:

... scooter, 12 kms using ~ 0.5kWh

... car, 15 kms using 4% / 2kWh

 

Dining out, not normal, so maybe add 2 or 3kWh for dinner prep & AC use, during that 2hrs out of the house.

 

Easily anther 5kWh added to meter,

so a 30kWh a day +/-

For an outdoor temps day of H33° / L24°

 

We used 1.5kWh from midnight - 0600 hrs

Actually fell asleep early, so we'll call that 7kWh +/-

overnight when not producing during warm temps.

 

Increased #s when daily temp H35+ & L30 +/-

come March, April, early May

 

EDIT: 0730 production now matching consumption. ????

[KhunLA]

53 minutes ago, KhunLA said:

EDIT: 0730 production now matching consumption. ????

Cancel that edit, only if staying in bedroom, not the worst idea, but ...

... In main room, making coffee, need AC on, so 3.5kWh 

... back on ESSs ????

 

EDIT: House cool, ACs maintaining temp, water kettle & coffee machine off.  Now we're producing consumption ????

 

[KhunLA]

With the above in mind, now 2.6kWh used since midnight, we'll need 8-10kWh for those 15ish hours of less/no production overnight/early AM 1700-0800 hs, on warmer days/nights.

 

One 10kWh ESS simply not enough for us, for off grid, unless very conservative use of ACs. 

 

Huge difference with change of seasons.  Overcast, rainy, cool temps and one 10kWh ESS was plenty.

 

1/3 of consumption during 2/3 of a 24 hr day.

[KhunLA]

The above should read ... 13 & 24BTU AC units (not 9)

[KhunLA]

Thought on ROI, for our solar system, in conjunction with having EVs.

 

Someone commented on my signature elsewhere, pointing out, I paid in advance for my energy, correct, but followed with, 'average ROI is 10 to 20 yrs'.  Not sure where or what price he based that on, but certainly not TH.

 

Out of conservative mode, as our system is more than enough to handle needs now.  Looking at recent numbers, with higher temps and AC use/abuse.

 

We're averaging, or will, average 20-30kWh a day, if not more during March, April & mid May.  But just using 20-30kWh a day, here's ballpark on ROI.

20kWh X 30 = 600kWh month, PEA cost ฿3223

30kWh X 30 = 900kWh month, PEA cost ฿4942

 

Need to add the ฿3000 a month, we no longer spend on petrol, so monthly cost, if using PEA & PTT, would be low of ฿6223 & high of ฿7942 monthly.  Divided into cost of our Solar system, which if DIY, would cost less:

฿445k ÷ ฿6223 = 71.5 ÷ 12 = 5.95 yrs

฿445k ÷ ฿7942 = 56 ÷ 12 = 4.67 yrs

 

So margin of error either way, and looking at a 4-7 yr ROI, not taking into account any consideration of fluctuating prices of electric or petrol.

 

Before anyone states, 'but you had to buy the EV also' ...

... yes, but the EV comes with a 50kWh battery pack, which would cost about ฿500k if adding that much ESSs to a solar system.  So that surely offsets the extra ฿200k that the EV version cost over the ICE version of the same car, which we owned prior.

 

After ROI period, everything forward is FREE ????

Hence the 'we save instead of spend' part of statement. You could even say, after 4-7 yrs, 'we're getting paid to have solar & EVs'  ????

[BritManToo]

18 minutes ago, KhunLA said:

Before anyone states, 'but you had to buy the EV also' ...

... yes, but the EV comes with a 50kWh battery pack, which would cost about ฿500k if adding that much ESSs to a solar system.  So that surely offsets the extra ฿200k that the EV version cost over the ICE version of the same car, which we owned prior.

10kWhr battery costs around 35,000bht.

Roi is 2-3 years if grid tie.

Roi is 6-7 years if with battery packs.

 

At 67 I doubt I have 7 years left,so no free period for me.

Thought you were old too, do you really think you will last another 7 years?

[KhunLA]

21 minutes ago, BritManToo said:

10kWhr battery costs around 35,000bht.

Roi is 2-3 years if grid tie.

Roi is 6-7 years if with battery packs.

 

At 67 I doubt I have 7 years left,so no free period for me.

Thought you were old too, do you really think you will last another 7 years?

All the 10kWh LiFePO ESSs I priced, that I'd consider buying, were in the ฿75k & up range, name-ish brand w/10 yr warranties.  Ours cost 90k & 95k installed.  Hopefully installer will be around, if an oops within warranty period, to assist in any warranty issues.

 

Piece of mind, for wife, next 10-20 yrs, after I'm long gone.

 

If not married w/house, I'd be nomadic, with a condo as a base, maybe, with no solar.

[BritManToo]

Just now, KhunLA said:

All the 10kWh LiFePO ESSs I priced, that I'd consider buying, were in the ฿75k & up range, name-ish brand w/10 yr warranties.  Ours cost 90k & 95k installed.  Hopefully installer will be around, if an oops within warranty period, to assist in any warranty issues.

You prefer to pay for a warranty which is probably no good.

I prefer to buy 2 battery packs for the same price with no warranty.

 

But the question still remains, do you expect to live long enough to get to the 'free' period?

[KhunLA]

7 minutes ago, BritManToo said:

But the question still remains, do you expect to live long enough to get to the 'free' period?

Edited my earlier post ... but no, all for wife & kid after my demise.  So they'll be self sufficient, with oops fund, and secure (financially) in their future.

 

Took the risk of them making bad investment away (doubtful they would), and gave them almost -0- monthly liabilities.  They just have to feed themselves.

[BritManToo]

21 minutes ago, KhunLA said:

Edited my earlier post ... but no, all for wife & kid after my demise.  So they'll be self sufficient, with oops fund, and secure (financially) in their future.

 

Took the risk of them making bad investment away (doubtful they would), and gave them almost -0- monthly liabilities.  They just have to feed themselves.

Just wondering what provisions your wife is making for your future if she should happen to die unexpectedly?

[Pink7]

1 hour ago, KhunLA said:

Thought on ROI, for our solar system, in conjunction with having EVs.

 

Someone commented on my signature elsewhere, pointing out, I paid in advance for my energy, correct, but followed with, 'average ROI is 10 to 20 yrs'.  Not sure where or what price he based that on, but certainly not TH.

 

Out of conservative mode, as our system is more than enough to handle needs now.  Looking at recent numbers, with higher temps and AC use/abuse.

 

We're averaging, or will, average 20-30kWh a day, if not more during March, April & mid May.  But just using 20-30kWh a day, here's ballpark on ROI.

20kWh X 30 = 600kWh month, PEA cost ฿3223

30kWh X 30 = 900kWh month, PEA cost ฿4942

 

Need to add the ฿3000 a month, we no longer spend on petrol, so monthly cost, if using PEA & PTT, would be low of ฿6223 & high of ฿7942 monthly.  Divided into cost of our Solar system, which if DIY, would cost less:

฿445k ÷ ฿6223 = 71.5 ÷ 12 = 5.95 yrs

฿445k ÷ ฿7942 = 56 ÷ 12 = 4.67 yrs

 

So margin of error either way, and looking at a 4-7 yr ROI, not taking into account any consideration of fluctuating prices of electric or petrol.

 

Before anyone states, 'but you had to buy the EV also' ...

... yes, but the EV comes with a 50kWh battery pack, which would cost about ฿500k if adding that much ESSs to a solar system.  So that surely offsets the extra ฿200k that the EV version cost over the ICE version of the same car, which we owned prior.

 

After ROI period, everything forward is FREE ????

Hence the 'we save instead of spend' part of statement. You could even say, after 4-7 yrs, 'we're getting paid to have solar & EVs'  ????

If anyone want to demand a theoretically correct ROI calculation is  also need to the alternative earning of the investment (interest etc.) and also  estimate future power prices and also inflation. Regarding EV, i guess some got more into EV options when discover the solar opportunities. Cheers for everyone who go solar route.. Hopefully money come back in reasonable time.. Let me also add that batteries maybe not give best ROI, but before i went solar route i was considering buying aggregate for emergency power. I would be VERY happy to have my ow backup power when grid down.

 

Pink

[Crossy]

The pack on our Sofar hybrid isn't (yet) big enough to store all our daytime surplus so we still spin the meter backwards.

 

But it's soooo, nice that our home power (almost) never actually goes off. The switch from grid to battery is almost seamless, just a flicker from the lights (and the guest A/C stops as it's not on the EPS output).

 

Minimum charge level in normal operation is 35% so even when we're "discharged" there's still 2-3 hours before the genset starts.

 

The genset starts so infrequently now that I've had to start doing check-runs to ensure that it still will.

 

[KhunLA]

1 hour ago, BritManToo said:

Just wondering what provisions your wife is making for your future if she should happen to die unexpectedly?

Daughter is already on all the house paperwork, and wills registered.  So all good there.  She adopted us last month ????  And wife is in/executor (?) of her will, JIC.

 

Win win for both of them, if we or either krap out.   Kid (24) gets house, as she would eventually.  Wife (45) gets her house, free & clear + 1 mil insurance + her investments.  Told daughter she shouldn't tell me things like that ????

 

Me & the dog are just trying to squeeze out 10 more yrs.

[Muhendis]

1 hour ago, KhunLA said:

Me & the dog are just trying to squeeze out 10 more yrs.

That's really good going and a well organised arrangement.

At ten years you and your dog are good for another battery bank yet.

 

[KhunLA]

12 minutes ago, Muhendis said:

That's really good going and a well organised arrangement.

At ten years you and your dog are good for another battery bank yet.

 

They should actually last 20 yrs, if not much more, as we never take them down below 50%, which in theory, doubles their longevity.  Rated on full cycles, and we don't even use half cycles.   Usually between 60-70% when wake in the morning.  Warranty is for 80% I think, so they are far from dead in 10 or even 20 yrs.  

 

By that time, the car pack will be ready to be added to the system, as doubt if the rest of the car will last as long as the battery pack & motors.

 

Without me, both would get way less use/abuse.  Lucky is she would drive 5k kms a year and she's freezing when I got the ACs comfy for me ... ????

[Muhendis]

1 hour ago, KhunLA said:

They should actually last 20 yrs, if not much more, as we never take them down below 50%, which in theory, doubles their longevity.  Rated on full cycles, and we don't even use half cycles.   Usually between 60-70% when wake in the morning.  Warranty is for 80% I think, so they are far from dead in 10 or even 20 yrs.  

 

By that time, the car pack will be ready to be added to the system, as doubt if the rest of the car will last as long as the battery pack & motors.

 

Without me, both would get way less use/abuse.  Lucky is she would drive 5k kms a year and she's freezing when I got the ACs comfy for me ... ????

You're well informed about longevity.

I would add that the two main killers are temperature and discharge rate. There is a third recommendation which is not to fully charge 'em. 90% of full will be less stressful on the chemical reactions. If the discharge rate is kept <0.2C and the temperature <30 then calendar aging may come into play.

 

Of course there has to be a break even point where increasing the number of batteries becomes more expensive than the potential lifetime savings. 

[KhunLA]

13 minutes ago, Muhendis said:

You're well informed about longevity.

I would add that the two main killers are temperature and discharge rate. There is a third recommendation which is not to fully charge 'em. 90% of full will be less stressful on the chemical reactions. If the discharge rate is kept <0.2C and the temperature <30 then calendar aging may come into play.

 

Of course there has to be a break even point where increasing the number of batteries becomes more expensive than the potential lifetime savings. 

Phosphates don't mind being charged up to 100%, and the solar bank & EV are both Phosphate.  Batteries are indoors, so as comfy as I am, and get charged up rather slow, 5-7kWh per hr, usually 3 ish.   Heating up not being an issue.

 

The EVs, even slower, 2.3kW per on granny, or 7.4kW on wall charger, which I don't use.   Only if on the road, and car will accept up to 50kw per hour, I think.

 

In that aspect, we baby our batteries  I've been playing with LiPo s for the last 10 ish years.  And they've really progressed, for some applications.  Still krap in phones, along with everyone getting a 'fast' charger, so they can kill the non replaceable battery ASAP ????  They really can't update any more techy stuff to warrant upgrades, so they set them up to die faster.  Phones you should slow charge, and keep between 60-80%.  But most don't .. drain then top up fast.  

 

Oh well.

[Muhendis]

58 minutes ago, KhunLA said:

Phones you should slow charge, and keep between 60-80%.  But most don't .. drain then top up fast.  

Agree entirely.

There isn't the will on the part of 'phone users to molly coddle their pride 'n joy and as for the manufacturers........If the battery outlived the guarantee by more than ten minutes they would probably consider replacing the entire design team I'm sure.

Having said that I do feel that a twenty year life span of a LiFePO4 is a bit optimistic.

Now.

If you want true longevity then you need look no further than a Nickle Iron battery (NiFe). Those have been know to go for 30 years and still perform like new (almost). They can be fully, 100%, charged and discharged every cycle with no ill effects over a very wide temperature range.

They do have problems of course. They need some TLC with de-ionised water every few weeks and the electrolyte has to be changed occasionally. Apart from that they are fine if you can live with the hydrogen gas they give off.

[KhunLA]

14 hours ago, Muhendis said:

Of course there has to be a break even point where increasing the number of batteries becomes more expensive than the potential lifetime savings. 

Not really about the money, cost, savings, though I really like that part.  More about not paying someone to provide something, I can provide myself, and better.  Though no issues with PEA or PWA service here, and very good & consistent, unlike Udon Thani.

 

I like being spiteful, and hate monopolies, big oil, PEA, and if for the same price, (savings a plus) can do better, that's great.  Infrastructure here is keeping up with the development, so not an issue for people here ... yet.

 

If it helps keep the planet and local air a bit cleaner, even better.  

 

With TH being import friendly with the affordable Chinese components, pricing really shouldn't be an issue for most folks.   Whether simply subsidizing their PEA bill, or eliminating it.

[KhunLA]

Bored, ran out of torrents, so playing with the #s.  Since getting the digital meter and basically 'off' grid, these are the daily average for the months we've had solar:

Feb (2)    23.17 kWh per day so far.
Jan (5)    19.48    2023
Dec (6)    19.21
Nov (6)    18.73
Oct  (4)    15.65
Sept (1)    11.96
Aug (5)    12.91    2022

 

We were conservative, until 2nd ESS was added, having 20kWh overnight instead of 10kWh.  Since having few krappy days in a row, and produced as low as 6 or 7 kW a day, to high of 49+ when sunny.

 

The single digit # after the month, is # of days we were out of the house, all day, and or overnight somewhere, 29 days in 6 months.

[KhunLA]

Seem to be meeting my expectations now, when planning the solar system, of 600-700 kWh a month. Not even hot season yet.

 

February ... best day was the 12th

 

 

[KhunLA]

Last month, Jan. was almost 20kWh a day.

This month, Feb and 23kWh a day.

 

On a 30 day month, knocking on 700kWh, and, not really hot yet.   Actually still chilly over night.

 

700kWh = ฿3800 PEA monthly bill.

EV savings ~ ฿3000 monthly

 

฿6800 a month, and that ROI is going to arrive quite fast (<5.5 yrs) ????