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Time Based Charging - initial observations

Time Based Charging - initial observations

Time Based Charging has been in enabled on my PW2 for 5 days now. It is part of a 4.5kW solar setup.

The amount of solar charge is highly variable at the moment, and the PW is doing a reasonable job at guessing enough charge overcharge to last until off peak kicks in the next night.

The app doesn’t have the clearest explanations as to the configuration options, and could do with the ability for you to opt for more or less conservative off-peak charge estimates.

Having off peak charging however makes the need for alerts in the app even more pressing. There’s a much higher probability of reaching 100% charge during the day, so it would be useful to be warned about this to enable you to use the excess.

For me, having a Samsung SmartThings device handler for the PW2 would enable me to do everything I want. Has anyone written one?

sashton | 24. maaliskuu 2018

My observations:
The peak/off peak settings don't appear to "stick". i.e. every time I go back into the app no hours are set.
The battery only appears to charge on off-peak to 10% under "cost saving".

...as my old teacher always said - Could do better.

I have just noticed an app update (3.3.4) - maybe they have fixed the above. Will check later.

I don't know about SmartThings but I have mine integrated with the car charger (Zappi - switched by their eSense input but hopefully more functional control when they release their API); appliance control (Home Connect API); load shedding (Vera with Qubino)

sashton | 25. maaliskuu 2018

Sadly 3.3.4 didn't fix the issue with setting peak/off peak hours. Playing with the app I find the settings will apply correctly as long as you set peak hours to end before or after midnight. The UK E7 off-peak tariff starts at midnight.

robin | 27. maaliskuu 2018

Mine initially didn't save right either. They do now. Because of BST, I set mine to 00:30-6:30, by dragging the far right marker over to the left.
It doesn't make any practical difference if you set the off peak times to start a bit later though.

robin | 02. huhtikuu 2018

Ok, so a week on... and actually this thing needs some serious work. It appears to be a pretty dumb algorithm, that probably works ok-ish in Nevada or California, but not so well in Northern Europe. Disappointing functionality, having waited 9 months for it. It needs to:

1) take some account of the upcoming weather for the day in order to be able to deal with the highly variable solar production that we get in Northern Europe.

2) give the ability to both manually over-ride the charge level and bias the algorithm towards more or less charge

3) stop using the energy during off peak periods that it has just stored up. It should only output stored energy during off peak if there was an excess level of charge going into the off-peak - at the moment it is just wasting energy by doing this.

mbird | 02. huhtikuu 2018

Can either of you describe what changed in your setup that enabled Time Based charging? I seem to have 1.15.1 on the Powerwall2 and App version 3.3.4. But I cannot see any Time Based Charging settings?

cwied | 02. huhtikuu 2018

Tesla is gradually rolling out the functionality to users. They have to turn it on in their backend for it to be available to you in the app.

mbird | 02. huhtikuu 2018

So I gather that a 1.15.1/3.3.4 configuration should be capable of TOU operation once the backend is enabled by Telsa on their server farm? Could you confirm that the target for this to be complete by 20th April includes installations in the UK?

sashton | 03. huhtikuu 2018

I have that config level and the app displays the new "advanced" customis(z!)e options. I am UK based as well.
My PW went from 1.15.0 to 1.15.1 yesterday ... I can tell as my Gateway always fails and needs to be powered off and on after every firmware update. Very annoying!

sashton | 03. huhtikuu 2018

...as an added bit of feedback. The new settings appear to work quite well. I have a UK E7 tariff which currently means my peak runs from 08:00 - 01:00 a.m.
The option used was "balanced"
A few days ago off peak started and the battery had 50% charge. 06:00 the battery came out of standby and ran down to 15% - just enough to keep us going through breakfast 08:30 (peak) and make it to the point where the PV kicked in at 09:00. ....so it is making a reasonable job of managing the charge.

Personally I would like a little simpler direct control i.e. just put the battery in to standby if it drops to X% during off-peak hours ... or if it is below that threshold when off-peak starts, charge it to X% during off-peak.
I would just set X to be about 20% in the summer and 50% in the winter.

steven | 10. huhtikuu 2018

I'm in Australia with 1xPW2 with solar. I have Version 3.3.4/1.15.1 but it has not option for TOU charging even though the Australia support FAQ describes this function.

Does anyone have an idea when this functionality will be available in Australia

robin | 17. huhtikuu 2018

E7 has a couple of issues. A large number of meters have the wrong time set on them (so the start and end times might not be what you think), and the hours are fixed (they don't change with daylight saving changes.

I have had mine on "Cost Saving", and its performance over the past month has been ridiculous. It has to take some account of weather to have any chance of being useful in Northern Europe. It is supposed to be a learning algorithm, but that's a crazy idea when half of the input it needs is missing. It also just hasn't been acting like a learning algorithm. It's pretty dumb, and it was rushed out. Particularly dumb is its tendency to feed out charge it has just stored before peak time starts - which means instead of using off peak electricity, you're using off peak less the 10% energy loss, and in the long term unnecessarily shortening the life of the batteries. It should only feed out in off peak times if it hasn't had to take in any off peak top-up. As you say @sashton, giving simple manual controls would have been a far better solution.

robin | 17. huhtikuu 2018

E7 has a couple of issues. A large number of meters have the wrong time set on them (so the start and end times might not be what you think), and the hours are fixed (they don't change with daylight saving changes.

I have had mine on "Cost Saving", and its performance over the past month has been ridiculous. It has to take some account of weather to have any chance of being useful in Northern Europe. It is supposed to be a learning algorithm, but that's a crazy idea when half of the input it needs is missing. It also just hasn't been acting like a learning algorithm. It's pretty dumb, and it was rushed out. Particularly dumb is its tendency to feed out charge it has just stored before peak time starts - which means instead of using off peak electricity, you're using off peak less the 10% energy loss, and in the long term unnecessarily shortening the life of the batteries. It should only feed out in off peak times if it hasn't had to take in any off peak top-up. As you say @sashton, giving simple manual controls would have been a far better solution.

Anthonylore | 17. huhtikuu 2018

I’m on 1.15.3 with 3.3.5. No time of use. My issue is that I’m wiping out my PW during super off peak by charging my Teslas with my high value on peak solar. Not the direction I want to go.

sashton | 17. huhtikuu 2018

Robin, I keep track of the E7 rate change by monitoring the economy feed from the meter. I don't know if all E7 meters are equipped with this but mine has a switched feed that goes live during off-peak. I think this is meant to supply storage heaters. Here it is connected to the car charger. The charger doesn't actually draw on this feed but you can program it to sense it going live and use it to trigger charging (along with other events such as the time.
Anthony, Firstly I would check with your installer. It doesn't look like Tesla monitor these fora for anything more than spam. If that fails you can obviate your problem by moving the Tesla input/export CT so it only senses your house usage i.e. on the house side of the EVSE feed. Then the battery would not "see" the car charge and therefore only respond to general house loads. This may require a small change to your wiring topology.

robin | 18. huhtikuu 2018

@Anthony, it's a pain in the butt, but as a short term solution you could turn off your PW over night whilst the cars are charging. You can do this on your phone by opening the PW interface. If your wiring to the car chargers isn't separated out, or easy to change, you could get an extra sensor current fitted on the charge circuit and reverse the polarity of it - this will remove it from the load "seen" by the PW.

sashton | 19. huhtikuu 2018

I agree with Robin that the additional clamp would address your issue. It must be the same type of CT as the existing import/export one. I do a similar thing with the Tesla solar CT as I have multiple inverters on separate metered circuits (a requirement to comply with the UK FIT scheme) with each CT wired in parallel to "add up" each inverters current.

tony | 22. huhtikuu 2018

I am in Australia and using 3.3.5/1.15.3. I have set the Time based control to cost savings but the PW2 charges spasmodically during the off peak time but has never exceeded 3% capacity. Does anyone have any idea how to improve this?

sashton | 25. huhtikuu 2018

I tried "Cost Saving" a couple of times but it really didn't do what I had expected at all. During peak hours it regularly drew about 1kw from the grid (which is patently daft) and it failed to charge the battery, more than minimally, during off peak.
So I have settled for "balanced". It is still too conservative - switching to standby far too early during off-peak - i.e. over-estimating the peak demand before the PV kicks in.
Whoever tested/verified these settings needs their head examined as "Cost Saving" neither delivers cost savings nor applies the rules set out on the Tesla web site. "Balanced" needs some more tuning.
*sigh*

sashton | 25. huhtikuu 2018

This poor level of programming and testing doesn't bode well for Tesla's Autopilot development. (Though I can't believe it is the same team working on this).

lenmoskowitz | 27. huhtikuu 2018

We have a 9.6 kW PV array. Our local utility just offered us time-of-day metering.

We're thinking about installing a PowerWall 2.

We'd like the PW2 to recharge only during off-peak times (9 PM to 7 AM), and never on-peak (7 Am to 9 PM). We want all of our PV-generated power to sell out to the grid.

Can we do that?

Also...

When the grid goes down (an outage), our PV generation does too. Will the PW2 disconnect from the grid and give our inverter the right signals to generate during an outage? Is the PW2 be smart enough to note that it's an outage, and re-charge from the PV array output?

Thanks!

lenmoskowitz | 03. toukokuu 2018

Where should I turn for answers to my last post, please?

cwied | 03. toukokuu 2018

Where are you located? The answers depend on what country you're in.

Presuming you're in the US, the answer is no. Powerwalls will only charge from solar, not from the grid. This is to make sure they qualify for the Investment Tax Credit. With the new time-based control (TBC) feature, you can charge during the shoulder period and discharge during the peak period to offset your house load, if you have a shoulder rate in your plan.

The backup gateway will keep your solar running when disconnected from the grid. This is one of the main features of the Powerwall.

lenmoskowitz | 04. toukokuu 2018

We're in the USA, in northern NJ.

Thanks for your answers.

The backup gateway is a great feature.

I hope that you will eventually allow charging from the grid. With time-of-use metering, it makes sense to send solar-generated energy out to the grid (on-peak), and then charge the PowerWall off-peak from the grid.

cwied | 04. toukokuu 2018

Just to clarify - I'm not a Tesla employee, I just registered on Tesla with an email address that includes the word "tesla" and the system won't let me change my forum name. I'm answering just based on my own experience (I have a two-Powerwall system).

roger | 07. toukokuu 2018

@sashton
I think I said something like your suggestions regarding a percentage option elsewhere. It seems a fairly straightforward option for them to offer, to me, so I agree with your comments above.
At the moment the app is just giving ridiculous values, so I am hoping the battery is doing what it should…
There are times when the app suggests that the battery is fully charged and I am, they claim, exporting almost double what my PV system is capable of producing.
Even Tesla alchemy is unlikely to be able to achieve that!
So, currently champing at the bit to get the option to customise to any kind of control other than the single option it has at the moment (Self Powered).

Marleenyuli | 09. toukokuu 2018

crossposting from TMC: here in Southern Cali.

TBC activated a few days ago and really like it on the cost-control setting. NetMeter 1.0 and Grandfathered to program for another 1.5 years. Peak 12noon-6pm.

So setting to cost-controlled, during Peak hours, all house use is powered by PW2 until reserve setting (70% for me). At 6pm, cuts off and any remaining solar starts recharging the PW2 while grid supports the house. The following morning, solar charges PW2 until full and PW2 on standby until 12noon to start pk house support. DURING PEAK -- solar pushes entirely to the grid, maximizing the net metering. :)

The next piece I'd LOVE to have -- charge PW2 at night during super off-peak levels. This would be the most ideal in smart grid support. Full arbitrage (allowing consumer to discharge battery to grid during peak) is not good for anyone long term IMHO.

For those inquiring on TOU reasons -- NEM2.0 as TOU peaks in the evening. The reason is a lot solar and wind now in CA and duckbill phenomena has occurred with plenty of energy during the day and demand spikes in the evening now. This is where PW2 and load shifting performs the best and the intent of SGIP to save on peeker plants -- use batteries instead. In the past OhmAlerts regularly happened mid-day. The vast majority now is 6-7pm and 8-9pm when all the folk return home or hit upstairs. New solar installs all have TOU peaks in the evening now which makes PW2 a good thing to have.

Last wishlist -- Tesla allows car to plug into PW2 for additional house support in case PW2 battery is drained.