Powerwall minimum charge rate

[ACarneiro]

So I finally had two more PWs installed and I now have a total of 4 on my 100A single phase supply.

Slight snag I’ve hit is that the installer said he can only make the PWs charge at a minimum of 16A for each.

So at “cheap o’clock” I now have a draw of 64A for the PWs (charging from mains in the winter) and 32A for the car. This is 98A (duh!) and leaves precious little to run the house and definitely not enough for the 16A immersion heater.

What I really wanted was for the PWs to charge at no more than around 10kW so about 45A in total (but still be able to discharge at the 20kW for the whole system).

Does anyone know if Tesla have the flexibility to set this configuration? Who should I contact to make this request?

 

[Dilly]

That’s a nuisance. I hadn’t really noticed before, but my two don’t’ seem to charge at less than 3.5 in total from the grid.
I can’t see why four would need 4 times that as a minimum.
They do charge at 7 or 8 sometimes. Maybe it’s to do with SoC and timing. Doesn’t make full sense though.

 

[ACarneiro]

There HAS to be a way. Supposedly the system is scalable to 10 PWs, it would not make sense to make it charge at a minimum of 160A then (far more than you’re allowed in a domestic supply…)

 

[ACarneiro]

Interestingly, if you query the status API you can see the fields

"max_charge_power":14800,"max_discharge_power":14800

This suggests a significant amount of granularity in configuring the max charge and discharge rates but I have no idea how to change it…

 

[WannabeOwner]

Long shot:

When mine is "Self-powered" I can jack it up to 100%, at the start of off-peak, and it will charge at somewhere around 3kW (I can't get form 0% to 100% within the off peak period in that mode ... but in the Summer its fine as I won't need hardly any top up)

When it is in "Time-Based" it charges flat out (10kW I think)

 

[ACarneiro]

Well, I’m usually in bed by 22:00 and off peak starts at 00:30 so that adjustment is not going to be possible for me…

 

[WannabeOwner]

I’m usually in bed

Me too! API will do that though (as far as I know)

P.S. worth trying manually just the once?

 

[btc1k]

So I finally had two more PWs installed and I now have a total of 4 on my 100A single phase supply.

Slight snag I’ve hit is that the installer said he can only make the PWs charge at a minimum of 16A for each.

So at “cheap o’clock” I now have a draw of 64A for the PWs (charging from mains in the winter) and 32A for the car. This is 98A (duh!) and leaves precious little to run the house and definitely not enough for the 16A immersion heater.

What I really wanted was for the PWs to charge at no more than around 10kW so about 45A in total (but still be able to discharge at the 20kW for the whole system).

Does anyone know if Tesla have the flexibility to set this configuration? Who should I contact to make this request?

Powerwall Customer Support?

Powerwall Customer Support | Tesla United Kingdom

Contact us for support with your Powerwall.

www.tesla.com

 

[ACarneiro]

Powerwall Customer Support?

Powerwall Customer Support | Tesla United Kingdom

Contact us for support with your Powerwall.

www.tesla.com

You know, I looked for that and couldn’t find it!
Thank you so much

 

[scdoubleu]

Support email is [email protected]

They've been pretty responsive whenever I've had reason to make contact, generally replying in a couple of days.

 

[ACarneiro]

Support email is [email protected]

They've been pretty responsive whenever I've had reason to make contact, generally replying in a couple of days.

Perfect, two fronts of attack.
Thank you so much guys

 

[ItsBlacknWhite]

Sorry I cant help but could i be cheeky and ask what firm you used for getting your PW installed?

 

[WannabeOwner]

what firm you used for getting your PW installed?

I used Cawoods, they are in Peterborough so may cover "midlands"

 

[ACarneiro]

I used Solar Star Power, based in Uttoxeter. Absolute gems, can’t recommend them highly enough…

 

[RagingWhisky]

This might seem a redundant question, but have you run everything full bore and got a record of the 98A usage?

Reason for asking, is that I had similar concerns with the 100A single phase on the property.

Got two inverters drawing a 'peak' 12kWh, 7.5kWh for the car, SunAmp heater on 3.4kWh and a 8 electric radiators coming on at intervals, all during a 4 hour off-peak window.

Even with crap math and averaging loads, That'd be anywhere from 100-125A, which during the spring made me consider a 3phase switch.

When in reality the inverters and the car actually demonstrated they had some brains to them > just last night instead of taking the full 32A on the Tesla, it capped its draw at 4 5-5.5kwh, and the inverter fluctuated between 6 and 12kWh pending max load.

I'm not using powerwalls (solax units), and my charger on the car is an Andersen unit, but even as an example, it may be that the 'smarter' devices pulling load may save the day.

If not, ignore everything I've said above and best bet is manually set the amps on your car....

 

[WannabeOwner]

manually set the amps on your car

Proper 1st World Problem, but I've done that (during the day to use PV without draining PowerWall) and then forgotten to reset them ... and then needed an overnight charge for the car and woken up to find it had charged all night long ... at 5AMPs

So I now use TeslaFi scheduler to set to 32 AMPs at midnight "regardless". If I want 5AMPs again tomorrow I'll need to set that myself ...

 

[ACarneiro]

This might seem a redundant question, but have you run everything full bore and got a record of the 98A usage?

Reason for asking, is that I had similar concerns with the 100A single phase on the property.

Got two inverters drawing a 'peak' 12kWh, 7.5kWh for the car, SunAmp heater on 3.4kWh and a 8 electric radiators coming on at intervals, all during a 4 hour off-peak window.

Even with crap math and averaging loads, That'd be anywhere from 100-125A, which during the spring made me consider a 3phase switch.

When in reality the inverters and the car actually demonstrated they had some brains to them > just last night instead of taking the full 32A on the Tesla, it capped its draw at 4 5-5.5kwh, and the inverter fluctuated between 6 and 12kWh pending max load.

I'm not using powerwalls (solax units), and my charger on the car is an Andersen unit, but even as an example, it may be that the 'smarter' devices pulling load may save the day.

If not, ignore everything I've said above and best bet is manually set the amps on your car....

Yes, it does draw the whole lot….
And yes, I could reduce the charge rate on my car but I commute 100 miles per day and really do need the whole shebang for the available 5 hours so that’s not really a great option…

 

[ACarneiro]

So I just thought I'd give this thread some closure for the benefit of anyone who might run into a similar problem.

Thank you to @scdoubleu and @btc1k for the contact details to Tesla Energy Support. They were quite good and did respond within 2 working days.
They added a "Site Import Limit" to my system which has been set to 22kW (around 95A at a nominal 230V, so that gives a bit of leeway if the voltage drops).
What this does is dynamically adjust the PW charge rate so that the total draw from the house is never higher than 22kW. Better than I hoped for! I can now run any loads that I want to, knowing that the PW charge rate will drop to accommodate the 22kW limit. Last night the system was pegged at 22kW for 4 hours (car charging, water heating, heat pumps running and PW charging).

As it turns out, I discovered you can set this limit as well from the Installation Wizard if you're brave enough to fiddle with that

So thank you everyone for your advice. I hope this bit of information may be useful to someone in the future, it seems my installer knew nothing about it.

 

[btc1k]

So I just thought I'd give this thread some closure for the benefit of anyone who might run into a similar problem.

Thank you to @scdoubleu and @btc1k for the contact details to Tesla Energy Support. They were quite good and did respond within 2 working days.
They added a "Site Import Limit" to my system which has been set to 22kW (around 95A at a nominal 230V, so that gives a bit of leeway if the voltage drops).
What this does is dynamically adjust the PW charge rate so that the total draw from the house is never higher than 22kW. Better than I hoped for! I can now run any loads that I want to, knowing that the PW charge rate will drop to accommodate the 22kW limit. Last night the system was pegged at 22kW for 4 hours (car charging, water heating, heat pumps running and PW charging).

As it turns out, I discovered you can set this limit as well from the Installation Wizard if you're brave enough to fiddle with that

So thank you everyone for your advice. I hope this bit of information may be useful to someone in the future, it seems my installer knew nothing about it.

Great to hear.

Now jealous of the 100A limit when mine is 80A....

 

[ACarneiro]

Great to hear.

Now jealous of the 100A limit when mine is 80A....

Have you asked your DNO if they can upgrade your fuse? Mine was 80A initially as well....