When UK going to let powerwall charge from grid? I am concerned about the lifespan of my powerwall battery

When UK going to let powerwall charge from grid? I am concerned about the lifespan of my powerwall battery

In the winter, my powerwall 2 is constantly below 50% power. I am concerned that this would cause the battery capacitance to drop. Rendering its life span to be less than it can be.
When would UK PW be able to charge from the grid at off peak rate? There are other battery products on the market which can do so already.

chris | 24 January, 2018

An email I saw a few weeks back from the powerwall team implied the end of January for this feature.

ida.ns.wong | 3 February, 2018

It's already Feb 2018. still has not happened yet.... my neck is getting longer...

sashton | 3 February, 2018

Just out of interest, where did you read that being unable to provide a full charge or averaging less than 50% charge would adversely affect the battery?
I was not aware that the current Li, unlike NiCd, chemistry exposes us to significant hysteresis effects.

...and we have had some good sunny days last week in the UK so, like me, you probably are returning to a full battery in the afternoon anyway!

psusi | 4 February, 2018

Isn't the *goal* to keep plenty of capacity to store power when the sun shines? Charing up more would leave less room for storing your solar power.

sashton | 5 February, 2018

@psusi It would be nice to be able to do a bit of both. e.g. When the following day is forecast to be cloudy charge the battery on an overnight cheap rate to, say 40% and if the forecast is sunny omit the overnight charge.
Once this feature is available and working I certainly will be ordering two more batteries.

paul | 6 February, 2018

Mike Keen, a Tesla owner in Dorset has posted on the TOGUK:
“Tesla UK have asked me to field test the long awaited PW2 firmware upgrade that will allow us to store E7/10 electrons as promised last July. Watch this space.”

raiderz | 6 February, 2018

Funnily enough my Powerwall 2 has started charging to 2% from the grid then discharging. It currently charges at 2kw for a few minutes every 30 mins or so. This happens only at times when not charging by solar. Has anyone elses? Firmware version 1.3.3

sashton | 9 February, 2018

@ida It might be worthwhile re-reading the PWII warranty for the UK. I think it is the same for most of the EU excluding Spain and Italy. It appears to change from unlimited charge cycles to a finite total charge if you switch from the solar storage mode.

sashton | 9 February, 2018

@Paul It's good to hear they are testing this feature but disappointing that they only decided to share the info with a self-appointed closed group which requires VIN/order details for entry.

Gizmo | 12 February, 2018

I get a spike of just under 2kW coming from the grid to the Powerwall 2 on most mornings whilst it is still dark outside, (being winter the battery has always been ‘flat’ for a few hours by then) this will last for about 15 mins, there is no increase in power demand from the home when this happens.

I cannot find an explanation why it does this.

murat.topcu | 20 February, 2018

This is also a very interesting feature I want to use. I also want to charge Powerwall using the grid at night or when weather is not great.

sashton | 20 February, 2018

@gizmo I too see a small short charge to the battery at night. e.g. this morning :-
This only started happening after FW 1.11 and it appears that it uses this to bring the SoC up to 5%. NB the 5% SoC does not appear to be recorded on the app which is a bit naughty as this would affect the effective capacity of the battery.
It may be as a related to the ambient temperature assisting the PW to accept higher charge rates from cold.