Energy storage vs heat batteries: what's the difference and which is better?

I know they’re relatively new. Perhaps are light on the software development function at the moment (we ain’t cheap). I know they got some investment recently so they really should be spending on that area pretty soon or, as you imply, they’re making a significant strategic error.

Ok… so relatively new to Lithium Battery storage for the house. Have a Sonnen 5Kwh system (and a 75kwh Tesla car but that’s a different story). 

Advantages - Electricity is the most usable form of energy for cooking, heating, lighting, run computers etc. I guess it’s pretty efficient at returning most of the power stored.

Disadvantages - Electricity is relatively expensive compared to primary energy (Solar heat, or gas), so unless you are charging from Solar PV it does not make sense to use it for heat.

Pretty much the battery is maintenance free. It just sits in the garage and supplies electricity when it needs to. To actually find out if it’s done anything I have to look at the app!

Future plans may change that balance of cost if OVO offered lower cost off peak electricity to fill the battery (e.g. like Drive plus anytime), where they that potentially surplus wind/solar energy from other sources and push it into the battery to offset at a later time (e.g. like the old storage heaters overnight).  That could both offer the owner of the battery much cheaper electricity and potentially also keep the peak costs down, reducing the average prices as well.

We have recently installed Li-ion battery storage to support our PV solar system. Although there is a future consideration about disposal of the cells, this is the same technology in use in modern EV builds as well as powering virtually all smartphones and other household electronics. 
A 7.8kW system allows us to take advantage of the generation more effectively and is small and light enough for domestic use. 
The system installed also allows a modified consumption pattern, charging at off-peak times and flattening the load level locally (if only OVO would let me use off-peak!)

With a 10 year warranty on the technology in use, this seems to me to be the next level (after solar PV) in domestic power systems

Like @hambrook we are a Tesla household when it comes to batteries. We have one 13.5kW Powerwall (and a 70kW Model S on the drive).

I won’t repeat what @hambrook has already written! Although lithium-ion technology uses a finite resource, we felt by choosing a reliable brand when installing our Powerwall (early 2021), we were less likely to get rid of it before it came to the end of its natural life.

We have had our Tesla for 6 years now (registered spring 2016) and it has done 120,000 miles so far with no significant loss of storage and this gave us great confidence when choosing the Powerwall. Octopus offer a Tesla Energy Plan for those with solar PV, a Powerwall and a Tesla car and this was the most significant financial incentive over other companies. The Tesla Energy Plan essentially hands control of the Powerwall to Octopus - we can’t choose when to store energy or use it (on average, their system stores energy into the battery at night and discharges back to the grid at 4pm).

We also considered Powervault batteries - these are ‘second life’ home storage batteries that were originally in Nissan and Renault EVs. The modular nature with easy storage increase was tempting, but when compared with the 13.5kW storage of the Tesla Powerwall, the maths didn’t stack up for us. The sustainability side of Powervault is definitely better than Tesla though.

Some really interesting points raised here, @jenthomson.

Particularly in stacking up the sustainability aspects of each battery model with the price/efficiency. 

Was this a major consideration for others when choosing your energy storage solutions? @BPLightlog , @malc_smith , @JoeC, @Heatherd  

I am with ovo. I charge at night during winter. i have e7. My enphase allows me to do this.

While we look forward to EV in the future, we currently use a hybrid but certainly there is a consideration of off peak supply to be available either directly or via storage systems. 
As the current grid will struggle to supply a full EV overnight demand, it would seem practical for suppliers to promote off peak use. 

It’s interesting coming back to this thread in the current climate. Although I’m not on a current ‘reduction’ trial, I have been experimenting with a series of controls to see how we could use solar+battery to move energy use out of peak hours. It takes a bit of juggling as some systems (including ours) don’t power all appliances and especially if several are turned on at once. 
One part of the solution is to know what is on, when so the IHD comes into its own coupled with a feed from the solar system to see what’s available. A more portable IHD would be useful (better battery).

Secondly encouraging some of the heavy consumption out of peak, especially with a busy household. 
I’m on the look out for an ‘all-in-one’ data screen which would be perfect (I hear the ivie bud gives some of this with the integration of solar indication at least). 
Yesterday (mid Nov) we were able to use no electrical power between 4 and 7 with only the 9kw shower banned during this time. An air fryer helps cooking a lot and regular nudges to the others makes them check what’s already on before they switch kettles, microwaves, hairdryers or heaters to on also. A check on forecast CO2 levels also allows the move of battery charging which coupled with a careful use during the rest of the day completes the process.