FoxESS Community - Owners & Installers Forum

Hi,
My system:
1 PHOTOVOLTAIC SYSTEM (7.20 kWp)
16 DMEGC 450W SOLAR PANELS
Defect:25 year(s) Performance:30 year(s)
- - -
1 FOXESS FOX H1-6.0-E-G2 - HYBRID INVERTER
Defect:10 year(s) Performance:10 year(s)
- - -
1 FOXESS FOX EP11 BATTERY
Defect:10 year(s) Performance:10 year(s)

Is it possible to increase my battery capacity and what is the best cost effective options.

My system settings for charge, discharge and self use are attached. Any advice is helpful.

Yes you can increase your battery capacity, the EP11 allows up to 4 batteries to be connected to your inverter giving you 10.36kWh, scaling up to a maximum 41.6kWh in 10.36kWh increments.

When adding additional batteries you have to install a junction box which allows the additional batteries to be added in parallel and so there will be an extra cost (a few hundred £’s) for this on top of the cost of additional batteries.

The EP11’s have to be wall mounted and so you will need to have a suitable clear wall space near your existing battery to mount the additional batteries.

You haven’t said where you are in the world - in the UK you have 2 options for installation (but different countries may have different regulations).
If you are in the UK either contact your existing installer and ask them to provide a quote which will give you continuity of your installers warranty, or alternatively some people do a battery self install. However this is more complex with the EP11’s which have to be mounted to a wall, need a junction box fitting and weigh in over 100kg (but it is still possible).

Hi Dave,

Thank you so much for your help. I am UK based. I will contact my original installer and get their input.
I am with Octopus Energy and on the Outgoing + Go tariff. Will I be able to fully charge any additional batteries within this bandwidth?
Joined Axle Energy with a Grid Event today. So battery is totally drained with no solar today.
Are you able to comment on my manual scheduler settings?
Thank you.

Your scheduler Force Charge will be limited to 6kW - this is the maximum charge power of an H1 6.0.

That means (at the very best at 20C) from 10% minsoc to 100% the charge is going to take 1 hour 36 minutes, in reality probably nearer the 1 hour 50 minutes because the charge rate slows down as it approaches 100%.

With your single EP11 battery you need to give it a bit longer at 00:30 to ensure it fully charges, I would suggest 2 hours.

With the 5 hours of Octopus GO, the maximum you would be able to charge a bigger battery stack in that time would be 30kWh - and so you wouldn’t be able to charge 4 batteries from 10 to 100% in that time.

Just running through the rest of the settings,

Between 05.31-08:59 you’ve got minsoc set to 60% - you’ll be starting out fully charged, but there is the possibility if you take a lot of power before 09:00 you may end up taking power from grid (i’d suggest minsoc=10%, maxsoc=100%)

Between 09:00-19:59 minsoc is 40%, you’re in self use so any solar will go to batteries anyway but if they fall below 40% and there isn’t sufficient solar they will top up from grid -

Same with 20:00-21:59 and 22:00-23:59

I think just set a single self use from 05:31 to 23:59 with minsoc 10%, maxsoc 100% is best for your wallet.

I would make sure that you are not buying more battery for the intention of pumping and dumping, the current export rates could be gone and then you are left with capacity, but no need.

By all means if you are needing 20kWh or more each day (for heat pump or some such) then that can make sense.

As Dave has already mentioned, in those 5hrs of Go that you have, you can only charge or discharge a max of 30kWh, say 15kWh of charge in 2.5hrs and 2.5hrs of export for 15kWh under ideal conditions. Or you could mostly charge up 3 batteries and you would have to discharge throughout the day.

Thank you for your advice.