On-grid domestic battery storage

EVandPV

Had ours for 2 years, 2 months and soh is now at 97%. 
I set the ac charge rate to 70% about 6 months ago and haven't seen any drop in soh since then so the lower charge rate might be helping slow down degradation ??

Solarchaser

Solarchaser said:

1961Nick said:

My pylontechs degrade about 1% for every 200 cycles. On this basis it’ll take 6000 cycles to reach 70% which is 1500 cycles better than the guarantee.

(849 cycles to date)

I wonder if you are straining them more than I am?
Not seeing any percentage difference from when I tested mine last year at this time.

Mine don't cycle every day and I have 4 connected to both inverters so less strain per battery.

Similarly due to a fairly large solar array and a fairly large daily consumption,  I'm finding that for every complete full to complete empty cycle, I'm having another couple of half cycles, and so as the 6000 cycle warranty is full to empty, I'm looking at more like a 12000 cycle warranty.

I typed this and thought, hmm that can't be right so went back over the batteries the last couple of hours and found I'm talking tosh.
Both the master batteries on my 2 stacks are still showing 100% and the software for interrogating the batteries is finicky at best.
That's my excuse and I'm sticking to it.

So anyway I have 9 pylontech batteries in total 
3x 2017 which have all done around 850 ish cycles, all show 100%

4x 2018 which have all done around 650 ish cycles and all show 94% down 2% from same time last year and 200 cycles less

1 x 2019 with 440 cycles at 96%
1 x 2019 (3.5kw) with 200 cycles at 99%

I guess the firmware on the 2017 ones is lying/not as good as the newer ones.
The 2018's seem to suggest 1% for every 150 cycles and the 2019's are quite different from each other.

Of the full cycles, in the last year, basically 200 on each battery, id guess about 160 of those are the octopus go faster charges for the more winter months where I tend to flatten the lot every day.

I almost always charge at 100% but as there are 5 x2.4's on one inverter and 3x2.4's and 1x3.5 on the other they are only gonna see 0.8kw, and their max is 1.25, so around 70%of their power rating to and from them.

1961Nick

I now have 7 x US2000 so they don't get as much punishment during the winter months with only 12kWh of Octopus Go available - 83% charge. The maximum charge/discharge rate is now only 0.44kWh/battery.

Overall I'm happy with the 96% SOH after 849 full cycles.

Solarchaser

Ahh only 1 inverter, you could go onto go faster and pick the 5 hour option i spose if you wanted the full 100%

Coastalwatch

Just had 2 x 8.2 kWh Givenergy batts installed complete with 3.0 kW AC Inverter for circa £6.5k. Warranty is for ten years with unlimited cycling at 100% depth of discharge. Assuming one charge/discharge cycle per day then 16.4 x 0.9 x 365 x 10 = 53874 @ £6500 thus 12.06p/kWh. If two full cycles a day then 6.03p/kWh.

Not sure how practical/often it might be to complete two full cycles per day!

1961Nick

Solarchaser said:

Ahh only 1 inverter, you could go onto go faster and pick the 5 hour option i spose if you wanted the full 100%

I’m one of the Go customers that got rolled over on the existing tariff so I’m keeping my head down for now - 5p/13p.

When I move to the current 7.5p/30p rate, I’ll enquire about Go Faster.

JKenH

Coastalwatch said:

Just had 2 x 8.2 kWh Givenergy batts installed complete with 3.0 kW AC Inverter for circa £6.5k. Warranty is for ten years with unlimited cycling at 100% depth of discharge. Assuming one charge/discharge cycle per day then 16.4 x 0.9 x 365 x 10 = 53874 @ £6500 thus 12.06p/kWh. If two full cycles a day then 6.03p/kWh.

Not sure how practical/often it might be to complete two full cycles per day!

That seems good value at less than £400/kWh. 

Solarchaser

Welcome to the obsession with watching apps every few hours Coastalwatch. 
It's a grand thing powering your house on your own batteries 

Coastalwatch

Yes indeed SC, as if I wasn't obsessive enough!

Had a neighbour charge his EV via Co Charger this morning, 40% of it came from the batt and 25% solar.

EVandPV

Came across an alternative Windows app to Batterview for Pylontech batteries, it's much better in my opinion.
Can also monitor some pv inverters and has a console tab for sending commands to the Pylontechs.

http://www.multisibcontrol.net/