On-grid domestic battery storage

Exiled_Tyke

QrizB said:

Thread bump!

There's someone asking about battery storage in the "other fuels" section here.

I've commented, and so has matt_drummer, but if anyone else wants to chip in with an opinion it might help the OP?

Nothing to add. You've already given the best advice possible. 

mickyduck55

I am having a ASHP installed in a couple of weeks and looking at my sons recent install a little more battery power would help.  I have 3 Pylontech US3000.  Does anyone know if the newer series are compatible with these? 

orrery

I'm using x4 US5000 with a Lux AC3600 and it works fine. With an ASHP you may need more power, but you can tandem two AC3600's with x2 stacks of batteries.

I'm not convinced the 3600 firmware has the latest data configurations for the US5000 batteries though. The US5000 is specified for usage between 5 and 100% charge, the older batteries are 10 to 100%, but the AC3600 wouldn't allow me to set 5% discharge level and they had to dial-in to set that manually for me (with a warning to me that I shouldn't set them for 5% discharge despite it being in the battery spec).

mickyduck55

orrery said:

I'm using x4 US5000 with a Lux AC3600 and it works fine. With an ASHP you may need more power, but you can tandem two AC3600's with x2 stacks of batteries.

I'm not convinced the 3600 firmware has the latest data configurations for the US5000 batteries though. The US5000 is specified for usage between 5 and 100% charge, the older batteries are 10 to 100%, but the AC3600 wouldn't allow me to set 5% discharge level and they had to dial-in to set that manually for me (with a warning to me that I shouldn't set them for 5% discharge despite it being in the battery spec).

Thanks I was thinking more about the possibility of mixing the old U3000 and the newer "c" series.  I'm happy to accept that the draw will be outside my inverter supply  a second inverter and batteries is probably a little OTT to save a few pounds on my bill 

1961Nick

mickyduck55 said:

orrery said:

I'm using x4 US5000 with a Lux AC3600 and it works fine. With an ASHP you may need more power, but you can tandem two AC3600's with x2 stacks of batteries.

I'm not convinced the 3600 firmware has the latest data configurations for the US5000 batteries though. The US5000 is specified for usage between 5 and 100% charge, the older batteries are 10 to 100%, but the AC3600 wouldn't allow me to set 5% discharge level and they had to dial-in to set that manually for me (with a warning to me that I shouldn't set them for 5% discharge despite it being in the battery spec).

Thanks I was thinking more about the possibility of mixing the old U3000 and the newer "c" series.  I'm happy to accept that the draw will be outside my inverter supply  a second inverter and batteries is probably a little OTT to save a few pounds on my bill 

I have a mix of US2000 Plus & US2000C & they work together seamlessly. According to the Pylontech literature you can mix their products as long as you set newest battery as the master. Obviously you set the minimum SOC to suit the oldest battery. I use 10% to accommodate US2000 plusses even though the US2000C can go down to 5%.

orrery

1961Nick said:

mickyduck55 said:

Thanks I was thinking more about the possibility of mixing the old U3000 and the newer "c" series.  I'm happy to accept that the draw will be outside my inverter supply  a second inverter and batteries is probably a little OTT to save a few pounds on my bill 

I have a mix of US2000 Plus & US2000C & they work together seamlessly. According to the Pylontech literature you can mix their products as long as you set newest battery as the master. Obviously you set the minimum SOC to suit the oldest battery. I use 10% to accommodate US2000 plusses even though the US2000C can go down to 5%.

There are some limitations, but not documented. I'm aware of one installation where the Lux hybrid inverter would simply drop power delivery from the battery to zero for no reason. The only way to get it back online was to do a forced discharge, then cancel it. Lux said it wasn't their problem, Pylontech said that some of their batteries (in this case all US5000) don't like being 'master'. Swapping the position of the top two batteries fixed the problem.

JKenH

I was just wondering if anyone has compared the round trip efficiency of their battery system in winter and summer.

 Unfortunately my DNO has declined permission for a grid tied battery system so I have been getting by with a couple of Poweroak (Bluetti) EB240 PPSs and about 6 months ago I added a Bluetti AC180 specifically to cook our evening meal and in emergency (or saving sessions) power my freezer which has a peak current of something like 1.7kw when the compressor kicks in. 

What I first noticed a couple of weeks ago after the EB180 had been stood in the garage for a few days was that the % of battery used to cook our pizzas was significantly higher than usual. The next time I used it all seemed ok so I thought no more of it. However last night after a weekend away we got home at 5pm and as our low wattage urn had been off I plugged in a 2kw kettle into the AC180 (which I had left charging in the garage) and was staggered by the rate at which the battery discharged. Unfortunately I don’t have any specific figures but suffice to say I unplugged the kettle and plugged it into the mains before it boiled. One of my EB240s had also been in the garage but I didn’t notice it behaving unusually when I brought it in to run one of my ASHPs for 4 hours. 

The EB240s are a traditional LiOn technology (I don’t know which) but the AC180 is LFP - the selling point being more cycles. I am thinking perhaps the LFP technology is the issue in cold weather. I know I need to do some scientific experiments - say, measuring the time taken to discharge to a fixed load such as a convector heater with a cold and warm battery - but I don’t just want to waste electricity for the purpose of science. 

Does anyone have an LFP grid tied battery system and if so have you had similar experience? 

More generally if you have a home battery system are you seeing any decline in effective capacity/efficiency in colder weather?

Waywardmike

JKenH said:

I was just wondering if anyone has compared the round trip efficiency of their battery system in winter and summer.

More generally if you have a home battery system are you seeing any decline in effective capacity/efficiency in colder weather?

Here is my month by month efficiency if it helps?  6.5kWh LiFePO AC coupled.

	%
May	90.49
Jun	90.49
Jul	89.84
Aug	92.39
Sep	90.96
Oct	89.78
Nov	83.07
Dec	80.86
Jan	85.10
Feb	87.08
Mar	87.42
Apr	90.02

This was a year when I solely charged from PV, so it didn't do much at all in December.  Thankfully this year I'm on Octopus Go, so it charges to 100% every day with a mix of off peak and PV charging. 

Mine's indoors so I see no difference as it doesn't suffer any swings in temperature.  I'm a member of several forums though and it can be quite a problem for some people.

1961Nick

JKenH said:

I was just wondering if anyone has compared the round trip efficiency of their battery system in winter and summer.

 Unfortunately my DNO has declined permission for a grid tied battery system so I have been getting by with a couple of Poweroak (Bluetti) EB240 PPSs and about 6 months ago I added a Bluetti AC180 specifically to cook our evening meal and in emergency (or saving sessions) power my freezer which has a peak current of something like 1.7kw when the compressor kicks in. 

What I first noticed a couple of weeks ago after the EB180 had been stood in the garage for a few days was that the % of battery used to cook our pizzas was significantly higher than usual. The next time I used it all seemed ok so I thought no more of it. However last night after a weekend away we got home at 5pm and as our low wattage urn had been off I plugged in a 2kw kettle into the AC180 (which I had left charging in the garage) and was staggered by the rate at which the battery discharged. Unfortunately I don’t have any specific figures but suffice to say I unplugged the kettle and plugged it into the mains before it boiled. One of my EB240s had also been in the garage but I didn’t notice it behaving unusually when I brought it in to run one of my ASHPs for 4 hours. 

The EB240s are a traditional LiOn technology (I don’t know which) but the AC180 is LFP - the selling point being more cycles. I am thinking perhaps the LFP technology is the issue in cold weather. I know I need to do some scientific experiments - say, measuring the time taken to discharge to a fixed load such as a convector heater with a cold and warm battery - but I don’t just want to waste electricity for the purpose of science. 

Does anyone have an LFP grid tied battery system and if so have you had similar experience? 

More generally if you have a home battery system are you seeing any decline in effective capacity/efficiency in colder weather?

My Pylontechs are running 24/7 so the temperature is pretty consistent in winter - current temperature 27C with an ambient of 8C.

Long term round trip efficiency is 79.5% (metered figures not the overly optimistic inverter data). 

zeupater

Hi All

Just a heads up .....

Noticed that there's early signs of some storage prices starting to slide back a little at distribution/wholesale sites ..... worth keeping an eye on .... however, from information I'm seeing, even though the sector almost exclusively claims to be in it for environmental reasons, installation still seems to be considered more a money-printing exercise than anything else!

Z