Navitron Renewable Energy and Sustainability Forum

SOLAR PHOTOVOLTAIC => Solar Photovoltaic Systems => Topic started by: kdmnx on March 26, 2020, 03:46:04 PM



Title: A few more batteries
Post by: kdmnx on March 26, 2020, 03:46:04 PM

(https://i.postimg.cc/fJdVX7JC/67-F49342-6645-44-A1-8-A0-F-31-CAC5-F0-B9-C7.jpg) (https://postimg.cc/fJdVX7JC)


Title: Re: A few more batteries
Post by: Solarchaser on March 27, 2020, 05:30:50 PM
Nice, what are you up to now?
I think Nowty is the one to beat (as if)


Title: Re: A few more batteries
Post by: nowty on March 27, 2020, 07:19:27 PM
I thought last year that I had gone completely over the top with the batteries but now I am heating my house with a heatpump and charging the EV, I now find the battery bank about the right size in comparison to my PV size and loads.


Title: Re: A few more batteries
Post by: dan_b on March 27, 2020, 08:11:49 PM
How much for 4-6kWh of these batteries plus a suitable inverter/controller and some sort of control unit/sensor/software?


Title: Re: A few more batteries
Post by: pantsmachine on March 27, 2020, 09:53:41 PM
About 2.5 grand Dan. Would get you a couple of batteries and a hybrid charge controller. After that it's hook up costs only. That's going on my set up only, there may be better prices on the controller....


Title: Re: A few more batteries
Post by: billi on March 27, 2020, 10:52:31 PM
Quote
How much for 4-6kWh of these batteries plus a suitable inverter/controller and some sort of control unit/sensor/software?

Quote
About 2.5 grand Dan


so the answer is including  the  rest of the gear ?


Title: Re: A few more batteries
Post by: kdmnx on March 28, 2020, 08:22:00 AM
These are 2.4kWh each, 2.2kW of which you can use. They are c. £800 each, but delivery can be expensive because they weigh 25kg each. I paid £2300 for the three, delivered, which I think is a good deal. I already had 2 so already had the inverter-charger. This brings my usable storage capacity to 11kWh and allows my inverter-charger to push/pull its max 3.6kw.

Previously with 2 batteries a sunny day looked like this:

(https://i.postimg.cc/QVfVCgYN/Photos-1-of-2.jpg) (https://postimg.cc/QVfVCgYN)

You can see I'm running on grid power overnight, then by 11am the batteries are full and I'm exporting to the grid, and by 9pm the batteries are empty again.

This is what I have now:

(https://i.postimg.cc/1484gnkp/Photos-2-of-2.jpg) (https://postimg.cc/1484gnkp)

Basically no grid power required (0.2kWh in, 0.2kWh out). Not bad for March! I installed an extra couple of panels yesterday bringing my array up from 3400kWp to 4080kWp.

I have a plugin-hybrid car on order (would be here by now but there is some kind of "bad cold" going round), that will use some additional power. The plan is to switch to Octopus "Go" in the winter so I can charge the batteries/car in the cheap hours when there isn't much sun around.


Title: Re: A few more batteries
Post by: pantsmachine on March 28, 2020, 08:50:48 AM
Quote
How much for 4-6kWh of these batteries plus a suitable inverter/controller and some sort of control unit/sensor/software?

Quote
About 2.5 grand Dan


so the answer is including  the  rest of the gear ?

I kept it vague as each person has different existing gear/needs/skills/discount access. I'd say about £3.25k to have an autonomous maintenance free 4.8 kw set up installed and functioning? Further capacity can be added to at a later date as a few have done and finances allow. As an aside, If I had realised the implications when system was specced along with the arrival of Octopus and their clever tariffs I would have bought the 5kw version of the Goodwe hybrid controller instead of the 3.6kw version. The rating dictated the maximum discharge capability of the unit. It doesn't affect us much but if i was in a younger continual washing machine/tumble dryer environment i'd enjoy the extra capacity of discharge before going to the grid.   I hope this helps, cheers.


Title: Re: A few more batteries
Post by: brackwell on March 28, 2020, 10:13:15 AM
No wonder you need all those batts when you are drawing 600-800W 24/7   (600W x 24hr = 14.4kwh/day )


Title: Re: A few more batteries
Post by: kdmnx on March 28, 2020, 11:18:01 AM
No wonder you need all those batts when you are drawing 600-800W 24/7   (600W x 24hr = 14.4kwh/day )

I know. My “baseload” is pretty high. I have a big American-style fridge-freezer, CCTV cameras and the fileserver they save to (as well as UPS), and a fish tank with heater, pumps, etc., all running 24/7/365.

I need to have a hunt round to see if there are any parasitic loads I might be missing...


Title: Re: A few more batteries
Post by: kdmnx on March 30, 2020, 10:56:26 AM
Definitely charging faster than before:


(https://i.postimg.cc/KRHYrjbH/3-FC44-EF1-C3-CC-4-C12-A6-F6-7-C117-A08-C2-BC-1-201-a.jpg) (https://postimg.cc/KRHYrjbH)


Title: Re: A few more batteries
Post by: pantsmachine on March 30, 2020, 12:18:51 PM
You should be charging at 3.6kw as well depending on your stack temperature and bms software. I have been surprised at the 'fluidity' that the 3rd battery brought.


Title: Re: A few more batteries
Post by: kdmnx on March 30, 2020, 12:49:51 PM
You should be charging at 3.6kw as well depending on your stack temperature and bms software. I have been surprised at the 'fluidity' that the 3rd battery brought.

Yeah, with a 4080kWp array, and a "baseload" power consumption of 400-600W the 3600W max charge should be more than enough. If the sun actually comes out for more than 5 mins I'll try to catch it charging even faster...

How deeply do you discharge your batteries? And, do you know what the difference is between the U2000 and U2000 Plus is?


Title: Re: A few more batteries
Post by: pantsmachine on March 30, 2020, 01:16:01 PM
I discharge to 90% when it gets that low. The 2000 is I think limted to 80%. 90% is personal choice though, I think most people stop at 80% for longevity. Same here for sun, excellent minutes at a time then clouds back over, seeing around 10 kwh off panels with a monthly high of 15 kwh.  Trending upwards! :)


Title: Re: A few more batteries
Post by: kdmnx on March 30, 2020, 01:37:57 PM
I discharge to 90% when it gets that low. The 2000 is I think limted to 80%. 90% is personal choice though, I think most people stop at 80% for longevity. Same here for sun, excellent minutes at a time then clouds back over, seeing around 10 kwh off panels with a monthly high of 15 kwh.  Trending upwards! :)

I've been discharging to 90%, have just set it to 85% for now. Will see how it goes. Have WAY more capacity than I need on grey days. I'll have a plugin car delivered at some point (some sort of "bad cold" going round has delayed it), that will use up some daytime power. I'll see how I go in winter, when I'll be charging from cheap overnight grid power.


Title: Re: A few more batteries
Post by: kdmnx on April 03, 2020, 06:29:13 PM
The batteries are charging nicely on the rare occasions the sun comes out:


(https://i.postimg.cc/gX5DX7rN/EEDBA875-3-B2-B-4273-86-CD-3-B867-BDD8572.jpg) (https://postimg.cc/gX5DX7rN)


Title: Re: A few more batteries
Post by: bleem2k on April 03, 2020, 11:31:22 PM
Lovely, thats the future now!

Just out of interest, slightly O/T, why did you chose the 2.4kWh batteries and not the 3kWh in the first place? On a £ per kWh basis the 3kWh seem to offer the best value.


Title: Re: A few more batteries
Post by: kdmnx on April 04, 2020, 08:01:02 AM
Lovely, thats the future now!

Just out of interest, slightly O/T, why did you chose the 2.4kWh batteries and not the 3kWh in the first place? On a £ per kWh basis the 3kWh seem to offer the best value.

I found the £/kWh to be the same. Getting the 2.4kWh ones into the loft was enough of a performance, I don’t think I’d have been able to get the 3.5kWh ones up there...