How do i connect storage battery's to my existing system.

[MHarv]

You do realise it’s all about ambient room temperature within inverter or battery specs.

My now cold double attached garage has reduced battery charging with Octopus Go
even more with the cold, would only charge from 41% to 87% for 11.6kW.

Prevalent in all electric devices, both LV and HV batteries, ambient temps in the location of battery is important to make for consideration

Yes I could use heater but not for me

 

[johnb2713]

Yes I could use heater but not for me

Could you not make a small insulated cover to go over the battery in cold weather?

 

[MHarv]

Could you not make a small insulated cover to go over the battery in cold weather?

Thanks John that has really prompted me to just do something like your suggestion to prevent the cold air reaching the large surface area of the battery covers.

Outside garage is -1’C, garage about 5’C
Battery status states battery temp now 10’C
Overall since 1st December Battery temp has dropped from nice 17’C to 10’C.

As you know John ambient temperatures are critical for batteries to be at optimal operating capacity.

Thanks again for your input, much appreciated cheers.

Festive Seasonal Greetings to You and All
Merry Christmas

 

[Kot]

I am sure i read somewhere that the latest batteries, their BMS controls internal battery cabinet temperatures during cold weather they must use battery power etc
The AC coupled Givenergy for example, has a operating temperature to -25C and is IP65 rated

 

[johnb2713]

I am sure i read somewhere that the latest batteries, their BMS controls internal battery cabinet temperatures during cold weather they must use battery power etc
The AC coupled Givenergy for example, has a operating temperature to -25C and is IP65 rated

It would make sense, I installed a heater in my DIY battery hut.

 

[johnb2713]

Thanks John that has really prompted me to just do something like your suggestion to prevent the cold air reaching the large surface area of the battery covers.

Outside garage is -1’C, garage about 5’C
Battery status states battery temp now 10’C
Overall since 1st December Battery temp has dropped from nice 17’C to 10’C.

As you know John ambient temperatures are critical for batteries to be at optimal operating capacity.

Thanks again for your input, much appreciated cheers.

Festive Seasonal Greetings to You and All
Merry Christmas

I used some of this to insulate the enclosure, works really well and a 40w heater running at about 30% duty cycle is holding the temp at 10 degC with an outside air temp of -2 degC

https://www.ebay.co.uk/itm/284395151357?var=585931271611

 

[MHarv]

40w heater nice have you got make, model and if available to purchase.

Do have a warm air heater but over 100w to 1.2kw not tried it yet but now have put insulation just boxes and covers and battery is reporting 1’C increase within last mentioning so see how charging will go tonight and hold a higher ampage above 7A or even just stay at 7A for longer before dropping down to 5A for rest of Octopus Go period

 

[johnb2713]

40w heater nice have you got make, model and if available to purchase.

Do have a warm air heater but over 100w to 1.2kw not tried it yet but now have put insulation just boxes and covers and battery is reporting 1’C increase within last mentioning so see how charging will go tonight and hold a higher ampage above 7A or even just stay at 7A for longer before dropping down to 5A for rest of Octopus Go period

This is what Ive used in my little shed for the batteries.

https://www.screwfix.com/p/dimplex-ecot1ft-wall-mounted-tubular-heater-40w-408-x-81mm/3951f

 

[MHarv]

This is what Ive used in my little shed for the batteries.

https://www.screwfix.com/p/dimplex-ecot1ft-wall-mounted-tubular-heater-40w-408-x-81mm/3951f

Excellent John thanks for the info

 

[bladerunnerpv]

I am sure i read somewhere that the latest batteries, their BMS controls internal battery cabinet temperatures during cold weather they must use battery power etc
The AC coupled Givenergy for example, has a operating temperature to -25C and is IP65 rated

Hi Kot,
I think that's the temperature spec for the AC inverter only.

The 9.5kW battery spec can be found here
https://www.givenergy.co.uk/pdfs/products/Version 2.0/Giv-Bat 9.5.pdf
It says 0deg C for charging

hope this helps

 

[binky]

I have had my inverter in the attic since January 2016 and so far no issue.
It has a built-in thermometer and I saw last summer that the temperature had reached 64 (while the operating limit from the spec is 60) at some points

I am considering adding extraction fans when I will add my new system as I think it will get hotter and hotter the more stuff I have up there.

I have no garage and my utility room is full!! so I do not have much choice and I will not do like you see in the marketing material, install the kits in my living room lol.

My own inverter is in my garage and gets up to 70C on hot days, but it self protects, so for the few days that's an issue, I'm not overly concerned.

 

[Spats]

If you are going to locate batteries in loft, the existing cable 4mm2 in loft to CU downstairs, imho will not cut it, for both Inverters and Batteries, probably would need 6mm2 twin and earth upgrade... there are tables that you enter details of cable size, and distance to get
a known voltage drop, you need to be within 1.25% could be less, can't remember exactly.... if replacing the existing cable.

You could lay another new cable 6mm2 just for the Battery system... then need to know are there any vacant slots on Main Consumer unit downstairs, PV & Batteries should be in own Mini CU (where at loft or near Main DB, not in Main DB, Inverter specs for AC size cable needs to be known... what inverter.. but 6mm2 is not much more expensive... than 4mm2 if inverter battery specs, AC isolators at loft and Consumer Unit for battery system for electrical safety and maintenance would be required.
No doubt you have to 2 x AC isolators for the existing system from loft to Main Consumer Unit for safe practice and emergencies.

Food for thought, on designing your battery system.. very doable...

Is there an specific reason not to locate the battery system near the Main Consumer Unit... lack of space, downstairs cupboard not big
enough. All consideration to be taken into account when planning, designing your battery system

Could you yourself lay new cable save some expense, along with the AC Isolators, mount inverter and possibly Mini CU,

Thanks,
There is no space in the hallway, there is a small cupboard enough to house the the Main Board with the regeneration meter, also Ev charger which is fitted independently.

I don't have a garage so it would really need to go in the loft.

Yes i can run 6mm2 cables and fit boxes batteries etc myself, I also have spare ways in the CU.

As for Inverter, batteries etc, i wouldn't know which ones to go for.

The cheaper the better.

 

[BorisJ]

The cheaper the better.

Usually not the case.

 

[Spats]

Usually not the case.

No I know that bud,
Does anyone know what would be size of batteries in Kwh that I would need for a 3.68 Kwh system.
Thanks

 

[MHarv]

Your present system is for PV Solar only, this will also only help to charge an AC Coupled battery system.

The size of Battery system will depend on various variables, usage and max loads
Look at UTube - Mr EV Puzzle who explains
Battery sizing for household use to minimise
Minimum Import use.

 

[Spats]

Thanks bud, will look into it.

 

[Bob Smith]

Hi @Spats
I have the same dilemma. Here is what I have been considering

1. My 24hrs kWh import over a year. I buy around 5500kWh per year so per day roughly 15.5kWh.
2. I want to be able to add more batteries (this will depend on my first year usage and what my PV are doing, but also considering that in a near future I may have one and two EV cars at some points).

I decided to start around 10 - 13kWh depending on the batteries.
My existing 4kWp generates 15kWh/day as an average from April til September but I am getting the batteries with additional PV (21 in total facing West, SE and NW), so I should have no problem charging them fully during that period as cover my needs.

I am considering, but will only take a decision once I have at least 12 months experience, to export either with Agile Tariff, or SEG but also Eco7 to charge them at a lower price. Depending how the figures stack up, I will add more batteries year 2 or 3 of the installation.

My view is that I prefer going into a "too small" battery to start with than too big as it is easier to buy news ones than then selling your extra batteries.

Hope this give you some food for thoughts.

 

[johnb2713]

My view is that I prefer going into a "too small" battery to start with than too big as it is easier to buy news ones than then selling your extra batteries.

I'm not sure thats the right angle to view battery size. If it's 'too big' it allows you to store additional energy for that rainy day (pun?) when your panels dont generate any power. Very useful to have more rather than less.

 

[Bob Smith]

I'm not sure thats the right angle to view battery size. If it's 'too big' it allows you to store additional energy for that rainy day (pun?) when your panels dont generate any power. Very useful to have more rather than less.

I can see your point John but at the price of the batteries I want to make sure I do not oversize it.
Maybe I will not wait a year to buy more. I'll keep you posted. The surveyor came yesterday so very early stage

 

[Bob Smith]

How long can you keep the charge in a battery? If you charge your very large battery in summer and you don't use most of it, do you still have any left in winter?